Permian-Triassic Evolution of Tethys and Western Circum-Pacific (Developments in Palaeontology and Stratigraphy)

DEVELOPMENTS IN PALAEONTOLOGYAND STRATIGRAPHY, 18

Permian-Triassic Evolution of Tethys and Western Circum-Pacific Edited by

Hongfu Yin

China University o[ Geoscience, Faculty of Geosiences, Wuhan, Hubei, China

J.M. Dickins Turner, Australia

G.R. Shi

School of Aquatic Science and Natural Resources Management, Clayton, Australia

Jinnan Tong

Paleontology Laboratory, China University of Geosciences, Wuhan, Hubei, China

supported by the National Science Foundation of China (NSFC)Project no. 49632070.

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FURTHER TITLES IN THIS SERIES

i. A.J. Boucot Evolution and Extinction Rate Controls 2. W.A. Berggren and J.A. van Couvering The Late Neogene-Biostratigraphy, Geochronology and Paleoclimatology of the Last 15 Million Years in Marine and Continental Sequences 3. L.J. Salop Precambrian of the Northern Hemisphere 4. J.L. Wray Calcareous Algae 5. A. Hallam (Editor) Patterns of Evolution, as lllustrated by the Fossil Record 6. F.M. Swain (Editor) Stratigraphic Micropaleontology of Atlantic Basin and Borderlands 7. W.C. Mahaney (Editor) Quaternary Dating Methods 8. D. Jan6ssy Pleistocene Vertebrate Faunas of Hungary 9. Ch. Pomerol and I. Premoli-Silva (Editors) Terminal Eocene Events lO. J.C. Briggs Biogeography and Plate Tectonics 11. T. Hanai, N. Ikeya and K. Ishizaki (Editors) Evolutionary Biology of Ostracoda. Its Fundamentals and Applications 12. V.A. Zubakov and I.I. Borzenkova Global Palaeoclimate of the Late Cenozoic 13. F.P.Agterberg Automated Stratigraphic Correlation

14. J.C. Briggs Global Biogeography 15. A. Montanari, G.S. Odin and R. Coccioni (Editors) Miocene Stratigraphy: An Integrated Approach 16. F.M. Swain Fossil Nonmarine Ostracoda of the United States 17. H. Okada and N.J. Mateer (Editors) Cretaceous Environment of Asia

CONTENTS List of contributors

vii

Preface Hongfu YIN, J.M. DICKINS, G.R. SHI, Jinnan TONG

xiii

Part 1. Permian-Triassic strata and palaeogeography Paleoclimatic constraints for Early Permian paleogeography of Eastern Tethys Jiaxin YAN and Hongfu YIN The Permian of Russia and CIS and its interregional correlation G.V. KOTLYAR

17

The Permian of South Europe and its interregional correlation G. CASSINIS, EDi STEFANO, F. MASSARI, C. NERI and C.VENTURINI

37

The Permian of China and its interregional correlation Yugan JIN and Qinghua SHANG

71

The Permian of Vietnam, Laos and Cambodia and its interregional correlation Cu Tien PHAN

99

The Permian of New Zealand and its interregional correlation H.J. CAMPBELL

lll

Permian-Triassic successions in Japan: key to deciphering Permian/Triassic events Y. EZAKI and A. YAO

127

Latest Permian and Triassic carbonates of Russia: new palaeontological findings, stable isotopes, Ca-Mg ratio and correlation Y.D. ZAKHAROV, N.G. UKHANEVA, A.V. IGNATYEV, T.B. AFANASYEVA, G.I. BURYI, E.S. PANASENKO, A.M. POPOV, T.A. PUNINA and A.K. CHERBADZHI

141

The Triassic of the Alps and Carpathians and its interregional correlation A. VOROS

173

The Triassic of China and its interregional correlation Hongfu YIN and Yuanqiao PENG

197

The Triassic of Indochina peninsula and its interregional correlation Vu KHUC

221

The Marine Triassic of Australasian and its interregional correlation H.J. CAMPBELL and J.A. GRANT-MACKIE

235

The northern margin of Gondwanaland: uppermost Carboniferous to lowermost Jurassic and its correlation J.M. DICKINS

257

Magnetic susceptibility and organic carbon isotopes of sediments across some marine and terrestrial Permo-Triassic boundaries H.J. HANSEN, S. LOJEN, P. TOFT, T. DOLENEC, Jinnan TONG, E MICHAELSEN and A. SARKAR

271

Part 2. Permian-Triassic biotic evolution

Evolution of the Permian and Triassic Foraminifera in South China Jinnan TONG and G.R. SHI

291

Radiolarian evolution during the Permian and Triassic transition in South and Southwest China Qinglai FENG, Fengqing YANG, Zhenfang ZHANG, Ning ZHANG, Yongqun GAO and Zhiping WANG

309

Asian-western Pacific Permian Brachiopoda in space and time: biogeography and Extinction patterns G.R. SHI and Shuzhong SHEN

327

Ammonoid Succession Model across the Paleozoic-Mesozoic transition in South China Fengqing YANG and Hongmei WANG

353

On zonation and evolution of Permian and Triassic conodonts Xulong LAI and Shilong MEI

371

vii

LIST O F C O N T R I B U T O R S 1. T.B. Afanasyeva, Far Eastern Geological Institute, Far Eastern Branch, Russian Academy of Sciences, Prospect Stoletiya Vladivostoka, 159, Vladivostok 690022, Russia 2. G.I. Buryi, Far Eastern Geological Institute, Far Eastern Branch, Russian Academy of Sciences, Prospect Stoletiya Vladivostoka, 159, Vladivostok 690022, Russia 3. H.J. Campbell, Institute of Geological & Nuclear sciences, Crown research Dunedin, 764 Cumberland Street, Private Bag, Dunedin, New Zealand. Fax: +61 3 4775232 4. G. Cassinis, Dipartimento di Scienze della Terra dell'Universitat~, Via Ferrata 1, 1-27100 Pavia, Italy, E-mail: [email protected] 5. A.K. Cherbadzhi Far Eastern Geological Institute, Far Eastern Branch, Russian Academy of Sciences, Prospect Stoletiya Vladivostoka, 159, Vladivostok 690022, Russia 6. J.M. Dickins, Innovative Geology, 14 Bent St., Turner, Canberra A. C. T. 2612, Australia, E-mail: [email protected] 7. T. Dolenec, Josef Stefan Institute, Ljubljana, Slovenia 8. Y. Ezaki, Department of Geosciences, Osaka City University, Sugimoto 3-3-138, Sumiyochi--ku, Osaka 558-8585, Japan, E-mail: [email protected], ac.jp 9. Qinglai Feng, Faculty of Geosciences, China University of Geosciences, Wuhan, Hubei, China, 430074 10. Yongqun Gao, Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074, The People's Republic of China 11. J.A. Grant-Mackie, Geology Department, University of Auckland, Private Bag, Auckland, New Zealand, E-mail: [email protected], Fax: +64 9 3737435 12. H.J. Hansen, Geological Institute, University of Copenhagen, Oster Voldgade 10.DK1350 Kopenhagen, Denmark, E-mail: [email protected] 13. A.V. Ignatyev, Far Eastern Geological Institute, Far Eastern Branch, Russian Academy of Sciences, Prospect Stoletiya Vladivostoka, 159, Vladivostok 690022, Russia 14. Yugan Jin, Nanjing Institute of Geology & Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China, E-mail: ygjin@public 1.ptt.js.cn, Fax: +86-025-3375200 15. Vu Khuc, Geological Museum, 6 Pham Ngu Lao, Hanoi, Vietnam, E-mail: [email protected], Fax: 84 4 254734 16. G.V. Kotlyar, All-Russian Research Geological Institute (VSEGEI), Sredny pr., 74, St. Petersburg, 199106, Russia, E-mail: [email protected] 17. Xulong Lai, Faculty of Geosciences, China University of Geosciences, Wuhan, Hubei, China, 430074. 18. S. Lojen, Josef Stefan Institute, Ljubljana, Slovenia

viii 19. F. Massari, Dipartimento di Geologia, Paleontologia e Geofisica dell'Universit/i, Via Giotto 1, I-35137 Padova 20. Shilong Mei, Faculty of Geosciences, China University of Geosciences, Beijing, 100083, E-mail: [email protected] 21. P. Michaelsen, Earth Sciences, James Cook University, Townsville, Australia 22. C. Neri, Dipartimento di Scienze Geologiche dell'Universit/~. Corso Ercole I d'Este 32, 144100 Ferrara 23. E.S. Panasenko, Far Eastern Geological Institute, Far Eastern Branch, Russian Academy of Sciences, Prospect Stoletiya Vladivostoka, 159, Vladivostok 690022, Russia 24. Yuanqiao Peng, Faculty of Geosciences, China University of Geosciences, Wuhan, Hubei, China, 430074 25. Cu Tien Phan, Research Institute of Geology and Mineral Resources, Thanh Xuan, Dong Da, Ha Noi, Vietnam, Fax" 84 45 42125 26. A.M. Popov, Far Eastern Geological Institute, Far Eastern Branch, Russian Academy of Sciences, Prospect Stoletiya Vladivostoka, 159, Vladivostok 690022, Russia 27. T.A. Punina Far Eastern Geological Institute, Far Eastern Branch, Russian Academy of Sciences, Prospect Stoletiya Vladivostoka, 159, Vladivostok 690022, Russia 28. A. Sarkar, Indian School of Mines, Dhanbad, India 29. Qinghua Shang, Nanjing Institute of Geology & Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China, Fax: +86-025-3375200 30. Shuzhong Shen, School of Ecology and Environment, Deakin University, Rusden Campus, 662 Blackburn Road, Clayton, Victoria 3168, Australia 31. G.R. Shi, School of Ecology and Environment, Deakin University, Rusden Campus, 662 Blackburn Road, Clayton, Victoria 3168, Australia, E-mail" [email protected], Fax: +61 3 92447276 32. P. Di Stefano, Dipartimento di Geologia e Geodesia dell'UniversitY., Via E.Toti 91, 190128 Palermo 33. P. Toft, Geological Institute, University of Copenhagen, Oster Voldgade 10.DK-1350 Kopenhagen, Denmark 34. Jinnan Tong, Faculty of Geosciences, China University of Geosciences, Wuhan, Hubei, China, 430074, E-mail: [email protected] 35. N.G. Ukhaneva, Far Eastern Geological Institute, Far Eastern Branch, Russian Academy of Sciences, Prospect Stoletiya Vladivostoka, 159, Vladivostok 690022, Russia 36. C. Venturini, Dipartimento di Scienze della Terra e Geologico-Ambientali dell'Universit/i. Via Zamboni 67, 1-40127 Bologna 37. A. V6r6s, Geological and Paleontological Department, Hungarian Natural History Museum, Museum krt. 14-16, H-1088 Budapest, Hungary, E-mail: voros@paleo. nhmus.hu 38. Hongmei Wang, Faculty of Geosciences, China University of Geosciences, Wuhan, Hubei, China, 430074. 39. Zhiping Wang, Faculty of Earth Sciences, China University of Geosciences, Wuhan

430074, The People's Republic of China 40. Jiaxing Yan, Faculty of Geosciences, China University of Geosciences, Wuhan, Hubei, China, 430074. 41. Fengqing Yang, Faculty of Geosciences, China University of Geosciences, Wuhan, Hubei, China, 430074. 42. A. Yao, Department of Geosciences, Osaka City University, Sugimoto 3-3-138, Sumiyochi--ku, Osaka 558-8585, Japan 43. Hongfu Yin, Faculty of Geosciences, China University of Geosciences, Wuhan, Hubei, China, 430074, E-mail: [email protected], Fax: +86 27 87803392; 44. Y.D. Zakharov, Far Eastern Geological Institute, Far Eastern Branch, Russian Academy of Sciences, Prospect Stoletiya Vladivostoka, 159, Vladivostok 690022, Russia, E-mail: [email protected] 45. Ning Zhang, Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074, The People's Republic of China 46. Zhenfang Zhang, Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074, The People's Republic of China

About the editor Yin Hongfu, Academician of Academia Sinica, President of China University of Geosciences (Wuhan, Hubei), Professor of Geology. Leader of IGCP Project no. 359 and chairman of the International Permian Triassic Boundary Working Group under ISC. He published 160 papers and is the co-author (or editor) of eighteen books, among which seven published in English: 1. Permo-Triassic events in the eastern Tethys. Cambridge University Press, Cambridge, 1992; 2. Geological events of Permo-Triassic transitional period in South China. Geological Publishing House, Beijing, 1993; 3. The Palaeobiogeography of China. Oxford Science Publica, ion, Oxford, 1994; 4. The Palaeozoic-Mesozoic Boundary. China University of Geoscience Press, 1996; 5. Late Palaeozoic and Early Mesozoic Circum-Pacific events and their global correlation. Cambridge University Press, 1997; 6. The Permian-Triassic boundary and global triassic correlations. Palaeo-geography,climatology, -ecology. Special issue, 143(4), 1998; 7. Proceedings of the International Conference on Pangea and the Paleozoic-Mesozoic transition. China University of Geosciences Press, 1999.

Correspondence: Faculty of Geosciences, China University of Geosciences, Wuhan, Hubei, China, 430074. Tel: 0086 27 7806812; Fax: 0086 27 7801763; E-mail: [email protected]

xiii

Preface Hongfu YIN

a,

J.M. DICKINS

b,

G.R. SHI c, Jinnan TONG

a

a Faculty

of Earth Science, China University of Geosciences, Wuhan, Hubei, 430074, China Geology, 14 Bent St, Turner, A.C.T. 2612, Australia c School of Ecology and Environment, Deakin University, Rusden Campus, 662 Blackburn

b Innovative

Rd., Clayton, VIC 3168, Australia

1. INTRODUCTION Permian and Triassic are the interval known for the integration and separation of Pangea, the closure of the Palaeo-Tethys and the opening of Meso-Tethys. They were associated with a series of worldwide events including the Late Palaeozoic glaciation and succeeding extensive evaporatic and reef formations, the end-Palaeozoic regression, strong orogenies (Hercynian, Uralian, Hunter-Bowen and Indosinian) and wide-spread volcanism (e.g. the Tunguss Trap and the Emeishan Basalt) and magmatism, and finally, the Permo-Triassic biotic macro-extinction. These events resulted in the formation of enormous reserves of coal, petroleum, evaporites, phosphorites and metal resources. The Permian and Triassic thus constitutes a time interval particularly important both for understanding the Earth's history and for exploration of mineral resources. It was toward this aim that the IGCP (INTERNATIONAL GEOLOGICAL CORRELATION PROGRAMME) project no. 359 (1993-1997) was established. This project is named LATE PALAEOZOIC AND EARLY MESOZOIC EVENTS OF TETHYS, CIRCUM-PACIFIC AND MARGINAL GONDWANA. To reconstruct the history of Pangea, Palaeo-Tethys and Palaeo-Pacific through stratigraphic, palaeogeographic and other interdisciplinary approaches, our efforts are concentrated on two tasks, which comprises the two parts of this volume. Part 1 deals with regional stratigraphy which is the basis for interregional correlation, and palaeogeography. Part 2 focuses on the events at the Permian-Triassic transition. Because the definition of Permian-Triassic Boundary (PTB) has been discussed in other publications [1-3], this book will concentrate on biotic evolution.

xiv 2. PART 1 Part 1 covers southern Europe, Russia, China, Indochina, Australasia and Japan. Cassinis et al. examined the Permian of southern Europe which essentially consists of continental terrigenous and volcanic deposits, as well as intrusive bodies. The authors emphasized a wide-spread "Mid-Permian'unconformity subdividing Permian (and Upper Carboniferous) into a lower fault-bounded basin infilling sequence and an upper continuous blanketing sequence, and related them to tectonic regime. Marine sediments of the westernmost Tethys, i.e. in Italian, ex-Yugoslav and Greek areas were emphatically described, and considered to be mainly Tethyan with certain influence of the northern sea. This relatively comprehensive review discussed regional stratigraphy, and presents palaeogeographic and other geological interpretations. The Triassic of southern Europe, accentuating on the Alpine-Carpathian region, was dealt with by Vor6s. He subdivided this region into four major terranes and described their stratigraphy, ammonoid zonation and facies in comparison with those of the epicontinental southern Europe and northern Africa. Discussion on the palaeogeographical positions of the terranes led to the conclusion that the crustal fragments carrying the later Alpine-Carpathian terranes were in close connection with the Eurasian continental shelf in the Triassic. Based on extensive past studies and especially recent progress in the Upper Permian, Kotlyar et al. summarized the Permian of CIS and Russia. This vast territory was subdivided into a Biarmian (traditional East European) and a Tethyan (near-equatorial) realm. A few provinces of the Biarmian realm were discussed and a generalized stratigraphic scale together with correlation among the provinces was given. Notwithstanding with the advantages of the lower Permian world stratotype [4] and the progress made in the Upper Permian of the Volga area [5], the author unbiasedly commented on the advantages and disadvantages of the Russian scale in correlation with the international scale. The Tethyan (near-equatorial) scale, exclusively based on marine strata, was widely used for subdividing the Permian deposits in the southern regions of Russia and CIS. Discovery of Changhsingian in most parts of this area has been a remarkable progress. As correctly signified by the authors, its subdivision was mostly based on foraminifers and thus their correlation with conodonts and ammonoids as well as more precise demarcation of stage boundaries need improvements. Instead of giving a general review, the Triassic of Russia and CIS was investigated by Zakharov et al. with stable isotopes and Ca-Mg ratio, plus invertebrates on Changhsingian and Early Triassic. Seven geochemical events have been discovered and interpreted as due to high bio-productivity of marine basins in conditions of transgressions and warm climate. Through global correlation, it was suggested that thermal maxim in the Tethys existed during early Changhsingian, middle Olenekian, early Anisian and early Norian. Based on the Permian time scale proposed and agreed upon by the majority during his chairmanship of SPS [6], Jin, and his colleague Shang, presented a refined regional

XV

chronostratigraphic scheme for the Permian of China, a summary of the Permian stratigraphic framework in major depositional basins and a tentative correlation between the regional Permian sequences. The paper confirmed the translocation of the "Late Carboniferous' Chuanshanian rocks into Lower Permian, corresponding to Cisuralian. The Lopingian correlation is refined based on bio-, magneto-, and sequence stratigraphy. Problems of correlation with international scheme due to biogeographic differentiation are also discussed. According to Yin and Peng, fragmentation of Chinese blocks ended and the Chinese continent integrated for the first time in Triassic. Sediments and biota of the Triassic of China were temperature-controlled and can be subdivided into six regions. Stratigraphic sequences of representative areasof these regions, plus Tibet-Qinghai and South China subregions, are indicated, and summarized into synthetic chart with different fossil zonations. Correlation with adjacent areas is briefly discussed. Triassic strata constitute a 2 nd order sequence set with a remarkable two-fold character (four 2 nd order sequences) and twelve 3 rd order sequences. Influence of the Indosinian Orogeny on the Triassic sequences and their distribution is emphasized. The Permo-Triassic of Indochina was composed of a mosaic of pro-Cathaysian and proGondwanan blocks separated by micro-oceans and seaways, which caused complication in stratigraphic correlation. At this stage, we can only start from description and preliminary correlation of the concerned strata. Phan's paper mainly dealt with the Permian of ex-French Indochina but accompanied by correlation with South China and other parts of Indochina. Although still using the Vietnamese twofold subdivision, the author admits that the newly suggested international standard better suits the situation of Indochina, especially the bases of Wuchiapingian (Dzhulfian, Upper Permian). Fusulinids are of special significance in dating and correlating Permian of this region, and the application of conodonts remains to be worked out. Khuc's paper subdivided the Triassic of Indochina into two types: the An Chau type with volcanogenic Anisian overlying on unconformity surface and Carnian either terrestrial or absent, and the Song Da type with carbonate Anisian conformable with Lower Triassic and Halobia-bearing marine Carnian. The first type is restricted to pro-Cathaysian blocks and thus the sequence is apparently controlled by the Indosinian Orogeny. The second type involves various sequences scattered in the seaways and epicontinental seas around the blocks. Triassic of Australasia and Permian of New Zealand were described by Campbell & GrantMackie and Campbell respectively, in terms of terranes, their known faunal content, biostratigraphic age control and correlation, both inter-terrane and regional. Considering the diverse tectonic settings and the fragmented sequences it is admirable that Campbell and Grant-Mackie managed to summarize what is known of the marine Triassic strata of Australasia and in particular New Zealand, New Caledonia, Australia, P a p u a - New Guinea and eastern Indonesia. All preserved sequences are related to the break-up of eastern Gondwanaland, demise of Tethys and development of the Australian Plate margin. Interestingly, the authors emphasized biostratigraphic gaps for Ladinian and Carnian time,

xvi which correspond to the first phase of Indosinian Orogeny in Eurasia. Permian rocks in New Zealand are recognized within six terranes. Stratigraphically coherent fossiliferous successions are confined to two of these terranes, which are host to all documented New Zealand Permian biostratigraphic units. Correlation, often through indirect links with palaeotropics, Russia and North America, shows however that virtually all Permian stages exist in New Zealand. The basic tectonic framework of the Japanese Islands was generated through subduction of the Panthalassa Ocean plates during Paleozoic to Mesozoic time. The paper of Ezaki and Yao first introduced this framework with special reference to the pre-Jurassic terranes, six in southwest Japan plus South Kitakami in Northeast Japan, and Permo-Triassic exotic blocks in Jurassic terranes. Recent progress on biostratigraphy based on radiolarians and conodonts has made it possible to elucidate pelagic Permo-Triassic sequences and their correlation with epicontinental deposits, which had been extensively studied previously. Accordingly, researches on Permo-Triassic events in pelagic settings, including the extinction-recovery process and corresponding environmental changes, got large impetus. Palaeobiogeography, especially South Kitakami was in situ or derived from Gondwana, also attracts attention. Hansen et al. viewed the Permo-Triassic event from two peculiar points--the magnetic susceptibility and organic carbon isotopes. They were able to correlate the Permo-Triassic boundary strata of 7 sections from three continents with magnetic susceptibility pulses at the resolution of Milankovic cycles, i.e. 20ka and 100ka. Despite traditional belief that magnetic susceptibility varies with weathering and thus highly environment-depending, such coincidence of pulses with biotic changes in sections may provide a new tool in high resolution stratigraphy. The organic carbon isotopic signals also gave high resolution correlation between some marine and terrestrial sections. Different from other regional papers focusing on stratigraphy, Dickins's paper on the northern margin of Gondwanaland mainly argues for his long-term concept of Tethys and Gondwanaland [7,8]. He claimed that there was no continuous sea from Africa to the Himalayas and further east in the latest Carboniferous and earliest Permian. During Asselian and early Sakmarian the sea of Gondwanan margin was characterized by glaciation, which had only temporary connection with the northern warm-water Central Asian Sea. In his sense the Tethys was only established since mid-Permian as a continuous warm-water seaway existed from southern Asia to southern Europe and northern Africa. From Late Permian through Triassic the northern shore of Gondwanaland can be traced with a southern sediment source. As Dickins has been working so long on Gondwanan Permian, his idea, quite different from the popular view of Tethys as depicted by Dercourt et al. and Scotese et McKerrow, probably will arouse interesting arguments. A majority of the papers have shown, either through direct indication or through implication, that Permo-Triassic stratigraphy, paleontology and paleogeography of the Tethyan, marginal Gondwanan and western Circum-Pacific can be best interpreted by an

xvii

archipelagic ocean model [9,10]. This was highlighted by Yan and Yin's paper in which Tethys was illustrated as an "unclean' ocean with many archipelagos, a mosaic of seas and lands including: rifted blocks and valleys, seaways; microplates and micro-oceans; and island arcs and marginal seas. The foregoing (northerly) blocks were accreting to Eurasia, while the back (southerly) ones were rifting away from Gondwana. Reconstruction in this paper emphasizes on paleoclimatic constraints but they also accord with tectonic, paleomagnetic and biogeographic data. This archipelagic model of Tethys accords with paleomagnetic and biogeographic data that Eurasia and Gondwana were widely apart, and also accords with the facts that deep ocean deposits and typical oceanic ophiolites were few, because according to this model the vast distance was filled by islands and micro-oceans and seas. Though still wedge-shaped toward west, this view is quite different from the traditional view and has attracted considerable attention.

3. PART 2 Part Two of this volume deals with the events at Permo-Triassic transition, and naturally concentrates on bioevents. Tong and Shi's paper based on the data from South China indicates that the Permian foraminifers experienced two episodes of mass extinction: end-Guadalupian and end-Changhsingian. The recovery did not started until the Middle Triassic and the genuine Mesozoic ecosystem was not fully organized until the Late Triassic. Foraminifer groups of different microstructures and compositions of tests had very distinctive evolutions during the great transition. The Permo-Triassic events resulted in the most significant transformation in the history of the Foraminiferida, that is: the alternation from the Late Paleozoic calcareous microgranular groups to the Mesozoic-Cenozoic hyaline perforate calcareous forms. Feng et al. revealed that not only shallow benthos, but also pelagic radiolarians suffered end-Permian extinction. The recovery of the Triassic radiolarian fauna began in early Anisian and considerable diversity was reached in middle and late Anisian. An interesting phenomenon is that progenitors of Mesozoic radiolarians probably already occurred in latest Changhsingian. As radiolarian evolution across the Paleozoic-Mesozoic boundary have been poorly reported except in Japan and Sicily, this report may have its significance beyond its regional scope. The paper of Shi and Shen worked on Permian brachiopod events using statistical analysis on a large database of the Asian-western Pacific region. Six intervals were subdivided and a review of the Permian marine provincialism was introduced as a framework. It was revealed that the Permian brachiopod diversity and extinction patterns are broadly compatible among the Gondwanan, Palaeo-equatorial and Boreal Realms as well as with those of the Asianwestern Pacific region. Similar to foraminifers two major extinction events are recognized:

xviii end-Guadalupian and Changhsingian, the former most pronounced in the Gondwanan and Boreal Realms, whereas the latter only in the Palaeo-equatorial and Gondwanan Realms, but much more severe and time-concentrated. They also found that there is a good correlation in timing between the end-Guadalupian extinction and an Asian-western Pacific regression. Unlike foraminifers and brachiopods, Yang and Wang recognized seven ammonoid extinction events from Late Permian to Early Triassic, of which the end-Permian event is the largest. Most of the seven extinctionevents coincide with geological boundaries of either series or stages, and exhibit cyclic pattern consisting of newborn explosion, relative stable development and mass extinction, which the authors named as the "stage model'. In the Early Triassic, the ammonoids recovered stepwise and radiated to high diversity and biologically high level much quicker than that of other organisms. The authors considered the intrinsic (biological) factors of ammonoids (speciation, evolution rate and adaptibility) as the key to the promptness of ammonoid evolution. Besides the end-Permian event, the conodont paper by Lai and Mei focused on conodont zonation and provincialization of whole Permian and Triassic. Being climate-controlled, conodont biogeography was subdivided into two bipolar and one equatorial provinces in Permian but remained undivided in Triassic. They recognized four stages and four events for Permian and six stages and seven events for Triassic, attributed respectively to what they named as Substitute Pattern and Extinction-Survival-Recovery Pattern. Permian zonation was established for warm and cool water respectively and 26 zones are proposed for Triassic.

4. S U M M A R Y

Contributions of this volume may be summarized into three aspects. First, Permian and Triassic regional stratigraphy of Tethys and western Circum-Pacific, especially of areas so far insufficiently known, or areas with remarkable progress recently, are extensively reported. Second, based on these data new views of Tethys in Pangea time, different from the popular patten given by Scotese and McKerrow, are suggested. To synthesize Permian-Triassic and test new views of Pangea and Tethys, data of so far less reported areas and facies are required, such as the Middle East and deep sea facies. Thirdly, besides comprehensive indication and interpretation, researches of the biotic alteration and causative global changes at the PermianTriassic transition are now being carried out concurrently taxis by taxis, which has revealed that the procedure was multi-phasic, more variable and irregular than previously thought. This turning point of geological history is an interval of worldwide events happened in causality like a string of time-bombs, which provides excellent material for high resolution subdivision and correlation. We need cooperation among researchers such as under new IGCP projects to press onward along these directions, to achieve a better understanding of Permian-Triassic stratigraphic framework, environmental change and resource distribution, so as to serve the

xix

society and to enlighten the effort of mankind on sustainable development.

REFERENCES

1.

H.-F. Yin, W.C. Sweet, B.F. Glenister, G. Kotlyar, H. Kozur, N.D. Newell, J. Sheng, Z.-Y. Yang and Y.D. Zakharov, Recommendation of the Meishan section as Global Stratotype Section and Point for basal boundary of Triassic System. Newsl. Stratigr., 34(2)(1996) 81-108.

2.

Yin Hongfu (ed.), The Palaeozoic-Mesozoic Boundary--Candidates of the Global Stratotype Section and Point (GSSP) of the Permian-Triassic boundary. China University of Geosciences Press (1996) 135pp.

3.

G.Lucas and Yin Hongfu (eds.), 1998, The Permian-Triassic boundary and global triassic correlations. Palaeo-geography, -climatology,-ecology. Special issue, 143(4), 215pp.

4.

V.I. Davydov, B.F. Glenister, C. Spinosa, S.M. Ritter, V.V. Chernykh, B.R. Wardlaw and W.S. Snyder, Proposal of Aidaralash as Global Stratotype Section and Point (GSSP) for base of the Permian System, Episodes, 21, N 1, (1998) 11-18.

5.

N.K. Esaulova, V.R. Lozovsky and A.Yu. Rozanov (eds.) Stratotypes and Reference

Sections of the

Upper Permian in the regions of the Volga and Kama rivers, Moscow (1998). 6.

Y.G. Jin, B.R. Wardlaw, B.F.Glenister and G.V. Kotlyar, Permian chronostratigraphic subdivisions. Episodes, 20(1 ) (1997) 10-15.

7.

J.M.Diickins, The nature of the oceans of Gondwanaland, fact or fiction.

In Gondwana Nine 1:387-

8.

