Geological Map of Asia and the Far East

I Earth sciences 11

I

Second edition 115 000 000

Explanatory note

Earth sciences 1 1

Titles in this series

1. The seismicity of the earth, 1953-1965/La dismicitk du globe, 1953-1965 by/par J. P. Rothe

2. Gondwana stratigraphy. IUGS Symposium, Buenos Aires. 1-15 October 1967/La estratigrafia del Gondwana. Coloquio de la UICG, Buenos Aires, 1-15 octubre de 1967

3. Mineral map of Africa. Explanatory note/Carte minerale de 1’Afrique. Notice explicative. 1/10 000 000

4. Carte tectonique internationale de 1’Afrique. Notice explicative/Intemational tectonic map of Africa. Explanatory note. 1/5000 000

practice by K. A. Wienert MBthodes d’observation et de prospection gkomagn&tiques, par K. A. Wienert

5. Notes on geomagnetic observatory and survey

6. Tectonics of Africa/Tectonique de 1’Afrique I. Geology of saline deposits. Proceedings of the

Hanover Symposium, 15-21 May 1968/G6ologie des dBp6ts salins. Actes du colloque de Hanovre, 15-21 mai 1968

8. The survelllance and prediction of volcanic activity. A review of methods and techniques

*9. Genesis of Precambrian iron and manganese deposits. Proceedings of the Kiev Symposit’m, 20-25 August 1970/Gen&e des formations prkatiibriennes de fer et de mangan8se. Actes du colloque de Kiev, 20-25 aoiit 1970

10. Carte geologique internationale de 1’Europe et de la region mbditerrankenne. Notice explicative/ International geological map of Europe and the Mediterranean region. Explanatory note. 115 000 000

11. Geological map of Asia and the Far East. 1/5 000 000. Second edition. Explanatory note Carte geologique de 1’Asie et de 1’Extrdme-Orient. 1/5 000 000. Deuxi8me edition. Notice explicative

(Multilingual edition: French, English, German, Spanish, Italian, Russian. )

*12. Geothermal energy. Review of research.

* T o be published

Geological m a p of Asia and the Far East Second edition 1 / 5 000 000

Explanatory note

United Nations. Unesco Economic Commission for Asia and the Far East.,

Published in 1972 by the United Nations Educational, Scientific and Cultural Organization Place de Fontenoy, 75 Paris-7" and the United Nations Economic Commission for Asia and the Far East, Bangkok

Printed by Imprimerie Louis-Jean, 05-Gap

0 United Nations 1971 Printed in France 5c.71 /XVII.ll /A

1972 International Book Year

The designations employed and the presentation of the material in this publication do not imply the expression of any oplnion whatsoever on the part of the Secretariats concerning the legal status of any country or territory, or of its authorities, or concerning the delimitations of the frontiers of any country or territory.

Preface

This second edition of the Geological Map of Asia and the’Far East has been prepared under the sponsorship of the United Nations Economic Commission for Asia and the Far East (ECAFE) in consultation with the Commission for the Geological Map of the World and Unesco.

Since the publication of the first edition of this map in 1961, much more systematic geological mapping has been carried out in most countries of ,the region and new national maps have been compiled. At the sixth session of the ECAFE Working Party of Senior Geologists held at Bangkok in 1966, 5t was decided that a second revised edition be published and the offer of the Director-General of the Geological Survey of India to act as co-ordinator for the task of revision was accepted.

At its seventh session (Teheran, 1968) the Working Party recommended that Unesco be jointly associated with the publication and distribution of the map and its explanatory note.

No geological map can be regarded as perfect or final, as substantial amendments and additions are constantly being made to geological knowledge. This edition of the map, therefore, represents a stage in the growth of the understanding of the geology of the region, which will be added to and improved continually subsequent to its preparation. It has been compiled from information available up to 1969, mainly from geological maps and other data supplied by the appropriate agencies of the governments of member countries in the ECAFE region.

Those who have taken part in the compilation and preparation of the map and the secretariats of ECAFE and Unesco wish to express grateful acknowledgements to : All governments of member countries in the ECAFE region for their ready

The Government of India for contributing the facilities available at the co-operation ;

Geological Survey of India and the services of its staff ;

The national geological surveys of all member countries in the ECAFE region

The Commission for the Geological Map of the World for its support and

The final draft of the map was completed at the Geological Survey of India, Calcutta, under the guidance of the Director-General, and the map was printed in Tokyo under the supervision of the Geological Survey of Japan. The brochure was prepared by the Geological Survey of India in co-operation with the ECAFE Secretariat (Mineral Resources Development Section) and the ECAFE/Unesco Science and Technology Unit.

It is well known that the region designated as Asia and the Far East is geologically and tectonically a highly complex one. The new map should therefore be of considerable value not only to scientists, specialists and academic circles, but also to everyone concerned with or interested in the development of Asia’s mineral resources.

for supplying the required material ;

assistance.

Contents

Foreword 9

1. Introduction

2. Summary of general stratigraphy Precambrian Precambrian-Paleozoic Paleozoic Paleozoic-Mesozoic Mesozoic Mesozoic-Tertiary Tertiary Tertiary-Quaternary (Cenozoic) Quaternary

3. Intrusive rocks F’recambrlm Precambrian-Paleozoic Paleozoic Mesozoic Pre-Tertiary Cretaceous-Tertiar y Tertiary Nondated or undifferentiated

13

16 16 20 22 44 47 66 67 79 82

86 86 88 88 91 93 93 94 95

Foreword

At the meeting of the ECAFE Working Party of Senior Geologists held at Bangkok in August 1966, the Geological Survey of India agreed to continue to act as Co-ordinator for the preparation of the second (revised) edition of the ECAFE Geological Map of Asia and the Far East, at a scale of 1:5,000,000. To facilitate compilation of the revised map, the Working Party requested the ECAFE secretariat to ask the appropriate organizations in all member countries of the ECAFE region to forward their latest geological maps to the secretariat for trans- mission to the Co-ordinator.

By the end of March 1968, the latest maps issued by eleven member countries had been received by the Director General, Geolo- gical Survey of India. A draft map was then prepared, embodying the changes shown on these maps that had been made since the first edition was compiled, and using the topographic details of the Mineral Distribution Map of Asia and the Far East (first edition) as a base; this was displayed at the seventh session of the Working Party of Senior Geologists, held at Tehran in July 1968.

Copies of the portions of the draft map covering each of the countries involved were subsequently sent by the Co-ordinator through the ECAFE secretariat for scrutiny by the organizations concerned in the respective member countries. At the suggestion of the Co-ordinator, the member countries were also requested to supply the following, for incorporation in the revised map: (1) data for distinction between continental and marine facies of sedimentary rocks; (2) submarine

9

Foreword

geological data; (3) criteria for distinction between different types of metamorphic rocks; and (4) the general trend of foliation of metamorphic rocks. A s this information was suppliedfor very few countries, it was decided, in consultation with the ECAFE secretariat, to issue the revised regional map without these additional details, except for foliation trends in India and Ceylon.

At the suggestion of the ECAFE secretariat, the blank areas of the portion of the map covering Nepal were filled by incorporating the data shown in the published geological map of the Himalayas by A. Gansser; this draft was subsequently approved by the authorities concerned in Nepal, subject to certain modifications incorporated at [heir request,

After scrutiny by the respective survey departments, the sections of the map dealing with Taiwan (China), the Philippines, Malaysia, Pakistan and Iran were returned to theCo-ordinator, with certain modifications. The latest geological maps of Afghanistan (printed in 1969), Thailand (unpublished), China, and Mongolia were received through the ECAFE secretariat during the latter half of 1968and early in 1969. The receipt of these maps necessitated extensive changes and recasting of the draft map and, in consultation with the professional staff of the ECAFE secretariat, the legend was modified in October 1969; preparation of the final draft was completed near the end of December 1969.

In the revised map, the recommendations of the Commission for the Geological Map of the World (CGMW) concerning legends for geological maps have been followed as far as possible. A s a result, the Precambrian rocks have now been subdivided into groups A, B and C instead of Archean, Lower Precambrian, and Upper Precambrian, and the Deccan Traps have been assigned a separate symbol and colour. The data on bathymetric contours have also been revised and these have been plotted from the base map of the Asian portion of the World Geological Atlas at scale of 1:10,000,000. Some geographic details have been amended and others added to the base map.

The Co-ordinator takes this opportunity to express his sincere appreciation for the co-operation and help received from the organizations concerned in the member countries, and the ECAFE secretariat, in the preparation of the revised edition of the regional map. He wishes

10

Foreword

to acknowledge the assistance rendered by Messrs. D.V. Ramanamurthy and S.K. Roy, geologists of the Geological Survey of India, Mr. Y.B. Kazmin of the ECAFE secretariat and Dr. D.J.C. Laming of UNESCO in the compilation and checking of the map. The Co-ordinator is also grateful to Miss F. Delany, Secretary General, Commission for the Geological Map of the World, for supplying the base map of the Asian portion of the World Geological Atlas from which the bathymetric contours used in the present edition have been taken.

M.S. Balasundaram (Co-ordinator)

Director-General, Geological Survey of India

1 1

1. Introduction

Purpose and validity

This brcchure sets out to provide an explanation of how the geology of the Asia and Far East region has been represented on the map, and to give more geological details than can be shown thereon. In general, the geological detail has been presented geographically (usually from west to east) for each stratigraphic subdivision or igneous rock-type, and percipient readers will notice the influence on such descriptions of having to derive the information from numerous country surveys, each with its own methods of description and presentation.

Neither the map nor the brochure should betaken as an authorita- tive account of the geology of the region; such an account is well beyond the resources of the compilers, and the information presented is only as accurate as the country sources can make it. Additionally, the information in most cases represents what was known in 1969, and it may well be that some details will be invalidated by the date of publication. Nevertheless, it is felt that any such limitations are far outweighed by the value of so much geological information assembled and co-ordinated in one publication. Users requiring confirmation of details of the geology shown on the map are recommended to approach the geological survey or bureau in the country or countries concerned.

Stratigraphic names

Most national geological surveys or bureaux are in process of modifying their stratigraphic terminology in conformity with national

13

Introduction

or international codes of stratigraphic nomenclature, which are generally similar in nature to the 1961 recommendations of the Amercan Com- mission on Stratigraphic Nomenclature. However, such a task is a formidable one, needing long periods of time for completion, and, for this publication, the terminology of actual use at the time (with a few exceptions) has been included whether it conforms to the moderns codes or not.

Capi'talization of formal terms has been standardized, however, so that all formal stratigraphic names are capitalized in the text and the legend, whether they accord with a modern code or with former established usage. It should be noted that former usage often permitted the terms System, Series and Beds to be applied where now the terms Supergroup, Group and Formation would be appropriate. These terms have not been altered to accord with m o d e m usage, however, as this is the prerogative of the geologists working in the areas concerned.

Representation of geological information on the map Both on the map and in the brochure, formations are identified

primarily by age, with indications of lithology only in the case of igneous rocks. A s shown by the legend on Sheet 111, geological systems are indicated by colours and code letters, with formations overlapping more than one system being given distinctive shades andcompound code letters. The legend mentions the more important formations included in each subdivision, and the countries where they may chiefly be found; further information on such points is presented in this brochure and the lithology of the stratigraphic units is described, together with a listing of characteristic fossils where possible.

The colours selected to represent the various stratigraphic units have been chosen in accordance with the International Colour Scheme suggested by the Commission for the Geological Mapof the Wbrld at its meeting in Paris in April 1968. For Precambrian rocks, various shades of crimson are used; shades of green represent Cambrian, Ordovician and Silurian rocks, brown for Devonian, grey for Carboniferous, light yellowish-green for Permian, mauve for Triassic, Prussian blue €or Jurassic, yellowish-green for Cretaceous, yellow for Tertiary andyell- owisbgrey for Quaternary. Stratigraphic units overlapping two systems

14

Introduction

are shown by the colour of the lower system with an ornamentation of easily-discernible character in a colour akin to that of the upper system.

For igneous rocks, the ages of acidic and intermediate intrusions are indicated by various shades of orange and red, augmented in some cases by subscript numerals from 1 to 7 (from Precambrian to Tertiary). Basic and ultrabasic intrusive rocks are all coloured yellowish-green, age being shown by subscript numerals only, placed after symbols indicating rock type. In the case of volcanic rocks, Quaternary and Cenozoic formations are coloured distinctive shades of red, purple and brown, indicating age and petrographic class. All other volcanic rocks, however, with the exception of traps, are indicated by a black overprint on the colour assigned to sedimentary rocks of the same age, the style of overprint indicating the petrographic class.

Petrographically, the intrusive igneous rocks have been grouped into acidic and basic. All syenites, porphyries, porphyrites and most diorites are included with granites and granodiorites in the acide group; the basic group includes gabbros, dolerites and some diorites, and all ultrabasic rocks. Rock types are indicated by Greek-letter symbols, b' for granites and granodiorites,& for diorites and syenites,MPfor gabbros and allied rocks, and sr7 for peridotites and other ultrabasic rocks. The Deccan Traps have been shown separately from intrusive and volcanic rocks, at the suggestion of the Commission for the Geological Map of the World, and are identified by the symbolT,

Volcanic rocks are also distinguished petrographically, acidic (P) including keratophyre, rhyolite, dacite and some andesites; the basic group (p) includes basalt and most andesites. Unclassified volcanic rocks bear the symbol (p).

Rocks of varying composition and uncertain age have been included under the heading Unclassified Igneous Rocks (i).

Metamorphic rocks are distinguished, where data permit, by broken red lines indicating general foliation trends.

Where information is available, Quaternary eolian deposits (including sand dune areas) have been marked out by black dots. No distinction has otherwise been made between marine and non-marine deposits of any age.

15

2. Summary of general stratigraphy

PRECAMBRLAN

Despite their wide distribution, precise correlation of the Pre- cambrian formations in Asia is not possible as they are classified differently in the various countries of the ECAFE region. On the map they are divided in order of descending stratigraphic position into three groups: Precambrian A, Precambrian B, and Precambrian C; in general terms, A and B comprise Proterozoic rocks, while C constitutes rocks of Archean age.

Precambrian C The most ancient basement rocks, generally highly metamor-

phosed and deformEd as well as intensely granitized, are included in this subdivision. In most cases they are referred to as Archean, or merely as basement crystalline rocks known by local names. Rock types are variously orthogneisses, paragneisses, crystalline schists, amphibolites, quartzites and marbles, and also large masses of granite-gneiss and granite.

In Iran, Precambrian C includes the basement complex which consists mainly of gneisses, various schists, phyllites, quartzites and marbles, with local granite intrusions. Slightly and non-metamorphosed rocks of the Kohar Formation, Morad Series and other units are also included, mostly green slates, sandstones and some green volcanic rocks; their Precambrian age is indicated by their stratigraphic position below dated Lower Cambrian.

16

Summary of general stratigraphy

In Afghanistan, the oldest basement rocks consist of gneisses, quartzites, green schists, mica schists and marbles. In India, Nepal and Burma, Archean and unclassified crystalline rocks consist mainly of various gneisses, crystalline schists and granites. A n Archean age is assigned to the Kadugannadwa Gneiss and Biotite Gneiss of Ceylon, and the Crystalline Schist System in Korea. The metamorphic rocks grouped under Precambrian C in Laos and Viet-Nam are crystalline schists and gneisses of the basement complex, which is exposed in scattered Precambrian massifs.

In China, the Archean is represented by gneisses, gneiss- granites, crystalline schists and some marbles, known in various regions as the Taishan Complex, Sangkanand Liaotung Series, Meijentou Gneiss, Kunglin Schist, etc. The Wutai System is also included in this classification, comprising metamorphic rocks of clearly recognizable sedimentary and volcanic origin, often intruded by igneous masses; the rock types are mainly crystalline schists, magnetite-bearing quartzites, mica schists, green schists and some marbles. Although many geologists in China refer the Wutai System to the Archean, some consider it to be younger than the Taishan and Sangkan Series, probably Proterozoic in age. In the lower part of the Wutai System in Anshan a recent Pb/U/Th age determination of orthitefrom migmatites gave 2,560 m.y., and a K/Ar age determination of muscovite from crystalline schists gave 2,270 m.y.

Precambrian 8-C The pre-Sinian basement rocks of China are undifferentiated

A rchean-Proterozoic, and are therefore shown in this subdivision which embraces both Precambrian C and Precambrian B. They are widely exposed along axes and uplifted blocks within fold belts in the south-western and western regions, generally consisting of variably metamorphosed and deformed gneisses, crystalline schists, mica schists, green schists, granites, limestones, and in some places shales and phyllites.

Precambrian B The rocks included in this subdivision are generally highly meta-

morphosed, often intruded by both granites and basic rocks, and have

17


undergone severe folding and faulting. They have previously been identified either as Proterozoic or Lower Precambrian, or described under local names.

The Dharwar System of India comes within this classification, comprising highly metamorphosed sedimentary and igneous rocks, such as banded hematite-quartzite, garnet-sillimanite-schist (known as khondalite), cordierite-biotite-gneiss, pyroxene gneisses and calc- granulites. Besides the type area in Mysore, formations corresponding to the Dharwar System are also found in Madhya Pradesh, Andhra Pradesh, southern Bihar, northern Orissa and Rajasthan. The Salkhala and Jutogh Series in the northwestern Himalayas and the Daling Series of the Darjeeling Himalayas, in Bhutan and Nepal, are also included in this subdivision; they consist of various slates, phyllites and quartzites, with some schists and gneisses.

In Burma, this subdivision is represented by undifferentiated metamorphic rocks and crystalline limestores, and also includes the Mogok Series, which is composed of biotite, cordierite and pyroxene- scapolite gneisses, garnet-biotite schists, crystalline limestones and quartzites. Khondolites and crystalline limestone compose the Pre- cambrian B in Ceylon.

The Proterozoic formations in China unconformably overlie the Archean rocks, including the Wutai System; they are referred to in various localities as the Huto, Liaoho, Namdechou, Kuyang, Kunyang and Lingchuan Series, and some others. These are comparatively weakly metamorphosed and less deformed rocks, mostly slates, phyllites, green schists, roofing slates, marbles and quartzites, and, in places, include 6ome metamorphosed volcanic rocks. The upper age limit of this group may correspond to the figures of 1,440 100 to 1,550 f 200 m.y., the absolute age recently determined for the Hut0 (Bayan-Obo) Series.

In Mongolia, this subdivision comprises the metamorphic rocks assigned to the Lower and Middle Proterozoic on the latest geological maps of Mongolia (1965). These formations constitute a single tectonic complex forming the Precambrian crystalline basement which appears within Paleozoic fold-belts. Most of the exposed Lower Proterozoic

18


rocks are gneisses, crystalline and mica schists, with some amphibolites and marbles. The Middle Proterozoic consists mainly of crystalline limestones and dolomites, quartzites , some crystalline schists, gneisses and amphibolites; in Gobi, it is represented by mica schists, green schists and metavolcanic rocks, with some limestones. In general, the Middle Proterozoic depositional facies in Mongolia appears to change eastward from carbonate through terrigenous- volcanic into terrigenous.

Precambr lan A -B Undifferentiated Proterozoic rocks exposed in northeastern

Mongolia are placed in this subdivision They forma basement complex made up of crystalline schists, mica schists and green schists, in places associated with some limestones and sandstones.

Precambrian A The rocks of this subdivision, previously referred to as Upper

Precambrian or Upper Proterozoic, rest unconformably over the older Precambrian formations and are relatively less metamorphosed and less disturbed.

In India, Precambrian A includes the quartzites, limestones, slates, hornstone breccias, etc. of the Cuddapah System inAndhra Pradesh, with scattered intrusions of granites and basic sills, and its equivalents in Mysore, in the Chhattisgarh Basin, and inparts of Bihar, Orissa and Rajasthan.

The Martoli Series and other Upper Precambrian formations in Nepal consist of various schists and quartzites.

In China, this subdivision is represented by the SinianSystem, which, in most regions, consists of a flat-lying or gently dipping thin sequence on pladorms and uplifts where superposed Cambrian rocks overlie them quite conformable. Quartzites , shales and some quartzitic sandstones are predominant in the lower part; limestones, particularly siliceous limestones with slates, compose the upper part of the sequence. In foldbelts, the Sinian rocks are metamorphosed and generally folded, and include mainly slates, phyllites and limestones, and, in some localities (Kurug Tagh, Nanshan), are associated with volcanic rocks , conglomerates and tillites. The Sinian limestones are

19


commonly characterized by abundant problematic algae, such as stromatolites and oncolites.

The Upper Proterozoic in Mongolia unconformably overlies the Lower-Middle Proterozoic basement formations and consists of a geosynclinal sequence of variably metamorphosed rocks, mainly green schists, mica schists, metamorphosed volcanic rocks and some limestones. In Gobi, predominantly crystalline limestones are associated with quartzites and cherts. Stromatolites and oncolites have been found in the Upper Proterozoic limestones in some localities.

The Sangwon System of Korea, comprising quartzites, phyllites, limestones, slates, etc., is believed to be late Proterozoic in age; it uncomformably overlies crystalline schists and granite-gneiss (Pre- cambrian C). Some of the limestones have yielded the doubtful fossil Collenia.

P R E C A M B RIAN-PALEOZOIC

The Vindhyan System of India, consisting of limestones, quartzitic sandstones, shales, grits, conglomerates, etc., is a sequence of less disturbed strata with more or less horizontal beds. This system unconformably overlies the Cuddapah rocks classified as Precambrian A. Some shales of the Vindhyan System have yielded small concentric, wrinkled discs of a carbonized chitinous substance, several spores and a few woody remains which indicate the possibility that the Vindhyan rocks may extend in age up to Ordovician. The Malani suite of igneous rocks, consisting of granites, granophyres and rhyolites, intrude the Vindhyan System in Rajasthan. The Hazara Slates, Simla Slates and the Nagthat, Chandpur and Jaunsar Series in the northwesternand central Himalayas, and the Buxa Series in the Himalayas of Sikkirn and Bhutan are probably of late Precambrian to early Paleozoic age.

In West Pakistan, this subdivision is mainly composed of unfossiliferous sedimentary and metamorphic rocks, including slates, limestones and sandstones.

The Precambrian-Paleozoic rocks in Nepal consist of schist8,

In Thailand, pre-Permian gneisses and schists occurring in the Chieng Mai, Tak and Uthai Thani areas are placed in this subdivision.

gneisses, phyllites, quartzites and limestones.

20


In southern Thailand, small outcrops of these rocks are exposed near Thapsakae and Ranong.

In Laos and Viet-Nam, some gneisses and metamorphic rocks, mainly various schists, quartzites, phyllites and crystalline limestones, may be both Upper Precambrian and Lower Paleozoic in age. They are widely exposed in the northern regions of those countries as well as east of the Bolovens Plateau.

The undifferentiated Sinian-Silurian deposits of China , included in this classification, are generally represented by a thick (2 to 7 km) geosynclinal sequence of variably metamorphosed and deformed rocks, mostly exposed within foldbelts in the central and southeastern regions; these are mainly schists, slates, phyllites, quartzites and some limestone. South of the lower Yangtze valley, the sequence consists mainly of marine clastic rocks, with limestones and shales in the middle part. In the Cathaysian foldbelt, in the southeasterncoastal region, the Sinian-Silurian is represented by the Lungshan Series made up of green schists, phyllites, clayey slates, limestones and cherts, with some quartzites, dolomites and local graphitic deposits. The Nanshan Series in Nan Shan (west central region) is composed of green schists, phyllites and quartzites; in the upper part, it also includes Devonian siliceous limestones with Puchypwu and Fuvosites.

In Mongolia , this subdivision includes Upper Proterozoic-Lower Cambrian metamorphosed geosynclinal rocks, mainly sandstones, phyllites and some limestones; in places they contain metamorphosed volcanic rocks, tuffs and cherts. Some limestones contain stromatolites and oncolites (Os@, Fungussia and Semichatovia).

In Indonesia., Japan., the Philippines and elsewhere in the region, basement complexes consist of gneisses and crystalline schists formed by metamorphism of rocks ranging from Precambrian to Paleozoic in age. In the Philippines, the basement complex is recognizedas pre-Jurassic and consists of broadly folded undifferentiated amphibolites, quartzo-feldspathic mica schists, phyllites and slates, frequently associated with marble and quartzites.

21


PALEOZOIC

Cambrian Cambrian rocks in the Spiti Valley, in the Himalayas of India.,

are known as the Haimanta System, and consist of shales, micaceous quartzites and dolomites. The system is divided into lower, middle and upper divisions, of which only the upper one is fossiliferous; it contains Redlichda noetlingi, Ptychoparda spitiensis, Lingula spitiensis, etc., which indicate a middle to late Cambrian age. Some pre-Silurian schists are also included in this group.

In West Pakistan, Cambrian sedimentary rocks include the Jhelum Group, comprising the former Salt Pseudomorph Beds, Magnesian Sandstone, Neobolus Beds, Purple Sandstone and the underlying Salt Range Formation (the former Punjab Saline Series) of doubtful late Precambrian age. The fossils include Redlichia noetlingi, Neobolus warthi, Lingula, olrthis and Hyolithes, indicating a middle Cambrian age.

In Thailand, certain Upper Cambrian deposits are known inthe southern peninsula region west of Nakorn Si Thammarat, on Tarutao Island, and in Tak province of northern Thailand; they are represented by the Tarutao Group, consisting of red sandstones containing saukid trilobites and orthid brachiopods. Also shown on the map as Cambrian is the Phuket Series, mainly shales and slates, extending northward from Phuket Island; however, according to informaiion received after the map had k e n compiled, the Phuket Series should be considered as the upper part of the Kanchanaburi Formation, which ranges in age from Silurian to early Carboniferous (shown on the map as Silurian- Devonian).

In Indonesia, presumed Cambrian rocks are exposed near the eastern part of the Central Range in West Irian. In the lowest part they include basalt flows of the Awitagoh Formation; most of the sequence is represented by the overlying Kariem Formation, consisting of close alternations of fine clastic and carbonate rocks with some cherts.

Cambrian rocks have a wide distribution in China, where in many localities they overlie Sinian rocks quite conformably. Lower Cambrian shales, sandstones and impure limestones are widely scattered in

22


northeastern, east central and southeastern China, and they contain a characteristic Redlichia fauna. The Middle Cambrian consists mainly of limestones and shales with Ptychoparia, Anornocarella, Dorypyge, hmesella, Dvepanura and AgnoscuS. The Upper Cambrian is generally represented by limestones with some shales, containing Ptychaspis, Tsinania, Cerutopyge, Chuangia, etc. The Middle and Upper Cambrian rocks have a wide distribution in northern, eastern and central provinces (south Manchuria, Liaotung, Shantung, Shansi); in southern China they are developed only in Anhwei, Hupeh and eastern Kwangsi.

In hngolia, this system is represented by Lower Cambrian deposits in-most parts of the country, and by Upper Cambrian rocks exposed only in the Altai mountain range, westernMongolia. The Lower Cambrian is composed of geosynclinal deposits characterized by rapid changes of facies. In the extreme north, west of the Hobsogol lake, these are mainly limestones, dolomites, sandstones and shales. Within depressed zones in western, northwestern and central Mongolia, the Lower Cambrian is represented by spilite-diabase flows interbedded with carbonate and terrigenous deposits, andesitic and diabasic lava, pyroclastic deposits and embedded ultramafic intrusions. In uplifted structural zones, this sequence is replaced by terrigenous and terrigenous-carbonate rocks, associated with submarine volcanic rocks, mainly rhyolitic and dacitic. In eastern and southeastern regions, nearly all exposed Lower Cambrian deposits are exclusively of carbonate-terrigenous facies. The lower Cambrian fossils in Mongolia include Spirocyathus yavwskii, S. densus, S. conden.sus, CoscinocyaUzus cornucopia and C. diantus.

The Upper Cambrian geosynclinal sequence in the Altai Range is represented by flysch-like deposits, metamorphosed to green-schist facies; they include various schists, slates, phyllites and some sandstones.

Cambr ian-Ordovician Cambrian-Ordovician deposits are present within the North

China-Korean Platform and the Sourh China Platform in eastern China (Liaotung, Hopei, Shansi, Shantung, Hupeh, Anhwei, HunanandKweichow provinces); they consist mostly of limestones and some shales, with

23


sandstones and dolomites developed locally. A geosynclinal sequence of the Cambrian-Ordovician is represented in Manchuria and Inshan (Inner Mongolia) by carbonate rocks. Cambrian-Ordovician deposits include mainly schists, gneisses, phyllites and some limestones in Tien-Shan and Kunlun, and predominantly metamorphosed marine clastic and volcanic rocks in Kurug Tagh. Phyllites, sandstones, limestones and cherts, with some metamorphosed volcanic rocks and jaspilites compose the Cambrian-Ordovician in Nan Shan In the Kalpin Tagh Uplift of the Tarim Stable Block in Sinkiang, western China, the Lower Paleozoic (shown as Cambrian-Ordovician) consists of slates, metavolcanic rocks and conglomerates.

In Mongolia, this subdivision includes the Lower Paleozoic Khara and Tszaga Series composed of unfossiliferous marine clastic rocks, mainly phyllites, sandstones and some conglomerates, extensively developed in the northern and central parts.

Ordovician The Ordovician in Thailand is represented by the Thung Song

Group, consisting mainly of massive black limestones with Actinoceras and fragments of brachiopods andcrinoids, identified to be of Ordovician or at least early Paleozoic age. Brachiopods and trilobites have recently been discovered in the black calcareous shale of the Thung Song Group at Amphoe Thungwa.

In China, widely distributed Ordovician deposits, predominantly composed of limestones and some shales, are found within the North China-Korean and South China Platforms in Liaotung, Shansi, Hopei, Shantung, Hupeh, Hunan and Kweichow provinces of southeastern and eastern China. The Lower Ordovician beds contain Piloceras, Suecoceras, Ophelita, Dendrograptus, Dictyonema, Dichogvaptus, Loga- mgrap tus , Desmograptus , Ph yllograp tus , A m p Lexogvaptus , Didymo- graph, Tetragraphs and Callo,yapEus. The Middle Ordovician beds, with Actinoceras, Orthoceras, Glossogvaptus hincksii and Trigono- papcuS lineatus, 'are separated in places from the Lower Ordovician beds by an unconformity. Upper Ordovician platform sediments of A shgillian age containing Climacopaplus latus and Wcellograplus sextans occur in western Hupeh and Anhwei.

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In most part of Mongolia, this system is represented by Middle- Upper Ordovician geosynclinal formations, mainly slates, phyllites, shales, limestones and sandstones, containing the fossils Camaratoechia bairimica, Stegerhynella sp., Nicholsonella, Dyplob-ypa, Zygospira, Rafinesquina, Catazyga, Cyathophylloides cf. aktahoubdeus, Streptelasma (Grewingkia) cf. buceras, Catenipora, Cyathophyllum cf. laxurn, Catenipwa robusta, Saffordophyl lum , L yopara, Nyetopora, Prohel io1 ites , etc. In southern Mongolia, the Ordovician terrigenous deposits are associated with metamorphosed basic and andesitic volcanic rocks, locally with thin limestones in the upper part; this sequence may also include Lower Ordovician strata.

Cambr ian-Si lur ian In Iran, a widely distributed distinctive group of cherty dolomites

and red or variegated micaceous shales and sandstones is designated as %fra-Camhrian". Though separated from the Precam'srian basement by an unconformity, the "Infra-Cambrian" everywhere grades upwards without any sharp break into a red sandstone sequence (Lalun Sandstone) of early Cambrian age which in turn is conformably overlain by dolomites, limestones and shales, containing a rich middle to late Cambrian trilobite fauna. In northern, eastern and northwestern Iran, shaly and sandy deposits with graptolites, and marls and limestone rich in trilobites, brachiopods and cystoids indicate an early to middle Ordovician age. Conodonts are the only paleontological evidence for the presence of Upper Ordovician in Kerman, and the Silurian, represented by coral limestones, is confirmed only in two areas.

In the Himalayas of West Pakistan, India and Nepal, Lower Paleozoic formations of the Himalayan geosyncline are developed, especially in Hazara, Kashmir, the Spiti Valley, Almora and Garhwas and in Nepal. The Spiti Valley area shows the best development of these formations, where the constituent beds include conglomerates, quartzites and grits, overlain by shales and limestones. The Ordovician fauna is rich in brachiopods (Orthis, etc.) and the Silurian fauna is dominated by corals (Favosites, etc.); they show closer affinities to the North American than to the northern European faunas. The Lower Paleozoic in Nepal consists mainly of siltstones and carbonate rocks, including the Iron Ore Formation in the Kathmandu area which has yielded trilobites and brachiopods of Ordovician-Silurian age.

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In Burma, no fossiliferous Cambrian rocks have yet been reported although a part of the ChaungMagyi Series of the Shan States, the Mer@ Series (quartzites, limestones, schists, argillites) of Mergui and some volcanic rocks (Rawdwin Volcanics) may probably be referable to the Cambrian. The Ordovician strata of the northern Shan States include (in upward order) the Ngwetaung Sandstone, the Naungkangyi Series and the Naunghaw Limestone. The Ngwetaung Sandstone has yielded Orthis and some crinoid stems. The Naugkangyi Series, consisting of limestones, marls and shales, has yielded Orthis, Calymene, AgnoscuS, Plectambonites, etc., which show close affinities with the corresponding European forms. The Nyaungbaw Limestone contains a remarkable crinoid, Camarocrhus aSiQticus, In the sourthern Shan States, the Ordovician is represented by the Mawson Series, consisting of calcareous shales and limestones bearing 'Orthoceras, Actimceras, Oxygites, etc., together with the Orthoceras Beds and Pindaya Beds, which are purple argillaceous limestones and shales containing crinoid stems and species of Orthis, MonograPCUS, etc. The Silurian of Burma has three subdivisions, in ascending order: the Panghsa Pye Graptolite Beds, the Namshim Seds (sandstones and marls) and the Zebingyi Beds (limestones and shales). The Graptolite Beds contain Diplograptus, M~o- graphs, Orthis, Phacops, etc., and the Namshim Beds have yielded Calymene, Encrinurus, Phacops, Fenestella, etc. The Zebingyi Beds contain a rich fauna of graptolites, brachiopods and cephalopods.

The Cambrian strata in West Malaysia are predominantly arenaceous, with minor amounts of argillites, pebbly sandstones, conglomerates and some silicified limestone at the top. The fossils in the arenaceous beds are poorly preserved saukid trilobites and brachiopods of late Cambrian age, The Ordovician, however, is more widespread and is found in the Langkawi Islands, Perlis, Kedah and Perak as a thick succession of limestones with some shale and sandstones. Fragments of the cephalopod Robsunoceras, indicating an early Ordovician age are found near the base of the succession. In the Langkawi Islands and Perlis, the deposition of limestone was continuous into Silurian time.

In southern Viet-Mm, the Dalat Series (shales, slates, phyllites, schists, some quartzites and sandstones) is considered to be of Cambrian to Silurian age from its stratigraphic position, but without

26


any supporting fossil evidence. Formations similar to and correlated with the Dalat Series are exposed in some southern and eastern parts of the Khmer Republic.

Undifferentiated Cambrian-Silurian rocks in China generally comprise a rather thick geosynclinal sequence within foldbelts in the northern, western and central region; they consist mostly of shales, slates, quartzites and cherty limestones, with some phosphatic rocks in eastern Tien Shan (Ma-tsung Shan) whereas shales and sandstones, with some limestones and volcanic rocks, are predominant in Astin Tagh and Nan Shan. Marine clastic and carbonate rocks comprise the geosynclinal sequence in Tsinling Shan, Inshan and eastern Gobi. In southern central China (Yunnan, Sikang and southern Szechwan), Cambrian-Silurian deposits are represented by marine clastic rocks and limestones.

The Chosun System of Korea, ranging in age from early Cambrian to middle Ordovician, rests with a pronounced unconformity on Archean rocks, and, wich a slight angular unconformity, on Proterozoic rocks. The fossils found within this system include Redlichia, Obolus, Ptychoparia and Tonkinella. The Cambrian faunas of northern and southeh Korea are closely similar to each other, but the Ordovician faunas in these two regions are different: that of northern Korea is akin to the corresponding fauna from Arctic North America, whereas the southern Korean fauna shows affinities to the Ordovician fauna of Europe.

Ordovician-Si lur ian Undifferentiated Ordovician-Silurian rocks in north-eastern China

consists of shales, sandstones, slates and some limestone; they comprise a geosynclinal sequence within foldbelts in eastern Tien Shan and Dzungaria.

Silurian The Silurian in northern Laos consists of shales, phyllites and

sericite schists with greywackes. Sandstones and limestones contain Encrinums pum.ctacuS var. laoensis, Licks cf. scabra and Spirifw su1caCu.s. In some localities the lower part of the sequence may include Ordovician beds; some Ordovician sericitic schists with Trinucleus cf. m C u s are known near Ban Ban.