J.M.Diickins, The southern margin of Tethys. In Gondwana Nine 2:1125-1134. Oxford & IBH

396. Oxford & IBH Publishing Co. Pvt.Ltd, New Delhi (1994). Publishing Co. Pvt.Ltd, New Delhi (1994). 9.

Yin Hongfu, Tethys-an archipelagic ocean model. Proc. 30th Int'l Geol. Congr., vol.11 (1998) 91-97.

10. Yin Hongfu, Wu Shunbao, Du Yuansheng, Yan Jiaxin and Peng Yuanqiao, South China as a part of archipelagic Tethys during Pangea time. In Yin Hongfu and Tong Jinnan (eds.): Proceedings of the International Conference on Pangea and the Paleozoic-Mesozoic transition, China Univ. Geos. Press, Wuhan (1999) 69-73.

Persian-Triassic Evolutionof Tethysand WesternCi,cum-Pacific H. Yin, J.M. Dickins,G.R. Shi and J. Tong(Editors) o 2000ElsevierScienceB.V. All rightsreserved.

Paleoclimatic constraints for Early Permian paleogeography of Eastern Tethys ~ Jiaxin YAN and Hongfu YIN Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074, People's Republic of China

East and Southeast Asia comprise a complex mosaic of allochthonous continental blocks. Smaller blocks among them are commonly ill-constrained in the Permo-Triassic paleogeographic reconstruction due to limited paleomagnetic data of high quality. Paleoclimatic constraint on the position of block is employed in this paper. A brief review of temporal and spatial distributions of paleoclimatic indicators revealed that the climatic regime in the Permian and, possibly, Late Triassic was of zonal circulation. The Chihsian (Early Permian) paleogeography is emphasized, in which paleoclimatic constraints inferred from changing climatic patterns are consistent with biogeographic and tectonic data and render satisfactory results. For example, the Qiangtang and Sibumasu blocks were located in the southern margin of the southern subtropical zone, and the Changning-Menglian ocean spanned the whole southern subtropical zone with a width about 10 degrees in latitude. The resulting paleogeography of Chihsian Subepoch is the pattern of an archipelago. It is also noted that Monodiexodina, a characteristic element of Permian transitional fauna, may also be present in warm-water deposits.

1. INTRODUCTION Much advancement has been achieved on the timing of amalgamation and accretion of blocks in the eastern Asia in the last decade. Recently, considerable attention has been directed to the reconstruction of eastern Tethys around the Paleozoic - Mesozoic transition[ 13]. A remarkable trend in the reconstruction is the increase in number of discerned blocks in the region. Additionally, configuration of eastern Tethys as an archipelago is emerging[4-6]. Accordingly, constraints on the reconstruction become of great concern. Generally, useful constraints on a reconstruction come from tectonic, paleomagnetic, biogeographic and paleoclimatic data. Although paleomagnetic data has been pre-eminent in recent years for interpreting paleolatitudes on most Paleozoic reconstruction, available paleomagnetic data for most of the smaller blocks in the region are still sparse and their reliability needs to be evaluated. Climatically sensitive deposits have long been used as evidence for the mobility of continents. Their potential latitudinal constraints were commonly used as independent "This work is supportedby the NationalNatural Science Foundationof China Project, No: 49632070).

verification of paleomagnetic data and even apparent polar wandering paths when the zonal circulation was proved[7,8]. In this paper, paleoclimatic constraints on block position are employed, emphasizing the Early Permian, because the Early Permian is the optimal interval to discriminate blocks of Gondwanan affinities from those of Cathaysian aff'mities in the light of paleoclimatic evidences. Four interesting paleogeographical problems, important but not fully resolved, will be detailed as examples of paleoclimatic constraints on the Early Permian paleogeography. Interestingly, the Early Permian is also the period that mixed fauna were well-recognized[9,10]. Wherever appropriate, thus, biogeographical and tectonic data will be incorporated in the discussion. As it is the first epoch of our Permo-Triassic paleogeographic reconstruction, we will briefly introduce the blocks in eastern Tethys and review the PermoTriassic paleoclimates relevant to our discussion of paleoclimatic constraints on positioning of the blocks.

2. BLOCKS IN EASTERN TETHYS Before further discussion, it is necessary to summarize current knowledge on the blocks in the eastern Tethys. East and Southeast Asia comprise a complex mosaic of allochthonous continental blocks separated by suture zones or large faults. The suture zones represent the remnants or sites of former ocean basins that once separated the now juxtaposed pieces of continental lithosphere in the region. As the blocks were non-rigid, they might have been modified by successive episodes of crustal shortening and strike-slip faulting, especially during the collision of India with Eurasia and subsequent northward indentation of India in the Cenozoic. In order to minimize the modification and to facilitate the further fit in the computer, some strike-slip fault belts were applied here (Fig. 1). The Indo-China, Sibumasu and western Burma blocks of Southeast Asia are modified from Metcalfe (1991)[ 11]. It is noted that the Tengchong-Baoshan region shows differences from the other sectors of the Sibumasu (or Shan-Thai) block in both sedimentary and faunal features[10]. For simplicity, the Tengchong-Baoshan region is still enclosed in the Sibumasu block here. The Lanping-Simao Block is separated from Indo-China Block along the NanLuang Prabang strike-slip fault belt[12,13]. In South China, the Lower Yangtze, Upper Yangtze, Cathaysia, Zhong-zan, Hainan Island and Bayan Har blocks are modified from Yin et al (1999)[5]. The North Qinling and South Qinling blocks originated from the Mid-Qinling microplate of early to middle Paleozoic age, which rifled from the Upper Yangtze block in Cambrian to Ordovician time and docked along the southwestern margin of North China in the Silurian. The resultant small oceanic basin to the south of the Mid-Qinling microplate was mainly closed in Late Silurian to Early Devonian, but deep-water radiolarian chert persisted to early or even later Carboniferous in the southwestern part (the Mianxian-Lueyang ophiolite melange belt)[5,14]. Eastward, Permian deeper shelf black shales, marls, cherts and small Hercynian alkalic intrusions at places still marked the closed oceanic basin. Interestingly, the Mid-Qinling microplate was separated into two slivers, namely South and North Qinling, in the Late Paleozoic, by a ritt trough evidenced by a belt of Late Devonian to Middle Triassic deep water deposits from Zheng'an to Xiahe[5]. It was the deep rift basin that separated the North China and South China blocks in the Late Paleozoic. The rift basin was wedge-shaped, opening to the west with a width above 1000 km in the Permian and it closed completely in

late Middle Triassic[ 14-16]. It is thus reasonable to treat the North and South Qinling blocks independently in terms of their movement in the Late Paleozoic. Mongolia block is similarly def'med as the Armuria of Zonenshain et al (1990)[ 17] and the southern Mongolia arcs ofNie et al (1990)[3]. It must be recognized, however, that a variety of allochthonous terrains in the eastern end, e. g. the Nadanhada terrain of Shao and Tang (1995)[18], should be excluded from this block. As the assemblage of North China, Qilian, Tarim and. Junggar had completed before Permian[3,19-22], only their boundaries in PaleoTethys are reiterated here. The Altun strike-slip fault separated Tarim to the northwest, and Qaidam and South Kunlun to the southeast (Fig.l). The Qilian and Qaidam blocks were separated by the North Zongwulong Fault, which is the western extension of the coeval ritt belt in Qinling region. This interpretation is supported by Triassic turbidites and talus in the region[23]. The Qaidam and South Kunlun blocks are separated by the median Kunlun ophiolite belt, which was closed in late Early Permian[24, 25].

Figure 1 Sketch map showing blocks in eastern Tethys. Abbreviations used: Ata, AnatolideTauride; Bay, Bayan Har; Cat, Cathaysia; Cp, Central Pamir; Dzi, Dzirula; EAAC, Eastern Anatolian Accretionary Complex; Far, Farah Rud; Hai, Hainan Island; Hel, Helmand; Koh, Kohistan; Lad, Ladakh; Las, Lanping-Simao; Lya, Lower Yangtze; Nir, NW Iran; Nql, North Qinling; Pon, Pontide; Qai, Qaidam; Qia, Qiangtang; Qil, Qilian; Sbm, Sibumasu; Sku, South Kunlun; Sp, Southern Pamir; Sql, South Qinling; SS, Sanadaj Sirjan; Tan, Tanghla-Qamdo; Tsh, Tianshuihai; Wbu, Western Burma; Yan, Yangtze; Zho, Zhong-zan. The Tianshuihai block is def'med by the Maza-Kangxiwar ophiolite belt to the north, by the Kongka Pass fault to the south, by the Altun strike-slip fault to the southeast and by the Karakorum fault to the southwest. Although the Tianshuihai is similar to Bayan Har in the development of Triassic turbidites[26,27], they are treated separately as they are distantly displaced by the Altun strike-slip fault. The Kongka Pass fault is the west part of the northern boundary of Early Permian fauna of Gondwana aff'mities[28]. However, the eastern extension

of the boundary is unclear. Permian faunas with Gondwana aff'mities are largely confined to the western Qiangtang region. Here the Qiangtang block is def'med tentatively to the west of the line connecting Yanghu and Dongqiao. To the east is the Tanghla-Qamdo block. Although the nature of the conjectured line is uncertain, biogeographical and sedimentary features of the two blocks were distinct in Permo-Triassic periods. The Lhasa Block is bounded by the Banggongco-Nujiang suture to the north and the Indus-Yarlung Zangbo suture to the south. Blocks to the west and southwest of Tibet are described in detail by Girardeau et al (1989)[29], Seng6r et al (1991)[30] and Zonenshain et al (1990)[ 17]. For simplicity, terrains in Turkey were grouped into two: the northern Pontides and the southern Anatolide-Tauride[31,32].

3. PERMO-TRIASSIC CLIMATES OF EASTERN TETHYS

3.1. Indicators of paleoelimate Paleoclimatic indicators include climate-sensitive deposits and inferences from biogeographic data[9,33]. Lithic paleoclimatic indicators include coal measures, bauxite, organic reefs, evaporites, carbonate ooids and deposits of definite glacial origin. The climatic significance of these indicators is discussed in numerous publications and will not be elaborated here. Noteworthy are the marine carbonate ooids, which form in modern warm environments of high salinity[34] and occur in ancient marine deposits with similar characteristics[35]. They have been used as potential indicators of warm, dry climatic conditions[7]. Also noteworthy is the paleoclimatic significance of fusulinid foraminifers. Their paleoclimatic significance is usually inferred from biogeographical data. As an integrated group, Ross and Ross (1985) considered fusulines to be tropical and subtropical[36]. In the Sverdrup Basin, Permian fusulines are present in the chloroforam and bryonoderm-extended skeletal grain associations of tropical-like to warm-temperate shelf carbonates, and disappear in the bryonoderm association of cold temperate shelf carbonates. In other words, fusulinids thrived in warm-water conditions but decreased in cool-water conditions there[37,38]. In the Salt Range, Pakistan, the lowest occurrence of fusulinids there, represented by Monodiexodina and Codonofusiella, are found in the Amb Formation. As climate ameliorated, the Amb Formation was overlain by the Wargal Formation with highly diverse fusulines of warm-water deposits (verified by the associated carbonate ooids)[39]. The Amb formation would be deposits of temperate conditions because the brachiopod and fusulinid faunas in the formation were thought to be transitional and mesothermal (the paleoclimatic significance of Permian transitional faunas will be discussed in detail later)[9] and is overlain directly by deposits of warm-water conditions. Both cases above show good levels of agreement concerning the paleoclimatic significance of fusulinids. An analogy may also be made to the distribution of large Cenozoic foraminifers along the southern Australia shelf, which are present in environments intermediate between warm- and cool-water carbonate realms, and disappear in cool-water environments[40]. It thus seems that fusulinids were limited to warm and warm-temperate environments, and decreased sharply in diversity with the drop of water temperature. Shelf carbonates with highly diverse fusulines, thus, are more appropriately assigned to warm-water deposits than to cool- and cold-water deposits. And the occurrence of fusulinids in the Early Permian shelf carbonates of the southern margin of Tethys would enable ambient temperatures equal to or above warm-temperate if exhumation and reworking

may be excluded. This inference is largely compatible with biogeographical data. In addition, we have noted that coal deposits is secondarily related to rainfall, and is mostly due to high groundwater table. As a reevaluation of Permo-Triassic coal beds for their paleoclimatic significance is not feasible at this time, the interpretation of coals as wet-climate indicators is incorporated with phytogeographic data and other climatic indicators throughout the following discussion.

3.2. Permo-Triassic paleoclimates in eastern Tethys Several significant changes characterize the Permo-Triassic distribution pattern of lithic paleoclimatic indicators in the region if a first-order trend is considered. In the Early Permian, two distinct dry climatic zones existed in the region. One, indicated by thick oolitic limestones and a fossil flora dominated by Walchia and Ullmannia[41], is present in the southern Junggar basin and Yili basin, northwestern China. This drier climatic zone was likely located at a paleolatitude about 30~ as inferred from the paleomagnetic data of the Tarim block to the south[42,43]. The other one, as will be seen later, is well represented by carbonates trapped in deposits of deep-water origin in the Changning-Menglian Belt, southwestern China (Fig.2). Coeval coal measures with Gigantopteris flora[33] occur on the Upper Yangtze, Cathaysia and North China blocks, and Bahama-type carbonates on the Tarim and Upper Yangtze blocks, indicating a warm and humid paleo-tropical zone. Three of the paleoclimatic zones shifted south in Late Permian, which may be attributed to the northward drift of the blocks. Consistent with the drift are indicators of dry climates, such as gypsum and redbeds that appear in the uppermost Permian of North China and Callipteris flora in the Upper Permian of Tarim[41,44]. The southern dry climatic zone occurs on the India block, as indicated by carbonate ooids in the Salt Range, Pakistan[39]. Coal measures of similar origin persisted from Early Permian to Late Permian in the South China region, and developed on the Tanghla-Qamdo block (Table 1). This pattern was apparently disrupted in the Triassic after the end of the Permian. Indicators of dry climates are found in the three zones mentioned above during the Early and Middle Triassic stages. For instance, thick evaporites and oolitic limestones of Early and Middle Triassic age occur widely in the South China region, and dolomitic and oolitic limestones in the India and Lhasa blocks. In the North China Block there occur thick purple or mottled fluviolacustrine clastic deposits which contain calcareous nodules, Pleuromeia-Voltzia flora, and lack coal deposits, indicating dry paleoclimates[44]. Interestingly, the zonal distribution pattern of lithic paleoclimatic indicators resumed in the region in the Late Triassic. Table 1 summarizes the changing climatic pattern during Permo-Triassic periods on blocks in a cross-Tethys profile from the Indian Block though the Tibetan Plateau to the Junggar Block. The blocks were chosen for they experienced considerable northward drift in the Permo-Triassic time and have relatively complete depositional records. Preliminary results show that marked differences exist on the two sides of paleo-Tethys. Blocks of Cathaysian affmities experienced a change from warm and humid climatic conditions through warm and dry to warm-temperate conditions. Climates on blocks of Gondwana aff'mities ameliorated in the Early Permian, becoming warm in the Maokouan, and dry in the Triassic. Blocks in the Tethys, e. g., the Tanghla-Qamdo, experienced changes from warm and humid climatic conditions to warm and dry climatic conditions. As longer time intervals are adopted here, minor climatic variations have been time-averaged.

Table 1 Permo-Triassic Paleoclimatic characteristics of main blocks in a cross-Tethys profile*

11

India Block India Block ~..............._~No_rthw_e_stern) ...... __ _.~N0_rt__heas_te_rn_ i ~ ~ ~ : - i - ~ ~ ~ _ t - ~ :

I's

........

Lhasa Block

Coal bed

TanghlaQamdo Block -~~:!]~-

Tarim Block

Junger Block :,1' i!I ~' Jl ~11'

-

Lopingian ~ [ iii

-_~........ ~

........ ~.......- ~ ~ .

.....~ _ _ :

N

~ i!jliji~[liii~llil!l[iii'!llii~,!!i;i:il,i

Maokouan ii:!llil;~i ~;ii~i] i ~ii:!;,ii~li,,!,;iii~li,iiii!,,~,;iil]ii~,ii;:!

~ ~

_ ~ - ] f

~!] Iranophyllum, ---~--i lpciphyllum,

~-~~~]~i~-_:: abundant fusulinids, i!;-~i~----i~:_~-i.-__--reefs

i-:=-.- :--

Abundant fusulinids

. .

:=

@a~gamo~teri~, E~de~, diamictites

Carbonates with fusulinids

Gangamopteris, diamictites

. . . . . . . . . . . . . . .

~

~

: ' if''

i'

'

-::--Z._--- L---_~ :_--.-:-

-]---]_-.-:i

Reefs and ~tromatolites : .

Chuanshanian

~,~, !'

Coal and abundant fusulinids Abundant fusulinids and some carbonate ooids

'"i, ':", ~~ri,-,,=,-:",~i!~i"-~'-!:',-~: :~ii-~;-: ~ -' !:'-:,- " ',~:~",' ;:l',~ I:~!! ~' ,' ' i!',i;', ; !~:~: ": :,: ;::

Uhihsian

I'

Coal

Abundant rusulinids and rare ooids

.

.

.

.

.

.

.

.

. .

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

-L .....

.

.

.

........ ...... .

.

.

.

.

.

.

.

.

.

.

= -=

.

.

.

.

.

i_- -U =.__--_-_-22 '_~;- --_--.=:.2~-_ 7.

I

---

: r .....

-]~_: : 2 - 7 7 - - - . _ - - - . . : _

2 . c_-_----

:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

Humid tropical (warm water)

Ii~-IIIIIiI~IIII-~!IIKilI:~UU~'[I~!i:IL~.IIII~I~/hI!~Ul! :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

h'ilh'hi.:l!!

*Note: Lithic paleoclimatic data and biogeographic data have been compiled mainly from works of Lin et al (1989)[45], Liu et al (1992)[46], Li and Wu (1994)[47], Wu et al (1995)[41 ], Wang (1990)[48], Wang (1985)[49], Bureau of Geology and Mineral Resource of Xinjiang (1991)[50] and Yin (1997)[51]. The Permian chronostratigraphic subdivisions are after Jin et al (1997)[52]. N for no recognized climatic indicators, where paleoclimate was conjecture based on geological context.

3.3. Paleoclimatic constraints on position of blocks

Global climatic patterns of zonal circulation may be modified by orographic, continental, and monsoonal effects. Because zonal circulation essentially parallels latitude, it is the zonal pattern that offers the most straightforward method for using paleoclimatic data to constrain paleolatitudes[7]. There is evidence for monsoonal circulation during the Pangea interval[7, 53-55]. Detailed discussions on climatic regime and on the origin of the apparent climatic changes at the P/T or T2/T3 boundaries mentioned above are beyond the scope of the present investigation. Nonetheless, zonal features of Permian age can not be excluded on the basis of present knowledge. For instance, the published biogeographic boundaries of the Permian roughly parallel paleolatitude[9,33]. Vast evaporite deposits of Permian age can be interpreted as the paleogeographic coincidence of large epeiric basins with the subtropics[56]. And it seems unlikely that the zonal pattern of lithic paleoclimatic indicators mentioned above in eastern Tethys could be explained by monsoonal or orographic effects. Combining paleomagnetic data with zonal distributions of lithic paleoclimatic indicators in the eastern Tethys, a zonal circulation is favored here for the Permian and possibly the Late Triassic as well. Application of paleoclimatic indicators to constrain paleolatitudes is best exemplified by the Tanghla-Qamdo block. Presently known biogeographic and tectonic data indicated that the block drii~ed north steadily during the Permian and Triassic periods till it docked along the northern margin of the Paleotethys in the Late Triassic time. On this block the Early Permian (here including the Chuanshanian, Chihsian and Maokouan subepoches) deposits are mainly carbonates, containing abundant fusulinids and some ooids. Upward is the thick coal measures of the Late Permian (Lopingian) with Gigantopteris flora (Table 1). Undoubtedly, this block would be located in the paleotropical zone in the Permian Period. This position is consistent with paleomagnetic latitudes of 13.2~ S or 16.1 ~ (Early Permian)[57]. In the Late Triassic, oolitic limestones and gypsum developed in the north portion of the block and coal measures in the southern portion. Such a spatial distribution pattern of climate-sensitive sediments suggests that the Tanghla-Qamdo block was just at the tropical/northern subtropical boundary in the Late Triassic. This position is consistent with paleomagnetic latitude of 26.4~ (Middle and Upper Triassic) from the block[58], and consistent with the Triassic paleomagnetic latitude of 31.1~ from its northern adjacent block (Kunlun)[59].

4. CHIHSIAN PALEOGEOGRAPHY OF EASTERN TETHYS 4.1. Location of Sibumasu Block

Early Permian in the Baoshan region includes the Dingiiazhai Formation, Woniusi Basalt, Bingma Formation and Shazipo Formation in ascending order. Chihsian deposits include the Bingma (or Yongde) Formation (marine clastic rocks and mudstones) and lower part of the Shazipo Formation (bioclastic limestones and oolitic limestones). The equivalent in the Tengchong region consists of bioclastic limestones and massive dolomitic limestones (Guanyinshan Formation and the lower part of the Dadongchang Formation)[60]. Undoubtedly the Shazipo Formation formed in an environment with warm and dry climatic conditions based on the occurrence of carbonate ooids. Brachiopod assemblages in the Bingma and Guanyinshan formations were assigned as cool-water "Costiferina-Waagenites" fauna and closely compared with those from the Wargal Formation and the overlying Chhidru

Formation of the Salt Range by Fang (1983)[61], Fang and Fan (1994)[62], and Shi and Archbold (1998)[10]. As mentioned above, the latter formations in the Salt Range are deposits of warm-water origin. Based on the comparison of brachiopod fauna to Salt Range, the Bingma and Guanyinshan formations were also warm-water deposits. Noteworthy is the fact that the brachiopod faunas from the Dingjiazhai and Bingma formations were assigned to a transitional, representing a temperate paleoclimatic condition, by Shi and Archbold (1995, 1998)[9,10]. A similar conclusion was reached by Fang (1994)[62]. We agree that the fauna exhibit transitional features. Nevertheless, we believe that a warm-temperate climatic condition is likely for the carbonate intercalations in the upper part of the Dingjiazhai Formation and in the Woniusi Basalt since moderately diverse fusulinids are present. At this point, it is reasonable to believe that the Chihsian deposits in the Tengchong-Baoshan region originated in warm-water, and possibly in a dry paleoclimate. The paleogeographical position of the Tengchong-Baoshan region during Chihsian time is not well constrained using presently known paleomagnetic data. For example, published values of 15.6~ 34.1~ and 43.75~ of paleomagnetic latitudes (on average) were reported for the Woniusi Basalt[63-65]. If northward drift of the region was consistent during the Permian, as demonstrated by biogeographical data[9,10], the changing climatic pattern mentioned above implies that the Tengchong-Baoshan region moved into the southern subtropical zone from the southern temperate zone during the Chihsia stage (Fig.2). For the whole Sibumasu block, similar positioning is likely despite the stratigraphical and biogeographical differences between the Tengchong-Baoshan region and the rest of the Sibumasu block[ 10]. 4.2. The Changning-Menglian ocean

To the east of the Tengchong-Baoshan region is the Changning-Menglian Belt (CMB). A consensus has developed in recent years that the siliceous deposits of Early Devonian to Middle Triassic age in the belt are of deep-water origin[66-67]. However, the importance of the CMB in palinspastic reconstruction is much debated in the literature. For example, whether the CMB was a broad ocean (Changning-Menglian Ocean: CMO) or merely a failed rift sag is unresolved[51 ]. Another related question is which belt, the CMB, the Lancangjiang belt or the Jinshajiang belt, was the demarcation line between blocks of Gondwana origin and those of Cathaysian origin. Paleoclimatically, both questions may be answered if it can be determined whether the CMB was the demarcation line between warm-water deposits and non-warm water deposits during the Permo-Carboniferous ice age. It was argued that "coolwater faunas" of Early Permian age occurred in the Lanping-Simao Block (to the east of Changning -Menglian and Lancangjiang belts), thus the Jinshajiang belt was the candidate for the demarcation line[68]. Recently, diamictites of Early Permian age were reported from the Lancangjiang belt by Nie et al (1997)[69], leading them to the belief that the Lancangjiang belt was the demarcation. Re-examination of the distribution pattern of Early Permian lithic paleoclimatic indicators within or adjacent to the CMB seems necessary. A stratigraphic unit of particular significance is a suite of oolitic limestones of shallowwater origin, continuous from Late Carboniferous to Early Permian, that are trapped in deposits of deep-water origin in the CMB[70,71]. It overlies Lower Carboniferous volcanic rocks that originated on a mid-ocean ridge or oceanic island[72]. The oolitic limestone unit, distinctive from its equivalents to the west (Baoshan and Tengchong region) and east (Lanping-Simao block), was believed to be the carbonate cape of oceanic islands formed in

the island archipelagos (CMO) that accreted to the western margin of the Lanping-Simao Block[70]. The presence of carbonate ooids in the unit has been confirmed by Yan et al (1999) [73]. As the development of marine carbonate ooids is restricted to low latitudes and strongly dependent on salinity, the carbonate unit concerned accumulated in a warm environment under a dry climate. Accordingly, the Changning-Menglian belt has been confirmed as the boundary separating the block of Gondwana aff'mities from that of Cathaysian affinities for the period from Late Carboniferous to Early Permian (Fig. 2). In addition, the "cold-cool water biota"[68] and "diamictites"[69] to the east of the CMB, as indicators of non-warm water conditions, need further substantiation.

Figure 2. Chihsian (Early Permian) paleogeography of Tethys, drawn schematically, emphasizing the position of blocks in the eastern Tethys. Lha=Lhasa; Nch-North China; Ich=Indochina. Other symbols as in Figure 1. 1, fluvial and lacustrine deposits; 2, marine sandstones and mudstones; 3, turbidite (flysch); 4, carbonate platform; 5, dolomites and dolomitic limestones; 6, evaporites (halite and anhydrite); 7, mid-ridge spreading system; 8, subduction zone; 9, transitional fauna; 10, Cathaysian Tethyan fauna; 11, coal deposits; 12, carbonate ooids; 13, algal reef; 14, conjecture position for the oolitic carbonate unit in the Changning-Menglian Ocean. In contrast, Chihsian equivalents on the Lanping-Simao block to the east possess little oolitic limestone, which is widespread in the subjacent interval. The Yangtze block spanned across the paleo-equator at that time[43]. Since the Lanping-Simao block shares many similarities with Yangtze block in Chihsian deposits and fauna, the Lanping-Simao Block should also be in the tropical zone in the Chihsian Subepoch. Because the Lanping-Simao Block was separated from Yangtze Block by a small oceanic basin[13], which was widest in the Early Permian[72], we suggest that the Lanping-Simao block was in the southern margin of the humid tropical zone during the Chihsian Subepoch. The CMO between the Sibumasu

10 and the Lanping-Simao blocks, thus, should span the whole southern subtropical zone with a width of about 10 degrees in paleolatitude in Chihsian time (Fig.2).

4.3. Positioning of Qiangtang block The typical Lower Permian succession on the Qiangtang Block is represented by the Doumar section, Rutog, which includes the Cameng, Zhanjin, Qudi, Tunlonggongba and Longge formations in ascending order[28, 74]. The Cameng and Zhanjin formations consist of sandstone, slate and diamictites with intercalations of basic volcanic rocks. No fossils were reported from the Cameng Formation. A Eurydesma fauna associated with the solitary corals Amplexocarina and Cyathaxonia was reported from the Zhanjin Formation[75]. The Qudi Formation is composed of sandstones, calcareous sandstones and slates with limestone intercalations in the upper part, in which fusulinids were abundant (32 species among 10 genera)[76]. The lower three formations are roughly correlated to the Horpatso Series of Norin (1946)[51] and were interpreted as turbidites with a total thickness of nearly 5000m. The Tunlonggongba Formation is dominated by bioclastic limestones with minor fine elastics in the lower part. Oolitic limestones were reported by Wu (1991) at the Bairebuco Section[77]. Interestingly, faunas in the Tunlonggongba Formation include not only characteristic Cathaysian genera such as Schubertella, Ipciphyllum and Polythecalis, but also typical "antitropical" genera such as Monodiexodina. The Longge Formation is composed of bioclastic, dolomitic and oolitic limestones with fossils characteristic for the Asian Tethyan region. The Chihsian strata in the region is the Tunlonggongba Formation[9, 78]. The "mixed fauna" in the Tunlonggongba formation has been attributed to fluctuations of water temperature derived from climatic changes[74,79] or the interplay of climatic amelioration and northward drifting of the block[9]. Although these explanations are possible, the "mixed fauna" may actually represent a warm environment that inherits its "mixed feature" from an active tectonic background. Firstly, a rifting scenario has been proposed[51], which is supported by the great stratal thickness and the occurrences of volcaniclastic rocks and turbidites. It is more likely that the active tectonic setting rather than the water temperature of the depositional environment was what governed the shallowing-upward succession from turbidites through shallow water elastics, alternations of elastics and carbonates to carbonates. Secondly, the faunas in the formation are not really "mixed". It was noted that faunas with distinct affinities occur separately (or alternately) in outcrops. Faunas with "Gondwana att'mities" or "antitropical" distributions are present in horizons of lower carbonate contents[74,79]. A similar phenomenon was shown in a biogeographical cluster analysis of Permian brachiopods[80]. This suggests that the "antitropicar' faunas there are the result of less favorable conditions related to an active tectonic background. To be more specific, the less favorable conditions might be attributed to a higher elastic influx rather than greater water depth or lower water temperature. Most importantly, indicators of a warm-water environment, such as oolitic limestones, are present locally in the formation and are widely distributed in the superjacent Longge Formation. Eastward, a similar sequence is present in the Chabu-Chasang area, visible despite being metamorphosed. The changing paleoclimatic pattern on the Qiangtang block is apparently comparable to that of Sibumasu. Paleogeographically, thus, the Qiangtang block should be located near the southern margin of the southern subtropical zone in the Chihsian Subepoch. A belief shared by many is that fauna with "antitropical distributions", best exemplified by

the fusuline Monodiexodina, are mesothermal and represent a temperate paleoclimatic condition. Monodiexodina occurs widely in the Chihsian strata on the Qiangtang and Sibumasu blocks. But it appears in warm-water environments on the two blocks as discussed above. The spatial distribution of the Chihsian transitional fauna plotted in Figure 2 also supported that some transitional faunas have extended into warm-water environments. Correlations of higher resolution will be necessary to eliminate possible time-averaged effects and to unravel this rather interesting problem. 4.4. Orientation of the India Block There are two solutions to the orientation of the India Block in eastern Gondwana during the Permo-Triassic periods. One is to fit the present southeastern margin of the India Block to Antarctica[I,2], and the other is to fit it to the northwestern margin of Australia[81 ]. Early Permian paleoclimatic data on the northern parts of the block have been reexamined to test which of the fits is favored paleoclimatically. Here the northwestern part of the India Block includes the Salt Range, Kashmir, Ladakh and Zanskar regions and the northeastern sector refers to areas to the east (Table 1). The Lower Permian in the northwestern part is well represented by successions outcropping in the Salt Range, Pakistan. As mentioned above, the Amb Formation which is the Chihsian equivalent was deposited in warm-temperate waters indicated by fusulinids. The overlying Wargal Formation of Maokouan age should be a warm-water deposit based on the occurrence of carbonate ooids[39]. By contrast, Chihsian faunas in the northeastern part, which are represented by successions in southern Tibet, were assigned as Gondwana-type[9]. Faunas in Maokouan Subepoch are similar to the "mixed fauna" of Shi and Archbold (1995). No Early Permian fusulinids were reported from the area[51 ] although a variety of bioclastic limestones are present. Similarly, few Early Permian conodonts were reported from the region[45]. Both conodonts and fusulinids are abundant there in Lopingian strata[45,82]. Hence, a cool- or cold-water and a warm-temperate environment are preferred, respectively, for the Chihsian and Maokouan deposits on the northeastern part (Table 1). The pattern of deposits of Early Permian age on the block suggests that a warm-water environment first invaded the northwestern part of the block, and then migrated northeastward. Such a retreat pattern means the temperature zonations on the block during the Early Permian intersected with the north margin and favors the first fit.

Figure 2 shows the Chihsian paleogeography of Tethys, emphasizing on the blocks of eastern Tethys. For reconstructions related to the blocks of South China, the reader is referred to works by Yin et al (1995, 1999)[5,14]. It should be pointed out that the map is not a standard projection and is highly schematic, especially with respect to the size and outline of the blocks. Nonetheless, the resulting land-sea configuration of eastern Tethys exhibits the archipelagic pattern of Yin (1998)[4-6].

5. CONCLUSIONS In summary, we delineate blocks in eastern Tethys and present a brief review on the temporal and spatial distributions of lithic paleoclimatic indicators in the region during the Permian and Triassic periods. Permo-Triassic paleoclimates in the region show considerable

12

change. Apart from the Early Permian climatic amelioration on the peri-Gondwana blocks, remarkable climatic change occurred at the Permian/Triassic boundary and the Middle and Late Triassic boundary. And the climatic regime in the Permian and possibly in the Late Triassic was of zonal circulation, which ensures paleoclimatic constraints on the positioning o f the blocks. Paleolatitudinal information inferred from changing paleoclimatic patterns is consistent with biogeographic and tectonic data in the region, and is of particular significance for blocks without reliable paleomagnetic data. As far as paleoclimatic evidence is concerned, the Qiangtang and Sibumasu blocks were located in the southern margin of the southern subtropical zone, and the Changning-Menglian ocean spanned the whole southern subtropical zone with a width about 10 degrees in latitude in the Chihsian Subepoch. The resulting paleogeography of the Chihsian epoch is that of an archipelagic pattern. It is also noted that Monodiexodina, a typical element of Permian mixed fauna, appeared in warm-water deposits.

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Persian-TriassicEvolution of Tethys and WesternCircum-Pacific H. Yin, J.M. Dickins, G.R. Shi and J. Tong(Editors) e 2000 ElsevierScienceB.V. All rightsreserved.

Permian of the Russia and CIS and its interregional correlation G. V. KOTLYAR All-Russian Research Geological Institute (VSEGEI), Sredny pr., 74, St. Petersburg, 199106, Russia

Significant progress has been attained in the studies of the Upper Permian in the stratotype of the Permian System. The results of the studies conducted by many geologists and paleontologists on the Permian deposits in different regions of Russia and the CIS are generalized. The status of the traditional East-European (Biarmian) stratigraphic scale and the auxiliary regional Tethyan (near-equatorial) scale is reviewed in the light of the latest evidence. The latter scale has been widely used for subdividing the Permian deposits in the southern regions of Russia and the CIS. The advantages and disadvantages of each of the scales are considered. The boundaries of the Permian System and its series and stages of the East-European and Tethyan scales are analysed, their relationships and the possibilities of tracing are demonstrated. Correlation of the reference Permian sections in Biarmian and Tethyan realms is presented. Permian, stratigraphy, stage, zone, correlation.

1. Introduction The separation of Permian marine basins, endemism of faunas, an abrupt climatic zonation, widespread lagoonal and continental deposits complicate markedly interregional and transcontinental correlation and give rise to difficulties in the use of a global international standard. Permian deposits in Russia and the CIS are represented by diverse facies and formations of marine and continental basins. The main Permian paleogeographic elements within Russia and the CIS consist of two major realms with a predominantly marine sedimentary regime - the Biarmian and Tethyan, and a continental one - Angarida, separating them [ 1] (fig. 1). Significant differences in the composition of faunal communities in the Biarmian and Tethyan realms has resulted in the complicated use of two parallel scales - the traditional East-European (Biarmian) and Tethyan (near-equatorial) in Russia and the CIS. However, comprehensive use of the sequence-stratigraphy, lithofacies, biozonal and paleomagnetic methods reveals a number of extensively traced restructuring boundaries, dated reference levels, and transit (mixed) faunal assemblages permitting reliable correlations.

17

18

c~Tll

l.

J, O]]II]].

Iilrl

Ill, till! Ill

,,

41111

!14:: ~, lll,~'

I-r J ,w

iSnga

Y $

s

s

i J

AJ

Z7

Fig. 1. Zonation of Russia and the CIS in the Permian (outlines of paleobasins are also shown for contiguous areas). Land and sea distribution corresponds to the maximum of the Late Permian transgression. 1 - Land; 2 - Sea. Provinces" 1 - East-European, 2 - Pechora, 3 - Novaya Zemlya, 4 Taimyr-Khatanga, 5 - Verkhoyanye-Okhotsk, 6 - Kolyma-Omolon, 7 - Transbaikal, 8 Centre-Siberian, 9 - Altai-Sayan, 10 - Transcaucasus, 11 - Central Asia, 12 - Far East.

2. Permian of the Biarmian Realm The traditional scale of the Biarmian Realm, based on sections of the eastern part of the Russian Platform and Urals, is subdivided into two series, seven stages and 17 assemblage zones (fig. 2). Its lower boundary is drawn at the base of the conodont Streptognathodus isolatus Zone of the Asselian [2]. The upper boundary of the Permian System in the type area is placed in continental facies at the top of the Tatarian. However, there is a stratigraphic break of unclear extent in the stratotype at this level. Some researchers using paleomagnetic evidence believe that the Tatarian corresponds, at least, to four stages of the Tethyan scale including part of the Dorashamian (Changhsingian), and it should be subdivided into three independent stages [3]. According to another viewpoint, based on studies of tetrapods and event boundaries associated with eustasy, the Tatarian corresponds to the Midian, Dzhulfian and the lower part of the Dorashamian. The Vokhminsky Horizon of the Lower Triassic in Eastern Europe corresponds to the upper part of the Changhsingian [4].

19

E a s t - E u r o p e a n scale Zone d. o

[..

Suchonellina fragiloides Suchonellina futschiki

~6

o

Regional scheme

Conodonts

Vyatsky Severodvinsky it.,.

Darwinula fragilis

9IlK . 8 4

U rzhum sky 9 -I.:

_

Nemdinsky Darwinula fainae

Povolzhsky

b

Sheshm insky Darwinula

angusta

Solikam sky A c r a t i a sim ilaris Paraparchites humerosus Bairdia reussiana Parafusulina lutugini Parafusulina solidissima Pseudofusulina concavutas Pseudofusulina urdalensis Pseudofusulina verneuli Pseudofusulina m oelleri Schwagerina sphaerica P seudofusulina firm a Schwagerina m oelleri Pseudofusulina fecunda Schwagerina vulgaris Schwagerina fusiforms

----I~ b

Irensky Neostreptognathodus pnevi

Filippovsky Saraninsky Sarginsky

N. p e q u o p e n s i s

Irginsky Sweetognathus

whitei

S. p r i m us

Burtsevsky Sterlitam aksky

M. la ta

Tastubsky M. u r a l e n s i s Streptognathodus postfusus

Shikhansky

1 Streptognathodus S. c o n s t r i c t u s

L

fusus

o

S. c r i s t e l l a r i s o

S. i s o l a t u s

Fig. 2. Permian East-European traditional scale.

3~"T"

~

20

LEGEND

Litholol~ic S ~ m b o l s

~~]

Limestone

~

Siltstone

Marl

~

Sandstone Conglomerate, Gravelstone

Reef

[~]

Dolomite

~

Volcanic Rocks

Evaporite

~

Tuffs

Clay, Shale

I"~'i~'~''l T i l l o i d

Special Symbols m

Sulphate - Carbonate

Coal Phosphate Glauconite Redbeds

Palaeontological Symbols 9

Foraminifers Fusulinids R u g o s e coral ;~ Bryozoan 9~ , B r a c h i o p o d s ]~y B i v a l v e s

~ ~ ~=~ ,.)~ ~ ~,

Ammonoids Fillopods Ostracods Tetrapods Conodonts Fishes

~. .'~ 9/~ ,t~ ~ ~

Conularia Insects Algae Stromatolites Macroflora Miospores

It is very difficult to agree with the first viewpoint because the paleomagnetic evidence indicates that the Tatarian Stage corresponds to a little more than two stages of the Tethyan scale [3]. The second viewpoint is rather interesting and requires additional consideration. Nevertheless, without doubt the Tatarian requires subdivision, which has been repeatedly mentioned [5, 6]. Furthermore, the lower boundary of the Triassic is drawn now at the base of the Otoceras woodwardi Zone of marine sections and the synchroneity of this level has not been demonstrated. The boundary between the two series of the East-European scale is drawn at the base of the Ufimian or the Solikamsky Horizon. However, there are serious evidences that confirm the assignment of the latter to the Kungurian. Recent finding of the Kungurian ammonoids Epijuresanites vaigachensis Bogoslovskaya and Epijuresanites sp. nov. in the equivalent of the Solikamsk Horizon in the Lekvorkutskaya suite of the Pechora basin and in the Tabjuskaya suite of the Pai-Khoy [7, 8], confirm a Kungurian age of these deposits. The representative Kungurian genus Tumaroceras is known from the uppermost part of the Tumarinsky Horizon in Verkhoyanye (Table 1), which is overlain by the Delenzhinsky Horizon with the Roadian ammonoid assemblage (Daubichites, Sverdrupites, Pseudosverdrupites ) [9]. Thus, it is necessary to assign the Solikamsky Horizon to the Kungurian. Stages of the East-European scale above the Artinskian, established exclusively on a lithological basis, do not conform to modern international requirements, and call for

21 improvement and definition of the lower boundaries. The first step in this direction has already been made. The lower boundary of the Kungurian has been lowered to the base of the Saraninsky Horizon and been made coincident with the base of the Neostreptognathodus pnevi conodont zone. This enables a reliable definition of the lower boundary of the stage and retains it as a standard unit, because the lower boundary of the N. pnevi Zone can be traced in all the realms. The Upper Permian stages established in the Volga and Kama area are composed of alternating continental, lagoonal and marine deposits that do not fully conform to the international requirements and cannot claim to be the global standard. Abrupt changes in the character of sedimentation at their boundaries interfere with the reconstruction of successive evolutionary changes in faunal groups, which rules out the possibility of providing reliable definition and tracing the boundaries. Detailed study and subdivision of the most complete, paleontologically well-defined Biarmian sequences will doubtless promote the improvement of the East-European scale, and aidsin the definition of the stage boundaries and retention of nomenclature of the Upper Permian stages. Such sequences are primarily the sequences of the Kolyma-Omolon Subrealm. The regional scale of this subrealm is based on a series of deposits of different facies of the continental slope, in piedmont, shelf to island [ 10]. The scale reflects the geological history of the Permian basins. Redeterming boundaries of different orders, revealed on the basis of synthesising sedimentological and paleontological evidence, were the basis for the distinguished units. The Permian System in this scale is subdivided into two series, five regional horizons and sixteen assemblage zones (figs. 3, 4). Integration of geological, sequence-stratigraphical and event- stratigraphical data enable the recognition of a number of reference correlation levels in this scale, associated with major biotic changes and resulting from eustatic sea level fluctuation. Thus, the Munugudzhaksky/Dzhigdalinsky Horizon boundary is rather well traced within the entire Biarmian Realm and is characterized by essential biotic changes [ 11, 12]. In the type area of the Permian System it corresponds to the second half of the Artinskian and is characterized by the Middle Artinskian event [ 13]. The very important Dzhigdalinsky/Omolonsky boundary is characterized by appearance of the Roadian ammonoid assemblage and is recognized within the entire Biarmian realm from Verkhoyanye to Novaya Zemlya. In the latter region it is drawn between the Belushinskaya and Kocherginskaya formations (Table 1). In Western Verkhoyanye this level is established between the Tumarinsky and Delenzhinsky Horizons [ 11, 14]. The deposits with Daubichites and Sverdrupites formed under a clearly expressed transgressive environment (fig. 5). The comprehensive analysis of the Middle Permian event that was repeatedly characterized enable the tracing this level on a global scale (Table 1). In the East-European scale this level corresponds to the Solikamsky/Sheshminsky Horizons of the Ufimian [9, 10, 11 ]. This level is the most natural boundary of two series in traditional scale. Conodonts have been found within the well-studied Kazanian Stage [ 15], which allow correlation of the Kazanian with the Wordian of Texas. The Tatarian is currently adeqately studied and subdivided into zones based on freshwater ostracods, bivalves, vertebrates [4, 16]. Detailed fish faunal assemblages have been recognized [16]. Macroflora and miospores have been also studied in detail [16, 17].

22

Horizon

Zone

Khivachsky

S. p a r a c u r v a t a

Gizhiginsky

C. obrustschewi

Lithology Biota ~ . . . . ~ . "_' " ~

c rvo,

-~.,,

-

-

1

M a g a d a n i a bajkurica

_t__.__~._ =~--L-..-r;

Terrakea korkodonensis ~

Omolonsky

Terrakea borealis

~

Omolonia snjatkovi

_~

M o n g o l o s i a russiensis

C2)

.0

l i.

!

~ I

I

I

A

Kolymaella ogonerensis i--.-- . - ~ ~ -

-

~

! '~g

.

o ,..~

~

Megousia kuliki

s

_

Anidanthus aagardi

~

.

i

9 !

Jakutoproductus

i

burgalensis

"~a ~ * t o l

Jakutoproductus rugosus Jakutoproductus terechovi

" ." ." ." . . -.~. ."... ~ d_ ~ - J ~

9

~

~

"D

~)

~3

Jakutoproductus verchoyanicus

" ~" ~" ~" " . - -

Jakutoproductus expositus

~. ~. ~. ~ ~. "_ ", : " . ~ _ _

9

"~

,

~

o

~

~

~

~

Fig. 3. Regional stratigraphic scale of the Kolyma-Omolon Province. The paleomagnetic data is also very important [ 16, 18]. Synthesis of recent evidence creates the prerequisites not only for detailed remote interregional correlations, but also for correlations with Gondwana and even Tethys sequences [4]. The available data indicate the necessity in dividing the Tatarian into a number of stage subdivisions as has been implied earlier [5]. A fundamental change of biota at the base of the Severodvinsky Horizon of the Tatarian has been repeatedly recorded. This level is also associated with the Kiaman/Illawarra paleomagnetic boundary. This is one of the most important geomagnetic marks that enable an intercontinental correlation.

23

u~ ~D

o

Foraminifer Zone

o

'~, ~ ,~ Brachiopod Zone mN~, I

I

Bivalve Zone

Ammonoids

l

l

I

.=- ~ ..~ jo ~

Stepanoviella paracurvata

Intomodesma costatum

Frondicularia maxima

Maitaia tenkensis Cancrinelloides curvatus

c...) ,~

=

Maitaia bella

'-- - ,-'~ Cancrinelloides obrutschewi

= ~~ ,-

r.~

|~

o

Frondicularia planilata

'

= Terrakea borealis o Omolonia snjatkovi Mongolosia russie nsis Kolymaella ogonerensis ,

i-.

9

m - i

,~ ~ ~ ~ "~ ,.~

i~ ".= , o 1 =~ ~, ~ .

Kolymia plicata

,

Anidanthus aagardi Jakutoproductus burgalensis ' Jakutoproductus rugosus Jakutoproductus terechovi Jakutoproductus verchoyanicus Jakutoproductus . expositus I

Kolymia multiformis

Frondicularia elongata

Kolymia inoceramiformis Frondicularia gane l inae

Aphanaia dilatata

Frondicularia . Aphanaia andrianovi prima

Megousia kuliki

e~o

9 .

Merismopteria permiana

Magadania bajkurica Terrakea korkodonensis

..~

=

Glyptoleda borealica

Frondicularia co mposi ta

Frondicularia zavodovskyi I

Sverdrupites harkeri

Epij'uresanites musalitini

Aphanaia lima I

I

Edmondia nebrascensis Protonodosaria and small Frondicularia .

Tolypammina confusa and small Protonodosaria

"~

Neoshumardites triceps Paleoneilo parencia

Fig. 4. Zonation scheme of the Permian of the Kolyma-Omolon Province.

I

24

Table 1 Correlation chart of the Permian reference sections in the Biarmian Realm. Chronostmti graphic Scale (36)

Pechora Province Novaya Zemlya Province East-European Scale ' Karskaya Severo- 1 BarentsovKarskaya Zona Pechorsk Zona skaya Zona , Zona ' ' 1 Valentinov~ Vyatsky ,,-" Shadrovskaya !m-./.," skaya ~9 ~ Severodvinsky ~ .,," NeogeoSavinskaya !.~. , i

,

I

/

./

./

/

=~

!

Urzhumsky

ceras

Silovskaya

,

E

,.-.-.l

~ ~

,

Nemdinsky . Povolzhsky

,~.~

.

Gerkinskaya

Erjagin. Seidinskaya skaya

Sheshminsky

O

~inozemel Sverdrupites skaya Kocherginskaya Sverdrupites

Tabjuskaya

Solikamsky

g

=

Irensky

'g

Filippovsky

Epijuresa - ~~~, nites

i~

T~k~ro-

i~0

r.~

Liurjagin-

9

~5 = =

i

Sar~nsky ~rginsky

e .-~e< i


species

'

~.

Conodonts

~

;U,LUr:

'

;

LU

U

'

~o

i

.,.,.

Distinctive

Fusulinid

_9 r

~

u..

I

==

S

[

~

o

'3C is0t.

04

-~m',~

| -

I

z.~

~

2

~

sf

....

04

~

i we~

267

< 500 9t~- t3. 0 . 0-780

60-975 500 110

IN E

~ Dardan Massif

210

0 t,,.

2oo Km !

C S

-

R

"-'

E

700

9

Fig. 9. Schematic Permian successions of selected areas of Bulgaria. Vertical distances not time- or thickness-related. On the inset maps: above, Bulgaria in the Balkan geographic context; below, morphotectonic subdivision of the country, according to Bonchev [77]. Symbols as in Fig. 8; small squares: halite; black points: palynomorph assemblages.

through a marked angular unconformity (up to 90 ~ locally), the already mentioned Upper Permian red sandy unit of the Moesian platform, lacking in volcanics, follows upwards. Triassic Buntsandstein occurs unconformably at the top. In the Kraishte region, i.e. in southwestern Bulgaria, there are locally some uppermost Carboniferous ?-Lower Permian clastic sediments. In contrast, the Upper Permian red cycle of the other country sectors shows wider development. In southeastern Bulgaria, Permian rocks are notably rare, only occurring in two places, exactly in Strandzha and in the eastern part of the Rodope massif, where they consist of shallow-marine carbonate sediments. These outcrops are attested by the discovery of some algae (Mizzia velebitiana, Epimastopora piae, etc.) in the former region (Kondolovo), and of foraminifers (Agathammina pusilla, Neoendothyra parva, Colaniella, etc.), which occur within silicified carbonate rock-fragments reworked into an Upper Jurassic-Lower Cretaceous terrigenous olistostrome, in the latter region (near Dolno Lukovo). However, the outcrops in question are generally interpreted as a result of tectonic transport from southern sectors, and specifically the Strandzha deposits still promote dating controversy.

4. T H E S O U T H E R N M O S T

MARINE SECTOR

4.1 B a s i l i c a t a

In the Southern Apennines, Fusulina limestones occur as reworked pebbles within the Lower-Middle Triassic Monte Facito Formation of the Lagonegro basin [79]. The fusulinids

57 in these clastics belong to the Neoschwagerina craticulifera and Neoschwagerina margaritae subzones respectively of the Middle and Upper Murgabian [80]. Elements lacking fusulinids, but showing small foraminifera of the Midian-Dorashamian ages, have also been recognized [81 ]. The fusulinid and foraminifer associations are similar to those of the Sosio succession in Sicily [82]. These reworked Permian limestones are considered to be possible remnants of the Northern margin of the Permian basin in Sicily.

4.2 Sicily Along the Maghrebian chain, Permian deposits consisting of mostly deep-water siliciclastic and clastic-carbonate rocks, have been identified in the Lercara-Roccapalumba area and in the Sosio Valley of central-western Sicily (Fig. 10- A). The age of these deposits spans from the late Artinskian up to latest Permian. They occur as "broken formations" in strongly deformed allochthonous complexes, which also show tectonic slices of Fusulina limestones, first described by Gemmellaro [83], and of Triassic deep-water rocks. These Permian-Triassic unit, known as Lercara Formation [84], are considered to be remnants of a basin fill in a wide deep-water domain (Sicanian basin) that extended along the Gondwanian margin (Fig. 10 C). As a consequence of the Neogene accretion of the Maghrebian chain, the Permian-Triassic rocks were sheared off either from their substrate or from the overlying sedimentary successions. This shearing initiated the floor thrust complexes that lie at the base of major basin-derived thrusts of Mesocenozoic rocks (Sicanian units). The Sicanian thrust pile is in turn overthrust on more external Mesocenozoic platform units that are southward connected to the foreland areas of the Hyblean plateau and the Pelagian Block (Fig.10 A). The Neogene thrusting obscured stratigraphic relations, so that only a composite stratigraphic column of the Permian succession can be restored (Fig. 10 B). The column is based on a large dataset collected in the last decade from the Lercara and Sosio allochthonous complexes [85, 82, 6]. The oldest unit is exposed in the Lercara area, and consists of a thick package of siliciclastic turbidites, known as Kungurian flysch [85]. They are characterized by reddish and greenish shales, siltstones and sandstones displaying Bouma divisions, flute casts and Nereites ichnofacies. Metamorphic and volcanogenic grains in the sandstones, along with abundant quartz and micas, suggest siliciclastics in the Kabilo-Calabride domain as the origin of these turbidites. Conodonts from the pelitic interbeds support the hypothesis that these rocks are late Artinskian-Kungurian in age [85]. Calcareous turbidites and debrites are also occasionally interbedded. Microfacies analyses suggest derivation from the disruption of an early Permian carbonate platform [86]. The finergrained beds are skeletal-lithoclastic grainstones/packstones with fusulinids, Tubiphytes sp., Archaeolithoporella sp., calcareous algae (Mizzia sp., Epimastopora sp., Pseudovermiporella sp.) and sponge fragments. The debrite beds consist of clast-supported, angular pebbles and of boulders of sponge/Tubiphytes boundstones, Tubiphytes/Archaeolithoporella bindstones, phylloid algae boundstones, Mizzia - fusulinid grainstones-packstones, and crinoidal packstones. On the basis of algal assemblages and fusulinids as Pseudofusulina (Leeina) kraffti Schellwien and P. vulgaris Schellwien [82], these elements are probably Lower Permian in age. Diabasic intrusions in the Kungurian flysch are common [87]. Radiometric dating for these magmatic rocks, which have a tholeitic affinity, is not available. However, structural and

58

Fig. 10 - A) Mediterranean area, and index map of the Permian outcrops from the southern Apennines, Sicily and Tunisia. B) Composite columnar section of the Permian deep-water succession from Sicily, restored from the allochthonous Permotriassic complexes from the Lercara area and the Sosio Valley. C) Paleogeographic sketch showing the western termination of the Permian Tethys [85, modified]. Tu siliciclastic/carbonate platform deposits in Tunisia, transitional to deeper-water shales. SI = deep-water siliciclastic and elastic-carbonate deposits in Sicily (Sicanian basin). LA -- shallow-water Middle and Upper Permian Fusulina limestones of the Lagonegro domain in Southern Apennines and possible prolongation in the Imerese domain in Sicily (IM).

59 textural characters recently observed along their contact with the turbidites suggest an intrusion in soft sediments, and thus an Early Permian age [88]. Younger Permian rock packages are exposed in the Sosio complex, outcropping along the Torrente San Calogero near Palazzo Adriano. This complex consists of tectonic slices of Middle and Upper Permian siliciclastic rocks, Fusulina-bearing limestones, Wordian ammonitic limestones, but also middle and Upper Triassic radiolarites, nodular limestones and Halobia limestones and marls [85]. The oldest Permian unit recognized in this area is represented by siliciclastic turbidites, named San Calogero flysch [6]. It consists of grey-to-blackish pyritic shales and siltstones, with intercalations of micaceous sandstones and hybrid arenites. Owing to the thrust tectonics, it outcrops as a chaotic clayey mass containing sandstone blocks. On the basis of conodonts, the age of this unit is lowermost Middle Permian [89]. Scattered elements of dark grey calcilutites with circumpacific radiolarians of early Kungurian age, and of shallowmarine limestones, suggest that these deposits could have been affected by synsedimentary sliding and reworking (Olistostrome unit) [85]. Stratigraphically younger deposits are found in a small limestone block known as Rupe del Passo di Burgio. They consist of white ammonoid-bearing calcilutites and reworked skeletal calcarenites that are interpreted as hemipelagic carbonates deposited in a distal slope setting. The hypothesis that these deposits, named Rupe del Passo di Burgio limestones, are Wordian in age is supported by rich fossil association, which is characterized by fusulinids, ammonoids, ostracods, crinoid ossicles, holoturian sclerites and conodonts [83, 90, 85, 91]. Varying Wordian deposits, consisting of yellow-to-grey clays with Mesogondolella siciliensis (Kozur), are found in a small outcrop close to the Rupe del Passo di Burgio [85]. Upper Permian limestones are exposed in the Pietra di Salomone, the most famous and fossil-rich limestone block in the Sosio Valley (about 200 m long and 100 m wide), but also in two smaller blocks, known as Pietra dei Saracini and Rupe di San Calogero. Since Gemmellaro's careful descriptions [83], many paleontological studies have been carried out on these deposits, which were regarded as reef limestones. Recent sedimentological and stratigraphic contributions [82] indicate that the Pietra di Salomone limestones are composed of poorly defined beds of coarse calcareous breccias that grade upward to fine-grained calcareous turbidites. The breccia elements consist of platformslope derived carbonates that span in age from Artinskian to Djulfian. Reef-derived boundstones/rudstones prevail, but floatstones and grainstones are also commonly observed. Sponges, Tubiphytes, Archaeolithoporella, phylloid algae, richthofenid brachiopods are the main framebuilding organisms, and are associated with highly-diverse, fusulinid- comprising assemblages. The Neoschwagerina, Yabeina and Reichelina Zones are represented [82]. The presence of rare conodonts of Late Permian age (H. Kozur, pers. comm.) and of Reichelina sp. in the matrix, suggest that the Pietra di Salomone limestone is Late Permian in age. These limestones, which reach a thickness of about 70 m, consist of debris flow and turbidite sediments deposited in a base-of-slope position. They were probably interlayered with the youngest Permian deposits yet to be recognized in the Sosio complex, which consists of Late Permian red clay and turbidites. The red clays of this last unit contain abundant circumpacific radiolarians, paleopsychrospheric ostracods and conodonts of Late Permian (Djulfian to Changxingian) ages [85, 92, 93]. Fine-grained siliciclastic and carbonate turbidites are commonly interbedded to the red clays. The calcareous turbidites are mostly skeletal

60 grainstones/packstones, with abundant Reichelina simplex Sheng, Archaeolithoporella/ Tubiphytes fragments and conodonts. On the basis of the stated lithostratigraphic units, the restored Permian succession from Sicily (Fig. 10 B), indicates a sediment-gravity filling of a deep-water basin, and that the infill persisted throughout the latest Artinskian up to the latest Permian. Siliciclastic turbidites were supplied by the Kabilo-Calabride Hercynian domain, while the abundant intra- and extrabasinal shallow-marine carbonate-clastics were repeatedly transported from adjacent carbonate shelves. The deep-water sedimentation in this basin persisted throughout the Mesozoic. 4.3. Tunisia Permian deposits are well documented in the Jeffara basin [94], a strongly subsiding basin that is related to a wide rift zone, which in turn extends as far as the North Syria [95]. Up to 6 km thick, the basin contains Middle and Upper Permian terrigenous-carbonate platform successions that were deposited with an upward regressive trend [96]. On the basis of wells and outcrop sections in the Tebaga area, and of wells in the Bir Soltane and Djeffara areas, facies distribution shows that the Permian platform deposits grade northwards into deeperwater shales and a reef belt [97]. These deposits cover unconformably either occasionally preserved Lower Permian shallow-water limestones, shales and sandstones, or older rocks. This unconformity indicates a mid-Permian uplift and erosion in the Jeffara basin. The Permian of Tunisia is considered to be the southern margin of the deep-water basin along the Gondwanian margin [85].