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In China, the Lower and Middle Silurian shales, sandstones and some limestones are widespread within the SQuth China Platform in parts of the southeastern provinces (Hunan, Kweichow, southwestern Hupeh, northeastern Y unnan, Kwangsi, southeastern Szechwan); they contain Momgraptus, Encrinus, Spirifer, Rastrites, Climacograptus, P e n t a m e m and Coromcephalus in most localities, and Favosites, Eospirifer, Protathyris, Modiolopsis, etc, in northeastern Y unnan. The highest Silurian beds of the South China Platform are generally continental red sandstones with fish and plant remains; sediments of marine facies are known only in southern Szechwan andnorthern Kweichow. A geosynclinal sequence of the Silurian in Yunnan consists of shales, limestones and phyllites. Shales, sandstones and slates, containing Akidograpclcs, Climacop-apclcs and Monograptus, with some phosphorites at the top, compose the Lower-Middle Silurian in the lower Yangtze valley. In northern Kiangsi (Mu-Ho), Silurian metamorphosed shales and sandstones contain Monograptus, Climaco- &-raptus, Eospirifer, Coronocephalus, etc. Shales and sandstones, with some slates and limestones containing Halysites, Favosites, &Zmanella and P e n t a m m , compose the deep water geosynclinal facies of the Silurian in the Tsinling-Shan. Geosynclinal deposits in Nan Shan and TienShan consist of weakly metamorphosed carbonate and marine clastic rocks; in western Kun Lun and Mustagh Ata they also include metamorphosed volcanic rocks.

In western Mongolia, this system is represented exclusively by Lower Silurian, consisting mainly of Wenlockian molasse-like marine clastic rocks with some limestones. Llandoverian strata, locally developed in the Altai, include black shales and limestones. A more complete sequence, including Lower and Upper Silurian geosynclinal deposits, is exposed within a west-east foldbelt, occupying the southern part of the country. In the west (the Gobi Altai) this sequence is made up of metamorphosed sandstones, siltstones, phyllites and cherts, with some limestones in the upper part. In the central and eastern part of the foldbelt, these deposits are associated with siliceous and volcanic rocks, including andesitic flows and tuffs, spilite and diabase; in some localities, the volcanic rocks comprise the major part of the sequence. In eastern and southeastern Mongolia, the Silurian deposits are characterized by carbonate and carbonate-terrigenous formations,

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with some acidic volcanic flows and conglomerates. The Lower Silurian fossils in Mongolia include Monograptus, Monoclimacis, SpirograpcuS, Retiolites, Microplasma, Propora, Mesofavosites, Favosites, Pynos- tylus, Crassilasma and Cerisster. The Upper Silurian beds contain Semicoscinium, Neomphyma, Cyrcaphyllum, etc.

Silurian deposits in West lrian are represented by strongly folded rocks of the Kemoem Formation, exposed in the northwestern region (northern Vogelkop); they consist mainly of slates with subordinate quartzites, containing MmgrapCUs marri and M. hwi- culab.

Silurian-Devonian

In the northern montane area of West Pakistan, Silurian-Devonian rocks include the Swabidhamla Sedimentary Group and the Lower Swat-Buner Schistose Group northeast of Peshawar, and the Abbottabad and Tanawal Formations (mainly quartzites, schists and dolomites) in Hazara.

In Kashmir and the Himalayas of India, the Silurian-Devonian consists of the Muth Quartzite which conformably overlies Silurian rocks with Pentarnerus oblongus in the Spiti Valley, and in turn is overlain by fossiliferous Lower Carboniferous rocks. The age of the Muth Quartzite is mainly Devonian, but the lower part is of late Silurian age.

In Thai land., the Silurian-Devonian Kanchanaburi Formation is the lower part of the newly-designated Tanaosi Group (Silurian- Carboniferous); it comprises the metamorphic rocks of the former Kanchanaburi Series and the equivalent strata of sedimentary rocks which may contain Silurian and Devonian faunas. The Kanchanaburi Formation consists of phyllites, slates, quartzites and shales, with some intercalations of bedded limestone.

Silurian-Devonian deposits in northern Laos and Viet-Nam are represented mainly by shales and greywackes with Spirifw, @this, Conocardium, Calymene, SCropheodonta and Atrypa reticularis.

In southeastern China, south of the Lower Yangtze valley, the Silurian-Devonian is represented by shales and sandstones. In Kalpin

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Tagh (western Sinkiang), the Silurian-Devonian rocks are mainly marine clastic deposits. In Tien Shan, a geosynclinal sequence of Silurian-Devonian is mainly composed of marine clastic and carbonate rocks, with volcanic rocks in places.

In Mongolia, this subdivision includes the Upper Silurian-Lower Devonian geosynclinal deposits found in scattered exposures within the east-west foldbelt in the southern regions. In the Gobi Altai, in the west there are phyllites, shales, limestones and some sandstones; eastwards they are commonly associated with intermzdiate and basic volcanic rocks and cherts, which are extensively developed in the eastern Gobi. In eastern Mongolia, the predominant part of the sequence is composed of carbonate and terrigenous-carbonate rocks. The Upper Silurian-Lower Devonian beds in Mongolia contain the fossils Riphacolites, Placoenites, Favosites gasimuricus, Lioclema aff. tenuirama, etc.

In Japan., Silurian and Devonian Strata crop out in narrow areas of Shikoku and northern Honshu. The lower part of the Crinoyana Series in Shikolcu, composed of limestones, sandstones, tuffaceous shales and small amounts of acidic volcanic rocks, is the oldest dated deposit; a Silurian (Wenlockian) age is indicated for it by fossils, including Falsicatenipmcr, Halysites, Scutellum and Covonocephalus. The lower half of the Devonian succession in the southwest is characterized by an abundance of pyroclastic material and reef limestones; in one part, limestones near the base contain corals, including Favo- sites, Thamnopora, Thecostegites and Cymatelasma. Large amounts of pyroclastic rocks also occur in the upper part in the southwest, but in the northeast, this interval consists mainly of thick clastic deposits.

Devonian In southern Viet-Nam, Devonian and Devonian-Carboniferous

(Dinantian) deposits are mainly represented by non-fossiliferous continental-epicontinental clastic strata, including slates, shales, sandstones and some siliceous shales. In central Viet-Nam (Annamitic zone) and in eastern and central Laos, Devonian neritic, partly brackish- water sediments include shales, marls, sandstones with minor limestones and, locally, with some red beds. The fossils include Athyris concentrica, Atrypa desquamata, A. reticularis, Sbropheodonta anna-

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mitica, Calceola sandalina, Favosites styriacus. Heliolites porosus, Spirifer ziczac and Actinopteria subdecussatu, indicating an age from Emsian through Francian. In western Laos and northern Viet-Nam, the Devonian geosynclinal deposits are characterized by rapid changes of facies from one place to another and from one part of the sequence to another. The rocks are mainly shales, greywackes, limestones, some sandstones, cherts, quartzites and jasper beds; they contain rich faunas of brachiopods, corals and lamellibranchs, and range in age from early to late Devonian in Laos, and from early to middle Devonian in many places in northern Viet-Nam.

In southeastern China, within the South China Platform and Cathaysian Foldbelt, the Lower Devonian generally consists of continental red sandstones and shales containing Arthrost&ma gracile and fish remains. The Middle and Upper Devonian, however, are represented there by marine deposits (shales, sandstones), exposed mainly in eastern Yunnan, Kweichow, Hunan, Kwangsi and southeastern Kwangtung, which contain the fossils Calceola sandalina, Stringocephalus burtini, Sinospirqer sinensis and Manticoceras. North- eastward, these rocks give way to continental deposits; in eastern Hunan and western Kiangsi the Middle-Upper Devonian consists of marine and continental clastic rocks, but, in the southeastern coastal region, within the Cathaysian Foldbelt, it includes predominantly continental clastic rocks with some residual iron and manganese ore. The Devonian geosynclinal rocks in Tsinling Shan are represented by limestones, phyllites, greywackes and some tuffs; in Lun-men Shan (northeastern Szechwan) they are mainly conglomerates and quartzites in the lower part, and limestones in the upper part. A geosynclfnal sequence of Devonian deposits in the Nan Shan consists of phyllites, greywackes, some volcanic rocks and limestones; in Tien Shan and Kurug Tagh it includes mostly carbonate and clastic rocks.

In southern and central Mongolia, and also in the easternmost region south of the Hailhain Go1 valley, this system is represented by a Lower-Upper Devonian geosynclinal sequence made up of phyllites, shales, cherts, greywackes, slates and some limestones, associated with large volumes of volcanic rocks including basaltic and andesitic lavas and tuffs, diabases and spilites. In northeastern and

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eastern Mongolia, including northeastern Gobi, and also in Gobi Altai in the southwest, this sequence is mainly composed of marine terrigenous and terrigenous-carbonate formations. North of the Kerulen valley, the Middle-Upper Devonian marine deposits are 'replaced by littoral and continental clastic rocks, including conglomerates, sandstones and some pyroclastic rocks. Continental clastic deposits of late Devonian age are known also southeast of Ulan Bator. In northern, northwestern and western Mongolia, this system is represented predominantly by lower Devonian-Eifelian molasse-like marine clastic rocks, with widespread andesitic, dacitic and rhyolitic flows and pyroclastic deposits. The younger Devonian beds in western Mongolia are known in western Altai, where they are represented by Givetian marine terrigenous rocks. The Lower Devonian fossils in Mongolia include Camarotoec hia dal eidens is , Spirifer h ys tericus , Leptos trophia beckii, L. explanata var. Kharkraica, Leptaena bouei and Phacops subcristata. The Middle Devonian beds have yielded the fossils Pa- chypora cervicomis, P. reticulata, Cyphaspis hydrocephala, Atrypa re ticularis , Natallophyllum give ticum, Alveolites aff . lemniseus and the plants Taeniocrada decheniana, Aphyllopteris sp. , Pseudouralia sibirica, Uralia cf. camdjalensis and Parvandeinopsis cf. beliakovii. The Upper Devonian contains Cyrtospirifer, Reticularia, Euphemites, etc.

Devonian-Carboniferous In the Khmer Republic, Devonian-Carboniferous deposits consist

of shale, shaly sandstones, marls and siliceous shales, with some limestones near the top. The limestones contain the foraminifera Endothyra, Mmgenerina and Geinitzia, which make possible the dating of the upper part of the sequence as Lower Carboniferous (Dinantian).

On the South China Platform in southeastern China (northwestern Y unnan, Kweichow, northern Kwangsi) rather thin epicontinental formations of Devonian-Carboniferous age occur, consisting mainly of sandstones, shales and limestones. In the southeastern coastal region (eastern Kiangsi, Chekiang, Fukien, northern Kwangtung), this subdivision includes Devonian-Lower Carboniferous continental sandstones.

In south central and central China (western Yunnan, Sinkiang, western Szechwan), a Devonian-Carmniferous geosynclinal sequence

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consists mainly of marine clastic rocks and limestones; in Tsinling Shan, limestones form the bulk of the sequence. Devonian-Lower Carboniferous deposits are represented by marine shales, sandstones and limestones in eastern Kunlun and by mixed marine and continental clastic rocks with some coal in northern Nan Shan.

Undifferentiated Devonian-Carboniferous deposits in central and northeastern Mongolia are represented by sandstones, cherts, siltstones and volcanic rocks in the lower part, and mainly mudstones, coarse sandstones and conglomerates in the upper part. In the lower part, they contain Devonian-Carboniferous fossils, including Thamno- pwa, Crassialveolites, Ceonites and Spirifer duplisicostus, and in the upper part, the plants Tomiodendron latchaticum, Chacassopteris cone innu, Noeggera thiopsis , Pecop teris and Paracal a m ites.

Carboniferous

In the Hindu Kush, in northern West Pakistan, the Carboniferous includes the Sarikol Shale or its equivalents.

In Kashmir and the Spiti Valley of the Himalayas of India, Car- boniferous limestones and shales contain Productus, Spirifer, Phillip- sia, Cmularia, Fenestella and Syringopora.

In southeastern China, within the South China Platform (eastern Y unnan, Kweichow, central and southern Hunan, northern Kwangtung, eastern and northern Kwangsi) the Lower Carboniferous marine epicontinental deposits, made up of limestones with some sandstones and shales, have been divided into four zones which, in ascending order, are the Cystophrentis zone, the Pseudouralina &ne, the Thy- sanophyllum zone and the Yuunophyllum zone. Typical fossils include Athyris, Schellwienella, Syringopora, Productus and kviesie1la* A continental deposit of early Carboniferous age occurs in the southeastern coastal region (Chekiang, Fukien, eastern Kiangsi) and in the lower Yangtze valley; the Wutung Sandstone within this bears the plant fossil Lepidodendron mzrabile. The Middle and Upper Car- boniferous strata in southeastern China are mainly composed of white limestones containing Fusulinella, Fusulinu, Chaetetes, En- teletes lamarcki, Choristites mosquemis, Striatifera striata, etc.

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In the North China-Korean Platform within eastern, central and partly northeastern China, Lower Carboniferous deposits are absent and Middle Carboniferous (Moscovian) sediments rest on Ordovician limestones with a faintly recognizable discordance. The Middle-Upper Carboniferous rocks in this area are represented by alternations of marine and continental deposits; they include shales, sandstones, limestones, occasional thin seams of coal and also some alumina shales and iron ores (in Shansi). Staffella, Fusulinella, Choristites, etc., are found in the limestones and the typical flora from the shales includes Neuropteris giganteus and Palaeoweichseliu.

In Tsinling Shan, central China, the Carboniferous geosynclinal beds consist of alternating continental and msrine clastic rocks, with some coal and limestones in the lower part of the sequence, marine clastics (shales, phyllites, quartzites) and limestomes in the middle part, and predominantly limestones in the upper part. Innorthern Nan Shan, the Lower Carboniferous includes marine clastic and some volcanic rocks while the upper strata are represented by coal-bearing formations. In Ma-tsung Shan and southwestern Gobi (northwestern Kansu), a thick (5-1 1 km) Carboniferous sequence is composed of sandstones, shales and limestones, with great volumes of basic and andesitic volcanic flows and tuffs in the middle part. In western China, the Carboniferous is com7osed of black shales, phyllites and sandstones, with thin beds of limestones in the Mustagh Ata Range and western Kunlun. In Tien Shan and Dzungaria, the Lower Carbo- niferous marine shales, sandstones and limestones pass upwards into Middle-Upper Carboniferous mixed marine and continental clastic rocks, associated with volcanic flows and tuffs.

In northern, western and eastern Mongolia, the Lower Carbo- niferous (including Namurian) is represented in most areas by mafine and continental, sometimes mixed marine-continental molasse-like clastic deposits, including sandstones, siltstones, gritstones and conglomerates, locally containing some limestones and thin coal beds; in Gobi Altai and western Gobi, southwestern Mongolia, they also include andesitic and dacitic lavas with rhyolitic lavas and pyroclastic rocks locally. A geosynclinal sequence of Lower Carboniferous sandstones, phyllites, cherts and tuffs is exposed in central Mongolia. In the southernmost areas, the Lower Carboniferous includes marine terri-

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genous deposits, some limestones and great volumes of andesitic and dacitic flows and tuffs. The Lower Carboniferous beds inMongolia carry the fossils Archaediscus, Eostaffella, Mediocriocris, Lonsdaleia, Fenestella, Pol ypora, Lingula, Productus, Spirifer, Schizophoria, Cama - rotoechia, etc, and the plant remains Angaropteridium cardiopteroides. A. vescum, Cardiopteridium asiaticum, Asterocalamites, etc. The Middle-Upper Carboniferous in most parts of Mongolia is composed of andesitic, dacitic and rhyolitic flows and pyroclastic rocks, associated with predominantly continental and some marine molasse-like clastic deposits, containing the fossils Phestia, Pseudoedmondia, Edmondiella, Crenipecten, etc., and the plants Noeggerathiopsis, Angarop teridium , Stenopteris , Cinkgophyllum , Cardiocarpus, L epido- dendron, Angarodendron, Tomiodendron, Pecopteris, Paracalamites, etc. In northwestern Mongolia and the Altai Range, the Niiddle- Upper Carboniferous formations consist of marine and continental clastic rocks with coal beds. Marine geosynclinal deposits of this age (greywackes, cherts and phyllites with andesitic and spilitic lavas and tuffs) are known in southern Gobi.

Devonian-Perm ian A continuous sequence of mainly limestones is present in Iran,

ranging in age from Devonian to Permian and possibly Triassic. Upper Devonian and Carboniferous dark limestones containing brachiopods and corals, occur from Azerbaijan through Alborz to central Iran, together with subordinate basic volcanic rocks; north of Kerman, the dark limestones may be of Middle Devonian age on evidence of conodonts and brachiopods. Lower and Upper Permian beds consist of sandstones, quartzites, black carbonaceous shales, red shales and subordinate sandy oolitic limestones containing brachiopods and fusulinids. In places, Permian limestones and dolomites show a transition into limestones of up to Lower-Middle Triassic age, which are also included in this subdivision.

In the Spiti Valley region of the Himalayas of India, this subdivision includes undifferentiated rocks of the Kanawar and Kuling Systems, the Krol and Infra-Krol Series, Zewan Beds, etc. In the Spiti Valley, the Muth Quartzites are overlain by limestones, shales and quartzites of the Kanawar System; the topof the lower part of the Kana-

35


war System contains Lower Carboniferous fossils, including Productus Cora, P. semireticulatus, Chonetes hardrensis, Sparifer kashmiripsis, Syringothyris cuspidata, Phillipsia cf. cliffordi and Cmularia wdrisul- cata. This part is correlated with the Syringothyris Limestone in Kashmir. The upper part of the Kanawar System, corresponding to the Fenestella Shales in Kashmir, contains middle Carboniferous fossils, including Fenestella, Productus scabriculus, P. undutus and Spirifer triangularis. The overlying Permo-Carboniferous Kuling System is composed of calcareous sandstones in the lower part, andincludes the Productus Shales in the upper part which form a persistent horizon in Kashmir, the Indian Himalayas and Nepal; it contains abundant Productus purdoni, P. abichi, P. giganteus , Spirifer spirigera, Xempsis , Cyclolobus oldhami, etc. In Kashmir, the Zewan Beds, consisting mostly of shales and limestones with a Middle-Upper Permian fauna of brachiopods, corals and bryozoa (Protoretepora amplal, lie on Upper Carboniferous-Permian shales and sandstones, associated with agglomeratic slates and volcanic rocks. The Krol (shales and limestones) and Infra-Krol (shales with thin beds of quartzites) Series compose the Upper Carboniferous-Permian in the Simla-Garhwal Region.

In Nepal, the Upper Paleozoic includes, in the lower part, the Everest Pelitic Series (mostly shales and slates of probable Devonian or Carboniferous age) which is overlain' by the Everest Limestone of Carboniferous age. The Everest Limestone is overlain conformably by the Lachi Series (limestones, calcareous sandstones, shales, quartzites and some pebble beds) containing Permian fossils and covering large areas north of Mount Everest and in northern Sikkim.