4.4. Greece In this country, Permian is represented by sparse and small exposures of generally marine deposits. Occurrences of Permian rocks have been recognized both in continental and insular areas. However, because the strong Alpine deformation does not generally allow suitable stratigraphic reconstruction, only a selection of the more representative sections will be described here. In the island of Hydra, the Permian succession, which consists mainly of carbonate platform sediments altemating with shales (Fig. 11), can be subdivided into four "Groups" separated from each other by tectono-sedimentary events [98]. On the basis of fossil data (foraminifers and algae), these events occurred: 1) in the late Asselian (onset of a first carbonate platform); 2) in the ?late Artinskian (uplift or tilting of the above platform with consequent erosion); 3) between the late Murgabian and probably the late Midian (as with the previous "Group", a palaeotectonic event affected a successor platform); 4) in the lower Dorashamian (deformation and erosion of a third platform, with a subsequent terrigenous influx). The presence of a gap at about the Lower/Upper Permian transition, and the intensity of tectonic activity during the Early Triassic, with consequent Permian olistoliths, are also worthy of attention. Among the above-mentioned events, the first generally seems to coincide with the inception of the younger Permian cycle in the Southem Alps and in other European regions, as well as with the formation of flysch-like deposits and olistostromes in western Sicily. The fourth tectonosedimentary event of Hydra can be related to environmental changes associated with important eustatic movements, as observed elsewhere [98]. This interpretation could be extended to the similar scenarios in Basilicata, Sicily, Montenegro, and the northern Julian Alps. Lower and Upper Permian shallow-marine blocks

61

Fig. 11. Synthetic Permian stratigraphic section of Hydra Island, Greece, with the distribution of the main Foraminifera. A - D: tectono-sedimentary events (see tex0. Atter Baud et a1.[98] slightly modified.

62 and olistoliths reworked into Lower-Middle Triassic sandy-shaly volcaniclastic successions also occur in Attica, north of Athens. On the island of Lesvos, near Turkey, Permian fusulinids and brachiopods have been found in intensively tectonized marbles and schists. In Chios the allochthonous unit of the northeast part of the island includes flysch-like deposits beneath carbonate platform sediments [99]; micropaleontological investigation has suggested that these sediments are correlatable with those of the Murgabian middle platform of Hydra [98]. The autochthonous sequence of Chios also consists of a flyschoid unit; as the youngest clasts in this unit pertain to the Upper Carboniferous [ 100] and since it is overlain by Lower Triassic deposits, this unit is generally ascribed to the Permian [99]. The Andros island also includes schists with intercalations of marbles that bear Early-?Late Permian fossils [ 101 ]. In Salamis and Crete, deep-water sediments also crop out. The fact that these outcrops occur from western Sicily to other more eastern areas of the Permian Tethys, and even as far as Japan, carries important palaeogeographic implications.

5. CONCLUDING REMARKS During the Permian, the Southern European regions examined in this paper are occupied by continental and marine domains. The former prevail to the west (Spain, Southern France, part of Southern Alps, etc.) and, generally, in the eastern Balkan areas, while the latter characterize Sicily, Greece, part of the Dinarids and the Carnic Alps. The continental realm is dominated by siliciclastic and igneous deposits. Diachronously emplaced in a "swell-and-basin" topography, these deposits resulted from a subsequent structural reorganization of the area affected by the Variscan orogeny. This reorganization clearly began during the Namurian and persisted up to the Late Permian and Triassic times. The igneous products formed intrusive and extrusive, locally widespread bodies. In Provence, Corsica, Pyrenees and elsewhere, this magmatic activity generally evolved from a calcalkaline acidic and basic suite to another one of alkaline bimodal composition, which developed in post-Autunian times, i. e. in the Early Permian p.p. and Late Permian. These latter magmatic activity is considered by the French authors to mark the beginning of the Alpine cycle. The Permian successions display unconformities of various types, duration and importance. In the Southern Alps, the stratigraphic discontinuity widely recorded below the Verrucano Val Gardena redbeds led us to subdivide the Upper Carboniferous-Upper Permian succession into two high-rank tectono-sedimentary cycles. The succession of the former cycle (lower or 1st cycle) infilled a number of narrow fault-bounded basins; the succession of the latter cycle (upper or 2 nd cycle) extended as an almost continuous blanket from Lombardy to the Camic Alps and Slovenia. Recent investigations [26, 30] assume that subsidence within mobile Lower Permian basins (locally slightly younger, even up to the onset of Late Permian) was mainly controlled by a progressive thinning in the Variscan crust and by strike-slip tectonics. In contrast, the deposition of the Verrucano/Val Gardena Fms. was the result both of a marked extensional tectonics and, probably, of a rifting regime. In the latter, subsidence evolved from tectonic- to thermal control, although local tectonics started at the end of Lower Triassic. The contrasting depositional geometries of the first and second cycle reflect this difference in tectonic regime.

63 The above-mentioned "Mid-Permian" regional unconformity has also been recognized in the Ligurian Alps, Spain, and Bulgaria. As a consequence, we emphasise that this bipartition is probably a widespread feature of the Permian successions in large parts of Europe, although they should not be considered as necessarly coeval. Undoubtedly, the significance of these changes can be interpreted as a crucial point in the geodynamic evolution of central Mediterranean and adjoining areas. As already stated, the Permian marine realm of South-Europe consists of evaporitic to shallow- and deep-water sediments. They were linked to the Tethys, but the Upper Permian (?) sabka deposits discovered in the Moesian Platform of Bulgaria and Romania could be also ascribed to the influence of a separated northern sea ("PalaeoTethys" sensu Seng6r) [102]. The presence of unconformities in the Tethyan areas is sometimes uncertain because of the lateral discontinuity in outcrops, erosion, Alpine deformation, and of the lack of detailed research. However, in some regions described (Greece, etc.), unconformities and gaps may be inferred from the Carboniferous to Triassic successions. The most representative events generally coincide with those yet again connected approximately with the Early/Late Permian tectonics, as well as with those recorded at or near the P/T boundary, as in the Southern Apennines, Greece, and other areas [80, 32, etc.].

Acknowledgements This paper represents a contribution to the IGCP Project No.359: "Tethyan, Circum-Pacific and marginal Gondwanian Late Paleozoic and Early Mesozoic correlation (biota, facies, formations, geochemistry and events)", to the activity of the "Continental Permian Working Group (S.P.S.)", as well as to the new Italian research programme on the "Late Palaeozoic stratigraphic and structural evolution in Alpine and Apenninic sectors. Comparisons with Sardinia and other areas of the Western Mediterranean". G. Cassinis and coauthors express cordial appreciation to Yin Hongfu for his invitation and help in preparing this summary. They also thank A. Ronchi and G. Santi for their assistance with the drawings. This work was supported by grants from C.N.R. and M.U.S.T. (40%, 60%).

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69 82. E. Fliigel, P. Di Stefano and B. Senowbari-Daryan: Microfacies and depositional structure of allochthonous carbonate base-of-slope deposits: the Late Permian Pietra di Salomone Megablock, Sosio Valley (Western Sicily). Facies, 25, 147-186, 1991. 83. G.G. Gemmellaro: La fauna dei calcari con Fusulina della Valle del flume Sosio nella provincia di Palermo. Fasc. 1. Cephalopoda; Ammonoidea. Giom. Sci. Natur. Econ., 19, 1106, Palermo; ibid., 1888, Ammonoidea, 20, 1-26; ibid., 1889, Cephalopoda, Nautiloidea, Gastropoda, 20, 97-182; ibid., 1898/99, Molluscoidea, 22, 231-238, 1887-1899. 84. P. Schmidt di Friedberg: Litostratigrafia petrolifera della Sicilia. Riv. Min. Sicil., 88-90, 198-215, 1964-65. 85. R. Catalano, P. Di Stefano and H. Kozur: Permian circumpacific deep-water faunas from the western Tethys (Sicily, Italy) - New evidences for the position of the Permian Tethys. Palaeogeogr., Palaeoclimat., Palaeoecol., 87, 75-108, 1991. 86. B. Senowbari-Daryan and P. Di Stefano: Microfacies and sphinctozoan assemblages of some Lower Permian breccias from the Lercara Formation (Sicily). Riv. Ital. Paleont. Stratigr., 94, 3-34, 1988. 87. P. Broquet: l~tude g6ologique de la region des Madonies (Sicile). Thesis Univ. Lille, 797 pp., 1968. 88. P. Censi, S. Chiavetta, P. Ferla, S. Speziale and P. Di Stefano: Magmatiti tholeitiche presenti nei depositi terrigeni del Permiano inferiore di Lercara (Sicilia Occidentale). Atti 79 ~ Cong. Soc. Geol. Ital., abstr, vol. A, 288-291, 1998. 89. M. Gullo: Studi stratigrafici sul Permiano ed il Trias pelagico della Sicilia occidentale. Ph.D. thesis Univ. Palermo, 203 pp., 1993. 90. H. Bender and D. Stoppel: Perm-Conodonten. Geol. Jb., 82, 331-364, 1965. 91. H. Kozur: Permian deep-water ostracods from Sicily (Italy). Part 1: Taxonomy. Geol. Pal/iont. Mitt. Innsbruck, 3, 1-24, 1991. 92. M. Gullo and H. Kozur: Conodonts from the pelagic deep-water Permian of central Western Sicily (Italy). N. Jb. Geol. Pal/iont. Abh., 184, 203-234, 1992. 93. H. Kozur: Upper Permian radiolarians from the Sosio Valley area, western Sicily (Italy) and from the uppermost Lamar Limestone of west Texas. Jb. Geol. B.-A., 136, 99-123, 1993. 94. A. M'Rabet, S. Razgallah, M. Dridi and M.C. Chaouachi: Upper Permian reefs and associated siliciclastics at Jebel Tebaga, Southern Tunisia. Field Trip Guidebook of the 17th IAS Re, 1996. 95. A. Baud, J. Marcoux, R. Giraud, L.E. Ricou and M. Gaetani: Late Murghabian (266-264 Ma). In J. Dercourt et al. (eds.), Atlas Tethys Paleonvironmental maps. Explanatory Notes, Gauthier Villars, Paris, 9-20, 1993. 96. P.F. Burollet, J.M. Mugniot, and P. Sweeney: The geology of the Pelagian block: the margins and basins of southern Tunisia and Tripolitania. In A.E.M. Nairn and W.H. Kaines (eds.), The ocean basins and margins, 331-359, 1978. 97. D.F. Toomey: Late Permian reefs of southern Tunisia: facies patterns and comparison with the Capitan Reef, southwestern United States. Facies, 25, 119-146, 1991. 98. A. Baud, C. Jenny, D. Papanikolaou, Ch. Sideris and G. Stampfli: New observations on Permian stratigraphy in Greece and geodynamic interpretation. Bull. Geol. Soc. Greece, 24, 187-206, 1991. 99. D.J. Papanikolaou and Ch. Sideris: Contribution to the Paleozoic of the Aegean area. Rend. Soc. Geol. Ital., 12 (1989), 349-358, 1990.

70 100. H. Besenecker, S. Diirr, G. Herget, V. Jacobshagen, G. Kauffmann, G. Ludtke, W. Roth and K.W. Tietze: Geologie von Chios (,~g/iis). Ein. (]berblick. Geol. Paleont., Marbourg, 2, 121-150, 1968. 101. D.J. Papanikolau: Contribution to the geology of the Aegean Sea: the island of Andros. Ann. G6ol. Pays Hell6n., 29, 477-553, 1978. 102. A.M.C. Seng6r: The Cimmeride orogenic system and the tectonic of Eurasia. Geol. Soc. Amer., Spec. Pap., 195, 1-82, 1984.

Persian-Triassic Evolution of Tethys and Western Circum-Pacific H. Yin, J.M. Dickins, G.R. Shi and J. Tong (Editors) o 2000 Elsevier Science B.V. All rights reserved.

71

The Permian of China and its interregional correlation Yugan J1N and Qinghua SHANG Nanjing Institute of Geology & Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China

Using a refined regional chronostratigraphic scheme for the Permian of China, a summary of the Permian stratigraphic framework in major depositional basins and a tentative correlation between the regional Permian sequences are presented. The Chuanshanian or Cisuuralian rocks in China, which used to be referred as the latest Carboniferous, are firmly defined. With helps of evidence from sequence stratigraphy, magnetostratigraphy and isotopic age, a more reliable correlation between the Lopingian rocks of different palaeobiogeographic regions is suggested. The currently most prominent difficulties of inter-regional correlation in China are closely related to the long-standing problems of international correlation, which are mainly caused by strong biogeographic differentiation between the Boreal, Gondwana and Pan-equatorial realms.

1. I N T R O D U C T I O N The earliest report on the Permian rocks in China was published in the eighties of last century[l]. Grabau made an attempt to set up the inter-regional correlation of Permian sequences in China in 193112]. Sheng [3] provided the first correlation chart for the Permian of major depositional basins in China, when he published a comprehensive summary on Chinese Permian. By that time, some 250 names of Permian lithostratigraphic units were presented, of which most are from North China and South China, only one tenth are from Xizang, Xinjiang and other remote regions. During the succeeding two decades, tremendous efforts were made in setting up local Permian sequences as a part of a country-wide geological mapping program at a scale of 1/200,000. Sheng et al. [4] compiled a correlation chart for the Permian sequences of forty-eight areas. In 1994, using a newly proposed Chinese chronostratigraphic scheme consisting of three series and 8 stages, Sheng and Jin presented a correlation chart of the Permian lithostratigraphic sequences of 83 areas in China. This paper is mainly designed to give a general impression of the Permian sequences in China. Only the dominant succession of lithological units and fossil zones, important lithofacies and biofacies changes in major depositional basins will be described.

72 2. C H R O N O S T R A T I G R A P H I C SUBDIVISIONS (Figure 1) The corresponding level to the GSSP for basal boundary of this system has not been identified in China. It can be approximately recognized in the slope facies or lower ramp facies of the carbonate platform in South China, which was defined at the base of the Pseudoschwagerina uddeni zone and the Streptognathodus elongatus-S, wanbaunsensis conodonts zone. In the outer shelf or lower ramp, the earliest occurrence of Occidentoschwagerina was taken as the indicator of this boundary. In the inner shelf facies, the genus Sphaeroschwagerina was often found in the bed directly overlying the Triticites noinskyi plicatus Zone, with no Occidentoschwagerina-bearing bed in between. In the shelf edge facies, early forms of Robustoschwagerina occur immediately above the latest of the Triticites zones, but below the introduction of species of Sphaeroschwagerina. In Central and Southem Xizang, the base of the Permian sequences is most conventionally marked by appearance of the Eurydesma bivalve fauna and a brachiopod fauna characterized by the occurrence of Stepanoviella or Bandoproductus. The indicative fossils of the base of Triassic System were proposed to be the earliest occurrence of Otoceras and Hypophiceras or that of Hindeodus parvus. The lithostratigraphic boundary between the Permian and the Triassic is approximately coincident with the major sequence boundary. In fully developed marine sequences, there is o~en a thin bed of the Changhsingian above the sequence boundary, such as the Mixed Bed 1 at the Meishan Section of Zhejiang and the Waagenites Bed at the Selong Section of Xizang[5]. The Permian is divided into three series, namely, the Chuanshanian, Yangsingian and Lopingian Series, and two subseries for the middle series, namely the Chihsian and Maokouan Subseries [6,7]. 2.1. The Chuanshanian Series.

This series was named by Huang in 1932 [8] and includes two stages, the Zisongian and the Longlinian Stage. The Zisongian Stage was originally designed to include the Pseudoschwagerina uddeni-P, texana zone and Sphaeroschwagerina genozone by Zhang et al. [9] with the Yangchang Section in Ziyun County of Guizhou Province as its stratotype. It contains three conodont zones, namely, the Streptognathodus waubansensis, the S. barskovi, and the Mesogondonella bisselli zones. The Longlinian Stage was suggested by Huang and Shi [ 10] as a new regional stage for the biostratigraphic sequence between the last appearance of Pseudoschwagerina and the first appearance of the genus Misellina. The reference point of the base of Longlinian Stage is delineated at the base of bed 23 of the Yangchang Section described by Zhang et al. [9]. It is marked by the first appearance of Pamirina divarsica. Since the lowering of the South China Sea became much more evident during the Late Chuanshanian regression, the dominant forms of the fusulinid assemblages were varied in different depositional sittings. They are characterized by a dominance of species of Nankinella, Staffella and Pamirina in the shallow inner shelf, by Pamirina and Chalaroschwagerina in the outer shelf and slope, and by Pseudofusulina in the shelf depression or in local basins [ 11 ].

73 2.2. The Yangsingian Series. Being named by Huang in 1932 [8], it corresponds with the stratigraphic sequence between the maximum regression occurring at the very beginning of Chihsian time and the commencement of the Lopingian transgression, or with two genozones, the Misellina zone and the Neoschwagerina zone. It used to be divided into two stages, the Chihsian and Maokouan Stage. Considering that the stratigraphic range of these two stages is so broad that actually corresponding to the Cathedralian and Guadalupian Series in USA, their ranks were upgraded as the subseries. Each subseries contains two stages: the Luodianian and Xiangboan Stage of the Chihsian Subseries, and the Kuhfengian and Lengwuan Stage of the Maokouan Subseries. The Luodianian Stage is proposed by Sheng and Jin [6] to include the stratigraphic range of the genus Misellina in outer shelf sequence. Usually, the Misellina genozone can be divided into the Brevaxina dyhrenfurthi, Misellina claudiae and Shengella zones. The type section of this stage has been proposed to be defined in the Yangchang Section with the base of bed 22 as its lower boundary [11]. However, it would be more suitable to place the reference point of this boundary at the base of Bed LNC106 in the Luodian Section [12]. The fossil succession from the Luodian Section is more complete, which includes three fusulinid zones, from Brevaxina dyhrenfurthi Zone to Misellina paramegalocula Zone, and conodont succession from the Neostreptognathodus pequopensis Zone, Mesogondolella gujioensis Zone to the M. idahoensis Zone. In the eponymous locality of the Chihsia Formation, in eastern suburb of Nanjing, the depositional sequence corresponding to the Brevaxina dyhrenfurthi Zone is absent or replaced by clastic beds, partly equivalent to the Liangshan Formation. The Xiangboan Stage was designed to contain the Cancellina Genozone[13]. The depositional sequence of this stage is best developed in the Houchang Section, Ziyun County of Guizhou Province[11]. The base of this stage is distinguished by the appearance of the primitive forms of Cancellina. Three fusulinid range subzones recognized at this section are the Cancellina elliptica, C. liuzhiensis, and Neoschwagerina simplex subzones. In the restricted shelf deposits, the fusulinids of this stage are usually dominated by Parafusulina multiseptata. This stage comprises the upper part of the Mesogondolella idahoensis and the Sweetognathodus hanzhongensis conodont zones. The Kuhfengian Stage was recommended for the stratigraphic succession from the base of Jinogondonella nankingensis Zone to that of the dr. postserrata Zone, with the Houchang Section as the reference section. The Kuhfengian fusulinids are grouped into the Neoschwagerina craticulifera and the Neoschwagerina magaritacea Zone. At the Sazhi Section in western Guizhou, from which the Maokou Formation was named, the fusulinids of this zone are dominated by Afghanella schenki. The ammonoids of this stage have been referred to the Waagenoceras Zone, the Kufengoceras Zone[14] or the AltudocerasParaceltites Zone [ 15]. This stage can be correlated with the Murgabian Stage of central Asia in terms of the fusulinid zones. The Lengwuan Stage was originally used as an extension of the Lengwu Formation in western Zhejiang, which contains the fusulinids Eopolydiexodina, Codonofusiella, Minojapanella, Reichelina and Metadoliolina, and conodonts of the Jinogondolella altudaensis, and dr. xuanhanensis zones. The base of the Lengwuan Stage is re-delineated at the base of dr. postserrata Zone in the Penglaitan Section of Laibin, Guangxi, which is

74 approximately at the same level as the first appearance of the genus Yabeina [ 16]. This stage includes a conodont succession from the Jinogondolella postserrata, J. shannoi, J. altudaensis, J. prexuanhanensis, J. xuanhanensis Zone to the J. granti Zone. 2.3. The Lopingian Series The name derived from the Loping Coal-beating Series [17] was firstly used as a chronostratigraphic unit by Huang [8]. Sheng [3] adopted the Lopingian as the upper series of a bipartite Permian and referred it to a series apparently higher than the Guadalupian Series, based on succession of fusulinids. This youngest series is characterized by the development of conodont genus Clarkina, fusulinids of Palaeofusulina-type, and ceratitid ammonoids. It includes two stages: the Wuchiapingian [18] and Changhsingian Stage [19]. The Wuchiapingian Stage has been widely used as a regional chronostratigraphic unit in the Late Permian in China since the lithostratigraphic and biostratigraphic successions were well studied. The Longtanian Stage [20] essentially covers the same stratigraphic range. It is not accepted because the originally defined lithostratigraphical unit of the Lungtan Formation consists of continental deposits and mostly falls within the Lengwuan Stage of the Maokouan Subseries. The base of the Wuchiapingian Stage is conventionally placed at the base of the Anderssonoceras-Prototoceras Zone and the "Clarkina bitteri-C, liangshanensis" Zone, usually overlying a terrigenous bed that resulted from a global regression. In an unbroken sequence from the Late Guadalupian to the Early Lopingian in the Penglaitan Section, Laibin County of Guangxi, three conodont zones, i.e. the Clarkina postbitteri, C. dukouensis, and C. asymmetrica zones occur below the C. liangshanensis Zone. The ammonoids associated with conodonts of the C. postbitteri Zone are referred to the Roadoceras-Doulingoceras Zone [21 ]. This stage is subdivided into the Laibinian and the Laoshanian Substages [22, 23]. The boundary between these two substages is redefined with the first occurrence of Clarkina leveni. The Laibinian Substage contains the Clarkina postbitteri, C. dukouensis and C. asymmetric conodont zones. The Laoshanian Substage embraces the C. leveni, C. guangyuanensis and C. orientalis conodont zones, and the Anderssonoceras-Prototoceras, Araxoceras-Konglingites, and Sanyangites ammonoid zones. The Changhsingian Stage was formally proposed by Zhao et al. as an international standard for the last stage of the Permian in1981 [24]. The D Section in Meishan was recommended as the stratotype of the Changhsingian Stage, while the base of the stage is located at the base of bed 2, the horizon between the Clarkina orientalis and the Clarkina subcarinata zones. The basal part of this stage is also marked by the occurrence of advanced forms of Palaeofusilina, and the tapashanitid and pseudotirolitid ammonoids. Two subdivisions of the Changhsingian Stage, the Baoqingian and Meishanian Substage, are recommended based on the proposed stratotype of the Changhsingian Stage in the Meishan Section. The boundary between these two substages is defined by the earliest occurrence of Clarkina changxingensis at the base of bed 13 of the D Section in Meishan, Changxing. 2.4. Correlation with the international standard Between the Chinese and the international standard Permian chronostratigraphic schemes[25] correlation of the basal systemic boundary, the basal boundary of the Artinskian Stage remain to be documented. And the corresponding level of the basal Guadalupian in the Tethyan Permian is a subject of debate. The Roadian Stage of the Guadalupian Series is proposed to be indicated by the first appearance of Jinogondolella nankingensis. In South

75 China, Kungurian and Guadalupian sequences were documented conventionally by the fine zonation of the fusulinids [12] and the conodonts [26] in South China,. The successive appearance of the Kungurian and Guadalupian leading species of conodont zones can be inter-correlated one by one between the slope sequences in the Loudian Section of South China [26] and the type section of SW USA. The base of the N. exculptus Zone is within the Pamirina Zone and therefore, the basal boundary of the Kungurian Series could be lower than that of the Bolorian Stage [12]. It was followed by the Mesogodolella gujoiensis - M.

Zonation

Chiness C~?nostratigraphyi_ __ Series ~ -

-7

T

Stages . . . . . . . . . .

'

Ammonoid -*-

Induan

-

-

i HyP~ ~ Otoceras

i ~,~

Rotodiscoceras ! "~lMeishanianl PseudotirolitesI "~1............ [ Pleuronodoceras ! "~_l [PseudosteDhanites; ~ lBaoqingianl pTaaPt~ohff:nitseSshevyrevites I ~i Ilranites- Phisonites ' ~ ~Sanyangites '~= Laoshaniant A raxoceras-Konglingites ~1 'Anderssonoce ras-Prototoce ras

"~ .

~

Global standard

Fusulinid

Conodont

Clarkina changxingensis

Palaeofusulina minima Gallowayinella meitienensis

C. subcarinata

Nanlingella simplexC9donofusiella kwangsiana

, Laibinian Roadoceras-Doulingoceras

C. orientalis C. guangyuanensis C. leveni C. asymmetrica 9dukouensis C

t

Lengwuan

Shouchangocera~ Shangraceras

Induan

Hindeodus parvus Palaeofusulina sinensis

Metadoliolina multivoluta Yabeina gubleri

Changhsingian

i

Wuchiapingian~

~.r

Jinogondolella granti J. xuanhanensis J. prexuanhanensis J. altudaensis J. postserrata

Capitanian 265.3

J. asserata

"~

Kuhfengian

'

Gub, angoceras

Neoschwagerina margaritae

Altudoceras-Paraceltites

N. craticulifera

Shaoyangoceras

Sweetognathus N. simplexsubsymmetricus Praesumatrina neoschwagerinoides Mesogondolella idahoensis Cancellina elliptica

1 I

] Xiangboan . . ,

i

........................

' .-~ i i Ma

Stages

Series

Wordian

,I. nankingensis

Roadian

= i

!

e.,

r,) i

Pseudohalorites

i Luodianian :Metaperrinites shaiwaensis- Misellina claudiae i '-

'

IPopanoceras ziyunense

~

Propinacoceras simile

i Longlinian

Popanoceras kueichowense- Pamirina -Darvasites ]Propinacocerasnandanense ordinatus

: iL

~ !] I Properrinites plummeri[ Eoasianites subhanieli I

9

.

C

Kungurian

S. whitei

Artinskian

,~;q=%e%y

i

i

.

] Brevaxina ~ dyhrenfurthi

M. gujioensis Neostrepto .gnathodus

.

.

.

.

.

Zisongian

][ Xiaodushanian

!

Robustoschwagerina schellwieni- R. zomnensis M. bisselli Sphaeroschwagerina Streptognathodus s.m~ barskovi Pseudosch.wagerina S. wabaunsensis

Sakmarian Asselian

~orm~

Triticites

S. elongatus

I

Gzhelian

Figure 1. Chronostratigraphic subdivisions for the Permian System of China [7].

'•

280.3

1

290.6

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76 is an interval with a dominance of a shallow water conodont fauna, such as Sweetognathus subsymmetricus and Sw. hangzhongensis between the M. idahoensis Zone and the J. intermedia, M. idahoensis and then Jinogondolella nankingensis in both sections. But, there nankingensis Zone. It remains an open question whether the Sweetognathus subsymmetricus Zone is a counterpart of the upper M. idahoensis Zone or the lower J. nankingensis Zone in SW USA. Presuming that the Sw. subsymmetricus Zone corresponds to the lower part of the type J. nankingensis Zone, the associated fusulinids will belong to the Praesumatrina neoschwagerinoides Zone. General surveys on the Permian ammonoids show that Daubichites is widespread and is confined to the Roadian Stage. In South China, Daubichites was reported from the Tingchiashan Formation, which is definitely the Kuhfengian in age[14].

3. C O R R E L A T I O N

3.1. Stratigraphic-tectonic provinces During the Permian period, there were four major blocks, namely, South China, North China, Tarim, and Central and Southern Xizang [northern part of India Craton]. Permian deposits on these blocks are dominated by shallow shelf facies [Figure 2]. During the Early Permian, deep water deposition occurred on the continental slopes around the northern margin of the India Craton, the northwestern margin of the Tarim Craton, and possibly the southern margin of the Sino-Korean Craton. It also appeared in such micro-aulocogens as the Dian[Yunnan]-Qian [Guizhou]-Gui [Guangxi] Basin, Songpan Basin and the Qinzhou Trough. The oceanic sediments and faunas of Late Paleozoic age in the Qinzhou area may indicate the possibility of an allochthonous origin, and the huge thick diamictites of the Early Permian in Central and Southern Xizang have been interpreted as glaciomarine. Meanwhile, terrigenous sediments were deposited in the intercratonic basins caused by extension during Middle and Late Permian time. In between these stable cratons, there are two pronounced mobile belts and three others, which were mostly diminished by post-Permian convergence. The Northern China Mobile Belt, extending from Beishan to the northeastern comer of China via Nei Mongol, Hinggan and Central Jilin successively subducted southward and formed three latitudinally trending accretional zones. To its northwest, compression basins of terrestrial deposits were created in North Xinjiang with the folded Late Carboniferous rocks as the basement. The Beishan - Nei Mongol - Hinggan region collided with the Carboniferous folded belt of the Dahinggan Gobialtay block during Late Maokouan, and formed a set of terrestrial basins caused by further compression. The Permian sequence in the far-east of this mobile belt in China represents an island arc sea, which closed after the Maokouan. The Western China Mobile Belt, occupying the contact areas between South China proper and the Tarim, Qaidam and India block is a complex composed of numerous troughs, volcanic islands and micro-blocks. Among the volcanic island arc seas are those developed respectively along the eastern Kunlun Mts., the Jun U1 Mts., the Qinghai Nanshan, the Yalong River, the Jinsha River and the Lancang River. The micro-blocks comprise the Shuang Hu, the Hob Xil Shan, the Qamdo, the Markam-Batang and others, in which Permian lithostratugraphic and fossil sequences are essentially the same as those of South China. In addition of these two major mobile belts,

77 Permian rocks relating to the island arc belts are preserved in the eastern part of Taiwan Island and the western part of Southern Tianshan of Xinjiang as relics of respective convergent zones. 3.2. Biostratigraphic successions Paleogeographically, nearly all depositional regions of China fall within Paleotethys in a broad sense. In South China, Tarim, Qaidam and the micro-blocks scattered in the Western China Mobile Belt, carbonate-dominated sequences accumulated in tropical and subtropical shelf seas. The Permian strata commonly contain rich Tethyan faunas and Cathaysian floras. However, palaeobiogeographically mixed faunas and floras frequently occurred in the transitional areas. The Potonieisporites-Vittatina and Striolatospora-SchweiterisporitesCalamospora palynomorph assemblages from the Chuanshanian beds of northwestern Tarim show an affinity with the European phytoprovince. And the Ullmannia bronni-Yuania magnifolia Assemblage from the Shihchienfeng Formation of Lopingian in North China is characterized in the Zechstein of the Euramerican phytoprovince.