In Burma , the Devonian-Carboniferous is represented by the Plateau Limestone, the Moulmein Limestone and their equivalents. The Lower Plateau Limestone, mainly dolomite or dolomitic limestone , contains an Eifelian and Upper Devonian fauna including Calceola sandalina, Favosites, C h m t e s and hvilleina. The Upper Plateau Limestone (dark limestones), with Fusulina elongata, Spirifer fasciger, Productus Cora, etc., is Carboniferous-Permian. The Moulmein Lime- stone beds, with some intercalated sandstones and shales, are also Carboniferous-Permian in age.

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The Ratburi Series of Thailand, identified on the map in this subdivision, consists mastly of limestones, although they are associated in the south with shales, sandstones, siltstones and some quartzites; the brachiopods and fusulinids in them indicate a Carboniferous- Permian age.

In the Khmer Republic the Devonian-Permianconsists of Devonian- Carboniferous slates, shales and sandstones, with some siliceous shales and jasper, and Permian carbonate rocks.

In southern V jet-Nam, this subdivision includes mainly Devonian- Lower Carboniferous (Dinantian) shales, sandy shales, sandstones and some limestones, locally with siliceous shales and marls. En northern and central Laos and the western part of northern Viet-Nam, the Devonian-Permian is represented mainly by marine clastic rocks associated locally with volcanic material. These geosynclinal deposits consist of shales, greywackes, sandstones, grits, some lavas and tuffs, and minor limestones; carbonate rocks become predominant in northwestern Laos. These Devonian-Permian rocks contain brachiopods, corals, bryozoa and lamellibranchs, indicating a late Devonian (Frasnian), Carboniferous and Permian (including Kazanian) age. In central eastern Laos and central Viet-Nam (Annamitic zone), as well as northeastern Viet-Nam, Carboniferous-Permian strata, mainly limestones but with some dolomites, locally with intercalations of marine clastic rocks, are shown in the Devonian-Permian subdivision. In central Viet-Nam and eastern central Laos, they include Lower Carboniferous-Upper Permian strata, although in most areas their age ranges from Westphalian (Moscovian) to Kazanian and Tartarian (late Permian); the limestones contain a large and varied fauna, including bryozoa, brachiopods, lamellibranchs, gastropods, corals and abundant fusulinids.

A: Pulau Langgun in West Malaysia, Devonian non-calcareous deposits contain at the base a rich fauna of dacryoconarid tentaculites together with some lamellibranchs and graptolites. Middle-Upper Devo- nian fossils, in mudstones at the same locality, include gastropods, lamellibranchs, brachiopods and trilobites; southwards, in central Perak, the Devonian is predominantly calcareous.

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Lower Carboniferous deposits of West Malaysia consist of a thick succession of carbonaceous shales, phyllites and quartzites, with bands of limestone occurring in the upper part. These limestones have yielded a rich brachiopod fauna, including Schizophoria, Avonia, Linoproductus and Spirifer. The shales contain mainly corals (Canznia, Lithostrotion, etc.) and plant remains (Lepidodendron, Stigmaria) , indicating a near-shore environment. Middle and Upper Carboniferous sediments are found sporadically in southern Kelantan (mudstones and pyroclastic rocks) and Perak (limestones). Throughout West Malaysia, the Permian is typically calcareous, but, in places, the predominating limcstones are associated with shales, siltstones, quartzites and andesitic-rhyolitic lavas and pyroclastic rocks. Fossils are fairly abundant both in number and variety and include foraminifera, corals, bryozoans, brachiopods, scaphopods, gastropods, crinoids and algae.

Shown under this subdivision, Upper Paleozoic (predominantly Carboniferous-Permian) formations in Burma are represented by sedimentary, metamorphic and volcanic rocks, including radiolarian cherts and ophiolites. They contain Fusulinu, Endothyra, Trochammina, Radiolaria, etc.

Also included in this subdivision are Upper Paleozoic, primarily Carboniferous-Permian, rocks of Indonesia , which occur in Sumatra and other islands of the archipelago. They consist mostly of limestones and shales, interbedded with thick masses of lava and tuff, and contain spivifer and Productus and fossil plants such as Pecopteris, Lepido- dendron. Sigillaria, Sphenophyllum, Calamites and Cordaites.

Carboniferous-Permian Undifferentiated Carboniferous-Permian platform-type deposits

in southeastern China (the South China Platform and Cathaysian Fold- belt) are represented mostly by limestones, with some coal-bearing for:ndi'wz !n the upper part. In the southeastern coastal region, marine limestone and shales are also interbedded with coal-clastic deposits. In the North China-Korean Platform, within east central and partly northeastern China, this unit includes beds of Middle Car- boniferous to Permian age; the lower part of the succession is made

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up of alternating marine and continental clastic rocks and limestones, the upper part being predominantly continental deposits with coal. In northern Takla Makan (Tarim Basin) in western China, the Carboni- ferous-Permian and Upper Paleozoic formations contain alternating marine and continental beds.

In the foldbelts of central China, including Kunlun and Tsinling, the Carboniferous-Permian or Upper Paleozoic deposits are generally represented by limestones, associated in the lower part with marine clastic rocks and in the upper part with mixed marine and continental clastics, some coal and conglomerates. In eastern Tien Shan and Ma- tsung Shan (western Gobi) of northwestern China, this group includes a Middle-Upper Carboniferous marine sedimentary-volcanic formation and Permian molasse-like marine and continental clastic rocks. In northeastern China, including Manchuria and Inner Mongolia, the Upper Paleozoic and Carbbniferous-Permian deposits are represented generally by metamorphosedlimestones, phyllites, some greywackes, cherts, sandstones, and, locally, some conglomerates and tuffs. In Tibet, Carboniferous-Permian marine clastic and carbonate rocks are associated with some volcanic rocks and coal beds; in Sikang and western Yunnan, carbonate rocks comprise the major part of the sequence.

In most parts of Mongolia, rocks ranging from Middle Carboni- ferous (Upper in places) to Lower Permian are common. The sequence consists of marine and continental molasse-like clastic deposits, mainly sandstones and siltstones; great volumes of andesitic, dacitic and rhyolitic lavas commonly associated with these strata are most extensively developed in the central and southern regions, in places forming the main part of the sequence. In southernmost Mongolia, southern Gobi, the Middle Carboniferous-Lower Permian is represented by a geosynclinal sequence consisting of greywackes, cherts and andesitic and spilitic volcanic rocks, in the upper part including some limestones with Lower Permian foraminifera Schwagerina, Schubertella, Parastaffella, Pseudofusdim, Qunsifusulina, Rugosofu- sulina and Pseudoschwagertna.

In Japan, Carboniferous and Permian strata consist of a thick accumulation of clay slates, greywackes, cherts, schalstein and limestone. The Lower Carboniferous is divided into four series and the fos-

39


sils include brachiopods (Kitakamithyris, Syringothyris, etc.) and corals (Suqiyamaelta , Dibunophyllum, Lithos trotion, etc.). The zoning of the Upper Carboniferous-Permian strata by fusulinids is established as follows (in ascending order): Millerella zone, Profusulinella zone, Fusulinella zone, Fusul ina zone, Pseudoschwagerina zone, Parafusulina zone, Neoschwagerina zone and Yabeina-Lepidolina zone.

The Carboniferous-Permian in West Irian in Indonesia is represented by the hifam Formation which occurs in scattered outcrops in the northwest (Vogelkop) and in the Central Range. It consists of terrestrial clastic deposits, mainly red Sandstones, shales, quartzites and conglomerates, exposed only in the Vogelkop, followed by a shallow marine sequence of slates, sandstones and limestones, which becomes paralic at the top, as indicated by coal beds and plant remains; the fossils include Productus, Spirifer, Derbyia, Neospirifer, tetracorals and fusulinids, and the plants Sphenophyllurn, Pecopteris, Taeniopteris, Calamites, etc., indicative of late Carboniferous-Permian age.

Permian

In Afghanistan, the Permian is represented mostly by sandstones and limestones containing Neoschwaqerina, Spiroloculina, and Tex- tularlidae, etc.

In the Salt Range of West Pakistan, the Lower Permian is represented by the Nilawachan Group (formerly the basalTalchir Boulder Bed, Olive Series, the Speckled Sandstone and the Lavender Clay) consisting mainly of calcareous sandstones and shales, with red sandstones, gypseous beds and some glacial or glacio-fluvial boulder beds at the base. The fossils include brachiopods, gastropods, lamellibranchs and bryozoa. The Nilawahan Group is overlain by the Zaluch Group (the former Productus Limestone), consisting mostly of limestones with some shales and sandstones in the basaland upper part, containing a rich fauna of brachiopods (especially Productus), gastropods and cephalopods, which indicate an age ranging from Artinskian to T huringian.

The Permian in eastern central China (Shansi, Hotjei, Shantung) within the North China-Korean Platform, is represented by continental sandstones, shales and clays, containing, in the lower part, productive

40


coal measures with plant remains (Sphenophyllum thoni, Taeniopteris multinervis and Walchia). In southeastern China (Szechwan, Kweichow, eastern Y unnan, Kwangsi, Hunan, Kiangsi, Fukien, southern Hupeh and Anhwei) the Lower Permian is essentially composed of limestone with shales, containing Glyph ioceras , Neoschwagerina, Verbeekina, Waaqeno- phyllum, etc. In Yunnan and western Kweichow, the Middle Permian is characterized by large sheets of basic lavas alternating with tuffs and shales. The Upper Permian includes in the lower part the Loping Formation, made up of shales, sandstones and coal seams with Gigan- topteris flora; this formation often includes thin beds of limestones with the well-known Loping fauna containing Productus, Lyttonia richthofeni, Richthojenia laurentiana and Orthotetes ti@. The Loping Formation is overlain by limestones, intercalated in some places with sandstones and shales which have yielded the Gigantopteris flora and the late Permian forms Pseudomonites, Pecten, Bellerophm, etc; Phillipsia is occasionally associated with these forms. In Tsinling Shan, central China, the Lower Permian is composed of limestones, which are overlain by thin shales with some limestones; the Upper Permian includes a coal-bearing formation and marine limestones. In Tien Shan, northwestern China, the Lower Permian consists of marine clastic strata with occasional beds of limestones; the Upper Permian includes mostly continental clastic deposits.

In Mongolia, the Lower Permian in most areas is represented by volcanic rocks, including rhyolitic, dacitic and locally andesitic flows and pyroclastic rocks, associated with marine and continental clastic rocks. These deposits contain the flora Paracalamites sibiricus, P. planicos tatus, Noeqqerathiops is derzavini, N. sib irica, Cordaicarpus, etc. The Lower Permian marine deposits are developed in eastern, southwestern and southernmost Mongolia; in the southwestern (Gohi Altai) and eastern regons they consist of marine terrigenous deposits, including sandstones and siltstones with some conglomerates and 1 i mes tones, containing Hexagonella, Cya thaxonia, Lophophyll idium, Goniocladia, Diplopolaria, Streptorhynchus and Uncinunell ina timorens is. In southern Gobi, the Lower Permian includes cherts, sandstones, some basic volcanic rocks and limestones with Lower Permian foraminifera.

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The Upper Permian marine terrigenous deposits form extensive exposures in central and northeastern Mongolia; these are mostly sandstones, siltstones and conglomerates accumulated within a large southwest-northeast elongated basin. In the southernmost regions, the Upper Permian consists of marine clastic rocks and limestones containing Streptorhynchus, Marginifera, Anidanthus, Spiriferella, Fenestella, Hexagonella, Dyseritella, etc. The Upper Permian, in widely scattered exposures within the rest of the country, generally consists of mainly continental, in places mixed marine and continental, molasse-like clastic deposits, locally associated with coal beds and intermediate-acidic volcanic rocks; the latter are extensively developed in northern Mongolia. These rocks contain the flora Pecopteris, Callip- tevis, Crass inevvia, Prynodacopteris, Puvacalamites, Noeggerathiopsis mit inaens is, Parasclzizoneura, etc.

Undifferentiated Paleozoic

In Iran, a succession of partly undifferentiated Paleozoic rocks shown by this designation on the map generally includes Infra-Cambrian dolomites, shales, cherts and some limestones, Lower Cambrian purple sandstones, and the Mila Formation which consists of shales, limestones and dolomites of Middle and Upper Cambrian age; in eastern Iran (north of Kerman) this formation is replaced by red beds. Overlying these beds in eastern Iran are Ordovician and Silurian marine limestones, shales and some dolomites and sandstones, which are followed by carbonate rocks of Devonian age. However, in other parts of Iran the Mila Formation is succeeded by Upper Paleozoic rocks which in northeastern Lran are limestones, quartzites and shales of Upper Devonian-Permian age. Elsewhere, including eastern, central (south of Kashan) and southwestern Iran (the Zagros ranges) Carboni- ferous quartzites, sandstones and shales are found, usually succeeded by Carboniferous-Permian and Permian limestones and dolomites, also including Lower-Middle Triassic carbonaceous strata in places.

The undifferentiated Paleozoic deposits in Afghanistan include rocks that are generally strongly deformed and variably metamorphosed, ranging in age from Ordovician to Carboniferous. They consist mainly of schists, phyllites, sandstones, limestones, quartzites and

42


locally, mica schists. Ordovician and Silurian rocks are best developed in eastern (near Kabul and Jalalabad) and northeastern Afghanistan; the Ordovician limestones and quartzites contain trilobites and brachiopods and the Silurian deposits have yielded conodonts and ortho- ceratites. Devonian marine sediments are known in the eastern (south of Kabul), central and western regions; in the western part of central Afghanistan they contain some gypsum and salt. Fossils in the Devonian sediments include Spivifer, Zaphrentzs and trilobites. Carboniferous deposits have a wide distribution; in places they contain brachiopods, crinoids and fusulinids.

The Paleozoic in the Hindu Kush area of West Pakistan consists of metamorphic and volcanic rocks, including the Carboniferous- Permian Darkot Group. In Kashmir, the unfossiliferous Tanawal Series, composed of phyllites, quartzites, quartz schists and conglomerates is included in this subdivision.

Paleozoic rocks in north-ccntral Nepal (in the Tibetan or Tethys Himalayas) include dark grey limestones, dolomites and shales with Silurian graptolites, which are succeeded by Carboniferous-Permian fossiliferous limestones rich in brachiopods, corals and bryozoans including Fenestella. In the lower Himalayas of southern Nepal, the Paleozoic is represented predominantly by carbonate rocks, with some shales, quartzites and phyllites.

In central Laos and Viet-Nam, the Paleozoic is represented by unfossiliferous schists, slates and carbonate rocks, underlying the Lower Indosinias.

In south-central China (Sikang, western Szechwan and southern Tsinghai), there is an undifferentiated Paleozoic geosynclinal sequence of marine clastic rocks, limestones, some conglomerates and volcanic rocks; these are generally folded and locally metamorphosed. In northern Manchuria (northeastern China) undifferentiated Paleozoic deposits include mainly limestones, shales and some sandstones, varying in age from Cambrian-Ordovician to Carboniferous-Permian. In Taiwan, the Paleozoic comprises gneisses, sericite schists, green schists and crystalline limestones exposed in the Central Range. A few fusulinids (Neoschwagerinu, Schwaqerina) of Permian age have been found in the crystalline limestones of the metamorphic complex.

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In Japan., the Hi&, Sangun, Ryoke and Sambagawa metamorphic rock units are shown as Undifferentiated Paleozoic on this map. The Hi& and Ryoke metamorphic rocks (gneisses and schists) indicate regional metamorphism of a low pressure-high temperature type. The age of the original rocks of the Hida metamorphic unit is not known, but for the Ryoke unit it is known to be Carboniferous-Permian. The Sangun and Sambagawa crystalline schists are of high pressure- low temperature type, and their original rocks were of Paleozoic age.

PALEOZOIC-MESOZOIC

Carboniferous-Tr iasstc The Gondwana System of India is included in this subdivision

although it extends to as late as early Cretaceous in age. This thick sequence of mainly clastic rocks is divided into two on the basis of the GZossopteris flora, which characterizes the lower division, of late Carboniferous to early Triassic (Scythian) age, and the PtyZophyZZum flora in the upper part, of middleTriassic(Anisian) to early Cretaceous age. The basal formation of this system is the Talchir Boulder Bed, consisting of sandstones, shales and tillites, which give evidence of glaciation, and is referred to the late Carboniferous. Humid conditions which followed the glaciation favoured the growth of luxuriant vegetation, resulting in the deposition of the Damuda Series (mostly grits and sanddtones) about 2,400 m thick and containing numerous coal seams. Red and variegated sandstones, clays and shales of the Panchet and Mahadeva Series and their equivalents were subsequently deposited under arid climatic conditions; they contain remains of reptiles and amphibians. Basic intrusions, mostly lamprophyres, are common in the Lower Gondwana rocks.

After the Hercynian Orogeny in West Pakistan and India, a part of Kashmir, Hazara and the northwestern Himalayas formed a highland. Volcanic activity in the region produced agglomerates and other pyroclastic rocks of the Agglomeratic Series and, later, lava flows ranging from andesite to basalt of the Pir PanjalVolcanic Series. This volcanic activity commenced during middle to late Carboniferous times and extended into late Triassic, as some of the lava flows are interbedded

44


with Triassic strata. Though usually unfossiliferous, the underlying Agglomeratic Slates, in some places, have yielded well-preserved fossils, including Spirifer, Dielasma, Protoretepora and Lima. Inter- bedded with the pyroclastic strata are some beds containing Lower Gondwana plant fossils, including Gangamopteris and Vertebraria. In the Hindu Kush range, northern West Pakistan, the Greenstone Complex of Carboniferous-Triassic age indudes volcanic, sedimentary and meta-sedimentary rocks.

In Laos and Viet-Nam, the Lower Indosinias strata, ranging in age from middle-late Carboniferous to middle Triassic, are predominantly sandstones and shales, with grits, calcareous shales and sandy limestones closely interbedded with massive limestones containing brachiopods and fusulinids of late Carboniferous and Permian age. In many places, the Lower Indosinias are intercalated with large volumes of andesitic, dacitic and rhyolitic lavas, tuffs and breccias. In many localities, especially in western Laos, northern Viet-Nam and north-central Khmer Republic, there are also intrusions and flows of porphyrites, gabbros and dolerites (shown on the map as Paleozoic basic intrusive rocks) which may be Carboniferous-Permian to early Triassic and some of them even older in age.

In China, undifferentiated Carboniferous-Triassic deposits are shown in vicinity of Nan Shan, in northern central China; they are composed mainly of coal-bearing formations and continental clastic rocks, with some limestones in the lower part.

In Mongolia this classification is represented by Middle Carbo- niferous-Lower Triassic terrigenous deposits in a monotonous flysch- like sequence mainly of sandstones and siltstones, which is developed in the northeasternmost regions along the border with the USSR.

In the Pyongan System of Korea, the basal Moscovian (Upper Carboniferous) beds and the succeeding lower part of the Lower Per- mian deposits are of marine origin, and the rest, up to Triassic, are of shallow water or terrestrial origin. The marine faunas include Fusulinella, Fusulina and Pseudoschwagerina. The Lower Permian flora includes Lepidodendron, Pecopteris, Pterophyllum, Cordaites and Noeggerathiopsis. The Triassic rocks contain Neocalamites, Thinnf el diu, Gigan top teris , L a ba tannularia, etc.

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In the northwestern part of the island of Borneo (East Malaysia, Brunei and tndonesiu) the Carboniferous-Triassic sequence consists of shales, - conglomerates, sandstones and some pyroclastic rocks of the Terbat and Sadong Formations.

In Indonesia., the Carboniferous-Cretaceous deposits in West Irian, comprising the Aifam (Carboniferous-Permian), Tipoema, Brug (Triassic-Jurassic) and Kembelangan (Jurassic-Cretaceous) Forma- tions, which occur over a large area innorthern Vogelkop, in the northwestern part of West Irian, are not differentiated on the map and are all shown as Carboniferous-Triassic.

Permian-Triassic

In Afghanistan, undifferentiated Permian-Triassic limestones, sandstones and shales are widely distributed in the southern part; the Permian and Triassic limestones appear to form a continuous succession. In northern Afghanistan, the Permian-Triassic, occurring as scattered exposures, is mainly composed of sandstones and volcanic rocks.

In southeastern China, this subdivision includes mainly marine limestones and shales, with some coal, of middle Permian and late Triassic age; continental formations are present at the top of the sequence. In eastern China (Shantung, Hopei and Shansi) the Permian- Triassic is composed of continental red sandstones, shales, conglomerates and some coal. In north-central China, in Nan Shan, mixed marine and continental clastic rocks comprise1 the lower part of the sequence and the upper part consists predominantly of continental clastic rocks. In western Tsinling Shan and eastern Kunlun Shan, central China, the Permian-Triassic geosynclinal sequence is composed of marine clastic rocks and limestones.

In Mongolia., this unit includes the Upper Permian-Triassic marine terrigenous deposits, mainly sandstones, shales and some conglomerates, exposed in eastern Gobi.

Und if f event iuted Pa leou, ic- Mesozo ic In the Khmer Republic, Laos and Viet-Nam, this category in-

cludes undifferentiated Indosinias, an extended sequence of dominantly

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continental deposits ranging in age from late Carboniferous to Creta- ceous; they are mostly of lagoonal and fluvial facies with intercalated neritic strata in some areas and, to a lesser extent, coal seams, lava flows and tuffs,

In West Irian, Indonesia., undifferentiated rocks of Cambrian- Jurassic age include the Kariem, Aifam, Tipoema and Brug Forma- tions developed on the southern slopes and foothills of the Central Range, where more detailed subdivision is hampered by lack of data and the strongly folded and faulted condition of the rocks. Pebbles containing fossils of Silurian and Devonian age in rivers flowing south from the central range indicate the presence of Silurian and Devonian strata on the southern slopes.

MESOZOIC

Tr iassic

The Triassic sequence in Iran starts in most places with characteristic thin platy limestones and calcareous shales containing poorly preserved lamellibranchs and abundant worm tracks, dated as early Triassic (Scythian). These are followed by dolomites and limestones attributed to Middle Triassic but devoid of diagnostic fossils. These are overlain by as much as 2,800 m of sandstones, shales and thin limestones, containing a rich fauna of corals, lamellibranchs and gastropods indicating late Triassic (Norian-Rhaetian) age. A very different sequence of the Triassic appears in northeastern Iran (the eastern Kopet Dagh Range), consisting of shales, sandstones, coal beds, conglomerates, limestones and abundant volcanic material; it contains a middle-late Triassic cephalopod fauna.

In northern Afghanistan, the Lower Triassic consists of limestones, shales and sandstones. Middle Triassic limestones are overlain by Upper Triassic sandstones with intercalations of conglomerate, gravel, argillite and clay, and some lenses of tuff, basalts and porphyrite. Marine clastic and carbonate rocks compose the Triassic sequence in central and eastern Afghanistan. Triassic fossils found include Meeko- ceras, Ophiceras, Megalodon, Dicerocardiurm, Ceratites and Daonella.

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In northern West Pakistan, undivided Triassic rocks west of Rawalpindi are a succession of limestones and dolomites, with some sandstones and shales.

The most complete section of the Himalayan marine Triassic in India is exposed in the Spiti region where the Lilang System, consisting of black limestones and shales, Gonformably overlies Permian beds; there is an abrupt change in fauna, however, with complete extinction of the Permian brachiopods. Beds of Lower Triassic (Scythian) age contain Otoceras, Ophiceras, Meekoceras and Hedenskoernia; the Middle Triassic (Anisian-Ladinian) beds contain Rhynchonella, Siberites and Daonella; while the Upper Triassic (Karnian) beds contain Halobia, Spiriferina and Tropites, and the Norian is characterized by Juvavites, Monotis and Megalodon. Rocks of this age are known to be extensive in the Himalayan region, and have been studied in Painkhand (Kumaon), Byans, Kashmir, Sikkim and Johar. In the Kumaon area of the Hima- layas, a Triassic sequence of dominantly carbonate rocks is divided into four major units (in descending order): Kioto Limestone, Kuti Shales, Kalapani Limestone and Chocolate Series. In Kashmir, the Triassic is well represented by fossiliferous limestones with some shales, which contain a rich fauna of brachiopods, ammonites and cephalopods of early, middle and late Triassic age.

In Burma, shales, sandy marls, sandstones and limestones of the Napeng Beds contain pelecypods of Rhaetian age. The Kamawkala Limestone is regarded as Norian, and the dark limestones of Karennia with Halobia and Monotis are also of Triassic age.

In Thailand., the Triassic is represented by the Lampang Group which consists of marine and non-marine sandstones, shales, conglomerates and some limestones, including red beds and volcanic rocks; it contains Halobia and &onella. These rocks are exposed mostly in northern Thailand, but are also found iri the peninsular part of the country, from where they extend southwards to west Malaysia. In northwestern Thailand, the Upper Triassic continental red beds of the lower part of the Khorat Group unconformably overlie folded Paleozoic rocks along the western margin of the Khorat Plateau.

In northern Viet-Nam, east of the Red River valley, marine Triassic deposits, mainly shales and sandstones, with some lime-

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stones containing intercalations of acidic volcanic rocks, range in age from Scythian to Karnian. The Upper Norian and Rhaetian contain continental coal-bearing formations. West of the Red River basin, Triassic rocks include a sequence of Lower-Upper Triassic marbles, shales, sandstones, with some cherts and limestones, associated with basic and intermediate volcanic rocks. A detailed classification of marine Triassic rocks in the region can be based on ammonite zones.

In most parts of Laos, southern Viet-Nam and the Khmer Re- public, the lower Triassic is represented mainly by the upper part of the Lower Indosinias and also includes andesitic, dacitic or rhyolitic pyroclastic rocks and lavas which were erupted over large areas. In northeastern Laos, marine Triassic shales, marls, sandy shales and sandstones with some limestones ,contain fossils indicating an age from Anisian to Norian. The marine Norian is overlain by red beds of late Norian-Rhaetian age (Middle Indosinias) which are locally replaced by beds of lagoonal facies. Rhyolite vulcanism persisted into the Karnian, and, in places, into the Norian.

Marine Triassic beds are widely spread over northern and northwestern Laos. Although there are some rare occurences of Scythian shales, the principal marine formations are of Karnian-Norian age and include fossiliferous shales, marls and limestones with Halobia, Placites, Trachyceras costulatum, Discokopites cf. sand- lingensis, Anodontophora munsteri, etc. The marine Triassic is overlain by continental deposits of the Middle Indosinias. In southern Viet-Nam and the Khmer Republic, the marine Triassic is represented within the Indosinias as fossiliferous beds of sandstones, shales, marls and limestones; among the known fossiliferous horizons, the entire range of the Triassic is present. In Laos, the Khmer Republic and southern and central Viet-Nam, widely exposed Upper Triassic continental deposits of the Middle Indosinias consist of sandstones, sandy shales, red shales and marls, with some conglomerates and breccias. In many localities, this continental facies is intercalated with marine or lagoonal strata. The Middle Indosinias rest unconformably on marine Triassic (Norian) and older strata, and themselves contain intercalations of fossiliferous marine beds of late Norian age. The upper part (unfossiliferous red beds) of the Middle Indosinias are probably Liassic in age.

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Except for a few isolated areas where deposition appears to have been continuous, the late Permian to early Triassic appears to have been a period of non-deposition throughout West Malaysia. Where deposition occurred .in the early Triassic, the sediments are similar to those of the Permian, with limestone dominating the sequence along with shales and pyroclastic rocks. By middle Triassic times, however, the pattern of deposition had changed and, throughout the country, flysch-type sedimentation occurred during middle and late Triassic times. Volcanic rocks are common, predominantly acidic tuffs, especially in south-central Pahang. Lamellibranchs, ammonites and conodonts Are the most commonfossils, and the abundance of ammonites has made zonation of the Triassic possible from the Scythian to the Karnian stages.

In Borneo, the Triassic is represented by both sedimentary and volcanic rocks; the fossils Monotis salinaria, Halobia, etc., suggest an Upper Triassic (Norian) age for these beds.

In the islands of Indonesia, Triassic rocks rest unconformably on Carboniferous-Permian or older rocks. In the eastern islands (Misool, Ceram, Bum, Sulawesi and Butung) t!!ey are composed of limestones, sandstones, marls and clays containing numerous species of &onella, Halobia, etc. In Timor, the Triassic deposits are characterized by rapid changes of facies, and include sandstones, limestones, oolitic limestones, shales, marls, cherts and some tuffs. They contain a rich fauna of ammonites, brachiopods, pelecypods, gastropods and foraminifera, indicating an age range from early to late Triassic. In Sumatra, the Triassic is represented by shales, sandstones and limestone containing Cardita, Myophoria, etc.

In Japan, the Triassic sequence overlies the Permian, usually with an unconformity, and is divided into Lower and Upper, with the demarcation at the Ladinian-Karnian boundary. These sections show a striking contrast in facies, suggesting an orogenic movement; the lower division is in a facies similar to the flysch and the upper is represented by molasse. Fossils include Pecten ussuricus, Mono- phyllites wengensis, Dictyoconites nipponicus , Eumorphotis multiformis, E. shikokuensis, Azonella kotoi, D. yoshimurai, M m t i s (Entornonotis) ochotica and Minetrzipnea kataymali.

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In some parts of southeastern China, Upper Permian limestones grade imperceptibly into Lower Triassic in some places. Shales containing Pseudomonites aff. peisbachi replace the lower part of the limestone at some places, but in others the limestone is impure and bears Lower Triassic fossils which include Myophoria, Ophiceras, Clypeoceras, Meekoceras, Xenodiscus and Sibirites. The Middle Triassic is composed of limestones, marls and sandstones which conrain Entrochus lilii$ormis, Tirolites, Dimrites, Halobia, etc. The Upper Triassic is mostly represented by continental deposits which have yielded Cladophlebis, Taeniopteris, Dictyophyllum, Podozamites , etc. In southern Kwangtung, the Triassic consists mainly of continental clastic rocks. In western Y unnanand southeastern Sikang, a geosynclinal sequence of Triassic rocks is composed of alternating marine and continental clastic rocks, limestones and some volcanic rocks. In east-central and northeastern China (Ordos, Shansi, Hopei, Shantung, Hupeh and Kiangsu), all Triassic deposits are continental and often devoid of fossils; these are red and greenish sandstones, conglomerates and shales. In Hupeh, there are also basic lava flows in the upper part. The middle and upper portions of the Upper Triassic Yenchang Forma- tion are composed essentially of sandstones and contain petroleum; this formation has yielded the flora Schizoneura gondwanensis, Thinn- feldia, Noeggerathiopsis, Gingko, etc. In the lower Yangtze valley, the Upper Triassic sandstones and sbles with some coal contain Cladophlebis, Taeniopteris, Dictyophyllum and Podozamites. In Tsinling Shan, Triassic sandstones, conglomerates and shales with some coal seams are metamorphosed and highly disturbed. In western Sinkiang and the northwestern regions, the Triassic is also represented by continental clastic deposits. Triassic marine shales and limestones form a geosynclinal sequence in the Himalayas, and epicontinental formations in Tibet.

In most localities of Mongolia, the Triassic depositsare generally continental; they contain mainly sandstones, siltstones and some conglomerates, commonly associated with large volumes of volcanic rocks. The latter include basaltic, andesitic and trachyandesitic lavas and pyroclastic deposits in the northern and central regions, and andesitic, dacitic and rhyolitic flows and tuffs in otherareas; in northern (Selenga

51


valley) and central Mongolia, they compose a predominant part of the sequence and are closely connected with early Mesozoic acidic and calc-alkaline intrusions. The Triassic continental deposits in Mongolia contain the flora Taeniopteris , Cladophlebis , Sphempteris , Neocala- mites , Schizmra, etc. Triassic marine terrigenous deposits are known in the northeasternmost regions near the border with the USSR.

Triassic-Jurassic

In the Salt Range andTrans-Indus Ranges of West Pakistan, this subdivision includes the Sanuna Suk Limestone and Datta Formation, both Jurassic in age, and also the Triassic rocks represented by the Kingriali Dolomite, the Khatkiara Sandstone Member, and the Landa, Narmia and Mittiwali Members (the last being equivalent to the former Ceratite Beds). Also in these areas are included narrow, inseparable outcrops of the Upper Jurassic-lower Cretaceous Chichali Formation and the Permian Zaluch Group. In the Quetta area, the Wulgai Forma- tion is Triassic in age. The ShiranobFormation, exposed in Baluchistan and the Central Axial Belt west of the Lndus basin, consists of limestone and interbedded shales; although it contains Permian fossils at the base, it is partly Triassic and mostly early Jurassic in age.

The Upper Gondwana rocks of India are Middle Triassic (Mus- chelkalk) to early Cretaceous in age. The constituent divisions include the Mahadeva, Rajmahal and Jabalpur Series. Some of these formations contain locally developed inferibr quality coal seams. The earlier Glossopteris flora of the Lower Gondwana is replaced by the Ptylo- phy22um flora. The topmost Umia Beds, probably of Barremian (Lower Cretaceous) age, contain Plesiosauw indica, and are succeeded by marine beds of Aptian age. Marine equivalents of the Upper Gondwanas are developed at places along the east coast.

The lower part of the Khorat Series of Thailand includes the Phu Kradung, N a m Phong and Huay Hin Lat Formations. Near the base of the sequence, fossil plants have been obtained from calcareous sandstones and siltstones intercalated with predominant conglomerates, and these have been dated as late Triassic or Rhaetian-Liassic. Plant

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fragments, including silicified wood, have been obtained also from the siltstones and sandstones of the Phu Kradung Formation, which suggest an early Jurassic age. The middle part of the Khorat Series or the Phra Wihan Formation includes the Sau Khau and Phu Phan Formation and consists predominantly of sandstones, conglomerates, siltstones, and some shales. Molluscan and reptilian fossils indicate a middle Jurassic age for the Sau Khua Member, while the non-fossiliferous Phu Phan Formation is regarded as the late Jurassic.

In the eastern part of the Khmer Republic, marine intercalations of Triassic-Liassic age occur in predominantly unfossiliferous rocks of the Indosinias, and marine horizons continue as far as the Upper Liassic. The marine beds, mostly sandstones, shales and marls with occasional limestones, contain ammonites and brachiopods ranging in age from early Triassic (including Scythian) to late Liassic (Toarcian).

In West Irian, Indonesia, this group is representedby the Tipoema and Brug Formations of presumably Triassic to early Jurassic age. The Tipoema Formation includes widely scattered red clastic and carbonate rocks, and the Brug Formation consists of oolitic dolomites exposed in the eastern part of the Central Range.

In eastern and central Yunnan, southern China, this subdivision includes Upper Triassic-Jurassic deposits, including coal-bearing beds in the lower part and red beds in the upper part. In western and southern Y unnan, they are replaced by alternating marine and continental clastic rocks, some limestones and, locally, volcanic rocks. In Dzungaria, northwestern China, the TriassicJurassic is composed mostly of continental clastic deposits with some coal.

In northern Mongolia (north of the Selenga valley) this subdivision is represented by Triassic-Lower Jurassic sandstones and conglomerates associated with great volumes of andesitic and rhyolitic flows, tuffs and agglomerates.

Jurassic In Iran, the lower part of the Jurassic sequence is developed

mainly in the central, northern and eastern regions. The coal-bearing

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sandstone and shale facies are mostly Liassic but in places extend into Middle Jurassic. Fossiliferous marine beds of early Jurassic age occur in the sequences containing plant fossils as intercalations of thin ammonite-bearing sandstones and limestones; the oldest sequence, of early Liassic age, is found in the Kerman area. Calcareous deposits predominate in the higher Middle Jurassic and Upper Juras- sic. The Upper Jurassic limestones in the Kerman Tabas area are associated with evaporites.

In northern Afghanistan, the Lower Jurassic consists mostly of carbonaceous shales with intercalations of siltstones, sandstones and some coal. The Middle Jurassic includes mainly sandstones, clays and conglomerates. Upper Jurassic shales and sandstones contain some limestones and dolomites. In western Afghanistan, the Jurassic includes oolitic limestones, while in the central regions there are clays, sandstones and calcareous rocks. In southern Afgha- nistan, this system consists of dark clays and shales, in places including some limestones and reefs.

In West Pakistan, the Jurassic includes the Winder Group and Zidi Formation in the southern Axial Belt (west of the lower Indus valley), consisting mainly of limestones with interbedded shales. In the central and northern Axial Belt, the Jurassic contains the Sulaiman Limestones Group and the underlying Spingwar Formation. In the Salt Range, the Samana Suk Limestone and Datta Formation are Jurassic in age.

In the Himalayan region of India, Jurassic deposits are well developed in the Spiti Valley, where the Megalodon Limestone (Trias- sic4 urassic) is overlain by Sulcacums Beds (ferruginous oolite) containing Belemnites sulcacutus in abundance. These in turn are unconformably overlain by the Spiti Shales carrying Belemnites gerardi, Perisphinctes oppelia, Hoplites and Holcostephanus (Spiticeras), and range in age from Oxfordian to Tithonian. The upper parts of the Spiti Shales, known as Lochambal Beds, also contain Hoplites (fleoco- mites) neocomemis and Acanthodiscus subradiah , which indicate a Neocomian age. East of the upper Ganges valley in the Himalayas, the Tal Quartzite (mostly quartzites, shales and limestones) overlies the Krol Series and contains molluscs and corals. It may represent the Jurassic, or even part of the Cretaceous.