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Figure 2. Stratigraphic-tectonic provinces of the Permian in China. I. South China, It SE China, 12 Jiangnan, I3 Yangtze, 14 Qing-Kang-Dian, 15 Tanggula-Hengduan, 16 Peri-Pacific; II Tarim, II~ Kelpin, II2W Tarim, II3 SW Tarim, 114 Qaidam; III North China, IIIl N Qilian, 1112 Daqingshan, III3 Jin-Ji-Lu, 1114 Huang-Hui; IV Northern China Borderland IV~ N Xinjiang, IV2 Beishan, IV3 Nei Mongol-Songliao; V Himalaya, V~ S Xizang, V 2 Yalung-Zangbo, V3 Gangdise, V4 Karakorun, V5 W Yunnan. Areas with cross-lines indicate major uplifts [27].

78 In Central and Southern Xizang, Permian sediments deposited in the peri-Gondwana seas are preserved, of which the lower group is made of clastics with floras and faunas closely related to the Gondwana Realm, and the upper group comprises mainly the carbonates and the fossils of Tethyan faunas. The Northern China Orogenic Belt with complex island arcs and troughs aligned on the northern margin of North China block accommodated Permian sediments of anomalous thickness with faunas and floras varying from Boreal to Tethyan affinities. In Xinjiang, Permian biostratigraphic successions are closely related to those of the Urals of Russia but are distinct from those of North China and South China. The succession of palynomorph assemblages has proven to be the most important criterion in correlation of the Permian beds throughout Northern Xinjiang since they can be readily recognized in various basins [28, 29]. Among these regions, the Permian sequences of South China have received more extensive study than those in other regions, and are regarded as a standard to which all correlation of the Permian in China are referred. However, faunas in the transitional areas between the Tethyan Realm and the Gondwanan or the Boreal Realm usually appear long-ranging, such as the Chuanshanian Eurydesma bivalve fauna, the Yangsingian Monodiexodina fusulinid fauna, and the Yangsingian and Lopingian Spiriferella brachiopod fauna.

3.3. Sequence stratigraphy Mainly based on data from North America and Russia, Ross and Ross[30, 31] referred the Permian sequences to a single second order cycle, the Transpecos Supercycle, consisting of about twenty-three third order cycles. They noted that two Wolfcampian cycles are closely related to the Tombstone Supercycle of the Pennsylvanian, and the post-Guadalupian cycle, to the upper Absaroka Megacycle. The eustatic curve drawn out by Holser and Magaritz [32] based on analysis of 68 major depositional basins shows three major regressions in the Late Artinskian, end-Guadalupian and end-Tartarian. Both eustasy curves decline gradually from the early Permian and reach the lowest point at the very end of Permian. On the other hand, with emphasis on importance of the sea level fluctuation in the extra-Pangea shelf seas, Jin et al. [16] interpret the Permian eustacy as one consisting of a complete supercycle between Late Artinskian and Late Guadalupian regressions and two partial supercycles, which are the Uralian sequence of the Pennsylvanian supercycle and the Lopingian sequence of the Triassic supercycle. Persistent overprinting on sea level-fluctuation in various blocks was imposed by tectonism during the Permian. First, the agglomeration of Pangea resulted in a differentiation of the shelves around low-lying micro-continents such as South China from the peri-Pangea shelves with appreciably higher geodesy. In extra-Pangea shelves, relative changes of coastal onlap during lowstand intervals are fully recorded, although the transgressive-regressive cycles during highstand times are less distinct. Second, gradual close of the Uralian and the Mongolian seas from the Kungurian to the Guadalupian epochs led to a steady elevation of continents in the northern hemisphere while the opening of tiffing seas around the northern margin of Gondwana and the North Sea caused a widespread regional transgression in the southern hemisphere from the late Guadalupian to the Lopingian. As a result of these tectonic influences, an up-tilt line can be traced between the profiles of sea-level changes for continents of the northern hemisphere and those for continents in the southern hemisphere.

79 Nevertheless, the following transgression-regression cycles can be recognized internationally after a careful evaluation of the tectonic influences. Chuanshanian TR Cycle. There is no dramatic sea level change at the beginning of the Permian, i.e. the early Asselian. A major sequence boundary and also a bio-evolutionary turning point is located at the base of the Carboniferous Kasimovian Stage. Asselian marine deposits are much more widespread than the preceding two stages but return to regression in the Sakmarian. In China, rocks of this sequence are referred to independent lithostratigraphic units such as the Maping Formation of South China and the Taiyuan Formation of North China. Yangsingian TR Cycle. The Permian sequence of South China comprises two major regressions that caused widespread erosional truncation (Figure 3B). The first regression appeared in early Artinskian [Pamirina zone or Charaloschwagerina zone in South China] and reached its acme at late Artinskian [9]. This regression also can be recognized in other blocks of Southern Tethys and peri-Gondwana. Usually, a continuous Permian marine sequence starts with the Artinskian transgression in these areas [33]. This sea level fall can be correlated to the major regression of the Late Artinskian revealed in eustatic curves as suggested by Holser and Magaritz [32]. It is divisible into two subordinate TR cycles corresponding with the Chihsian and the Maokou Formation. The end-Guadalupian regression started approximately in the upper part of the Jinogondolella. postserrata Zone, reached its lowest point at the top of the J. granti Zone and than shifted into the Lopingian transgression. Lopingian TR Cycle. Contrary to the traditional view that Late Guadalupian regression continued during the Lopingian, and accelerated near the Permian\Triassic boundary, the Lopingian sequences of South China apparently reflect a transgression system of the forthcoming supercycle (Figure 3A). Coal-beating deposits bracketed by basinal pelagic beds were developed in depressions behind carbonate platforms. These beds represent basinal floor fans deposited when these depressions were drained. Overlapping the coal-beating beds in shelf areas are marine beds with typical Wuchiapingian brachiopods, conodont faunas of the Clarkina leveni Zone, and ammonoid faunas of the Anderssonoceras-Prototoceras Zone, which form a widespread transgression surface. The Lopingian sequences above the transgression surface consist of a transgression system despite a relatively greater regression that occurred at the Wuchiapingian\Changhsingian boundary. The erosional surface caused by this regression divides the Lopingian sequence into two third-order cycles. A close study of lithological changes in tens of sections on the Yangtze craton shows the Wuchiapingian cycle comprises two secondary cycles, and the Changhsingian cycle, two and half secondary cycles[20]. A transgression Lopingian sequence in South China is not just a local development. It is consistent with conditions all over the Tethyan area including the Salt Range, Kashmir, Xizang, Japan, Iran, Southern Alps etc. during the Lopingian Epoch. End-Changhsingian transgression. With the progressive transgression during the Changhsingian stage, condensed deposits dominated by cherty shale of the Talong Formation occurred in basins and outer shelves. The sea level rose to a greater height than during the three previous cycles of the Lopingian. Surprisingly, following the Lopingian there is not a great regression as predicted by most popular models of Permian eustacy. In contrast, a rapid transgression appeared in the latest Changhsingian and was accompanied by a sudden endChanghsingian flooding. Carbonate accumulation on the middle and outer shelf was replaced

80 by condensed deposition. Coincident with this rapid transgression, up to 90% of the Changhsingian marine biota does not extend upward into the topmost part of the Changhsingian. It is noteworthy that similar acritarch assemblages have been found in the Goudikeng Formation, a transitional bed between the latest Permian and the earliest Triassic red beds in both slopes of Tianshan, Xinjiang [28]. Coastal deposits with marine bivalves and acritarchs dated as earliest Triassic also appear in between red beds in the southern part of North China. In southern Xizang, Changhsingian marine deposits occur below the Otoceras Zone of the basal Triassic. These occurrences indicate that the end-Changhsingian transgression had climbed to the lower lands of Tarim and North China from which sea water had been withdrawn in Artinskian time. 3.4 Magnetostratigraphic sequence Permian magnetic polarity zones are referred to two magnetostratigraphic superzones, namely, the Carboniferous-Permian Reversed Superzone and the Permian-Triassic Mixed Superzone (Figure 1). Chuanshanian magnetic polarity zones are referred to the CPRS. Normal magnetic polarity horizons have been identified in the Jinci Sandstone and the Ximing Sandstone in the lower part of the Taiyuang Formation in Shanxi, the Pseudoschwagerina and Sphaeroschwagerina Zone of the Maping Formation and in the Chihsia Formation in Yishan County of Guangxi [34]. Xia et al. [35] found a succession with 9 alternative normal and reversed polarity horizons in the Chuanshanian strata in Zheng'an County of Shaanxi. The Guadalupian and Lopingian magnetic polarity zones are referred to the PTMS. Its base is named as the Illawarra Reversal, and located in the Yats Formation in SW USA, which is usually dated as Late Guadalupian. It is identified in the upper part of the Maokou Formation in Wulong County, Sichuan [36], which is correlated with the Yabeina Zone of the Lengwuan Stage. In North China, the Illawarra Reversal occurs in the Upper Shihotse Formation [37]. With calibration of biostratigraphic zonation and isotopic ages, the Permian part of the Permian-Triassic Mixed Superzone [PTMS] can be assembled into four zones [38]. The N2P Zone ranges from the uppermost Kuhfengian Stage to the Jinogondolella altudaensis Zone of the Lengwuan Stage and is represented by two normal polarity horizons and one reversal between them. The top part of the Lengwuan Stage and the lower part of the Wuchiapingian Stage are dominated by reversed polarity and, are thus referred to the R2P Zone. The N3P Zone consists of at least four normal polarity horizons and ranges from the Clarkina guangyuanensis Zone of late Wuchiapingian Stage to the lower Changhsingian Stage. The upper Changhsingian Stage is assigned to the R3P Zone, which combines two reversed and one normal polarity horizons in between. 3.5. Radiometric age Major advances on isotopic dating of the Permian have been achieved recently. Dating of samples from the Urals suggests that the age of the mid-Asselian is 290 + 3.0 Ma, and that the Sakmarian/Artinskian boundary is 280.3 + 2.5 Ma. These results suggest an age of 296 Ma for the Carboniferous-Permian boundary (Figure 1).

81 For the Permian-Triassic boundary bentonite bed of the Meishan Section, a SHRIMP age of 251.2 + 3.4 Ma and 4~ age of 249.9 + 1.5 Ma have been provided. A recent study on isotopic age of the Changhsingian bentonite beds in South China yielded a reliable date of 251.4 + 0.3Ma for the boundary bentonite bed, 253.4 + 0.2Ma and 252.3 + 0.3Ma respectively for the base and the upper member of the Changhsingian Stage. Since the age of zircons from a bentonite bed just below the base of the proposed Capitanian stratotype is 265.3 + 0.2 Ma [39], the age for the basal boundary of the Lopingian Series is estimated as 259 Ma.

4. REGIONAL STRATIGRAPHY 4.1. South China (Figure 3) Generally, there are two major deposition regions during the Permian Period in South China: the Yangtze and the Huanan region. The core parts of the Yangtze region are craton areas which emerged aider Caledonian orogeny and submerged as epeiric seas until the Early Luodianian. The micro-aulocogen-type basins and the outer-shelves surrounding the Yangtze platform are referred to the Dian [Yunnan]-Qian [Guizhou]-Gui [Guangxi] Basin. The Huanan Region comprises the shelves on the Cathaysia massifs around the southeastern coastal areas, and the Jiangnan Basin. The latter consists of a series of depositional units, from north to south, including the Loping depressions, the Chengzhou, Liuzhou and Qingzhou basins. As the deepest basins of Permian sedimentation, they contain the most complete Permian sequences in South China. These basins located along eastern and northeastern margins of the Yangtze craton and were structurally controlled by the development of the Cathaysia craton in a great extent during the Late Permian. However, the oceanic sediments and faunas of Late Paleozoic in Qingzhou area also indicate the possibility of an allochthonous origin. The Zisongian deposits are exclusively composed of carbonate facies and are conventionally named as the Maping Formation in the Yangtze Region, or the Chuanshan Formation in the Huanan Region. A range of rock types from dolomites, white packstone and grainstone to black wacksteone and packstone accumulated respectively on shore, inner shelf and outer shelf. However, as a result of frequent sea level change, the most common sequences are alternating white and black limestone beds, and alternating dolomite and limestone beds. The global regression occurring during the Longlinian and Luodianian Stage induced strong facies differentiation. The Longlinian deposits mainly consist of interbedded shale, siltstone, bauxitic clay beds and thin-bedded limestone with a thickness usually less than 20m. Being characterized by development of the eluvial deposits, they were accumulated around erosional areas of the Jiangnan, Kangdian, and Yunkai massifs and on the core part of Yangtze Massif. Deltaic facies composed of sandstone up to 250m thick and containing minable coal seams were well developed surrounding the southern and eastern sides of the Yangtze Massif, and also the northeastern side of the Jiangnan Massif. Thick sequences with alternating carbonate and terrigenous beds were accommodated by a mini-graben in western Guizhou.

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Figure 3. Restored stratigraphic sections of Permian rocks in the Upper Yangtze Region. AA'. A section of Lopingian coal-bearing series and carbonates across the delta and shelf from Huize of Yunnan Province eastward to the basin in Duyun of Guizhou Province; successive maximum floodings are indicated by westward expanding of cherty shale of the basinal facies. BB' A section of Yanghsingian carbonate rocks across the inner and outer shelf from Zhunyi southward to the slope near Luodian, through shelf edge in Ziyun of Guizhou Province. Key fossil zone to respected facies is marked.

83 The Early Chihsian deposits consist of argillaceous carbonate sequences on the inner shelf while those in the outer shelf and basin are much the same as the Longlinian facies. Then, aggregation during the highstand stage of the late Chihsian resulted in strong differentiation in facies. Depositional sequences that formed in depressions are dominated by alternating beds of shale and thin-bedded limestone, and those on submarine highs by nodular limestone and a characteristic brachiopod fauna with abundant and diverse forms of Cryptospirifer and such fusulinids as Neoschwagerina simplex, and Verbeekina grabaui. The latter are deposits of an intertidal environment with alternate deposition of carbonate shoals and mud fiats; its dispersal areas are more or less coincident with the eluvial and deltaic deposits of the Longlinian Stage. The sequences shift into the outer shelf dolomite facies [the Maokou Formation]; reef facies, for example, the Xiangbo Reef along the shelf margin; and cherty limestone in local basins. At the beginning of the Maokouan, the pattern of facies distribution in the eastern area was remarkably changed. The predeltaic and basinal deposits [the Kuhfeng Formation and its allies] accumulated in basins behind carbonate platforms during the emergence of the Cathaysia Uplift which consisted of a set of submarine highs. Lithologically, they are marked by having rich chert, phosphate nodules, stony coal beds and manganese carbonate beds, and coastal coal-beating deposits in the upper part. They are bounded by a disconformity at the base, which is possibly coincident with the maximum flooding surface, and gradually shift into deltaic facies or patch-reef facies upward. The isolated reef limestone that occurs in western Zhejiang was designated as the Lengwu Formation. The eruption of the Omeishan Basalt was a prominent feature of Late Maokouan and Early Lopingian in South China. This volcanic group spreads over eastern Sichuan, western Guizhou and eastern Yunnan and extends to the Panxi Rift Belts between South China and West China. The total area covered by the Omeishan Basalt approaches 330,000 square km. The average thickness is 705m and the total volume of volcanics is about 280,000 cubic km. The volcanic rocks rest directly on the Maokouan limestone, often with a residual clay bed tens of centimeters thick in between. Marine clastic beds or limestone intercalations with such fusulinids as Metadoliolina sp., and Neoschwagerina douvillei occur in the basal part of the basalt in eastern Yunnan, and western Guizhou. They are mostly continental volcanic sequences, except for the area near the tiffing belt on the west, in which the basalt shift into marine facies. Above the basalt is the Hsuanwei Formation, a coal-beating unit. The basal contact is unconformable in the western areas, and conformable in the east where it may include intercalations of basaltic lava and tuff beds. It changes laterally into the inner shelf facies represented by the Wuchiaping Formation and subsequently the Changhsing Formation, and then into basinal facies of the Talung Formation. The Changhsingian deposits consist of black laminated wackestone accumulated in slope environments; also thick-bedded, massive, light-colored packstone and grainstone that represent the deposits of carbonate shoals and reefs; and sequences dominated by dolomite and dolomitized limestone representing back reef facies. Platform deposits consist of shale and cherty beds. In slope and basin environments, the Changhsingian volcanic clay or ash beds were deposited. The Permian in the Qinzhou area is distinct in China, as it includes a pelagic shale sequence from the Zisongian Stage to the Lengwuan Stage in its lower part, and a fluvial to paralic clastic sequence of the Changhsingian in its upper part. Between these sequences is an

84 angular oceanic terrains China,

unconformity. Zonation of radiolarians is closely comparable to coeval tropical deposits represented by banded chert with highly diverse fossil radiolarian from the in circum-Pacific regions such as southern Japan, the Philippine, western Yunnan of and Oregon, USA. In Japan, the radiolarians of the Follicuculus charveti, Neoalbaillella optima and N. ornithoformis zones are correlated respectively with the Lepidolina kumaensis, Nanlingella simplex and Palaeofusulina sinensis zones [40]. This correlation indicates that the radiolarian succession in the Qinzhou area ended in the Changhsingian.

4.2. North China (Figure 4) The transgression of epeiric seas initiated in the Moscovian of the Late Carboniferous and swept over most parts of North China in the Zisongian. The post-Zisongian deposits of the Permian represent a gradual regression and are exclusively composed of terrigenous sediments ranging from paralic to inland basinal facies. The rock types are uniform over wide areas and are interpreted as indicating the presence of a peneplaned platform with uptilted northern and northwestern margins, tectonically comparable to the present-day Andes. Distribution of major facies is parallel to the latitudinal trending Yinshan Uplift. The continual raising of the Yinshan Uplift along the northern margin resulted in successive migrations of the coal-bearing deltaic system southward. Consequently, the main stratigraphic levels of the minable coal seams form important characteristics of the Permian sequences of each lithological province. The Permian sequence in the areas around the southern margin of the Yinshan, the equivalents of the Taiyuan Formation are composed of alluvial and fluvial deposits, with a few thin beds of limestone at the top. Early Zisongian fusulinid assemblage consisting of Staffella and Nankinella was reported from the upper part of this formation [41 ]. The main minable coal measures occur in a stratigraphic position corresponding to the upper part of the Taiyuan and Shanxi Formation. In central areas, the Permian part of Taiyuan Formation contains two major depositional cycles. The Permian conodonts from the Taiyuan Formation are included in the Sweetognathus whitei Zone and the Streptognathodus elongatus- S. wabaunensis-S, fuchengensis Zone. The overlying Shanxi Formation contains three main depositional cycles each of which begins with a fiver bed sandstone and ends with lacustrine fine-grained clastic beds. Development of widespread bauxite clay beds in the top part of the Lower Shihhotse Formation indicates a possible erosional surface. The succeeding Upper Shihhotse Formation forms the lower part of a major depositional cycle and the frequent occurrence of cherty beds composed of sponge spicules in this formation implies repeated inundation by sea water. It contains the Gigantonoclea hallei - Fascipteris spp. - Lobatannularia ensifolia Assemblage of fossil plants, an equivalent of the flora from the Lungtan Formation of the Late Guadalupian and Early Lopingian in South China. In the southern areas, the intercalated beds of limestone of the Taiyuan Formation may be up to twelve. The main minable coal seams occur in the Lower Shihhotse and the Upper Shihhotse Formation, which formed a shallow-water deltaic system; these are absent in the northern and central sectors. Thin cherty beds composed of sponge spicules appear in the Upper Shihhotse Formation, occasionally accompanied by Lingula. The appearance of palynofloras with a few acritarchs and other marine fossils in the Shihchienfeng Formation in

85

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Figure 4. Schematic stratigraphic section of Permian deposits in North China proper (A) and Chuanshanian sketch palaeogeographical map of North China (B). Areas occupied by coastal plain, shallow shelf and Huang-Hui shelf corresponds respectively to the northern, central and southern belts.

86 the southem belt has been interpreted as an indication of an inundation phase of the Changhsingian Stage [ 16]. In Taiyuan of Shanxi Province, the Illawarra Reversal is identified in the lower part of the Upper Shihhotse Formation t371. The upper part of this formation is dominated by reversed polarity and thus, agrees with the Wuchiapingian reversal polarity zone. As with the latest Wuchiapingian and the Changhsingian marine sequences, the topmost of the Shihhotse Formation and the Sunjiagou Formation reveal a prevalence of normal polarity. In Northern Qilian, Permian rocks form an east-trending narrow strip around the southem margin of Tenggar Desert and the eastern part of Beishan, including from west to east, the northern part of the Qilian Mts., the Longshoushan Mts. and probably the westem part of the Helanshan Mts. The lithological and biostratigraphic sequences are comparable to those of the North China Region proper. However, they are almost entirely composed of continental deposits with the exception of a limestone bed with brachiopods and rare fusulinids at the top of the Taiyuan Formation. There are virtually no coal measures in the Permian rocks in spite of a few thin coal seams in the Taiyuan Formation. The rest of the Permian sequences is exclusively dominated by red bed facies, variegated, green and red shale, lithic sandstone and conglomerates, all of alluvial origin. One of the striking characteristics of Permian fossils from this area is that plant fossils from the uppermost Permian contain elements of the Angaran phytoprovince, a feature now considered to denote the boundary between the Cathaysian and the Angaran phytoprovinces.

4.3. Northern Xinjiang (Figure 5) The Permian in Northern Tianshan, Junggar Basin and Altay Shan are essentially composed of continental deposits. Permian sediments in the intermontane basins of the Altay and northern Junggar Mts. overlie unconformably pre-Bashkirian strata. They are characterized in the lower part by volcanic facies, which consist of andesitic to rhyolitic lava, tufts and alluvial-fluvial sandstone and conglomerates containing volcanic detritus. Plant fossils of the Angaropteridium-Zamiopteris Assemblage from the Chuanshanian tuffaceous deposits in northern Junggar which is characterized by the occurrence of Zamiopteris and the "Noeggerathiopsis" derzavinii and N. latifolia, are comparable in composition to the flora of the Upper Balakhonsk Group in Russian Altay. The upper part of the Permian sequence includes fluvial and lacustrine deposits with coal seams, which mostly accumulated in small grabens that appeared during the Early Permian. Permian sequences at the southern margin of the Junggar Basin are comprised of sediments accumulated in a back arc basin, and usually overlie Gzhelian beds with an unconformity. In the type area, the suburb of Urumuqi, the nine Permian Formation are conventionally assembled into three groups: the Lower Chiechietsao, the Upper Chiechietsao and the Tsangfanggou Group, which are dominated respectively by coastal, lacustrine and alluvial deposits. The Lower Chiechietsao Group is composed of a fining-up, transitional sequence from shallow marine to estuarine facies. The lower part of the section here contains rhythmic paralic deposits which are replaced upwards by fluvial deposits. A return to coastal lacustrine conditions occurred in the Lucaogou Formation of Maokouan age, which is the most widespread of the Permian units that appear in the Junggar Basin and its neighboring basins. The Lucaogou Formation include fish fossils Turfania taoshuyuanensis, Ulumqia liudaowanensis, Chichia gracilis, etc., bivalves are Anthraconauta, Mrassiella, Microdonta, and Palaeodonta,

87

N. Junggar

Urumqi

Karamali

Karamay

J

ph ~ J

P~

Burqin

I, (

c~

I

conglomerate sandstone siltstone

~ basalt

~

rhyotlite

andesite

~': r

oAksu

L0

-.....

\

:-::~:-..

i.---X ~~ ~-Guli.a.,~ ~ "~":-..'.:' ''~'~ ~::l_.....i::_~ ~ : o . -.6"... :~.

,-

~-100

"~"x

: :..

"-~'.

~

\ c~ C~'

1

/

'

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I,.

~200m

/1" --.~

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1,

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1

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'"~ ~ - - "~i-rla"

:".

..:.:i~.~.~ ~ , , ~ ~ ~

~x _

~

outcrop

~/,~

subsurface

['":':'.1 desert

Figure 5. A. Schematic stratigraphic sections of the Permian in Northern Xinjiang, showing the variation of thickness and lithology respectively in the intermontane basins (Burqin and N. Junggar), foreland basin (Karamay, Karamali), and back-arc basin (Urumqi). C2 - Late Carboniferous units, P~ - Chuanshanian units, the Lower Chiechietsao Group, P2 - Yangsingian units, the Upper Chiechietsao Group, PI2-the Lucaogou Formation, Ph2 - the Hongyanchi Formation, P3 - Lopingian units, the Lower Tsangfanggou Group. B. Distribution of Permian strata in Northern Xinjiang and locations of regional successions.

88 and ostracods Tomiella, Permiana and Darwinula. This formation is succeeded by red bed facies of the Lower Tsangfanggou Group and than by a brief expansion of lacustrine deposition of the Goudikeng Formation at the end of the Permian. The two phases of the dominance of lake facies are possibly correlated with the Kuhfengian and the end-Permian flooding in South China. The Lower Chiechietsao and the Upper Chiechietsao Groups contain micro-floras dominated by striate disaccate pollen Hamiapollenites, Striatoabieites and Striatoparvisaccites or the monosaccate pollen Cordaitina. Occurrence of the Dicynodon vertebrate fauna from the Tsangfanggou Group confirms an age of the Late Tatarian. A micro-flora containing Aratrisporites, Lundbladisporites, Lueckisporites virkkiae and Taeniaesporites from the lower part of the Goudikeng Formation indicates the latest Tatarian age. Paleomagnetic studies on the Permian sections of this area have been undertaken repeatedly. The normal polar zone probably corresponding to the Illawarra Reversal was located in the upper part of the Lucaogou Formation. Two normal polarity zones were detected respectively from the Wutonggou and the Goudikeng Formation. This fact suggests that the middle part of the Hongyanchi Formation and the upper part of the Lucaogou Formation belong to the Maokouan Subepoch. 4.4. Tarim The Permian of Tarim consists of a transgression sequence of the Chuanshanian and a regressive sequence of from the Yangsingian to the Lopingian. The Chuanshanian shallow shelf carbonate deposits developed over most of the Tarim platform. The distribution of shoal sandstone and grainstone indicates the presence of an uplift extending from Wushi to the southeastern corner of the platform. To the west of this uplift are the dolomites and wackstone of the inner shelf, and then, the packstone and grainstone of outer shelves. The subsequent Permian sequences are mainly composed of continental deposits with the coastal deposits in the western, and the fluvial deposits in the eastern. In Kalpin of northwest Tarim, Permian carbonates deposited in a rimmed shelf, which shifted northward to the troughs of Southern Tianshan (Figure 6). The Chuanshanian carbonate beds overlap eastward on to the Devonian and older beds, and are exclusively named as the Kankarin Formation. To the west they are replaced by reef facies that are scattered around the shelf margin, and rest conformably on Late Carboniferous beds. Further to the west are thick flysch that indicate the troughs surrounding the northwestern border of the Tarim platform. After a regression in association with sea level lowering of the Longlinian, the former shelf margin and slope area was covered by a shallow embayment in which calcareous fine-grained clastic beds of the Sarezhiyi Formation were deposited, and a delta system developed on the site of the previous shelf areas. The deltaic sequence, namely the Kalender Formation, contains thin coal seams in the upper part and is overlain by the basalt trap [42]. In southwestern Tarim, a relative broad carbonate shelf developed from the early Late Carboniferous to the Late Longlinian (Figure 7). The Qipan Formation with Neostreptognathodus sulcoplicatus (Youngquist, Hawleym et Miller) should be assigned to the Chihsian since this species appears first in the Cathedral Formation of the U.S.A. while the Kiziriqiman Formation, should be assigned to the Sakmarian, as it contains Neostreptognathodus pequopensis, a species that appears first at the base of Neal Ranch

89

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Figure 6. Generalized stratigraphic sections of Permian deposits in Kelpin area, northwest Tarim showing Chuanshanian marine sediments thinning eastward, and post-Chuanshanian terrigenous sediments thinning westward.

Formation. Continental Permian rocks crop out in areas north of Hotan County and west of Yecheng and Sache Counties. Commonly, they rest conformably on the marine beds of Late Carboniferous carbonate beds and comprise alternating sandstone and siltstone [43].

90

A

SOUTHERN TARIM

Kaplanggou Qipan II I

Hotan III

[-1~"

,-400m

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l

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Figure 7. Fence diagram across the rimming shelves respectively around the southern margin of Tarim, Qaidam and Qilian, showing the thickness and facies relationships of Permian deposits.

4.5. Beishan - N e i M o n g o l - J i l i n (Figure 8) This region includes, from west to east, the Beishan in northern Gansu and eastern Xinjiang, most of Nei Mongol, and the northern part of Northeastern China. In general terms the Permian may be divided into two major sections: a Yangsingian sequence composed of marine volcanics and volcanic derived sediments, underlying a Late Yangsingian to possible Lopingian sequence of finely banded argillite, and massive sandstone and conglomerate. Following migration of the collisional axis towards the southeast, the progressively retreating depositional sequence from northwest to southeast were successively accumulated in Beishan, Nei Mongol - Hinggan, and eastern Jilin. In the Beishan area, Permian rocks are characterized by a dominance of Yangsingian basaltic and clastic deposits that lie unconformably over the strata older than Moscovian age and lacks Chuanshanian deposits. Marine faunas are usually dominated by brachiopods and ammonoids but do not contain fusulinids. Paleogeographically, this belt represents a marginal arcwhich ended by early Maokouan time. Behind this volcanic arc is an elongate back-arc

91

Jinta

Stages

....... ~., ~.... Gansu i

Jisu Neimongol

II

Xi U j i m q i n Ulanhot N e i m o n g o l III N e i m o n g o l

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i i ', ', ', ', i

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. . . .