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The Jurassic of the Kutch Region of India includes mainly marine limestones, sandstones and shales in the lower parr, while the upper is predominantly non-marine and plant-bearing. The fossil assemblage includes Macrocephalites , Reineckeia, Perisphinctes , Peltoceras , Tarammelliceras, Torquutisphinctes , Waagenia, Phylloceras , Clado- phlebis and Colombiceras. Jurassic rocks occurring in Bikaner and Jaisalmer in Rajasthan consist of sandstones, limestones, shales and conglomerates, containing ammonites.

In Ceylon, the Jurassic is represented by fresh-water deposits, mainly sandstones, clays and conglomerates. They have been dated as of Upper Gondwana age, although no exposures of Cretaceous rocks have been found.

The Jurassic of Burma includes the Namyau Series consisting of red sandstone, conglomerates, shales and occasional limestone bands, with brachiopods and lamellibranchs of Bathonian age (Bumirhymhia, TerebraEula, Pecten, etc.); it also includes the shales, sandstones and coal seams of the Loi-an Series and the red sandstones of the Tenas- serim and Kalaw areas (the Kalaw Red Beds), The flora of these formations include species of Ginkgoites, Cladophlebis, Pagiophyllum. Brachyphyllum and Podozamites.

The history of marine sedimentation in eastern Indochina ends with the Liassic marine beds in theeasternpart of the Khmer Republic, southern Laos and central and southern Viet-Nam. Ln the eastern part of the Khmer Republic and southern Viet-Nam, marine intercalations of Liassic age occur in the predominantly unfossiliferous sandstones and shales of the Middle Indosinias. The marine beds include the ammonite Coroniceras multicostahm. In southern Laos, various marine marl, sandstone and limestone horizons occur interbedded with the red beds of the Lower Indosinias and include characteristic ammonites and lamellibranchs. In central Viet-Nam, the marine shales and sandstones, with limestone intercalations, are rich in ammonites, lamellibranchs and gastropods.

In Indonesia the Jurassic rocks in the western part of the archipelago are generally metamorphosed; in Sumatra, they are composed of altered phyllites and schists with some belemnites, corals and pelecypods. In Java, schists with basic volcanic rocks and

55


radiolarian cherts are considered to be of doubtful Jurassic age. In Misool, the Jurassic includes shales with Macrocephalus, Oppelza, Stephanoceras, lnoceramus, Aucella, etc., which are succeeded by bathyal limestones and tuffites containing the radiolaria Cadosina and Stomiosphaera.

In western Borneo, (East Malaysia, Brunei and Indonesia), Jurassic sandstones, shales, and limestones contain a fairly rich fauna of ammonites, including Reineckeia, and the pelecypods Mytilus, Cardium, Pecten, Ostraea and Pholadomya, as well as corals and plant remains. The so-called Danau Formation with its radiolarian cherts may be partly of Jurassic age.

In the Philippines, arkose, subgreywacke and mudstone in Min- doro, associated with chert in Busuanga and northern Palawan, are included in the Jurassic. The fossils include Myoporella orientalis and Heticocera.

In the inner belt of south-western Japan, Jurassic deposits are of inland basin type. However, the Upper Jurassic is marine on the Pacific side and contains reef limestone. In Hokkaido, the Jurassic is of the geosynclinal type, characterized by basaltic submarine vulcanism. The fossil groups represented include algae, foraminifera, stromatoporoids, hydrozoa, corals, echinoids, crinoids, lamellibranchs, gastropods , brachiopods and ammonites

The coal-bearing formations of the Taedong System of Korea, early to middle Jurassic in age, were deposited in widely scattered and isolated basins which survived the post-Triassic folding.

In China, Jurassic marine argillaceous sediments occur in Kwangtung province and in Hong Kong, where they contain the ammonite Hongkongites. A thick sequence of marine Jurassic limestones and shales is known in western Yunnan. Marine Jurassic sediments extend from the Himalayas into southern Tibet, where considerable areas are covered by limestones, slates, quartzites and conglomerates, with the Spiti Shales at the top of the sequence. In all other parts of China, the widespread Jurassic strata are represented by continental or freshwater lacustrine deposits which are usually coal-bearing and contain a copious Angara flora, including Pterozamites, Thyrsopteris, Hyrnenop-

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teris, Dicksonia, Pterophyllum, Taxites, Todites and Podozamites. These deposits are associated in some localities with volcanic flows and tuffs which are most extensively developed in the northeast (predominantly andesitic) and the southeast (mostly rhyolitic).

In Mongolia, the widely scattered exposures of Jurassic rocks are generally represented by Middle and Upper Jurassic mainly continental deposits formed within intermontane depressions. The Middle Jurassic is mostly composed of clastic rocks, including sandstones, siltstones, gritstones and conglomerates, locally with some coal, and containing Coniopteris, Cladophlebis nebbensis, C. ex gr. hoiburnesis, Carpolithus, and Phaenicopsis. The Upper Jurassic, and in places also the upper part of the Middle Jurassic, consist mainly of volcanic rocks, most extensively developed in eastern Mongolia, and continental clastic rocks. The volcanic rocks are predominantly andesitic in the lower part and mainly dacitic-rhyolitic in the upper part of the sequence. The clastic deposits contain the flora Gingkoites corninnu, Carpolithus cinctus, Equisetites, Coniopteris ex gr. obmtschewi, Phoenicopsis and Podozamites. In the middle Selenga valley in northern Mongolia, this system is represented mainly by Lower Jurassic rhyolitic flows and tuffs and the top of a Triassic-Lower Jurassic volcanic sequence.

Jurass ic-Cretaceous

In Iran, undifferentiated Jurassic-Cretaceous is represented mainly by calcareous facies (limestones, marls, calcareous slates), although, in the Zagros Mountains, the Jurassic-Cretaceous deposits are more siliceous.

In Afghani stan, undifferentiated J urassic-C retaceous deposits include mainly limestones and sandstones in the southeastern region and predominantly shales, marls and limestones in the south and southwest.

The Jurassic-Cretaceous in the western part of West Pakistan (Waziristan) consists of sandstones, limestones, some marls and shales.

In India, the Umia Series of Kutch is composedof sandstones, conglomerates and shales. Its lower part contains a Tithonian fauna,

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including Hibolites clavigev and Ptychophylloceras tithonicwn, and beds with TrigOnia. At the top of the Umia Series, there are plant beds containing a flora of early Cretaceous (Aptian) age.

The Upper Indosinias of the Khmer Republic, Laos and Viet-Nam comprise members of the Terrain Rouge facies, as well as equivalents of the Ban Na Yo and Salt Formations (Cretaceous) of Thailand. The lower part of the Upper Indosinias includes sequences of massive sandstones, while the upper part comprises the succeeding salt- bearing red formations. In the southwestern part of the Khmer Republic, the Upper Indosinias rest unconformably over the folded Lower Indo- sinias and consist essentially of massive white or pink quartzites and sandstones interbedded with shale or marl. Pollen analyses of samples from the upper part of the group have indicated an early Cretaceous age. In the eastern part of the Khmer Republic, southern Laos and neighbouring parts of Viet-Nam, the sandstones overlie and contain intercalations of the marine Upper Lias (Sinemurian-Toarcian).

The continental red beds of the upper part of the Upper Indosinias are developed in southern central Laos (exLending eastward from Savannakhet), where Occurrences of gypsum and rock salt are known and Cretaceous fossils have been recorded (including plant remains, reptilian bones and the fresh-water lamellibranchs Trigonoides, Plica- tounio and Unio).

In West Malaysia, the J urassic-Cretaceous continental deposits include the Gagau Group, consisting of sandstones and conglomerates with minor shales, sandstones, coal and volcanic rocks; they contain a flora indicating late Jurassic-early Cretaceous age.

The Bau Series of Borneo (shales, sandstones, radiolariancherts, greywackes and some limestones) contain the foraminifera Pseudo- cyclammina litzcus and Orbitolina birmanica, and is of late Jurassic to early Cretaceous age. Some early Cretaceous rocks containing Ammobaculites, Nodosaria, Textularia, etc., also occur near Bau.

In West Irian, Indonesia., the Kembelangan Formation belongs to this subdivision. It is widely distributed in the northeastern and central regions where it consists mainly of marine clastic strata including

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shales, sandstones, claystones, some phyllites, quartzites and glauconitic rocks with subordinate limestones intercalated locally. The fossils Sternrnatoceras cf. fiechi, Macrocephalites, Globigerina infva- cretacea, Globotruncam, etc., indicate a Bajocian-Maestrichtian age, although in some places the presence of Globorotalia velascoensis in limestones in the upper part indicate that locally the Kembelangan Formation persists into the Paleocene.

The Kyongsang System of Korea consists of a lower Naktong Series (terrigenous sediments), a middle Silla Series (terrigenous and volcanic rocks) and an upper Pulguksa Group consisting almost entirely of intrusive and a few extrusive rocks. The Naktong Series contains one or two coal seams developed locally. The associated fossils include Unw, Melania, Conioptaria, Equisetites, Dictyozamites and Ginkgodium, which indicate a late Jurassic to early Cretaceous age. The Silla Series carries plant fossils, including Filicales, Cyca- dites, Caniferales and Angiospermae, which indicate early to late Cretaceous age.

In China, undifferentiated Jurassic and Cretaceous continental and lacustrine dsposits are widely scattered in interior basins and grabens; they are commonly associated with volcanic rocks, most extensively developed in the eastern regions, and include some coal beds of Jurassic age. Andesitic and basic volcanic rocks are typical of the Jurassic, and rhyolitic and dacitic flows and tuffs are mainly associated with the Cretaceous deposits. In northeastern China (Great Khingan), and in the southeastern coastal region, this subdivision is represented mostly by Jurassic-Lower Cretaceous volcanic and continental formations. The same formations are exposed also in northeastern Mongolia.

Cretaceous The most complete Cretaceous succession in northern Iran is

found in the Kopet Dagh Range where it consists mainly of marine shales, marls, limestones and subordinate sandstones. In the Alborz Mountains, the oldest marine beds are Orbitolina-bearing limestones, regarded as Aptian-Albian, but they may include stages as old as

59


Barremian and as young as Cenomanian. Detailed stratigraphic studies of the Upper Cretaceous in a few limited areas show a succession of detrital limestones, reef limestones, marls and shales interrupted by conglomerates, and red beds indicating sedimentary gaps and un- conformities which reflect the unstable sedimentary environment during the initial phases of the Alpine Orogeny. In southeastern Iran, volcanic rocks, mainly basic lavas apart from the ophiolites of the Coloured Melange, are associated with limestones, marls and radiolarian cherts of late Cretaceous age.

In northern Afghanistan, the Lower Cretaceous is represented by Neocomian terrigenous deposits, Baremian marine deposits and Aptian-Albian continental and marine deposits consisting of sandstones, clays and limestones. The Upper Cretaceous is composed of a succession of marine clays, marls and limestones which were deposited continuously from Cenomanian through Maestrichtian and Danian times. In southern Afghanistan, the Lower Cretaceous is represented by continental formations of Hauterivian and Aptian age, while the Upper Cretaceous consists of marine sandstones and limestones with some conglomerates and alkaline volcanic rocks. In the southwestern region, south of Herat, the Upper Cretaceous includes calcareous beds and marls with some gypsum. Cretaceous rocks in central Afghanistan are metamorphosed.

In West Pakistan, the Cretaceous rocks are widely exposed west of the Indus valley, in the Axial Belt and Baluchistan. The Lower- Middle Cretaceous includes the Belemnite Beds (the Chichali and Sembar Formations), mainly ,shales and sandstones, with hvalziz dilatatus, Belemnites latus, Gryphaea oldhami, etc, and the Parth Limestone (limestones, some marls and shales), containing lmceramus. The Upper Cretaceous is represented by rhe Hemipneustes Limestone (Campanian-Maestrichtian), beds carrying Cardita subcomplanuta, lndo- ceras baluchistamsis, etc., and flysch-like sandstones known as the Pab Sandstones which contain Cardita (Venericardita) beaumonti. These sandstones are intercalated with and occasionally overlain by volcanic materials, mainly dolerite and basalt. In Chagai (northwestern Baluchistan) the Cretaceous includes the Sinjrani andKuchakki Volcanic Groups (mostly agglomerate, lava and tuffaceous sediments) and the Humai Formation composed of limestones, shales, sandstones, conglo-

60


merates and agglomerates, containing late Cretaceous lamellibranchs, gastropods, foraminifera, etc. In the Quetta area, the Cretaceous is represented mainly by the Lower Cretaceous Sembar Formation, while in Sulaiman, Waziristan and Kohat-Potwar provinces, it consists of various beds and formations of early and late Cretaceous age. In Hazara, different facies of rocks are developed in the northwestern and southeastern parts; in the former area some cherty and ferruginous patches in sandstones contain the Albian ammonites Lyelliceras lyelli, Douvilleiceras mamillotum, etc., whiie, to the southeast, sandstones ranging in age from Neocomian to Albian have calcareous intercalations containing Trigonia.

In India, Cretaceous marine geosynclinal deposits are widely distributed in the Himalayan area. In the Spiti area, the Jurassic Lochambul Beds gradually merge into sandstones and quartzites which constitute the Giumal Sandstone, containing Holcostepharus (Astieria) aff. atherstoni, Stephanoceras, Perisphinctes and abundant Cardium gicumalense, Pseudomonites superstes, etc. The age of the Giumal Sandstone ranges from upper Valanginian through Albian. It is overlain by the Chikkim Series (mostly limestones and shales) with a Maestrich- tian fauna, including BeZemnites, Hippurites and some foraminifera. A group of unfossiliferous sandstones and shales of flyschfacies overlies in turn the Chikkim Series, and, in places, even the Neoco- mian is represented by flysch formations. In North Kumaon, the Upper Cretaceous is represented by the Upper Flysch deposits of Turonian- Senonian age, mostly shales and sandstones, with glauconitic sandstones and radiolarian chert, containing a very few ammonites. A similar assemblage of flysch-type sediments occurs in the Johar area near the Tibet-Indian border.

The Bagh Beds of central India (southwest of Allahabad) are overlain by the Deccan Traps; they include sandstones, shales, limestones, quartzitic sandstones and some marls, and contain Knemiceras minoti, Protocardium pondicherriense, Turritella multi- striata, etc., ranging in age from Cenomanian to Senonian (but mainly Turonian). The Lametas Beds of Turonian age occur in the central part of the Deccanpeninsula; they consist of estuarine and lacustrine deposits containing dinosaurian remains and P~YSQ (Bullinus)

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prinsepii. The Cretaceous in the east coast, south of Madras, is represented by marine deposits, mainly limestones, marls, clays, silts and sandstones, which are divided into four stages (in ascending order): Uttattur, Trichinopoly, Artyalur and Niniyur, and which have yielded a rich ammonitic fauna of Albian-Danian age. In Kutch, the Cretaceous is represented by sandstones with the marine fossils Colombiceras and Cheloniceras, indicating Aptian age. Marine Creta- ceous rocks occur in Assam, where *ey consist of sandstones, shales and limestones and contain a Senonian fauna closely related to that of the southern east coast.

In Burma, geosynclinal sediments, probably of flysch type, constitute the Cretaceous in the Arakan coast and Indo-Bum ranges. In the Irrawaddy basin of northern Burma, the Cretaceous rocks are mostly limestones and calcareous shales containing Orbitolina and other foraminifera and molluscs.

The upper part of the Khorat Series of Thailand is divided into two, with the Salt Formation as the uppermost part and the Khok Kruator Ban Na Yo Formation as the lower. The latter consists of red to purple-grey bedded sandstone, siltstone and shale with interbedded calcareous conglomerates, sandstones, sandy limestone, calcareous siltstones, etc., and includes fossils which indicate an early Cretaceous age. The Salt Formation comprises siltstones, shales, sandstones and rock salt with minor sandstones, and is assigned a late Cretaceous age from its stratigraphic position.

In western central Borneo, a geosynclinal sequence of Cretaceous rocks, mainly shales, sandstones and marls, ranges in age from Valanginian to Senonian and contains abundant ammonites, pelecypods, echinoids, orbitoids, etc. In southeastern Borneo, limestones with minor sandstones and shales containing Cenomanian-Senonian fossils are exposed.

In Sumatra, Indonesia, Cretaceous shales, limestones and sandstones contain Neocomites, Tumannites, Osterella, Nerinea, Ov-bitolina, etc. The Cretaceous on Misool is represented by Lower Cretaceous bathyal limestones, often cherty, with some fine clastic rocks and tuffs; they contain Globigerina infiacretacea and Globotmcncana. The Upper Cretaceous consists of locally exposed marls and marly limestones with rudists (Duraniu), echinoids and Inoceramus.

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In the Philippines, an extensive transgressive greywacke-shale sequence intercalated with spilites constitutes the Cretaceous. These rocks are associated with tuffaceous clastic strata in Rizal and with limestones in the Caramoan Peninsula, Catanduanes Island and central Cebu. Fossils include Orbitolim aff. kurdica, Orbitolina texana and Globotruncana ama.

In Japan, the Cretaceous is represented by marine, estuarine, neritic littoral and terrigenous deposits, and ranges in age from Berrasian to Maestrichtian-Danian. It is divided into six series: the Kochian Series (Lower Neocomian); the Aritan Series (Upper Neoco- mian) with OYbitolina shikokuensis; the Miyakoan Series (Aptian and Albian) with Cheloniceras, Colombiceras and hsmoceras latidorsatum; the Gayliakian Series (Cenomanian and Turonian) with Desmoceras japonica and Tragodesmoceroides subcostatus; the Urakawan Series (Lower Senonian) with Kossmaticeras kotoi, Anapachydisczes fascico- status and A. mz.wnanni; and the Hetenaian Series (Maestrichtian- Danian) with Canadoceras kossmati. The biostratigraphic division of the Cretaceous System in Japan is based mainly on lnoceramus and ammonites.

In China, within the Tibetan zone of theHimahyas, the Cretaceous is composed of a geosynclinal sequence of flysch-like terrigenous deposits with some limestones and volcanic rocks. Marine limestones and clastic rocks of Cretaceous age are known in westernKunlun Shan and Tibet. In other parts of the country, the Cretaceous is represented mostly by lacustrine and continental clastic deposits formed within continental basins, the largest of which are Ordos-Shensi and Szechwan. The fossils include Lycopteria sinemis, L. woodwardi, Estheria, Cyrena, Unio, Mycetopus and Brachyphyllum. Some of the gypsiferous beds associated with the Cretaceous may belong to the Tertiary. Both the Ordos-Shensi and Szechwan basins are known for their petroleum reserves. In Inner Mongolia, this system is made up of fresh-water lacustrine deposits. In eastern China, particularly in the northeast (Manchuria, Great Khingan) and southeast, the C retaceous continental formations include great volumes of volcanic rocks, mostly dacitic and rhyolitic flows and tuffs.

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The conglomerate bed found in the lower part of the Paleogene shale sequence in Taiwan contains corals (Actrocenia sp. and Elephan- taria sp.) of probable late Cretaceous age.

Exclusively continental and lacustrine Cretaceous deposits in Mongolia consist mainly of sandstones, shales and conglomerates, with some coal, marls and sandy limestones. In places they include volcanic rocks, mainly acidic-intermediate and trachy-basaltic flows and tuffs in the Lower Cretaceous, and andesitic-basaltic lavas in the Upper Cretaceous. The associated fossils and flora indicate an age for the sediments ranging from Neocomian (Valanginian) to Turonian. They include the molluscs Cyrem, Lwplax, Benedictia, Vivipara, Limnaea, Cypridea, Trignoides, Sainschandia, Physa, Hydrobia and Bithynia; the reptiles (in the Gobi region) Psittacasaurus, lguunodon, Saurolo- phus, Caumsaria, Omithomimidae, Paralligator, Sysmosauncs, Proto- ceratops and Dyoplosaurus; and a flora including Xemxylon, Cupres- sinoxylon, Mesernbrioxylon, Taxodioxylon, Podocarpoxylon, Arawario- xylon, Cedroxylon and Dvyoxylon.

Undifferentiated Mesozoic In Iran, undifferentiated Mesozoic deposits include limestones

with sandy marls and calcareous slates which unconformably overlie Permian or older formations. They contain some bryozoans, algae and hydrocorals, and most likely range in age from late Triassic to Jurassic, although they may include lower Cretaceous strata. In places these calcareous deposits are replaced by a littoral facies, including sandstones, slates, conglomerates and some limestones.

In the northern montane 'area of West Pakistan, this subdivision includes undivided Cretaceous, Jurassic and Upper Triassic deposits, mainly marine clastic and carbonate rocks.

In Nepal, the Triassic fossils Halobia cf. charleyana and Ptychites sp. , and Jurassic fossils Belemnites (Discoelites) sulcacutus, Hoplites wallichi, Perisphinctes cf. beplex, etc., have been collected from Mesozoic clastic and carbonate rocks of the Tethys zone of the Hima- layas near Mukhtinath, north of the crystalline peaks in the central part of the country.

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In Thailand, a group of Mesozoic volcanic rocks, including rhyolites, andesites, tuffs and agglomerates are of post-Permian age; they are closely associated with the Khorat Group, although in some places they underlie it.

In western Borneo (East Malaysia) a Mesozoic age is assigned to the Serabang and Sejingkar Formations, both consisting of shales, sandstones, radiolarian cherts, greywackes and basic volcanic rocks, and to the Sebangan Formation, made up of cherts and hornstones, although there is no direct evidence of their age. Radiolaria from cherts indicate that the formations are, at least in part, of young Mesozoic age.

Also in Borneo, andesitic and undifferentiated lavas and tuffs, comprising the Matan Complex in southwestern Kalimantan, are associated with pre-Tertiary plutonic and hypabyssal rocks, and were extruded during a pre-Tertiary phase of folding in early Mesozoic or possibly late Paleozoic times.

In the eastern islands of IRdoResla., the Mesozoic deposits comprise Cretaceous, Jurassic and partly Triassic strata. In Sulawesi (Celebes), clay-shales, sandstones and limestones of Triassic age contain Cussianellu, Hoemesia, MisolM, Rhynchonella arpadica, etc. Triassic limestones, shales and cherts are known in the Timor archipelago, where the Jurassic consists mostly of shales and limestones with cephalopods, pelecypods and brachiopods. Most stages of the Jurassic are developed as dark calcareous shales with some cherts on the islands of Sula, Obi, Ceram and Buru. In Sulawesi, Cretaceous beds are composed mostly of limestones, but, on the Sula Islands, there is a shale facies containing Phyllocerus, Hoplites, Styeblites, etc.

In the Timor area, the Cretaceaus is represented by fossiliferous limestones, shales and cherts; in some places, red shales with manganese nodules and radiolaria are also present.

In China, undifferentiated Mesozoic marine clastic and carbonate rocks are present in Tibet and western Kunlun Shan.

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MESOZOIC - TERTIARY hnesozoic - Paleogene

The outermost belt of southwest Japan contains the Shimanto Group of thick geosynclinal deposits consisting mainly of sandstones and shales with small amounts of limestones, cherts and submarine basic volcanic rocks; in this group, molluscan fossils of Cretaceous and Paleogene age occur very rarely, and ammonites and Paleogene foraminifera are also rare.

Cretaceous -Ter t ia r y The Cretaceous-Paleogene deposits in northern Afghanistan are

represented by the Ghori Limestone of late Cretaceous toearly Paleogene age, distributed over a large area north of the Kho-i-Baba Range.

In the Chagai Hills, southwestern Afghanistan and northern Baluchistan (West Pakistan), the Cretaceous-Paleogene consists of acidic-intermediate lava flows, agglomerates, tuffaceous sedimo,nts and unseparable Chagai intrusions, and, along the southern edge, some shales and sandstones of the Upper Cretaceous Humai Formation. North of Rawalpindi, the Cretaceous-Tertiary strata consist mostly of Eocene nummulitic limestones, Cretaceous limestones and the Cretaceous Giumal Sandstone.

The Cretaceous-Paleogene in peninsular India is characterized by intensive volcanic activity, resulting in the formation of the Deccan Traps; these are composed of basaltic and doleritic lava flows wnich, due to repeated eruptions from Cretaceous to early Eocene times, attain a thickness of up to 2,000 m; the lava flows are intercalated with thin beds of tuffs and lacustrine sediments known as the Inter- Trappean Beds.

In Burma, the Arakan Yoma Beds, consisting of flysch-like deposits, mainly sandstones, limestones and shales, form 8 wide belt extending northward from the Arakan Yoma; they contain Acantho- ceras, Placenticeras, Mortoniceras, Cardita beaumonti, Orbitoides, etc., and range in age from Cretacous to Eocene.

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In Borneo, the Cretaceous-Tertiary is represented by predominantly geosynclinal clastic rocks and some limestones, with develop- ments of chert and spilite at several stratigraphic levels. The Chert- Spilite Formation of probable late Cretaceous-Eocene (in places including Miocene) age are present in many places in northern and western Borneo; it comprises chert, spilite, basalt, green tuff and agglomerate, together with red sandstone, siltstone, Trey and red shale, limestone and marl; in some localities in the north, chert is predominant.

In West Irian, Indonesia, this subdivision includes the Imskin Formation exposed west of Geelvink Bay, which consists mainly of limestones with occasional marls and contains the foraminifera G l o b o t m m m , Globorotalia, Globigerina, etc., indicating an age from Cretaceous to Miocene. Also included in this subdivision is the Onin Formation, made up of pelagic limestones with Globorotalia and marls. According to latest information, the Onin Formation may include strata of Eocene-Miocene age only.

Undifferentiated greywackes and metamorphosed shales in the Philippines, interbedded or intercalated with spilitic, basic and intermediate lava flows or pyroclastics, are probably of Cretaceous- Paleogene age.

In Mongolia, this group includes undifferentiated Upper Creta- ceous-Tertiary lacustrine and continental basin deposits, most extensively developed in the south; they include mainly cross-bedded calcareous and clayey sandstones, drab and red clays, and, locally, some chalk

TERTIARY

Tertiary deposits from Paleocene to Pliocene are present over much of Iran. Flysch-like deposits of Paleocene age lollow the Upper Cretaceous of southeastern Iran and in turn are overlain by the Mekran Formation of Miocene age. Elsewhere, deposition commenced inEocene times; in northwestern and east central Iran, these sediments consist of thin limestones and conglomerates containing AZveoZina and Num- mulites of early to middle Eocene age. In the Zagros Mountains, south-

67


western Iran, the Eocene facies changes from marls to conglomerates and limestones with nummulites. In northern, eastern and central Iran pyroclastic deposits and lavas (mainly andesites and porphyrites) com- mence the Eocene succession, associated with conglomerates and red beds; eruption of intermediate lavas continued into the Miocene in the volcanic belt extending from the southeast towards the northeast and in some places in the Alborz Mountains. In southwestern Iran the Eocene is followed by the Asmari Limestone of Oligocene to early Miocene age, which is directly overlain by the Caprock Anhydrite containing stringers of foraminiferal limestone. The Miocene Fars Formation comprises evaporites and red beds of the Lower Fars, marine beds of the Middle Fars, and freshwater or estuarine beds of the Upper Fars; the sequence ends with the Bakhtiari Beds of Mio- Pliocene age, with thick conglomerates in the upper part.

In central Iran, the Oligocene-Miocene sequence begins with gypsiferous and saline red beds of the Lower Red Formation, followed conformably by middle Oligocene-early Miocene marine limestones of the Qum Formation. This is succeeded by red beds and gypsum of the Upper Red Formation (Miocene). Conglomerates of Mio-Pliocene (possibly Pliocene) age, probably equivalent to those in the Bakhtiari Beds, end the succession.

The Tertiary sequence north of the Alborz Mountains is quite different from that of central Iran; the Eocene is characterized here by the presence of volcanic rocks, the Oligocene-Miocene includes thick conglomerates, and the Miocene and Pliocene resemble similar deposits in the Caspian basin.

In northern Afghanistan, the lower part of the Paleogene sequence includes the Paleocene Bokhara Limestone in the west, equivalent to the upper part of the Ghori Limestone in the east. The Eocene is represented by marine limestones, marls, clays, sandstones and siltstone. The Oligocene consists of clays and sandstones in the northwest, while in most of northern Afghanistan it is represented by the lower part of the Shafa Formation of Oligocene to Miocene age, made up of red clays, siltstones, sandstones and conglomerates. In the eastern part of southern Afghanistan, the Paleogene is represented by Paleocene-Eocene flysch-like sediments containing Nummulites

68


and Alveolites, locally with sand beds and some thin layers of salt and coal. In the western part of central and southern Afghanistan, these Paleogene red conglomerates and sandstones are associated with volcanic fomitions.

The Neogene sequence in northern Afghanistan consists of red terrigenous sediments known as the Miocene Khoshtanga Formation, the upper part of the Oligocene-Miocene Shafa Formation, and the Plio- cene Rustaq, Kockchy and Kishm Formations. Talus deposits were formed during Oligocene-Miocene times in the Hindu Kush. In central Afghanistan, the Neogene red beds, locally associated with acidic volcanic rocks, are widely distributed from the east (Jalalabad) to the western border. In the southeastern regions, within the Indus-Baluchistan geosynclinal sedimentary basins, the Neogene molasse-like deposits contain conglomerates, cross-bedded red sandstones and clays. In the Helmand depression, covering a large part of the southwestern area, the Neogene beds consist of clay, sandstonesand some conglomerates.

The Paleocene of West Pakistan is a marine sequence of shales and sandstones, with some limestones andconglomerates, also including some volcanic rocks in Chagai (northwestern Baluchistan). The Eocene deposits are predominantly marine calcareous and argillaceous; limestones are dominant in the Indus Basin, whereas a m3re argillaceous sequence, including the thick Ghazi Shales, is developed in Baluchistan. Thin coal seams are present at Quetta and in parts of Sind. In most parts of Baluchistan, the Oligocene is composed of the Kojak Shales, which extend from north of Quetta (the Toba Kokar Range) southwest to the Makran Range; this formation is a thick flysch-like sequence composed mainly of shales and sandstones. It is overlain by mainly marine siltstones, sandstones and some limestones and shales of Miocene age, which form the upper part of the Oligocene-Miocene marine formation In the South Makran Belt, the Miocene-Pliocene sequence includes the Talar Sandstone, and the sandy clays, sandstones and conglomerates of the Omara Formation, representing a deltaic and offshore environment.

Near Quetta, the Oligocene is represented by the marine Nari Series, consisting of fossiliferous limestones in the lower part, with mostly shales and sandstones in the upper part. Farther south, in the

69


lower Indus basin, the N a n Series is followed by the Lower Miocene Gaj Series, consisting of marine limestones and shales in the lower part which are succeeded by red and green shales, occasionally gypseous.

In the Salt Range, the Eocene limestones are overlain by the Murree Series (Lower Miocene), and that in turn by the Siwalik System of Upper Miocene to Pleistocene age. Oligocene rocks are missing from this area, and also from the Potwar and Kohat regions.

In East Pakistan, the Miocene of Chittagong includes the S u m a Series (sandstones, shales with some conglomerates), Tipam Sandstone (ferruginous sandstones and shales) and Girujan Clay.

In the Himalayan region of India, the Eocene in the Simla-Garhwal region consists of grey and red shales (partly gypseous) and limestones of the Subathu Beds. In the central western Himalayas and Jammu, Eocene deposits consists of nummulitic limestones, shales and marls. The Himalayan Eocene is overlain by the Lower MioceneMurree Series, which is known also as the Dharmsalas in Himachal Pradesh and the Dagshai and Kassauli Beds in Simla; these are brackish or lagoonal deposits consisting of purple and grey sandstones, shales and pseudo-conglomerates, with remains of mammals, impressions of palm leaves (Sabal major) and Unio shells. The Murree Series is overlain unconformably by the Siwalik System of late Miocene-Pliocene age.

In western India, the Eocene deposits of Ku~ch, Cambay and Rajasthan comprise the marine Laki Beds(most1y shales with Assilim) of early to middle Eocene age, which, in places, are underlain by gypseous shales with lignite. The overlying Middle-Upper Eocene Kirthar Series includes nummulitic limestones and shales; they are followed by the Nari and Gaj Series, comprising the Oligo-Miocene sequence of limestones, shales and marls. The Nari Series contains Nummulites intewnedius and Lepidocyclina and the Gaj Series is rich in fossils, including Breyaia carimta, Ostrea angulata, Camarinu intermedia and C. clipea; they are overlain by the Dwarka Beds (gypsiferous clays and limestones) or the Manchhar Series (sands, clays, conglomerates), included in the Mio-Pliocene sequence. In the southern part of the Deccan peninsula, fossiliferous Miocene beds are found near Trivandnun; they comprise Quilon Beds consisting of limestones with

70


0vbiculin.a malabarica, corals, lamellibranchs and gastropods, overlain by shales with lignite, known as the Warkalli Beds. On the eastern coast, there are Tertiary rocks in which Eocene foraminifera have been found recently, but the extent of these rocks is not known; they are unconformably overlain by the Mio-Pliocene Cuddalore Sandstone, which contains some lignite beds, and its equivalents.

In Assam, the Eocene is represented by the Disang Series (northern Assam) and the Jainta Series (southern Assam) consisting of calcareous shales and nummulitic limestones. They are succeeded by the Barail Series composed of sandstones and carbonaceous shales, representing marine and estuarine facies. The Barail Series, shown on the map as Oligocene, also includes Upper Eocene strata. The Surma Series, separated from the Barail Series by a marked unconformity, is Oligocene-Miocene in age; the Miocene part of the sequence consists of ferruginous sandstone, conglomerates and shales of the Tipam Series, containing occasional lignite and fossil wood, while the overlying Dupitila Series (sandstones and clays) is Mio- Pliocene.

The Tertiary rocks in the Andaman and Nicobar Islands (India) are composed mostly of sandstones and conglomerates of Eocene age, although they may include younger strata.

In Nepal, the Eocene includes shales, which may be correlated with the Subathu Beds of India. Undifferentiated Tertiary deposits on the map comprise mostly the Siwalik System, mainly the Lower and Middle Siwalik, and the coarse sediments of the upper part of the Siwalik are shown as Pliocene-Pleistocene.

In Ceylon, the only exposedTertiary rocks are Miocene limestones and some sandstones of the Kudermalai and Jaffna Series, which carry abundant foraminifera and molluscs.

In Burma, the Tertiary rocks of the central basin show an alterna- tion of marine and continental facies, the latter gradually increasing higher in the stratigraphic column and towards the north. The Eocene is developed in the Arakan Yoma and comprises the Yaw Stage (shales), Pondaung Sandstone, Tabyin Clays, Tilin Sandstone, Laungshe Shale and Paunggi Conglomerate. The Oligocene consists of sandstones and clays belonging to the Lower Pegu System. The undifferentiated P e p

71


System includes Oligo-Miocene deposits. The Miocene is represented by sandstones and shales of the Upper P e p System in the lower Irrawaddy basin and the Tipam Series in the upper Chindwin basin. The Irrawaddy System of Mio-Pliocene age consists of a fluviatile succession of cross-bedded sandstones, and coarser rocks with pebbles and boulders, containing mammalian fossils and silicified wood. Undifferentiated Tertiary deposits in the northern part of Burma are of estuarine and freshwater facies.

In northern Thailand., Tertiary deposits are developed in isolated intermontane basins. These are mainly clays, sands and some lignite with fish remains, mastodont fossils and leaves. They have been assigned a mainly Pliocene age, although, in some places, there are Paleogene plant remains. In peninsular (southern) Thailand, calcareous shales and sandstones locally with lignite beds and some limestones, contain marine and non-marine fossils of early to late Tertiary age.

Restricted outcrops of Neogene lacustrine and fluviatile deposits (mostly Pliocene) are recognized in a number of small isolated basins in Viet-Nam and northern Laos.

In West Malaysia, Tertiary rocks occur in isolated lacustrine basins of limited extent consisting predominantly of carbonaceous shales and lignitic beds of non-marine origin.

The Kulapis Formation, consisting of red sandstone and shales, is shown separately as Eocene in the northernpart of Borneo, whereas, in other parts of the islands, it is included in the undifferentiated Tertiary sequence. Oligocene-Miocene deposits succeeding the KOlapis Formation have a varied lithology, mainly sandstones and argillaceous rocks with volcanic tuffs and agglomerates, with some limestones, calcareous shales and cherts. The Miocene-Pliocene rocks comprise mainly shallow-water marine, neritic and deltaic deposits (mudstones, sandstones and some marls).

In northwestern Borneo (Ease Malaysia and the adjacent part of Kalimantan) Eocene marine shales and sandstones (the Belage, Kelalas and Trusmadi Formations) are present; they become increasingly arenaceous northwards to the northern part of the island, where

72


flysch-type sedimentation continued well into Miocene time. The Oligocene-Miocene in the central part of East Malaysia includes deposits with facies changing from paralic to neritic towards the present coast line, and also characterized by increasing deltaic facies southwards and upwards through the sequence. The deposits inland consist mainly of alternations of sandstones, sands and clays, with some lignite and conglomerate; towards the present coast, the facies becomes marine, including shales, sandstones and some limestones. Mainly arenaceous deposits of great thickness were deposited in basins which subsided during Miocene-early Pliocene time (the Belait, Seria, Miri Formations, etc.), which were succeeded in late Pliocene time by neritic and deltaic deposits, which continued in places into the Pleistocene.