! Oertu Fm (Ct) r Benbatu Fm (C2) i i

i

Figure 10. Correlation chart of Permian stratigraphic sequences in China. The top lines of the column identify the major tectonostratigraphic regions, and the geographic names of type sequences for the provinces. Urmuqi and Jisu of the Northern China Boulder Region are type areas of Northern Xinjian and Beishan - Nei Mongol - Jilin regions respectively. Conformable relationships are indicated by straight lines, disconformity by dash lines, unconformities by saw-tooth margins, faulted boundaries by dotted lines, and facies boundaries by oblique straight lines. Hiatuses are marked by vertical shading, but with a question mark if the time interval of hiatuses have no precise biostratigraphic control [7].

96

The basal boundary of the Permian can be recognized in Permian sequence with Tethyan faunas in China. However, a major sequence boundary and also a bio-evolutionary turning point is located at the base of the Carboniferous Kasimovian Stage. There is no dramatic sea level change or faunal turnover at the beginning of the Permian, i.e. the early Asselian. Attempts to utilize this boundary level in field geology in China are currently discourage. The most prominent difficulties of inter-regional correlation in China are closely related to the long-standing problems of correlation between the Boreal, Gondwana and Pan-equatorial realms. The Permian in Northern Tianshan and the Junggar Basin and the Altay Shan are essentially composed of continental deposits. Permian biostratigraphic successions are closely related to those of the Urals, Russia but are distinct from those of North China and South China. The Lopingian marine strata in the Himalayas lack diagnostic fossils and thus, are hardly possible to correlate with Tethyan successions precisely.

6. A C K N O W L E D G E M E N T We acknowledge the financial supports from Chinese Academy of Sciences [Grant K2951B 1-409] and the National Natural Science Foundation of China [Grant 49672092].

REFERENCES

1. 2. 3. 4.

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35. Xia G.Y., Ding Y.J., Ding H., Zhang W.Z, Zhang Y., Zhao Z. and Yang F.Q., 1996. On the Carboniferous-Permian boundary stratotype in China. Geological Publishing House, Beijing. (in Chinese, with English Abstr.) 36. Chen H.H., Sun S., Li J.L., Heller, F. and Dobson, J., 1992. Permian-Triassic megnetostratigraphy of Wulong Area, Sichuan. Sciences in China, B(12): 1317-1324. (in Chinese, with English Abstr.) 37. Embleton, B.J.J., McElhinny, M.W., Ma X.H,, Zhang Z.K. and Li X.L., 1996. Perm-Triassic magnetostratigraphy in China: the type section near Taiyuan, Shanxi Province, North China. Geophys. J. Int., 126: 382-388. 38. Jin Y.G., Shang Q.H. and Cao C.Q., 1999. Callibration between Late Permian magneto- and biostratigraphic sequences of Tethyan areas. Sciences bulleting of Chian, 44(8): 800-806. 39. Bowring, S.A., Erwin, D.H., Jin Y.G., Martin, M.W., Davidek K. and Wang W., 1998. U/Pb Zircon Geochronology and Tempo of the End-Permian Mass Extinction. Science, 280(5366): 1039-1045. 40. Ishiga H., 1990. Palaeozoic Radiolarians. In: Ichikawa, K. et al.(Editors), Pre-Cretaceous Terranes of Japan. Nippon Insatsu, Osaka. pp. 285-295. 41. He X.L., Zhang Y.J., Zhu M.L., Zhang G.Y., Zhuan S.X., Zheng Y. and Zhu P., 1990. Research on the Late Paleozoic coal-beating stratigraphy and biota in Jungar, Nei Moungol [Inner Mongolia]. China Univ. Min. Techn. Press, Xuzhou. pp. 407 (in Chinese, with English Abstr.) 42. Institute of Geology, Bureau of Geology and Mineral Resources of Xinjiang, and Institute of Geology, Chinese Academy of Geological Sciences, 1987. The Carboniferous and Permian stratigraphy and biota in Kalpin Region, Xinjiang. Press of Oceanography, Beijing. pp.277. (in Chinese, with English Abstr.) 43. Zhou Z.Y. and Chen P.J. (eds), 1990. Biostratigraphy and geological evolution of Tarim. Science Press, Beijing. pp 366 (in Chinese). 44. Liang X.L., 1981. Early Permian cephalopods from Northwestern Gansu and Westem Nei Mongol. Acta Palaeontologica Sinica, 20(6): 485-500. (in Chinese, with English Abstr.) 45. Xia G.Y., 1982. Early Permian fusulinids from Maolipenhong Region in Nei Mongol Zishiqu. Bull. Of The Tianjing Inst. Of Geol. and Min. Res. CAGS., 5: 133-147. (in Chinese, with English Abstr.) 46. Ding Y.J., Xia G.Y., Duang C.H., Li W.G., Liu X.L. and Liang Z.F., 1985. Study on the Early Permian Stratigraphy and fauna in Zhesi District. Inner Mongol. Bulletin, Tianjin Institute of Geology & Mineral Resources, CAGS., 10:1-160. (in Chinese, with English Abstr.) 47. Liu F. and Waterhouse, J.B., 1985. Permian Strata and Brachiopods from Xiujimqinqi Region of Neimongol [Inner Mongolia] Autonomous Region, China. University of Queensland, Department of Geology, Papers, 11(2): 1-44. 48. Han J.X., 1981. General accounts on the fusulinid fossil zones of Early Permian age in the northern part of northeast China. Geol. Rev., 27(6):539-542. (in Chinese, with English Abstr.) 49. Sun H.Y., 1990. Permian fusulinids form the Dasuangou Formation in Yanbian County, Jilin. Acta Mictopalaeontologica Sinica, 7(3):257-264. (in Chinese, with English Abstr.) 50. Jin Y.G., 1985. Permian brachiopoda and palaeogeography of the Qinghai-Xizang [Tibet] Plateau. Palaeontologia Cathayana, 2:19-56. 51. Jin Y.G., Liang X.L. and Wen S.X., 1977. Additional material of animal fossils from the Permian deposits of the northem slope of Mount Jolmo Lungma. Scientia Geologica, 3: 236-249. 52. Norin, E., 1946. Geological Exploration in westem Tibet. In:Ibid. 29, III. Geology, 7: 1-214. 53. Wang X.D., Tetsuo Sugiyama and Katsumi Ueno, 1998. Carboniferous and Permian stratigraphy of the Baoshan Block, West Yunnan, Southwestern China. Permophiles, 32: 38-40.

Persian-Triassic Evolutionof Tethys and WesternCircum-Pacific H. Yin, J.M. Dickins, G.R. Shi and J. Tong(Editors) o 2000 ElsevierScienceB.V. All rightsreserved.

The Permian correlation

of Vietnam, Laos and Cambodia

99

and its interregional

Cu Tien PHAN Research Institute of Geology and Mineral Resources, Thanhxuan, Hanoi, Vietnam

The newly obtained research results allow correlation of the Permian of Indochina with those of China and other regions although with varying confidence. The clearest boundary in the local Permian stratigraphic scheme has been assigned to the base of the Dzhulfian formations. Some new data allow determination of a boundary at the base of the Permian and possibly the Upper Carboniferous - Permian. In Indochina, the fusulinids are of special significance because of their common occurrence and rapid evolution; however the contribution of data from other groups of organisms is and will remain of great significance. Lower and Upper Permian could be retained as series of the Permian according to their general usage and subseries can be recognized in the Upper Permian of Indochina Peninsula and adjacent territories of Southeast Asia and Eastern Asia.

1. I N T R O D U C T I O N This paper will not deal with the whole Indochina Peninsula. It is concerned mainly with Cambodia, Laos and Vietnam, the Indochina countries; however the Permian formation of the three countries will be correlated with those of Thailand, Malaysia of Indochina Peninsula and South China, Japan as well. The first description of the Permian formation of Indochina were presented in the beginning of this century. These are Productus Quartz Sandstone, Fusulinid-bearing Limestone and others [1, 2, 3]. Relating to the tectonostratigraphic interpretation, Fromaget considered the Permian formations of Indochina as parts of Anthracolite Limestone or Indosinias Terrigene [4]. In the view of stratigraphic correlations. Saurin classified the Permian formations into Artinskian, Kungurian, Kazanian, or some fusulinid horizons [5, 6]. Since 1954, in the geological publications, the Permian formations of Vietnam and its relationship with the Carboniferous were described as a monotonous sequence belonging to the "tectonic leveling" of the territories [7]. However on the basis of newly collected data, Permian formations of Vietnam in particular and Indochina Peninsula in general were recognized to be complicated with various composition and abundant mineral resources[8-10]. In the geological development of Vietnam and adjacent territories, the Permian geological events accompanying the change of structural framework, palaeogeography and volcanic

100 activities have been identified.

2. P E R M I A N

VOLCANO

- SEDIMENTARY

FORMATIONS

In Indochina, the following stratigraphic regions have been classified in the geological map of Cambodia, Laos and Vietnam: Vietbac, West Bacbo, Truongson, Kontum Savannakhet, Dalat Stungtreng and Northwest Laos [9]. These regions are separated from the West Thailand region by the Nan Suture (Fig. 1). In the Vietbac, the lower part of Permian is characterized by monotonous, black, grey limestone corresponding to the upper part of the Bacson Formation of Carboniferous Permian. The definition of Permian is mainly based on Schwagerina or Robustoschwagerina, Misellina, Cancellina, Neoschwagerina, Lepidolina - Yabeina horizons of Asselian - Midian [11-15]. Here, the Dongdang Formation of D z h u l f i a n - Darashamian age overlies unconformably on the eroded surface of the above mentioned limestones and comprised basal bauxite beds, shale, chert and limestone. The limestones contain Codonofusiella aff. paradoxa Dunbar et Skinner, Dunbarella sp. in the lower part and Palaeofusulina prisca Deprat, Colaniella parva (Col.), Reichelina pulchra M. Maclay, Neoendothyra eostaffelloidea Liem and Leptodus sp., in the upper part. The Lower Triassic sandstone, silstone containing Claraia, Glyptophiceras overlies the above - mentioned formation with an either conformity or a disconformity [16]. In some places such as Baichay, the Upper Permian comprise quartzite, shale, chert and coal seams. The collected fossils are Meekella cf. ufensis Tchernyshev, Lyttonia sp., Productus gratiosus Waagen, Martiniopsis aff. orientalis Tchernyshev, Spiriferina cambodgiensis Mansuy, Pseudomonotis cf. garforthensis King, Pseudophillipsia cf. acumulata Mansuy,... [1 ]. In the West Bacbo region, the Permian sedimentary sequence is presented mainly by the Lower Permian and may be Upper Carboniferous as well (Table 1). In the southwestern periphery of the region, at Thanhhoa area, the Lower Permian limestone continuous from the Upper Carboniferous limestone; however the Upper Permian mafic volcanics of the Camthuy Formation overlies unconformably the older formations. The formation is composed of volcanics belonging to the picrite - basalt association, 700 - 800m thick. Overlying the mafic volcanics, there are shale, chert, coal shale, coal seams, limonite, hematite beds in places and limestone of the Yenduyet Formation. The thickness of the coal seam varies, from 20 - 30 cm to 6 m. Limonite, hematite beds have the thickness of 3 m, Fe203 varies from 23 - 37% to 62% in places, A1203 22 - 23%, SiO 2 12-17%. The collected fossils in shales comprises Leptodus sp. (cf. L. nobilis Waagen), Squamularia sp., Schellwienella sp., Chonetes sp., Actinodesma sp., Spiriferella sp., Neophricodothyris cf. asiatica Chao and Aviculopecten sp., Oldhamina sp., Marginifera cf. lopingensis (Kayser), Andersonoceras sp., Pseudotirolites sp., Gigantopteris sp., Pterophyllum sp. [18] and Chonitipustula sp., Dielasma sp., Productus (Alexenia ?) sp., Chonetes sp., Spirifer sp., [7]. Similar sections also crop out in Sonla, Laichau along the eastern periphery of the Songma anticlinorium, the collected fossils comprise Peltichia kwangtungensis (Zhan), Acosarina minuta (Abich), Rhipidomella hessensis King, Schuchertella cf. cooperi Grant, Derbyia sp., Waagenites soochowensis (Chao), Spinomarginifera chenyaoyanensis Huang, Marginifera gen. et sp. indet. [17]. The relationship between the Upper Permian and Lower Triassic is conformity or disconformity.

101

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SONLA BACBO

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NORTHWEST

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4.~ i~.../" ..,, /

DALATf

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150 I

225 I

300 Ikm

Figure 1. Stratigraphic Regions of Cambodia, Laos, Vietnam (main land) and adjacent regions. VIETBAC

Stratigraphic region name

/

i

Deep - seated fault

102 In the Da river valley, mafic volcanics have great thickness, various composition and are closely related to ultramafic and mafic intrusions. It seams possible to define 3 magmatic associations from the lower part to the upper part of the section. These are picrite basalt andesite association closely related to the picrite diabase association; basalt komatiite and trachydacite, trachyandesite basalt association. The above association underlie siltstone, shale, marl, sandstone of the Lower Triassic (Olenekian). In the picrite basalt of the picrite basalt andesite association, the percentage of basalt reaches 70 - 80%. According to the petrochemical characteristics, these rocks are rather highly alkaline and high in TiO2. Total alkaline reaches 3% in subultramafic and 3.6% in mafic intrusion; TiO2:1.8 and 2.2 respectively; K20/Na20: 0.38; A1203:8.4 - 24 and FeO: 8.4 -

14%.

Pertaining to the picrite diabase association, there exist dike, veins and subvolcanic bodies of peridotite, picrite diabase and gabbro ophyte belonging to the ultramafic, ultramafic - mafic and mafic groups. The ultramafic group is characterized by low alkalinity. Na20 + K20 < 1%; TiO2 < 1; A1203:5.17 - 5.56; relatively high MgO: 3.0 - 4.5%; Na is predominant. Basalt komatiite association is recently defined in the center of Da river valley and composed of komatiitic peridotite (20 - 40% MgO), komatiitic basalt (12 - 20% MgO), olivine bearing basalt rich MgO and leucocratic basalt (< 8% MgO). Petrochemically, the association is characterized by TiO2:0.12 - 0.19; CaO/A1203:0.8 - 1.1; CaO/TiO2:14.4 - 21.5 and A1202/TiO2:18.3 - 23.4%. The trachydacite-trachyandesite-basaltoid association crops out mainly in the eastern periphery of the region and seems to be of Permian and Permian-Triassic age. This association is characterized by high alkaline, alkaline and subalkaline rocks, SiO2:49.4 - 67.5; TiO2:0.7 - 3.7; A1203: 14; MgO: 0.4 - 6.3; CaO: 1.1 - 8.3%; total alkaline > 4%, among them K > Na in trachyandesite. The contacts between the volcanic formations and other ones are mainly tectonic. The intercalation of sedimentary and volcanic rocks can be seen in some places such as the Hoabinh hydroelectric dam site. In ascending order this section comprises of: 1) basaltic porphyrit, 20 m thick; 2) limestone, marl, 20 m thick; 3) carbonate siltstone containing badly preserved brachiopods, 10 m thick; 4) limestone containing Triticites (?) sp., Pseudofusulina sp., Misellina ovalis Deprat, 20 m thick; 5) basalt, tuffs, 17m thick; 6) sandstone, siltstone, marl containing Ditomopyge sp., Aulacorhyncus protechwensis Grabau et Tien,

Propinacoceras aff. aktubense Rhyzhensev .... 15m thick; 7) limestone containing Misellina ovalis (Deprat), Neofusulina sp., Pseudofusulina sp., 30 m thick [8]. In the Truongson region, Permian and Carboniferous limestones crop out in continuous sections at Quydat, Muongxen of Vietnam and Nonghet, Khammoun, Vangvieng of Laos. Permian limestone contain abundant fusulinids corresponding to the Schwagerina, Robustoschwagerina, Misellina, Cancellina and Neoschwagerina horizons. Uppermost part of the Permian have been observed in places. At Khegiua area, limestones contain Codonofusulina nana Erk, Neoendothyra eostaffelloidea Liem, Palaeofusulina (?) sp., Reicheline (?) sp. [13], and at Camlo area, shales contain Leptodus nobilis (Waagen), Chonetes subtrophomenoides Huang and Meekella kweichowensis Huang [18]. The relationship between the above limestones and older formations is not defined yet. The Permian volcano sedimentary formation of this region is restricted to the narrow band along the fault in Alin area of Vietnam and enlarged in Khangkhay area of Laos. Along the

103 road N017 from Phonsavan to Khangkhay, the formation is composed of grey shale, marl containing Plicatifera sp., Schuchertella sp., Anarsalites sp. of the lower part; red coloured carbonate, siltstones, sandstones of upper part [9]. In the Dalat Stungtreng region, the Daklin Formation of the Upper Carboniferous-Permian crops out in the same name in Vietnam and comprises shale, chert, andesite, basaltic andesite in the lower part; andesite, tufts, sandstone in the middle part; and andesite, basaltic andesite, dacite, rhyolite, marl, limestone in the upper part. The collected fossils are badly preserved bryozoans, crinoids, brachiopods in shale and Sschwagerina sp., Pseudofusulina sp., Verbeekina sp. in the limestone. The volcano-terrigenous formations distributed in the Stungtreng, Preah Vihear, Siemreap of Cambodia can be correlated with those in the Daklin area. The intercalations of volcanic rocks and limestone were observed in the right band of Mekong River, North of Stungtreng, in Chhep and Stungtreng [19, 20]. Permian limestones crop out in Hatien of Vietnam, Campot, Phnomxa and Battambang of Cambodia. The Hatien Formation in Vietnam is characterized by limestones containing Verbeekina verbeeki Genitz, Neoschwagerina margaritae Deprat, Codonofusiella sp., Parafusulina sp., Nankinella sp. and gastropods, rugose corals and crinoids [9, 16]. In Phnomxa of Cambonia, the Permian formation is composed of: 1) basal conglomerate containing fragments of quartzite, sandstone, rhyolite; 2) oolitic limestone; 3) fossiliferous marl, limestone; 4) siliceous limestone containing sponge and radiolarians; 5) massive limestone [ 19]. According to Dottin and Langle [20], the Permian stratigraphic scheme of Cambodia is composed of: 1) limestone containing Yangchienia and Cancellina of Artinskian age; 2) limestone containing Praesumatrina dunbari in Phnom Svai and Verbeekina verbeeki, Neoschwagerina douvillei in Battambang of Kungurian age; 3) limestone containing Yabeina and Lepidolina of Kazanian age; 4) limestone containing Brachiopoda in Battambang of Upper Kazanian and 5) limestones schists in Svaycheck of Tartarian age. The uppermost part of Permian crops out in Tathiet, at the Cambodia-Vietnam border and comprises siltstone, sandstone, shale containing Streptorhyncus cf. perlargonatus (Schlotheim), Uncinunellina sp. (aff. U. timorensis Beyrich), Giriypecten sp., Palaeolima sp. in the lower part and limestone containing Palaeofusulina prisca (Deprat), Colaniella parva (Col.), Reichelina pulchra M. Maclay, Neoendothyra dondangensis Liem in the upper part. The above-mentioned sediments conformably underlie sandstone, siltstone containing Claraia, Otoceras (Motococeras) of the Triassic [ 16, 21 ]. Except the carbonate terrigenous formations, andesite, rhyolite, tufts, aglomerate in Honchong of Vietnam and in Campot of Cambodia were classified into Permian-Triassic in the correlation with those in West Thailand and Malaysia [22, 23]. In the Northwest Laos region, the Songda Formation at the Muongte area of Vietnam is made of coglomerate, sandstone, shale, chert, andesite, rhyolite and limestone containing Pseudofusulina sp., Parafusulina ex gr. japonica (Gumb.), Misellina ex gr. ovalis (Deprat) and Chonetes sp. [7, 9]. In the territory of Laos, the Permian formations comprise also sandstone, shale, tufts and limestone containing Orthoceras sp., Griffitides sp., Productus aagardi at Sayabuli and Pseudofusulina japonica, P. gigantea at Nambac valley [5]. In this region, Fromaget [4] described a coal-bearing formation of Permian age at Soppong. Here, sandstone, shale and coal-shale contain Gigantopteris nicotinaefolia, Cordaites cf. Principalis and Schizoneura gondwanensis. The relationship between the Permian volcanosedimentary, carbonate and coal-bearing formations has not been defined yet.

Table 1 9Permian Stratigraphic Correlation of C a m b o d i a , Laos and V i e t n a m Dalat

West Bacbo

Truongson

- Stungtreng

|

Hatien, Battambang

i

Tathiet

West Hue, Xiengkhoang

Daklin, Stungtreng

Quydat, Nonghet

Sonla, Thanhhoa

Vietbac Vanyen, Hoabinh

Lower Triassic

Lower Triassic:

Otoceras

Claraia and

Lower Triassic 9

Costatoria and

Clarata, Lingula

(Metotoceras) and

Lytophiceras ....

Eumorphotis ....

and Glyptophicera

....................... Yenduvet Formation

Lobatannularia,

Dongdang Format

Palaeofusulina and

Pecopteris,

Palaeofusulina an

CodonofusieUa Horizons

Gigantopteris ....

Codonofusiella

Leptodus Chonetes and Gigantopteris, ...

Volcanics

Claraia .... i -9- - . - - ~ - P e r m i a n - Triassic i Volcanics

...................

Permian - Triassic

Camlo s h a l e s

Volcanics

Leptodus, Chonetes

9

and Dyctyoclostus .... .....................

Tathiet Formation

..................

Palaeofusulina Horizon

Viennam Formation

Horizons Leptodus

Volcanics

Upper pa~ of

!

Hatien (Battambang)

A l i n (Khangldaay)

Formation:

Lepidolina and

Daklin Formation

Neoschwagerina

Verbeekina

Horizons

Pseudofusulina and Schwagerina (?) .... Volcanics

Muonglong

Upper part of

(Nonghet) Damai Formation :

Bandiet Formation

Bacson Formation

Formation 9

Formation:

Neoschwagerina,

MiseIlina, and

Neoschwagerina,

Plicatifera, Anatsalites

Neoschwagerina,

Misellina,

Robustoschwagerina

Misellina,

and Schuchertella ....

Cancellina, Misellina, Robustoschwagerina and

Horizons

Robustoschwager

Volcanics

Robustoschwagerina and

Propinacoceras

and Schwagerina Hor

Schwagerina Horizons

Schwagerina Horizons

Schwagerina ,,--"""

?

Upper part of

Neoschwagerina,

"rtticttes Horizon

...'"""" Horizons

Titicites Horizon

Triticites Horizon

105 3. S T R A T I G R A P H I C C O R R E L A T I O N OF PERMIAN FORMATIONS. The newly obtained data in Cambodia, Laos and Vietnam allow a correlation of Permian formations of the three countries with those of South China and adjacent regions although with different confidence. In the Vietbac region, the boundary between the Neoschwagerina-bearing limestones of the Bacson Formation can be correlated with the base of the Wuchiaping Formation of the Lopingian Series or the top of the Maokou Formation of the Yangsingian Series [24]. The latter have been correlated with the Guadalupian Series [25]. In the West Bacbo, the mafic volcanics of the Camthuy Formation is easily correlated with the Omeishan Basalt Formation in Yunnan and Guizhou of China although their origins may be complicated. The Yenduyet Formation may correspond to two formations of Lopingian Series and the volcanics of Bandiet Formation are also correlatable with those of the Maokou Formation in the above-mentioned provinces of China (Table 2). For long, in China the lower boundary of the Permian has been placed at the base of Chihsia Formation containing Misellina claudiae which was originally defined in the Nanjing area where the formation lies with a hiatus on older beds [24]. This practice has also been followed in Vietnam [ 14, 15]. More recently practice has tended to look for a Lower Permian basal boundary equivalent to the base of the Asselian as used in the Ural area and many other parts of the world. The traditional subdivision is thus rather in a state of flux. As discussed below a return to the orginal definition of the Chihsia has a potential for a clearer correlation with Japan and the two subdivisions of the Upper Permian (for a twofold Permian System), the Yanghsingian and Lopingian [ 10]. The geological events at the top of the Bacson Formation in the Northeast and West Bacbo of Vietnam or the Maokou Formation in the Yunnan and Guizhou of China seem to be unclear in the Truongson and Dalat Stungtreng regions. Fromaget [4] recognized the Moscovian geological event in Indochina. However it is unconfirmed by recent investigations. Some newly obtained data in Vietnam and in Laos allow determination of boundary at the base of the Khangkhay, Daklin and possibly Hatien Formation. May be, this boundary coincided with the boundary in Upper Carboniferous-Permian in the regional column of Khorat Plateau [26, 27]. The Tathiet Formation at the uppermost part of the Saigon river can also be correlated with the limestones in the Doi Pha Pleung, Amphoe Ngao and Changwat Lampang areas and in some other places [28]. The Permian - Triassic Honchong Formation may also be equated with the volcanic sequences of the same age in Thailand and Malaysia [20, 22]. Considerable progress has recently been made in Central and Western Thailand. In Central Thailand, strong folding and orogenic activity with flysh formation has been described in the Kubergandian- Midian [29]. In Western Thailand, an unconformity seems to present at the base of the Permian or Upper Carboniferous sequences. However the detailed descriptions and age remain unclear [30, 31]. In most recent publications [32, 33], a local subdivision of the Permian has been used, in which the Lower Permian remains poorly known, the rest being composed of Kubergandian and Murgabian belonging to Middle Permian and the Midian together with the Dzhulfian and presumably the Dorashamian and equivalents belonging to Upper Permian. Whether the Midian-Dzhulfian event is present in Thailand as found in Vietnam, China and Japan is thus unclear. The Middle Permian, however, is apparently represented in the beginning of the orogenic event in the Kubergandian, and Dawson [32, 33]

Table 2 9Stratigraphie Correlation of Permian in Vietnam and Adjacent Regions Traditional standard Southern

Proposed classifi cation of SPS

Urals

Changhsinglan

Armenia Iran, Pamir

South China Changhsingian Palaeofusuhna smensls P. minima Gallowaynella meitwnsis Wuchiapin~oian Nankinella simplex Codonofuswlla kwangstensts

Darashamian

-~o Wuchiapingmn Tartarian

i

Wordian

Ufimian

Roadian

Kungurian

Kungurian

.~

Artinskian

Murgabian

=

Kubergandianian

~:~ >-

Blorian

Yakhtanshian

Sakmarian

Sakmarian

Sakmarian

Asselian

Asselian

Asselian

[251

G

Maehaman

Lepidolina kumaensis Lepidohna kumaensts

i

Palae@r

Palaeofusulina Condonofuswlla

slnensIs

Gallowaynella Colaniella Codonofuslella

Jin et al (1997)

[251

Kotlyar, 1987 Leven et al, 1993 in Jin et al., (1994)

[241

y.

Lengwuan Metadoliolina multtvoluta Yabema gubleri Kuhfengian Neoschwagerma margaritae N. craticulifera

Midian

._~

Chuvashov, 1993 in Jin et al., 1997

Nabekoshian Palaeofusulina sp.

~o

Vietnam

Thailand

E

Capitanian

Kazanian

Artinskian

Dzhulfian

South Kitakami, Japan

=

Iwaizakian Lepidolina multiseptate Kattizawan Colantella douvillei Monodwxolina matsubaishi Misellina claudine

Xiangboan N. simplex Cancelhna ne oschwagerinoides Luodianian Mtsellina claudiae Brevaxina dyhrenfurthi Longlinian Panurina darvastca Darvasites ordinatus Zisonglan Robustoschwagerina schwellwiem R.ziyunensis Sphaeroschwagerina moellert Svulgaris Pseudoschwagerina muongthensts

9

Ne oschwagerma Verbeekina Parafusulina

Kabayama

N 9 9

E

Pseudofusulina fusiformis p. vulgaris (s. l) Kuwaguchi Rugosofusilina alpina Zelha nunosel

Minato et al., 1965 in Dickins (1990) [35] Sheng & Jin (1994) [24]

Lepidolina Neoschwagerina Cancellina

Pseudofusulina slameilsls

Pse udoschwagerma talensis Robustoschwagerina Triticites suzukit

R.Invagat - Helmck (1994) [281

Misellina Robustoschwage Pseeudofusulina Pseudoschwage Schwagerina

This paper

107

for example, suggest an unconformity might be present at this level. In the Malayan Peninsula, the Chuping Limestone is generally regarded as equivalent to the Rat Buri Limestone. It is structural relationships, however, are not at all clear. Metcalfe [34] has argued that the collision occurs at the Permian- Triassic boundary inferring a major period of tectonism at this time because of a lower order of folding associated with the Bentong - Raub Suture in the Triassic compared with the Permian. Whether this is a local or general future from the existing evidence is an open question and why the folding in Central Thailand should not also represent a collision requires an answer. A threefold subdivision of the Permian is used in Japan: Lower, Middle and Upper Permian [35]. The lower Permian corresponds to the Lower Permian of the Russian twofold subdivision and the Lower Middle and Upper Permian correspond to the Upper one of the Russian sequence. Further the Upper Permian of Japan corresponds to the traditional Upper Permian of China. The Kanokura Series making up the Middle Permian has Misellina claudiae at its base according to Ozawa [36] and has marked discordance and magmaticvolcanic and tectonic activity. Reliable correlation is available with China with the boundary of the Konokura and Toyoma Series (the Upper Permian) corresponding to the Maokou Wuchiaping boundary. As in China (and Vietnam) in Japan this boundary is associated with complex volcanic and tectonic activities.

CONCLUSION The newly collected data from Cambodia, Laos and Vietnam allow a varying degree of correlation of the Permian of Indochina with those of adjacent areas. The review suggests that the most suitable scale for the Permian of this region is a threefold one that can be fitted in to the framework of the traditional twofold Permian System. This scale reflects data from many groups of organisms especially the fusulinids. In this scheme, the possibility of retaining the Chihsia according to its original definition would allow using the names Yangsingian and Lopingian as Subseries names of the Upper Permian. Retention of Bolorian in the Lower Permian and Midian in the lower of the two Upper Permian Subseries is also recommended. For this, a study and comparison of critical fusulinids such as Misellina claudiae could prove to be of considerable significance.

ACKNOWLEDGEMENTS The author is very thankful to the Departements of Geology and Mines of Cambodia, Laos and Vietnam for kind support for geological surveys. Warms thanks are extended to Dr. J.Dickins, Prof. Yin Hongfu and Dr. Guang R.Shi for very valuable discussions.

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1. 2.

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11. 12. 13. 14.

H. Mansuy, Faunes des calcaires ~. Productus de i'Indochine, 1e serie. Mere. Serv. Geol. Indoch, Vol II, fasc. 4, Hanoi (1913), 137 pp. J. Fromaget, L'Indochine frangaise, sa structure geologique, ses roches, ses mines et leur relation possible avec la tectonique. Bull. Serv. Geol. Indoch, Vol XXVI, fasc. 2, Hanoi (1941), 140 pp. E. Saurin, Les Fusulinides des calcaires de Kylua, Langson. Bull. Serv. Geol. Indoch, Vol XXIV, fasc. 5, Hanoi (1950), 36 pp. E. Saurin, Indochine. In Lexique stratigraphique Internationale. Centre Nationale de la Rech. Scient., Paris (1956), 140 pp. A.E. Dovjikov (ed) et al, Geology of Vietnam. Explanatory note to the geological map of North Vietnam, Hanoi (1965) in Vietnamese, 584 pp. Phan Cu Tien, Upper Permian- Lower Triassic sediments in Northwest Vietnam. Nhung van de dia chat TBVN, Hanoi (1977), in Vietnamese, 109 - 151. Phan Cu Tien (ed) et al, Geology of Cambodia, Laos and Vietnam. Explanatory note to the geological map of Cambodia, Laos and Vietnam, 2 nd edition, Hanoi (1991), 156 pp. Phan Cu Tien and J. Dickins, Subdivision and correlation of Permian Stratigraphy of Vietnam and adjacent regions of Southeast Asia anf Eastern Asia. Journ. Geol. Series B, Vol. 5-6, Hanoi (1994), 3747. Nguyen Van Liem, On the stratigraphic subdivision of the Upper Paleozoic in the 1:500.000 geological map of North Vietnam. Dia chat, Vol. 74, Hanoi (1967), in Vietnamese, 6 - 8. Nguyen Van Liem, The Bacson Series of Vietnam. Stratigraphic correlation between sedimentary basins of the ESCAP region. Min. Res. Dev. Series 45, United Nation, New York (1979), 62 pp. Le Hung, New data on the biostratigraphy of Upper Paleozoic in North Vietnam. Tuyen tap Khoa hoc ky thuat, Hanoi (1975), in Vietnamese, 142- 183. Le Hung, Permian stratigraphy in Vietnam and its correlation with equivalent formation in Indochina.

Proc. 1st Conf. Geol. Indoch., Hanoi (1986), 89-100. 15. Tran Duc Luong and Nguyen Xuan Bao (eds) et al, Geological map of Vietnam, 1:500 000 scale, Hanoi (1988). 16. Vu Khuc and Bui Phu My (eds) et al, Geology of Vietnam. Vol. 1. Stratigraphy, Hanoi (1988), in Vietnamese, 174 - 214. 17. G. Shi and S. Shen. A Changhsingian (Late Permian) brachiopod fauna from Sonla, Northwest Vietnam. Journal of Asian Earth Sciences, Vol. 16, n o 5-6, (1998) 501 - 511. 18. Tran Thi Chi Thuan, Les brachiopodes permiens de Camlo. Ann. Fac. Scient., Univ. Saigon (1962), 485498. 19. J. Gubber, Etudes geologiques darts le Cambodge Occidental. Bull. Serv. Geol. lndoch., Vol XXII, fasc. 2, Hanoi (1935), 176 pp. 20. BRGM, Cartes geologiques de reconnaissance du Cambodge ~, l'echelle 1:200.000 et les notices explicatives. Paris (1968-1972). 21. H. Fontaine et al, The Permian of Southeast Asia. CCOP. Tech. Bull., Vol 18 (1986), 171 pp. 22. B.K. Tan and T.T. Khoo, Review of the development in the Geology and Mineral resources of Malaysia and Singapore. Proc. 3 rd Reg. Conf. Geo SEA, Bangkok (1978), 655-671. 23. S. Bunopas, The regional stratigraphy, paleogeographic and tectonic events of Thailand and continental Southeast Asia. Stratigraphic correlation of Southeast Asia, Bangkok, (1994), 2-14. 24. Y, Jin, J. Utting and B. Wardlaw (eds) et al, Permian Stratigraphy, Environment and Resources. Vol.l: Paleontology & Stratigraphy, Nanjing (1994), 262pp. 25. Y. Jin et al, Permian chronostratigraphic subdivision. Episodes, Vol. 20, n~ (1997), 10-15. 26. C. Mouret, Geological history of Northeastern Thailand since the Carboniferous relation with Indochina and Carboniferous- Early Cenozoic evolution model. Stratigraphic correlation of Southeast Asia, Bangkok (1994), 132-158. 27. O. Chinoroje and M. Cole, Permian carbonates in the Dao Ruang #1 Exploration Well- Implications for Petroleum Potential, Northeast Thailand. Intern. Conf. Geology, Geotechnology and Mineral Resources of Indochina, Khon Kaen (1995), 563 - 576.

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28. 29. 30. 31. 32. 33. 34. 35. 36.

R. Invagat-Helmck, Paleozoic paleontological evidence of Thailand. Stratigraphic correlation of Southeast Asia, Bangkok (1994), 43 - 54. D. Helmck and H. Lindenberg, New data on the Indosinian orogeny from Central Thailand. Geol. Rdsch. Vol. 72, n ~ 1 (317 - 328). S. Chantaramee, Tectonic synthesis of the Lansang area and discussion of regional tectonic evolution. Proc. Reg. Conf. Geo SEA, Bangkok (1978), 177 - 186. T. Thanasuthipitak, Geology of Uttaradit area and its implication on tectonic history of Thailand. Proc. Reg. Conf. Geo SEA, Bangkok (1978), 187 - 197. O. Dawson, Fusuline foraminiferal biostratigaphy and carbonate facies of the Permian Ratburi limestone, Saraburi, Central Thailand. Jour. Micropalaeontology, Vol.2 (1993), 9-3. O. Dawson et al., Permian foraminifera from Northeast and Penisular Thailand. Stratigraphic correlation of Southeast Asia, Bangkok (1994), 323 - 332. I. Metcalfe, Gondwana dispersion and Asia accretion. Journ. Geol. Series B, Vol. 5 - 6, Hanoi (223 267). J. Dickins, Permian of Japan and its significance for world understanding. Proc. Shallow Tethys 3, Sendal (1990), 343 - 353. T. Ozawa et al., Biostratigraphic zonation of Late Carboniferous to Early Permian sequence of the Akiyoshi Limestone Group, Japan and its correlation with reference section in the Tethys region. Proc. Shallow Tethys 3, Sendal (1990), 327 - 341.

Persian-Triassic Evolutionof Tethys and WesternCircum-Pacific H. Yin, J.M. Dickins, G.R. Shi and J. Tong (Editors) 92000 ElsevierScienceB.V. All rights reserved.

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The m a r i n e P e r m i a n of N e w Z e a l a n d H. J. CAMPBELL a alnstitute of Geological and Nuclear Sciences Ltd., PO Box 31-312, Lower Hutt, New Zealand. This paper summarises what is known of the marine Permian rocks of New Zealand in terms of terranes, their known faunal content, biostratigraphic age control and correlations. Fossiliferous sedimentary rocks of Permian age are comparatively restricted in distribution in New Zealand but are recognised within six tectonostratigraphic units or terranes (Fig.l). Well-exposed, readily mappable and stratigraphically coherent fossiliferous successions are confined to two of these terranes, the Brook Street and Dun Mountain-Maitai Terranes. Strata within these two terranes are host to all documented New Zealand Permian biostratigraphic units [1, 2]. Permian sequences in all terranes are exclusively marine or marginal marine. 1. T E C T O N O S T R A T I G R A P H I C F R A M E W O R K OF N E W Z E A L A N D Two major tectonostratigraphic divisions are recognised in New Zealand (Fig. 2). These are the Western Province and the Eastern Province, and each consists of a number of terranes [3, 4]. All Eastern Province terranes were metamorphosed during Late Jurassic Early Cretaceous time. Western Province terranes were variably metamorphosed in the Paleozoic and again in the Mesozoic. Correlation between Eastern Province and Western Province metamorphic events, if any, is unclear.

1.1. Western Province The Western Province [5], bordering the Tasman Sea, is essentially a fragment of Australian continental foreland comprising distinct Paleozoic terranes (Buller, Takaka). This 'province' constitutes the dispersed New Zealand segment of autochthonous Gondwanaland. The Western Province is notable because it includes the oldest known rocks in New Zealand (Middle Cambrian) and it is also host to extensive plutonic rocks of Cretaceous age that are conspicuously absent within the Eastern Province [6]. A fragmentary record of a Gondwanaland cover sequence with strong eastern Australian affinities is preserved within the Western Province and this includes Devonian, Permian and Triassic successions and Jurassic dolerite of Ferrar Magmatic Province affinity [7, 8]. Curiously, there is no fossil evidence of a Carboniferous sedimentary record.

112

170 ~ E

175 ~ E

N

WESTERNPROVINCE undifferentiated

35 ~ S

35 ~ S

MEDIANTECTONICZONE Median Batholith

oQ

EASTERNPROVINCE CentralArcTerranes

MEDIAN TECTONIC ZONE

1. BrookStreet 2. Murihiku 3. Dun Mountain- Maitai

TorlesseSuperterrane

WESTERN PROVINCE/

4. Caples 5. Waipapa 6. Rakaia 7. Esk HeadMelange 8. Pahau 9. Waioeka

40~ S

EASTERN PROVINCE

40 ~ S

Australian Plate Pacific Plate

Torlesse Superterrane

45"S

45~ S

EASTERNPROVINCE --

2

CentralArc Terranes

MEDIAN TECTONIC ZONE (MTZ)

0 I

.,,

165 ~' E I

I

170 ~ E I

175,-~ E I

1 O0 I Kilometres

200 I

180oE I

I

Figure 1. Simplified basement map of New Zealand showing distribution of the major tectonostratigraphic entities: provinces, terrane assemblages, terranes and their fault boundaries. Key components of the modem tectonic setting are also shown.

GEOLOGICAL

TIME

Series

Stage

TRIASSIC

Olher

Relevant Regional Stage Correlation

Changhsingian Lopingian Wuchiapingian

EASTERN PROVINCE

NEW ZEALAND BIOSTRATIGRAPHY

Stages

Bmchiopod Zones

Cenlral Arc Terranes Dun Mountain Maitai

Brook Street

Makarewan

W. rostrata

I

Wai~ian

M. planata S. spinosa

Puruhauan

P. multicostata M. woodi

iFormation S =Wooded Pk. Lst.

Mudhiku

Tramway

,

\

.

, ..

\

Guadalupian

Wordian Roadian

Ufimian Kungurian

Cisumlian

Artinskian Sakmadan

E ova~is W. ingelarensis E maxwelli

Barrettian

E.discinia S. supplanta

Irenian Filippovian

Waipapa

C,R,S

\ \ -... \

.

C,R S

\

\ \

\

.

\

.

Mangapirian

E. prideri S. adentata

Telfordian

N home# N. zea/andicus

.

.

.

P,S Productus Creek Group

. \

\ \

\

\

.

\ .... \

\

\

\

\

\

\ \

\

\

\ \

\ \.

\\\\,

\\\ \\\

\

\ \.

-

\\

,

, . . . . . . . \ \ \

\\,

\ \ \ \ " . . . . \ \ \ \ "

Sterlitamakian

\ \ \ \ "

. . . . -,, \

-,, \.

\

\

\.

\.

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\\\\',

-..

-..

\\\ \\\

\.. \ _ . \ . . \ . \ ,. \ -., \ . ,

R radiolarians S shellyfauna ( brachiopods,molluscs, bryozoans, echinoderms)

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C conodonts F fusulines P palynomorphs

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.

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. . . . .

\.

\\\\\ S Takitimu Group

Flowers Formation S

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FI

.

\

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\

M. solita

Asselian CARBONIFEROUS

Rakaia

T. elongata

Flettian

Midian Murgabian Kubergandian

\

\

.

Kazanian

Caples

Kudwao Group S,P

\

Capitanian

WESTERN

I!,ROVINCE

TorlesseSuperterrane

~ \ \ \ \

MV MantleVolcanics WB Wairaki Breccia

Figure 2. Correlation diagram for marine Permian sequences within New Zealand,showing age range of terranes (Brook Street, Murihiku etc.) and relative position of key faunas through geological time. Only relevant lithostratigraphic units are named for any one terrane. Biostratigraphic information from all major terranes and sedimentary basins are included. Jagged lines denote limit of rock record; wavy lines denote unconformity. Shading denotes no known rock record.

~

114

1.1.1. parapara Group There is one known Permian succession within the Western Province, namely the Parapara Group [9]. It has very limited (200m) of possible Late Carboniferous-Early Permian age. The youngest unit within Parapara Group (Walker Formation; >200m thick) contains detrital zircons suggesting that it cannot be older than Early Triassic [9]. 1.1.2. Median Tectonic Zone The Western Province is separated from the Eastern Province by the Median Tectonic Zone [10], a belt of long-lived subduction-related magmatic rocks that have recently been interpreted as a Cordilleran batholith (Median Batholith) [11, 12], evidence of a major crustal boundary. It includes some intrusives of Permian age. 1.2. Eastern Province The Eastern Province [3] is an assemblage of accreted allochthonous terranes making up northern New Zealand and the Pacific margin in the south. Two distinct groupings of terranes are recognised on the basis of gross composition. The first includes three terranes of island arc association, dominated by volcaniclastic sediment. These are the Brook Street, Dun Mountain - Maitai and Murihiku Terranes, referred to as the Central Arc Terranes (=Hokonui Assemblage [4] ). They occupy a central position between the Western Province and a second eastern group of Eastern Province terranes referred to as the Torlesse Superterrane (=Te Anau and Alpine Assemblages [4] ). The Torlesse Superterrane is an assemblage of five terranes that includes vast areas and volumes of predominantly quartzofeldspathic sediment that must have been derived from dominantly terrigenous granitoid sources located outside the New Zealand sector but still within eastern Gondwanaland. These terranes include Caples, Rakaia, Waipapa, Pahau and Waioeka Terranes [13]. The Waipapa Terrane also includes quartzofeldspathic sediment but is characterised by finer-grained, thinner-bedded lithologies suggestive of a more distal location with respect to an accretionary sedimentary wedge. It also appears to include a greater proportion of rocks of oceanic association (chert, hemipelagite, limestone and basalt) than do other terranes within the Torlesse Superterrane. Within the Eastern Province, fossiliferous marine Permian rocks are known from the Brook Street, Dun Mountain-Maitai, Murihiku, Caples, Rakaia and Waipapa Terranes (Fig. 2). 1.2.1. Central Arc Terranes 1.2.1.i. Brook Street Terrane The Brook Street Terrane is an Early to Late Permian oceanic volcanic arc and includes a 14-16 kilometre thick sequence of moderately metamorphosed volcanic and volcaniclastic

115 rocks of mainly basaltic-andesite composition with minor rhyolitic and dacitic lithologies. It comprises a series of discrete successions, including the fossiliferous Takitimu and Productus Creek Groups. Fossils include bryozoans, corals, brachiopods, rostroconchs, bivalves, gastropods, conulariids, rare nautiloids, fragmentary echinoderms, rare trilobites, fish and plant remains, palynomorphs and trace fossils. No ammonoids, conodonts or radiolarians have been recovered from these rocks. The Takitimu Group is thick and mostly unfossiliferous but does contain several biostratigraphically important fossil horizons [2]. It is overlain conformably by Productus Creek Group [14, 4]. The Productus Creek Group (c.l,000m thick) contains the richest and most diverse Permian faunas known from New Zealand. Recent stratigraphic interpretation [4] suggests that there are just two units within the Productus Creek Group: the Mangarewa Formation and the Glendale Limestone. Two other fossiliferous Permian units previously attributed to the group (Hawtel Formation, Wairaki Breccia) are treated as allochthonous out-of-sequence tectonosedimentary bodies within the Letham Ridge Thrust Fault [4]. One other recent study suggests an even more complex structure for Productus Creek Group, partly on the basis of biostratigraphic interpretation [ 15]. This analysis requires testing but for the purposes of this review the simpler interpretation is adopted [4]. Mangarewa Formation is especially fossiliferous but thin (410-1,000m 4. Late Middle Triassic Tongchuan Formation. It includes a coarser lower member, dominated by sandstone, and a finer upper member, composed of interbedded fine sandstone, siltstone and shale intercalated with many oil shale layers. It yields more than 30 species of plants, which are characterized by Tongchuanophyllum, Danaeopsis magnofolia, D. marantacea, Annalepis and the large-sized Equisetites and Neocalamites, together with Pleuromeia. Based on analysis of the flora, its age is Middle Triassic. The sporopollen assemblage is similar to that of the Ermaying Formation, while the bivalves are characterized by the Unio-Shaanxiconcha longa group, but no definite Sibireconcha has been found, indicating an age probably older than the Yanchang Group. The conchostracans and ostracods are similar to those of the Yanchang Group. In addition, there are also the pisces Hybodus youngi and the plesiosauridae. 100-596m 3. Early Middle Triassic Ermaying Formation. It is composed of greyish white, yellowish green and yellowish pink quartzose arkose in the lower member and dominated by purple silty mudstone, containing calcareous and gypsum nodules in the upper member. This formation abounds in the Sinokannemeyeria Fauna, with Sinokannemeyeria, Parakannemeyeria, Shansisuchus, Sinognathus and Shansiodon in the upper member and Paoteodon, Ordosiodon, Ordosia, Shanbeikannemeyeria and Parakanne-meyria in the lower member. The plants include Protoblechnum wongii, Bernoullia (Symopteris) cf.

201

zeillerL Aipteris wuziwanensis, Todites shensiensis, Annalepis sp., Pleuromeia wuziwanensis and Voltzia walchiaeformis, while the sporopollen is represented by the Punctatisporites-Chordasporites-Plicatipollenites assemblage. Based on comprehensive analysis of fossil vertebrates, plants and other groups, this formation is of Early Middle Triassic age. 416-700m 2. Late Early Triassic Heshanggou Formation. It is composed of purplish red sandy mudstone interbedded with fine arkose sandstone. The fossils include the plants Pleuromeia sternbergi, P. rossica, Yuccites? sp., Voltzia sp., Neocalamites sp., Equisetites sp.,Neuropteridium sp. and Anomopteris mougeoti, the sporopollen VerrucosisporitesLundbladispora-Taeniaesporites assemblage, the vertebrates Fugusuchus hejianensis, Procolophonidae, Benthosuchidae, Ceratodus heshanggouensis and Ordosia, together with 4 species of the ostracod Darwinula. The vertebrates correspond to the Olenekian Fuguan stage of Lucas (1998) and plants to the Early Triassic-Anisian Pleuromeia-Voltzia Flora. 103-280m 1.Early Early Triassic Liujiagou Formation. Greyish purple arkose in the lower part, and greyish purple feldspathic silicarenite interbedded with siltstone in the upper part. The fossil plants include Pleuromeia rossica, P. jiaochenensis, Crematopteris sp., Yuccites sp., Neoglossopteris shansiensis, Gangamopteris? qinshuiensis, Phyllotheca yusheensis and Samaropsis milleri, the last four species generically affine to members of the Glossopteris Flora, thus showing the essential significance in biogeography. The sporopollen is represented by the Lundbladispora-Taeniaesporites-Cycadopites assemblage. In addition, there are also conchostracans, Apus and vertebrate fragments. The sporopollen, plants and conchostracans all point to the Early Triassic. This formation is tentatively correlated to early Early Triassic. 350-633m conformity Upper Permian Shiqianfeng Formation

2.2.2. North Tianshan-Junggar (Fig. 1, II14) The sequence of Junggar is as follows [8]. Lower Jurassic Badaowan Formation conformity 5. Late Triassic Haojiagou Formation. Grey mudstone, siltstone and fine sandstone, sometimes intercalated with conglomerate, carbonaceous shale and coal streaks. Both bed 4 and bed 5 yield basically similar plants, bivalves, gastropods, conchostracans, insects and Apus. The flora contains 37 known species in 25 genera, belonging to the Yanchang Flora. This indicates that the Huangshanjie and Haojiagou Formations are Late Triassic in age. 40-100m 4. Late Triassic Huangshanjie Formation. Greyish green lacustrine mudstone and siltstone intercalated with carbonaceous mudstone and limestone lenticles, yielding pisces Sinosemionotus. 15-450m 3. Middle to early Late Triassic Karamay Formation. Red mudstone, intercalated with a small amount of greyish green sandstone; upper part yields the pisecs Fukangichthys longidorsalis, Bogdania fragmenta and Fukangolepis barbaros, hence probably Upper Triassic; lower part yields vertebrates Parakannemeyeria, Sinosemionotus, Parotosaurus, Turfanosu-chus and Vjushkovia, alternated with and overlain by the Danaepsis-Bernoullia (Symopteris) Flora, and thus Middle Triassic. In addition, this formation also yields relatively abundant bivalves, conchostracans, ostracods, sporopllen, charophytes, Apus and

202

Palaeoniscus. 20-400m 2. Late Early Triassic Shaofanggou Formation. Purplish red sandstone intercalated with mudstone containing sporopollen of late Early Triassic age, also Labyrinthodontia and ?Lystrosaurus. 1. Early Early Triassic Jiucaiyuan Formation and top of Guodikeng Formation. They are composed of red mudstone and greyish green sandstone, yielding Dicynodontia-dominated vertebrates Prolacertoides, Santaisaurus, Chas-matosaurus, Lystrosaurus and Jimusaria, and the Darwinula minuta ostracod assemblage, thus belonging to the early stage of Early Triassic. Formations 1 and 2 have an overall thickness of 200-600m. conformity Upper Permian Goudikeng Formation 2.3. Other depositional areas (Text-fig. 1, Ill 2s, II 21) Besides the Shaanxi-Gansu-Ningxia basin, there are similar continental deposits in Yanshan and southern Northeast China, North Qilian-Hexi corridor-Beishan area and scarcely in South Tianshan. In the South Qilian area there developed marine deposits of platform type.

3. TRIASSIC OF THE EASTERN TETHYS OF EURASIA (Fig. 1, III) During the Triassic, the Tethys was an archipelagic ocean [5], composed of a mosaic of northward drifting blocks separated by rift seaways and micro-oceans. The demarcation line of northern or Eurasian and southern or Gondwanan Tethys probably lies along the YarlungZangbo line (Yin and Lin, 1994). The Eastern Eurasian Tethys consisting of areas within Chinese territory up to Karakorum is here called the Cathaysian Tethys, which is again subdivided into two parts along the Longmenshan--Red River (Song Hong) line. The eastern Cathysian Tethys, or South China, is now mainly covered by platform deposits such as in Yangtze, Cathaysia and part of Indochina Blocks, whereas most basinal sediments have not been preserved except in the Youjiang Basin. The western part, or the now Tibet-Qinghai Plateau, involves a series of paleo-latitudinally arranged blocks, represented by platform type and paraplatform type continental or marine Triassic and separated by what are now folded belts with major deep fractures and ophiolite zones. From south to north they are the Gangdise-Nyainqentanglha-(turning south) Baoshan block, the Bangong Co-Nujiang Folded Belt, the Karakorum-Qiangtang-Tanggula-Qamdo-(turning south)-Lanping-Simao block, the Bayan Har-Songpan-Garze Folded Belt and the Qinling Folded Belt.

3.1. Triassic of the Tibet-Qinghai Plateau The Qiangtang-Qamdo area and western Qinling Belt are chosen to represent this important Triassic area of China. 3.1.1. Qiangtang-Qamdo Area (Fig. 1, III~ a) The Lower-Middle and the Upper Triassic are better represented respectively in Qiangtang and Qamdo [9,10]. In the Kamru-Caka Formation of Qiangtang, the lower member contains two cycles composed of conglomerate, feldspathic arkose, siltstone and silty shale, totaling more than 630m thick. Faunal data permit recognition of three assemblages, from older to younger, the Claraia stachei assemblage, the C. aurita assemblage and the Eumorphotis

203

multiformis assemblage of Induan age. The middle member is a large suite of grey calcirudite, thin-bedded limestone and marl interbedded with siltstone and silty shale, nearly 1,000 m in thickness, containing the Eumorphotis inaequicostata-Pteria cf. murchisoni assemblage, and corresponding to early-middle Olenekian. The upper member contains silicarenite (100m) in the lower part and limestone (about 380m) in the upper, yielding the Spathian ammonoid Tirolites assemblage. In the Middle Triassic Kangnan Formation, the lower part contains grey sandstone, 90m thick, which grades upward into calcareous sandstone interbedded with sandy limestone, also 90m thick, while the upper part is composed of greyish black thin-bedded limestone, more than 100m thick, containing Anisian ammonoid, bivalve and brachiopod assemblages. In Qamdo [9,11], The lowermost horizon of the Triassic, the Dongdacun Formation, is a suite of grey rocks composed of sandstone, siltstone and mudstone in the upper and lower parts, and limestone in the middle part, totaling 840m in thickness. This contains fossil bivalves of the Middle to the Upper Triassic age. In some places, the lower part assumes a red color. The unit unconformably overlies the pre-Carboniferous schists, and underlies the Upper Triassic Jiapila Formation with a slight angular unconformity. The Upper Triassic may be divided in ascending order into the purplish red clastic rocks of the Jiapila Formation, the limestone of the Bolila Formation, and the coal measures of the Bagong Formation. The Jiapila Formation (2,161m thick) yields such fossils as Myophoria (Costatoria) mansuyi of Carnian age. The Bolila Formation (about 500m thick) is extremely rich in fossils of many groups, among which the ammonoids include 10 genera and 16 species, such as Cyrtopleurites bicrenatus, Anatibetites kelvini and Placites oxyphyllus of middle Norian age. Brachiopods are the most numerous, largely belonging to the Late Triassic, while the bivalves include Halobia cf. superbescens, H.cf partschi, also mainly of Norian age. In addition, there are also corals. The Bagong Formation may be divided into the Adula Member (below) and the Duogaila Member (above). The former is composed of black to greyish black shale intercalated with coal streaks, yielding Norian bivalves, such as Burmesia lirata, Costatoria napengensis and Indopecten, while the latter is composed of interbedded sandstone, siltstone and shale intercalated with coal seams, yielding D.-C. Flora and brackish bivalves, and is in conformable contact with the overlying Jurassic Chaya Group. 3.1.2. The Bayan Har-Songpan-Garze Folded Belt (Fig. 1, III14) This is represented by an extensive distribution of Triassic strata lying to the north and east of the HohXil-Jinshajiang Deep Fracture and to the west of Longmenshan. It has the same developmental history of the Proterozoic basement and Palaeozoic up to Middle Triassic platform as the Yangtze Platform, and the Late Triassic turbidite basin as the Qinling Belt. The Triassic development of the Bayan Har Folded Belt resembles that of the Qinling Belt and represents from the Induan-Anisian platform to the Ladinian-Late Triassic rift and sag deposits resulting from Indosinian palingenetic activities.

3.1.3. The western Qinling Folded Belt (Fig. 1, llllS). This belt is characterized by passive-margin deposits from the Lower Triassic to the Anisian that belonged to the northern margin of the Yangtze Platform. During the Ladinian, slope debris-flow calcirudite and flysch appearred, indicating rift and sag of the platform and development of a mobile belt. This lasted into Late Triassic until the terminal-Triassic orogeny. The stratigraphy may be stated as follows, taking the Guojiashan-Daheba (Dangchang County) section of Gansu as an example [12].

204 fault 7. Late Triassic Daheba Formation. Siltstone, calcareous siltstone, shale, micrite, fine greywacke and quartzitic arkosite, usually constituting rhythmic sequences, with carbonate contents decreasing upward; sediments containing turbiditic structures like graded beddings, flute and groove casts and yielding Late Triassic palinomorphs (30 species) and plants. > 2000m 6. Carnian(?) Dengdengqiao Formation. Greyish black thin- to medium-bedded limestone, containing Late Triassic radiolarians Betraccium microporum, Archaeospongoprunum collar and Flustrella spp., tentatively placed in the Carnian stage. 200m 5. Late(?) Ladinian Huashiguan Formation. Thin-bedded limestone, siltstone and slate, forming flysch intercalated with brecciform limestone, tentatively placed in the late Ladinian stage. 2400m 4. Early Ladinian Qinyu Formation: its upper part composed of siliceous limestone; lower part composed of thick-bedded of massive limestone, containing Ladinian conodonts Neogondolella mombergensis and N. excelsa, and a basal black shale, yielding the bivalve Daonella cf. moussoni, of early Ladinian age. 990m 3. Anisian Guojiashan Formation. Grey, thick-bedded to massive limestone, containing the bivalves Leptochondria subillyrica, L.subparadoxica, Bakevellia inaequivalvia and B. acutaurita, the gastropods Worthenia sp. and Naticopsis sp., the ammonoids Procladiscites? sp. etc., and the brachiopods Pseudospiriferina sp. and Parantiptychia sp., all being Anisian. 280m 2. Spathian Maresongduo Formation. Grey, thick-bedded, crystalline dolomitic limestone, dolomite, and purplish red micritic limestone, with evaporite-solution brexccia tens of meters thick at the top. Fossil zonation in ascending order: conodonts Neospathodus triangularis zone, N. hungaricus-N, hameri zone, and bivalves Chlamys weiyuanensis Bed, all being Olenekian. 882m 1. Griesbachian-Smithian Zalishan Formation. Grey thin- to medium-bedded micrites intercalated with silty shale, including respectively, in ascending order, 4 conodont zones: Hindeodus parvus, Neospathodus dieneri, N pakistanensis and PachycladinaParachirognathus, and 3 bivalve beds: Claraia concentrica, C. aurita and EumorphotisEntolium. 628m conformity Upper Permian Changxing Formation: oolitic limestone.

3.2. Triassic of South China This region includes 3 subregions, i.e., the Yangtze Platform, the Cathaysia Platform and the Youjiang Folded Belt. Table 1 shows the comparison among the three subregions: 3.2.1. Yangtze Platform (Fig. 1, II12l) This subregion is represented by sections in southwestern Guizhou, which are briefly introduced as follows [13]:

205 Table 1. A comparison of characteristics among different subregions of South China [3]

Stratigraphical development

Sedimentary characteristics Biotic province and biofacies

Yangtze Platform Completely developed with Lower, Middle and Upper Series (locally lacking Ladinian and Carnian strata) Normal marine to evaporite facies of stable type Tethyan, mainly with benthic taxa

Volcanic activities very rare

Youjiang Folded Belt Mainly composed of Lower and Middle Series, Upper Series only locally found

Cathaysia Platform Lower Series locally, Middle Series lacking, Upper Series most developed

littoral-neritic clastic facies of platform type mainly with bivalve Tethyan, mainly of planktonic ammonoid faunas of CircumPacific type and halobiid facies with continental with sporadic medium-acidic medium-acidic eruptions occasionally volcanic rocks found in late stage developed in early, middle and late stages flysch facies of mobile type

Lower-Middle Jurassic: Ziliujing Group conformity Norian-Rhaetian? Erqiao Formation 18. Sandstone Member. Lithic quartzarenite intercalated with siltstone, mudstone and carbonaceous shale, containing the plants Clathropteris meniscioides and Dictyophyllum cf. nilssoni. 110-400m 17. Shale Member. Clayrock, siltstone, carbonaceous shale and thin coal seams, containing the plant Lepidopteris ottonis, and the bivalves Indosinion elliptica, I. emeiensis in northern Guizhou. 10-70m Norian Huobachong Formation 16. Paralic rocks composed of grey to greyish green lithic quartzarenite and siltstone with carbonaceous shale and coal beds, yielding bivalves gunnanophorus boulei (usually upper) and Burmesia lirata (usually lower); and plants Taeniocladopsis rhizonoides and Pterophyllum cf. ptilurn; together with brachiopods and ostracods. 261-678m Carnian Formations 15. Banan Formation. Rhythmic interbeddings with unequal thicknesses composed of yellowish grey fine- to medium-grained lithic quartzarenite, siltstone and clayrock, yielding bivalves Costatoria kweichowensis and Angustella angusta and an ammonoid genus Trachyceras; together with brachiopods and plants. In corresponding formations of eastern Yunnan and Longmenshan area there have been found Halobia comata, H. superba, H. yunnanensis and Tosapecten. Guizhou is not typical for the Late Triassic plant zonation in South China. Different from the Yanchang Flora of North China, that of South China is called the Dictyophyllum nathorsti-Clathropteris meniscioides or D.-C. flora, which can be subdivided into a lower (Carnian--Middle Norian) Rireticopteris--Pterophyllum longifolium assemblage and an 150-463m upper (Late Norian--Rhaetian) Ptilozamites--Lepidopteris assemblage.

206 14. Laishike Formation. Rhythmic interbedding with unequal thicknesses, composed of grey or greyish green clayrock with siltstone and sandstone, yielding ammonoids Trachyceras cf. janurius and Paratibetites clarkei, and the bivalve Halobia rugosoides. 67-732m Ladinian-Carnian Falang Formation 13. Carnian Wayao Member. Grey to black calcareous clay rock intercalated with limestone and marl, yielding ammonoids Protrachyceras deprati, P. douvillei; the conodont Gondolella navicula; bivalves Halobia kui, H. rugosoides, Daonella bulogensis bifurcata; and crinoids. 16-238m 12. Ladinian Zhuganpo Member. Grey medium-bedded micrite and nodular limestone, yielding bivalves Halobia subcomata, Daonella bulogensis; the ammonoid Protrachyceras primum; and the aquatic reptilian Kueichousaurus hsui 30-696m Ladinian Yangliujing Formation 11. Light grey to grey dolomite, breccia dolomite and a small amount of limestone (upper part) with rare fossils. 20-230m Anisian Guanling Formation 10. Shizishan Member. Grey to dark grey wormlike calcirudite and argillaceous limestone, yielding bivalves Leptochondria illyrica, Costatoria goldfussi mansuyi; and the ammonoid Prognoceratites sp. 0-530m 9. Songzikan Member. Lower part composed of dolomite and dolomitic limestone, with brecciated structure due to evaporite solution; middle-upper part of variegated clayrock intercalated with marl, yielding bivalves; basal part taking a 1-3m yellowish green vitric tuff as its boundary with the Lower Triassic. 108- 390m In the platform-marginal area the Guanling Formation changes into the Qingyan Formation, which yields ammonoids, in ascending order, Parapopanoceras nanum

(Leiophyllites angustum billicus, Hollandites yangbunaensis), Nicomedites yohi, Paraceratites binodosus, P. trinodosus. Olenekian Yongningzhen Formation 8. Member 4. Yellow to grey dolomite and karst breccia intercalated with clayrock, containing rare fossils. 26-218m 7. Member 3. Grey micrite, usually with wormlike rudaceous structure, intercalated with dolomite, yielding bivalves Entolium discites microtis, Eumorphotis inaequicostata. 7m 6. Member 2. Interbeddings with unequal thicknesses, composed of purplish red to yellowish green clayrock, marl and dolomite, yielding the ammonoid Tirolites spinosus, and the bivalve Pteria cf. murchisoni. 24-221m 5. Member 1. Micrite, calcarenite, bioclasts and oolitic limestone, yielding bivalves Eumorphotis teilhardi and E. hinnitidea. 24-290m Induan Yelang Formation or Feixianguan Formation (clastic facies), Daye Formation (carbonate facies) 4. Member 4. Purplish red to yellowish green clayrock, yielding the blivalve Eumorphotis multiformis. 76m 3. Member 3. Grey limestone intercalated with sandy mudstone, with upper part yielding the bivalve Eumorphotis multiformis and the lower part yielding bivalves E. multiformis, Claraia aurita and C. stachei. 284m 2. Member 2. Yellowish grey to bluish grey siltstone and mudstone, yielding bivalves Claraia griesbachi, C. clarae and C. aurita; and the ammonoid Ophiceras demissum. 217m

207 1. Member 1. Yellowish green to grey sandy silty mudstone, containing the bivalve Pseudoclaraia wangi; the ammonoid Ophiceras sinensis; and at its base bivalves Towapteria scythica, Pteria ussurica variabilis, together with the conodont Hindeodus 19m parvus conformity Upper Permian Changhsing Formation (limestone) or Dalong Formation (silicolite and clayrock). The relief of the Yangtze subregion in Early Triassic was higher to the west and lower to the east. During Early Triassic the facies changed eastwards from elastics to carbonates. In Anisian time, this subregion became higher to the east and lower to the west. Reversely, The facies changed eastwards from carbonates to elastics. In the Ladinian Stage, the whole subregion became elevated, with subsequent marine deposits confined to a few areas including southwestern Guizhou, eastern Yunnan, western Sichuan, and western Hubei. Although the names of formations are different in different areas, the whole subregion is identical in biotic features.

3.2.2.

Cathaysia Platform (Fig. 1, |II2 2)

This subregion is similar to the Yangtze both in lithological character and in fossils of the Lower and Middle Triassic. Anisian deposists only locally developed, and the Ladinian was lacking due to uplift. The Middle-Late Triassic Indosinian orogeny changed the tectonic framework of South China. The elevation of the Yunkai-Xuefeng-Huangling area isolated this subregion from the Yangtze Subregion. As a result, this subregion was separated from the Tethys, and belonged to the Palaeo-Pacific regime i14j. During Late Triassic, terrestrial sediments with coal measures similar to those of the Yangtze were deposited. The sea intruded from both south and east, forming the Guangdong-Fujian-Hunan-Jiangxi and Southern Jiangsu gulfs respectively, where the biota belonged to the Circum-Pacific type.

3.2.3.

Youjiang Folded Belt (Fig. 1, 11123)

The Youjiang Folding Belt may be represented by the sections around the western and southwestern Guangxi which are briefly related below [ 15]: Lower Jurassic Wangmen Formation conformity 6. Norian (and Rhaetian?) Fulong'ao Formation. Upper member composed of purplish red conglomerate and sandstone intercalated with mudstone and coal seams, yielding fossil plants Clathropteris meniscioides, Dictyophyllum nathorsti, Lepidopteris cf. ottonis, and brackish bivalves; the lower member contains purplish red sandstone and siltstone intercalated with mudstone and conglomerate 425-4552m 5. Carnian?-Norian Pingdong Formation. Purplish red gravel-bearing sandstone, sandstone, siltstone and mudstone, yielding the marine bivalves Waagenoperna obrupta, Modiolus problematica, etc. At present, there are still controversies over the character of this bivalve assemblage, in which some people have identified elements of the Yangtze (Tethyan) type, such as Yunnanophorus, while others have listed some elements of the Pacific type, such as Bakevelloides liuyangensis, Parainoceramus matsumotoi, etc. 210-3114m unconformity 4. Ladinian Hekou Formation. Turbiditic sandstone interbedded with mudstone or mudstone intercalated with siltstone and limestone; divisible into upper and lower members by a

208 coarse sandstone bed, yielding the ammonoid Protrachy- ceras douvillei and the bivalves Daonella lommeli and D. indica. 794-3129m 3. Anisian Baifeng Formation. Turbidites composed of sandstone, mudstone; flysch with tuff or tuffstone in its basal part; yielding ammonoids Balatonites balatonicus, Danubites kansa, Hollandites sp. and Japonites sp.; and bivalves Daonella producta, D. elongata. 1252-6484m Lower Triassic Luolou Group. 2. Neritic mudstone and shale intercalated with siltstone, fine sandstone, marl and limstone, sometimes silicolite, silicious shale, conglomerate, volcanic clastics and volcanics which may locally form the main portion of the group. This group yields abundant ammonoids and bivalves; the former constitutes 9 zones in ascending order: Induan, Ophiceras sinense, Vishnuites marginalis, Proptychites kwangsiensis, Koninckites lingyunensis; Olenekian, Owenites costatus, Pseudowenites oxynostus, Tirolites darwini, Columbites costatus, 37-2042m Procarnites oxynostus. conformity 1. Upper Permian, Dalong Formation: silicolite The Youjiang subregion differs from the Yangtze and Cathaysia subregions in the presence of frequent and widespread volcanic activities which continued from the Permian, and there occurred a rapid sag in the Middle Triassic that accepted a great thickness of turbidites. By the end of Middle Triassic, the whole subregion was folded and uplifted. During the Late Triassic, only foreland basin deposits of continental and paralic purplish red clastic rocks accumulated on its southern piedmont and further on what was previously the Qinzhou "Geosyncline', the northeast branch of the Indosinian "Geosyncline'.

4. TRIASSIC OF THE EASTERN PART OF GONDWANAN TETHYS (Fig.l, IV) Within the border of China, this area mainly lies in the Himalayas, including the Himalayan (northern margin of Indian Plate) platform margin and the Yarlung Zangpo-Indus Folded Belt.

4.1. Triassic of the Himalayas platform margin (Fig. 1, IV1) This may be represented by the Tulong Section of Nyalam County, Xizang [9]. Stratigraphical names in parentheses are from [ 10]. Lower Jurassic (?) Pupuge Formation. Sandstone, shale and sandy limestone conformity 10. Rhaetian Zamre Formation (upper Derirong Formation). White massive coarse silicarenite with conglomerate at base. The intercalated carbona-ceous shale yields the sporopollen Classopollis sp., and Punctatosporites sp. 165.2m Norian Stage 9. Derirong Formation (lower, middle Derirong Formation and top of Qulong-gongba Formation). Interbeds of light grey thin-bedded quartzose siltstone and brown thin-bedded fine quartzarenite intercalated with carbonaceous shale, yielding bivalves Indopecten cf. himalayensis, L cf. margariticostatus, Myophoricardium fulongense, and Palaeocardita mansuyi, sporopollen, and acritarchs. 240.3m 8. Qulonggongba Formation. Grey shale intercalated with quartzarenite and bioclastic limestone, containing extremely rich fossils including ammonoids in ascending order,

209

Indojuvavites angulatus, Cyrtopleurites socius ~ibetites rayili, Paratibetites wheeleri), "Himavatites columbianus' (Dittmarites, Distichites); and bivalves Burmesia lirata, Indopecten serraticostatus, Pergamidia timorensis, Halobia superbescens and many other species; together with brachiopods, ostracodes, conodonts, foraminifers, sporopollen, nautiloids, belemnities, ichthyosaurids. 571.3m 7. Yazhi (Dashalong) Formation. Rhythmites composed of greyish black shale and bioclastic limestone, yielding ammonoids, in ascending order, Nodotibetites nodosus, Griesbachites himalayanus + Gonionotites tingriensis and bivalves Halobia cf. sirii, Myophorcardium tulongense, and Unionites griesbachi; together with brachiopods, conodonts, ostracods, foraminifers, sporopollen, acritarchs and nautiloids. 66.6m Carnian Stage 6. Kangshare (Zamure) Formation. Lower part composed of sandy shale; upper part of bioclastic limestone with nodular strucutre, containing ammonoids, in ascending order: Indonesites dieneri, Haplotropites lyelli+H, acutus, Parahauerites acutus, and conodonts Epigondolella diebeli, and Neogondolella polygnathiformis; together with bivalves, brachiopods, ostracods, bryozoans, and foraminifers dominated by miliolids. 4m Ladinian Stage 5. Upper member of Qudenggongba (Laibuxi) Formation. Upper and lower parts dominated by limestone while middle part composed of dark green sandstone and shale, containing ammonoids, Joanites kossmati, Protrachyceras longobardicum, etc. (totaling 14 genera and 18 species); and bivalves Daonella lommeli, D. indica and Posidonia sp.; together with brachiopods, conodonts, ostracodes, many species of foraminifers, sporopollen, crinoid stems and radiolarians. 127m Anisian Stage 4. Lower member of Qudenggongba (Laibuxi) Formation. Variegated silty shale, containing abundant brachiopods, such as Tulongospirifer stracheyi, Diholkorhynchia sinensis, Nudirostralina griesbachi, and N. mutabilis, with less abundant ammonoids, such as Hollandites voiti, Japonites magnus, etc. in addition to forminifers, ostracodes, bivalves, conodonts and nautiloids. 65.1m Olenekian Stage 3. Upper Member of Tulong (Kangshare) Formation. Light grey thin- to medium-bedded limestone, intercalated with variegated shale in middle part, yielding ammonoids Procarnites xizangensis, Owenites cf. egrediens, conodonts Neospathodus homeri, N. timorensis, N. waageni, N. pakistanensis; together with bivalves, nautiloids and brachiopods. 27.0m Induan Stage 2. Lower Member of Tulong (Kangshare) Formation. Composed of purplish red to variegated shale in the upper part and bioclastic limestone, thin-bedded limestone and dolomitic limestone in the lower part, yielding ammonoids Gyronites psilogyrus, Prionolobus lilangenis, Ophiceras cf. demissum, the conodonts Neospathodus dieneri, N. kummeli, Neogondolella carinata; and the bivalve Claraia sp.; near the base have been found Hindeodus parvus and Otoceras woodwardi and even lower there are O. latilobatum and brachiopod Waagenites (already Permian) [ 16]. 83.2m disconformity 1.Upper Permian Nimaloshiza Formation. Greyish black shale, containing Upper Permian sporopollen, acritarchs, scolecodonts, arthropods, together with small brachiopods and bivalves. 18m

Chronostratigraphy Se-

Stage

North China

rles

Norian

N TianshanJunggar Haujiagou

Rhaetian

U

Cathaysian Tethys South China Tibet-Qinghai

Central Asia

Yangchang Gr.

Huangshanjie

Yangtze

Youjiang

QiangtangQamdo

Erqiao

Fulong' ao

Bagong

Banan Laishike Wayao

Pingdong

Anisian

Ermaying

Karamay

Jiapila

Hekou

Dongdaqiao

Yangliujing

Diener. Induan

Griesb.

Liujiagou

Guanling

Baifeng

Qinyu

Kangnan

Guojiashan

U Shaofanggou Yongningzhen Jiucaiyuan Guodikeng (top)

Yelang (Daye Feixiangkuan)

F i g u r e 2 C o r r e l a t i o n of Triassic s t r a t a of C h i n a Gr, G r o u p ; t h e w o r d " F o r m a t i o n ' is omitted.

Huashiguan

I I

M

Olene- Spath. kian Smith. Heshanggou

Derirong Qulonggongba

Dengdeng-qiao Kangshare

Zhuganpo Tongchuan

Himalaya

Yazhi

Carnian

Ladinian

Age

Zamre Daheba

Bolila

Huobachong

Qinling

Gondwanan Tethys

Qudenggongba L

Mar~songduo o

M

Luolou Gr.

KalIlru

Caka

A

Tulong

-

Zalishan

211

4.2. Triassic of the Yarlung Tsangpo and Indus Rivers (Fig. 1, IVy) These tectonically active depositional regimes may be divided into two belts. The North Belt is distributed along the ophiolitic melange zone of the Yarlung Zangpo. The melange includes flysch, ophiolites, volcanics, strongly tectonically transformed and thus no Triassic sequence has been recognized. The South Belt lies between the North Belt and the platform margin of the Himalayas. The Triassic there includes deep-water flysch, intercalated with a large amount of volcanic rocks and silicolites, slightly metamorphosed and with little or without melange.

5. DIVISION AND CORRELATION OF THE TRIASSIC IN CHINA The correlation of the Triassic in China is shown in Figure 2. A synthetic correlation of biostratigraphy of the Triassic in China and its correlation with adjacent regions is given in Figures 3--6. Ammonoid, bivalve and conodont biostratigraphy and their correlations with other parts of the world have been published in Yin (1997). Owing to the limited space, only a synthetic scheme of the five major Triassic fossil groups in China (ammonods, conodonts, bivalves, nonmarine vertebrates and floras) is given together with sequence stratigraphy and sea level changes. The synthetic zonation is based upon the following data indicated already in the text: the Early Triassic ammonoids--Youjiang region [17], Middle Triassic--Early Carnian ammonoids--Yangtze region (Guizhou) [13], Late Carnian and Norian ammonoids--Himalayas [18], bivalves--Yangtze region (Guizhou) [19], conodonts-Himalayas and Hubei [20-22], plants--North China [23,24], vertebrates--North China and North Tianshan-Junggar Basins [25]. Both sequence stratigraphy and sea level changes are based on data from South China, where marine sequence was most completely developed. The correlations with adjacent regions and different parts of the world, are shown on Figure 3. A detailed correlation with the Tethys, Boreal and adjacent regions has been shown in [2]. In this paper only a brief correlation with the Tethys as a whole is made plus recent data from the Primorye (Russian Far East) [26,27] and Indochina (basically Vietnam, Laos and Cambdia [28]. The Tethys scheme is basically taken from [29], with minor changes based on recent discussions on the Permian/Triassic boundary, Anisian/Ladinian boundary and Rhaetian [30]. It is hard to correlate the European three- or four-fold Middle and Upper Triassic substages with Chinese ones, so in this paper only Upper and Lower Substages are used. For example, the Lower Anisian may correspond to the Aegian and the Bithynian, and the Upper Norian may correspond to the Alaunian plus part of the Sevatian. The marine Chinese zonation (Fig. 4, Fig. 5 partly) shows remarkable similarity with that of Indochina (Vietnam) throughout the Triassic. The difference of some corresponding zonal fossils, e.g. the Rhaetian Unionites (Indochina) and Indosinion (China), may be merely nominal but essentially congeneric. Some corresponding zonal fossils may be different but morphologically similar, e.g. Costatoria curvirostris (Vietnam) and C. goldfussi mansuyi (China), or the Vietnam fossil may occur in the same zone of China, but not mentioned in Figure 3, e.g. Claraia concentrica and Daonella elongata (Vietnam). The similarity is because during the Triassic northern Vietnam and northern Laos were small

212

EPOCH STAGE

BIOSTRATIGRAPHY OF ADJACENT REGIONS TETHYS PRIMORYE INDOCHINA

208 ~D

Choristoceras marshi Rhabdoceras suessi

Monotis ochotica

Halorites macar Himavavites hagarti Cyrtopleurites bicrenatus

Eomonotis scutiformis Otapiria ussuriensis

Gervillia inflata

212

r

Juvavites magnus Malayites paulckei Guembalites jandianus

cD

220

Anatropites Tropites subbullatus Tropites dilleri

Pterosirenites kiparisovae

/

StriatosirenitesArietoceltites

Margaritropites

A ustrotrachyceras austriacum Trachyceras aonoides

228

Fankites regoledanus Protrachyceras archelaus P. gredleri Eoprotrachyceras curionii

234

241

~ = ~)

"~ i

.d~

Flemingites rahilla Gyronites frequens Ophiceras tibeticum Otoceras woodwardi

"=

(partly)

~9

246 J

Nevadites secedensis ~D Reitzites reitzi P. trinodosus Balatonites balatonicus A nagymnitoceras ismidicum Nicomedites osmani , Aegeiceras ugra Tozericeras spiniger =~ Tirolites cassianus ~ Wasatchites pakistanum "~ meekoceras gracilitatis

Discotropites

Ussurites ProtrachycerasRimkinites Daonella densisulcata Ptychites oppeli Acrochordiceras kiparisovae

Kellnerites Paraceratites Balatonites

Leiophyllites pradyumna

Neocolumbites insignis Tirolites-Amphistephanites Anasibirites nevolini Hedenstroemia bosphorense

Tir ol ites-Columb ites

Gyronites subdharmus

FlemingitesParanorites Gyronites-Koninckites

Glyptophiceras ussuriensis

Ophiceras commune

251 Figure 3

Synthetic correlation of the Triassic of China and adjacent regions.

Part 1" chronostratigraphy and biostratigraphy of adjacent regions.

213

CHRONOSTRATIGRAPH ! Y STAGE 208

BIOCHRONOSTRATIGRAPHY OF CHINA AMMONOID

CONODONT Misikella posthersteini Misikella hersteini

212 E. bidentata U

"Himavatites columbianus' Cyrtopleurites socius

E. postera

Indojuvavites angulatus

Epigondolella multidentata

Gries bach ires-Gon ion o tires Nodotibetites nodosus Parahauerites acutus Halpotropites Indonesites dieneri

E. abneptis

L

220 U

Paragondolella polygnathiformis

Epigondolella diebeli Protrachyceras deprati

228 U

Protrachyceras primum Paragondolella excelsa -Neogondolella mombergensis

234 U

241

246

Sm D

G

251

Paraceratites trinodosus P. binodosus

Nicomedites yohi Parapopanoceras nanum Procarnites oxynostus Columbites costatus Tirolites cassianus Pseudowenites oxynostus Owenites costatus Koninkites lingyunensis Proptychites kwangsiens& V. marginalis O. sinensis

Neog. constricta-Neos, germanicus

Neogondolella regale Neos. timorensis Neos. homeri Neos. triangularis Neos. waageni Neos. pakistanensis Neos. cristagalli Neos. dieneri Neos. Kummeli Neog. Carinata I. isarcica Hindeodus parvus

Figure 4 Synthetic correlation of the Triassic of China and adjacent regions. Part 2: ammonoid and conodont zonations of China.

214

BIVALVE

BIOSTRATIGRAPHY OF CHINA PLANT

VERTEBRATE

Indosinion

Yunnanophorus boulei

Burmesia lirata

Danaeopsis fecundaBernoullia (Symopteris) zeilleri (Dictyophyllum nathorsti-Clathropteris meniscioides in South China)

Halobia superba Costatoria kweichoowenis Fukangichthys (Bogdania Fukangolepis) Halobia rugosoides Halobia kui Daonella lommeli Daonella indica AnnalepisTongchuanophyllum Sinokannemeyeria Parakannemeyeria

Daonella producta

Costatoria goldfussi mansuyi Leptochondria illyrica

Shansisuchus Shansiodon

Voltzia-Aipteris wuziwanensis

Paoteodon Shanbeikannemeyeria

Sp Pteria cf. murchisoni

Fugusuchus Benthosuchidae

Sm Pleuromeia- Voltzia Eumorphotis multiformis Claraia aurita Claraia stachei Pseudoclaraia wangi Towapteria soythica

Chasmalosaurus Lyslrosaurus

Figure 5 Synthetic correlation of the Triassic of China and adjacent regions. bivalve, plant and vertebrate zonations of China.

Part 3:

215

SEQUENC_E lit

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CHRONOSTRATIGRAPHY

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RELATIVE CHANGE OF COSTAL ONLAP

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2,000 but 1,000 m), post-date Monotis sequences and pre-date fossiliferous

246 Jurassic sequences. Otapirian faunas have not been recognised in any other New Zealand terrane. Rhaetian radiolarians have been recorded from a single locality within Rakaia Terrane [39].

1.3.9. Triassic- Jurassic boundary Fossiliferous sequences that encompass a change from Triassic to Jurassic faunas are preserved within the Murihiku Terrane and probably the Torlesse and Waipapa Terranes. As yet no section has been recognised that enables a precise biostratigraphic determination of the onset of Jurassic time. 1.3.10. Chronostratigraphic potential of New Zealand Triassic successions Both the Dun M o u n t a i n - Maitai and Murihiku Terranes have potential for absolute dating of marker horizons. Both are well endowed with tuffs that are interpreted as primary air-fall volcanic ash beds. The Murihiku Terrane sequences are particularly rich in vitric and crystal tufts with suitable mineral compositions for dating purposes, and some have been dated [56].

2. N E W C A L E D O N I A Fossiliferous marine Triassic strata of the Tdremba Terrane [57] are well exposed along part of the southwest coast of New Caledonia. These sequences are almost identical in every way with those of the Murihiku Terrane of New Zealand. The Kaihikuan, Oretian, Otamitan, Warepan and Otapirian New Zealand local stages are recognised, representative of Ladinian to Rhaetian time in just the same manner as in the Murihiku Terrane [58]. There are subtle differences in terms of diversity and richness of fossil occurrence. The faunas are as for the Murihiku Terrane, but as yet no conodonts or radiolarians have been retrieved from the T6remba Terrane. The oldest Triassic rocks attributed to the T6remba Terrane are those of the Moindou Formation [57]. This unit has a small poorly preserved Early Triassic fauna comprising Ophiceras (Lytophiceras) species and 'Glyptophiceras' attributed to the Induan Commune Zone. An isolated halobiid fossil, Daonella jadii Campbell, is also known. This species was originally described from the Etalian Stage of the New Zealand Murihiku Terrane and is thought to indicate Varium Zone [3]. Rare occurrences of Middle to Late Triassic fossils have been recognised in a second terrane within New Caledonia, the Koh Terrane [57]. Fossils include undescribed Anisian ammonoids, Norian Columbianus and Cordilleranus Zone Monotis faunas, and radiolarians. The Koh Terrane is a diverse magmatic complex with oceanic sea floor associations and volcaniclastic sedimentary enclaves, and is quite different in character from any of the described New Zealand Triassic terranes.

3. A U S T R A L I A Marine strata of Triassic age exist on land in Australia only as small isolated exposures on the western and eastern margins of the continent. They are associated with much more extensive non-marine sequences, and more voluminous submarine deposits in the west, on the

247 Northwest Shelf and in the Perth Basin (Fig. 1) [60]. The latter are known from oil exploration drilling, from the Ocean Drilling Program Leg 122 [61], and from bottom dredgings. Possible locations of the coastline for Anisian and Norian times have been estimated from these deposits and their relations to non-marine strata, and broad marine environments postulated [62]. Early Triassic marine deposits occur both on-land and in the off-shore zone. Well-dated Middle and Late Triassic are known, however, only on the Northwest Shelf. Gondwanaland break-up in the region was under way in the Early Triassic, with a narrow rift valley allowing marine flooding southwards into the Perth Basin between the Indian and Australian part of Gondwanaland. Here along the Northwest Shelf all Triassic stages are probably represented (Fig. 4), although Ladinian and Carnian ages are so far rare. 3.1. Early Triassic The Kockatea Shale of the Perth Basin accumulated during most, if not all, the Early Triassic. Early Induan (early Griesbachian) is indicated by the bivalve Claraia stachei Bittner, middle Induan by Ophiceras (Discophiceras) cf. subkyokticum Spath (late Griesbachian), and Gyronites cf. frequens Waagen, Proptychites, and conodonts (Dienerian), and late Induan (Smithian) by the ammonoids Subinyoites kashmiricus (Diener), Anasibirites kingianus (Waagen) etc. [63, 64]. The Locker Shale in the Carnarvon Basin has conodont faunas indicating late Olenekian (Spathian) age [65]. In Queensland, Gympie Terrane rocks of the Kin Kin Beds have yielded a more diverse ammonoid fauna readily correlated with the Olenekian (early Smithian) Romunderi Zone (species of Latisageceras, Dieneroceras, Anaflemingites, Paranorites, Arctoceras, etc.). The associated Brooweena Beds contain a bivalve fauna dominated by Bakevellia and Neoschizodus regarded as Olenekian (Smithian) by its association with the Kin Kin fauna [60], but comparison with New Zealand faunas of Murihiku and Rakaia Terranes suggests a much younger late Ladinian (local New Zealand Kaihikuan Stage) correlation. Probable marine Triassic is known at one horizon low in the Newport Formation at the top of the Narrabeen Group, Sydney, containing many specimens of a small, undescribed modioline mussel. From stratigraphic position and palynoflora this horizon is believed to be Olenekian (Spathian) in age [66]. 3.2. Middle Triassic An ammonite tentatively identified with the early Anisian Nicomedites is known from the Mt Goodwin Formation in the Bonaparte Basin where it is associated with undetermined halobiid bivalves [64]. The oldest known Triassic dinoflagellate flora in Australia also comes from the Bonaparte Basin and is correlated with the Anisian part of the late Anisian - early Ladinian Sahulidinium ottii dinocyst zone [67]. A rich foraminiferal fauna, Anisian by palynological correlation, has been described from the Northwest Shelf, constituting the oldest known and well preserved such fauna in the region [68]. No certain Ladinian correlation is known, but strata of this age are probably present in the Sahul Group in the Bonaparte Basin and may be represented in the Mungaroo Formation of the Carnarvon Basin.

248 I VVestern Marginal Basins I Eastern Basins I

-

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9

9

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9

Conodont Zones

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9

Dinocyst Zones

Arnmonoids

Other

Foraminifera i

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R. thaetica

Tr/Ds/na hentkem 36

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..... E. b/denfata

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E. b'iangularis

09