In western and central Borneo (western East Malaysia and west-central Kalimantan) Paleogene-Neogene sandstones, subordinate shales and some conglomerates have been referred to as the Plateau Sandstone Formadon, The Paleogene in southeastern Borneo consists of orbitoid limestones, marls and green sandstones with coal seams; in eastern Borneo, the Paleogene com2rises fossiliferous limestones. In southeastern Borneo, the Neogene is mostly of marine facies and includes shales, clays, sandstones, coal seams, some tuffs and occasional beds of massive reef limestones. In northernand central Borneo there are basaltic lavas and tuffs of Neogene age.

In other islands of Indonesia, the Tertiary covers large areas. The Paleogene of Sumatra starts with conglomerates which grade upwards into sandstones and shales (with coal seams in the south), interbedded tuffs and some marine deposits near the top. The Older Andesite developed near Danau Toba represents terrestrial vulcanism at the end of Paleogene time. The Neogene is represented by deeper marine facies, including clay shales, m a r k and fossiliferous limestones. Marine conditions of sedimentation prevailed during late Neogene time in the north, while, in the south, the Upper Neogene is composed mainly of continental deposits with coal seams and volcanic tuffs, which are predominant also in the Neogene of southern Sumatra. The Telisa Beds, Lower and Middle Palembang Series and their equivalents comprise a Miocene sequence of predominantly marine and vol-

73


canic deposits. The Upper Palembang Series of Pliocene-Pleistocene age includes tuffs, tuffaceous sandstones, bentonites and a few coal stringers, and contains silicified wood. In Java, the Paleogene rocks are conglomerates, sandstones, coal seams, shales and limestones with Camevinu, Discocyclina, Pellatispira, etc. The Neogene, however, is developed in different facies; massive limestones occur in the north and south, Globigerina marls are predominant in the east, and clayey marls and some sandstones are typical of the central part. Tuffaceous layers become more frequent towards the top of the Neogene.

The Tertiary of Sulawesi (Celebes) is characterized by great volumes of volcanic material (liparites, basalts and tuffs). In southern Sulawesi, the Paleogene begins with conglomerates and sandstones with a few coal seams, followed by a thin limestone sequence which continues into the Lower Neogene. The limestones are overlain by marine shales and clays with some coal seams.

In West Irian, Paleocene-Miocene deposits in most areas consist of shoal limestones known as the Ogar Formation (in the northernmost part of the Onin Peninsula), the Koemawa Formation (in the Koemawa Peninsula) and the New Guinea Limestone Group; the last-named is developed over the whole length of West Irian from West Vogelkop and has been subdivided in many areas into several formations. Fossils include bryozoa, algae, corals, molluscs and larger foraminifera , including Alveolina, Lacazina, Neoalveolina, Flosculinella bontangensis, F. bomeensis, Alveolinella quoyi, Marginopora and Smites. Undiffe- rentiated Eocene-Miocene deposits are represented by the Auwewa Formation (and its equivalent, the Botana Formation) developed in northern West Irian, including the islands of Batana and Waigeo. In its lower part, it comprises predominantly basalt and spilite lavas, breccias, tuffs and tuffaceous sandstones, with some limestones near the top; in the upper part, limestones are predominant over the volcanic rocks and contain abundant pelagic foraminifera and occasional larger benthonic foraminifera. Undifferentiated Paleogene on Misool is represented mostly by limestones, which are sandy and oolitic in the lower part (Paleocene-Eocene) and predominantly shoal facies in the upper part (Eocene-Oligocene); they contain Alveolina, Lacazh, Num- mulites fichteli-intermedia and Neoalveolina pypaea. The Oligocene- Miocene in the northwestern part of West Irian (Vogelkop) comprises

74


clastic strata of the Sirga Formation, including some coal beds. On the islands of Soepiori and Biak, north of Geelvink Bay, the Oligocene- Miocene Soepiori Limestone is laterally replaced southward and northward by the Wafoerdori Marls, containing pelagic foraminifera, corals and algae. The Middle-Upper Miocene (shown on the map as Miocene) Klasafet, Akimeugeh and Iwoer Formations consist of clastic strata and are developed in the Vogelkop, as well as west of Geelvink Bay and south of the Central Range; some intercalations of pelagic limestone occur locally in the lower part of the Klasafet Formation. East of Geelvink Bay, the Middle-Upper Miocene Makats Formation is composed of greywackes and shales; its fauna includes benthonic and pelagic foraminifera, molluscs, corals, algae and bryozoa. Undiffe- rentiated Paleogene deposits have been found in a number of places, mostly in the form of creamy orbitoid limestones. Associated Neogene deposits consist of sandstones, shale, conglomerates, some lignite seams, marls, massive limestones and Globigevim marls; they are associated locally with volcanic rocks.

In the Philippines, Paleogene deposits comprise thick transgressive mixed shelf and deep water marine deposits, largely greywackes and shales, associated with reef limestones, together with conglomerates, dacite-andesite (Paleocene) and keratophyre-andesite (Oligocene) flows and tuffs. The Paleocene in Mindoro and Palawan consists largely of arkosic and quartzitic clastic deposits; on Catan- duanes Island there are Paleocene paralic coal measures., The Paleo- gene fauna includes the foraminifera Globoratalia velascoensis, G. aequa, G. ciperoensis, Globigerina triloculinoides, Alveolinu prirnaeva, Nummulites fitcheli and N. globulosa.

Oligocene-Miocene mixed shelf marine deposits, primarily sandstones, greywackes, shales and reef limestones, are found in Luzon, the Visayan islands and Mindanao, associated with basic to intermediate lavas and pyroclastic deposits; in places they include paralic coal beds. In southern Mindoro and Palawan, this sequence consists of marine clastic rocks. The fossils include Globigerinoides bisphaerim, Borelis p y g m a m and Miogypsinoides.

Neogene rocks (Upper Miocene-Pliocene) in the Philippines include, in the lower part, predominantly maril?e clastic deposits

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overlain by extensive, locally transgressive tuffs and tuffaceous sedimentary rocks, associated with silty limestones and calcarenites in some parts of Luzon, Mindanao and the islands between them. In western Mindanao, there are limestones intercalated with dacite. and andesite flows; mainly arkosic sandstones are developed in Palawan. The fossils include Globorotalia crassifomis, Sphaeroidinella dehiscens immatura , Miogyps ina and Tribl io1 ep idina.

In Japan, the Eocene marine rocks of Kyushu and southwestern Honshu carry Nummulites and Discocyclina, and the fresh water deposits of northern Japan (Hokkaido) contain a flora of Woodwardia, Musophyllum, etc. The marine Oligocene of southwest Japan contains the Ashiya fauna, which includes Chlamys ashiyaensis and Venericardia subnipponica. The main coal seams occur within the Paleogene sediments. The Lower Miocene is represented by shallow marine sediments conmining Lepidocyclina while the Middle Miocene shallow marine deposits contain a Miogypsina-Operculina fauna; brackish water deposits contain Vicarya and non-marine deposits contain the L iquidambar-Comptoniphyllum flora. The Omma-Manganji shallow marine fauna, comprising Acila insignis, Pecten kurosawaensis, Ana- dura amicula, etc., is the characteristic Pliocene fauna in southwestern Japan on the northern (Sea of Japan) side, while the Lower Pliocene Kakegawa warm shallow marine fauna, comprising Amussio- pecten praesignis, Venericardia panda, etc., is found on the southeastern (Pacific) side. A cold sea current greatly influenced the fauna on the Pacific side of northeastern Japan. The non-marine uppermost Pliocene beds carry the flora Pinus trgolia, Pseudolark, Acer, etc., associated with Stegodon orientalis and other mammalian remains. All of the oil and gas reservoirs being exploited in Japan are restricted to the Neogene sequence.

In Korea, the Tertiary is represented by alternating marine and terrestrial deposits, in places terrestrial only, consisting mainly of shales, sandstones and some conglomerates, associated with rhyolitic volcanic rocks, lignite and coal seams and containingmarine and terrestrial fossils, including plant remains. In northern Korea there are interbedded basalt flows, tuffs and agglomerates of Tertiary age.

In China, Paleogene marine deposits in the Himalayas are

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mostly composed of carbonate rocks with Orbitolina. In southern Tibet, the Paleogene is represented by Eocene marine deposits, while elsewhere in mainland China the Paleogene deposits are found within continental depressions and down-faulted basins. In southeastern China, including the Yangtze valley, the Paleogene occupies elongated intermontane basins and is represented mostly by red beds. In central and eastern China (southern Kansu, Shensi, Hopei, Shansi, Honan and Shantung), continental clastic rocks are normally associated with lacustrine deposits and contain beds of marls, fresh water limestones and some gypsum. Lacustrine deposits are predominant within Inner Mongolia, where they are locally interbedded with some basaltic flows. In Manchuria, northwestern China, Oligocene coal beds and basaltic lava flows are intercalated in the Paleogene sequence; the Oligocene coal in southern Manchuria is of great economic value. In western and northwestern China, a Paleogene continental clastic sequence includes lacustrine deposits, thin lignite beds, coal-bearing sandstones and some gypsum. The Paleogene basin sediments inChina have yielded such fossils as Planorbis, Physa, Lophioletes or Caeno- lopsis, Sinohadrianus, Protitanothwbm, Baluchitherbm and Amynodon.

Neogene formations in mainland China are exclusively continental. In south-central and southeastern China, they are predominantly Pliocene lacustrine deposits which contain some coal beds in Yunnan and Kwangsi. In Inner Mongolia and in Ordos and Shantung (northeastern China), Miocene formations contain Lamprotula, Platy- belodon, Stephanoceras, Melosira, etc. Pliocene fluvio-lacustrine and continental deposits are extensively developed in northern China. Three cycles of erosion and deposition have been recognized in the Neogene of northern and northeastern China. The first cycle, Lower Pliocene (Pontian) in age, is represented by a series of fluvio-lacustrine deposits of the Paotuh Stage which contain Prosiphneus and Hipparion richthofeni. The second cycle, known as the Ertemte Stage, is represented by terrace gravels along the Huang Ho (Yellow River) and by red clays bearing Prosiphneus intermedius. The third cycle of erosion, the Fencho Stage, was followed by deposition of red clays with Siphacus tingi and fluviolacustrine deposits with Melania, Lam- p-rotula, Eqwus, Hipparion, Ulmus, A c w , etc. In western andnorth- western China, the Neogene is characterized by red beds found within

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intermontane basins. In northern and northeastern China, the Neogene deposits are associated with basalt flows.

For lack of sufficient information, and partly on account of the scale of the map, the above-described Paleogene and Neogene continental deposits in many regions of China, particularly in its northern part, are shown as undifferentiated Paleogene-Neogene.

The earliest sediments laid down in the Tertiary geosyncline of western Taiwan are dark gray shales and siltstones of Paleogene age. A considerable part of Taiwan underwent regional orogenic movement in late Oligocene to early Miocene times. The shelf sediments of Miocene age in the north include sandstones, orthoquartzites and thin coal beds, locally associated with basic volcanic rocks; basin deposits of the same age in the south are characterized by clastic sediments, including greywackes, shales and claystones. In eastern Taiwan, the Miocene includes shales, conglomerates and sandstones with andesitic lavas and agglomerates in the lower part. The exposed Pliocene deposits are mainly marine sediments of geosynclinal facies, consisting of shales, sandstones and grewackes.

In Mongolia, the Paleogene deposits are exclusively of continental or lacustrine facies. The widely scattered outcrops of these strata are not differentiated on the map but are included as a part of the Upper Cretaceous-Neogene or Cenozoic sequences. The Paleogene andNeogene deposits are composed mainly of variegated and red clays, sands, sandstones, conglomerates, gravels, some siltsrones and m a r k Neogene volcanic activity resulted in the extrusion of basalts which are present mostly in the northern and southeastern regions. Paleogene formations range in age from Paleocene to Oligocene and have yielded a rich mammalian fauna (mainly in Gobi) including, Prodinoceras, Pseudictops, Palaescaptar, Mesonyx, Mongolothwium, Amynodon, Caenolophus, Ca- durcodon, Hypsamynodon, Baluchitherhm, Allacerops, Hyaenodon, Cy- clomylus, Parahyrachodon, Ergila, Brachiodon, Schizothwhm, Entelo- don, Coenopus and Cadurocotherum. The Neogene is represented by both Miocene and Pliocene sediments, containing Hipparion, Anchi- therium, Sevridentinus, Samotherium, Gobiocerus, Gobitherium, Chilo- thevium, etc.

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TERTLARY - QUATERNARY (CENOZOIC) In Iran, the Plio-Pleistocene comprises red beds, consisting of

gypsiferous silty clays and marls with some sands and pebbles, and also fresh-water deposits composed of sands and white chalky limestones with gastropods and lamellibranchs.

In the coastal region of Pakistan (West wing), the Plio-Pleistocene consists of the Pliocene Chatti Mudstone and the Ormara Formation of late Pliocene and possible Pleistocene age. In Pakistan (East wing), this includes the undivided Dihing and Dopitila Formations, mainly sandstones, clays and pebble beds with some lignite in the lower part.

In India, Nepal and West Pakistan, the Siwalik System comprises the well-known sequence of Middle Miocene-Lower Pleisto- cene freshwater molasse deposits, forming the foothills of the Hima- layas and extending from Assam to the Salt Range. Sandstones, grits, conglomerates, clays and silts of fluvial character comprise the rocks of the Siwslik System; the great bulk of them are unfossiliferous, but locally there are fossils of molluscs, fishes, reptiles and mam;nals, as well as plant remains. The Siwalik System is usually divided into Lower, Middle and Upper Siwalik.

In northeastern Assam, India, the Plio-Pleistocene DAhing Series consists of pebble beds with subordinate sandstones and clays, and is equivalent to the Upper Siwalik. In Nepal, the Pliocene-Pleistocene includes mainly coarse clastic deposits of the upper part of the Siwalik Series.

In Burma, basaltic and acidic flows and pyroclastic deposits of the Chindwin, Popa and Mergui Volcanics are broadly describedas Cenozoic.

Volcanic activity during Tertiary and Pleistocene times resulted in extrusion of basaltic lavas over large areas in southern Viet-Nam, the eastern part of the Khmer Republic and southern Laos, and in smaller scattered areas in northwestern Laos and in northernand central Thai land.

In Borneol, Pliocene-Pleistocene deposits near the seashore include marine shelf and other shallow water sediments (the Togopi, Sebahet, Timohing Formations, etc.). Undifferentiated Cenozoic volcanic

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rocks in northern Borneo range in composition from intermediate to acidic.

In Indonesia., the Upper Palembang Series represents the Pliocene- Pleistocene in the eastern part of Sumatra; it consists of tuffaceous sandstones, tuffs, bentonites and some coal stringers with silicified wood. In western Java, the Plio-Pleistocene includes predominantly marine deposits (marls, clays, sandstones) associated with great volumes of tuffaceous rocks, including tuffs, tuffaceous sandstone and tuffaceous glauconitic marls. In central Java, the deposits of this age start with transitional beds, and, higher in the sequence, the facies changes from marine to continental, with an admixture of conglomerates and volcanic rocks. The Plio-Pleistocene in eastern Java and Madura consists of marine clays, marls and some limestones of neritic or littoral facies. Undifferentiated Cenozoic volcanic rocks of Indonesia are represented by lava flows, tuff 6, agglomerates and tuffaceous rocks, which range in composition from intermediate-basic (predominantly andesite to basalt) to intermediate-acidic (primarily dacite- rhyolite, but also andesite-dacite), although change in composition from basic to acidic within a sequence is typical in many localities. In West Irian, the Miocene-Pleistocene includes clastic sediments of the Kalsaman, Steenkool and Boerol Formations in Vogelkop, Bomberai and the southern part of the Central Range. In the western- most regions (Salawati basin) the sediments are marine and they contain abundant pelagic foraminifera, including Globiqerina dubia, Pulleniatina obliquiloculata and Globoquudrana conglomerata; in the eastern regions they contain the benthonic foraminifera Alveolinella, Marginopcwa, Rotaliu, Elphidium and some corals. In northern regions east of Geelvink Bay, mainly clastic strata (the Mamberamo Formation) comprise the Upper Miocene-Pleistocene, but limestones (the Hollandia Formation) occur locally, with Lepidocyclim, Miogypsina, Alveolina quoyi and Culcurina. On the island of Wsigeo, this interval is predominantly limestone (the Waigeo Formation), and mainly marls (the Seoerdori and Korimdori Marls) on the islands of Soepiori and Biak, with abundant pelagic foraminifera, including Pulleniatina obliquilo- culuta. On Misool, the Plio-Pleistocene deposits contain banked coral limestones with intercalated marls and lignite.

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In the Philippines, the Plio-Pleistocene deposits comprise largely marine and terrestrial molasse-like clastic sediments, associated with extensive reef limestones in the Bicol peninsula (southeastern Luzon), in the central islands and in Mindanao; and pyroclastic deposits in the western and southern parts of the central basin of Luzonand the northern Bicol lowland. In places, they consist predominantly of marls and reworked tufls, and also include coastal and fluvial terrace gravels. The fauna includes Globorotalia tmcatulinoides, Sphaeroidi- nella dehiscens, Cycloclypeus carpenteeri and Alveolinella; Pliocene- Quaternary volcanic rocks include plateau basalts, pyroxene andesites of non-active cones, dacitic and andesitic plugs and basaltic dykes, associated with pyroclastic beds and volcanic piedmont deposits.

Cenozoic volcanic rocks in Korea consist of plateau basalts and some andesitic lavas and tuffs, which are primarily of Quaternary age, but may also include some Upper Tertiary flows.

In China, this subdivision is represented by continental molasse- like deposits developed in western, mainly northwestern, China which were accumulated in intermontane basins and foreland depressions and plains. These are mainly sandstones, clays and siltstones in the lower part and predominantly coarse clastic rocks, including conglomerates in the upper part.1n the Dzungaria and Tsaidam basins, there are also thin beds of limestones and saline deposits.

Undifferentiated Cenozoic sedimentary deposits in southern Mongolia and northern China (Gobi and Gobi Altai) are represented by limestones and continental clastic strata, consolidated and unconsolidated, including conglomerates, sandstones, sands, clays and some gravels.

Cenozoic volcanic rocks are widely developed in northern and eastern Mongolia, and northern and eastern China, where basaltic, andesitic and doleritic lava flows are associated with continental deposits of Paleogene, Neogene and Pleistocene age. The Cenozoic plateau basalts cover rather large areas iileasternMongolia and northeastern China, including Inner Mongolia and Kirin and Heilungkiang in Manchuria.

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In Taiwan, the Rio-Pleistocene is represented by the Toukoshan Formation, consisting of fluviatile to deltaic conglomerates, coarse sands, some silts and shales. According to some recent information, this formation may be Lower Pleistocene in age.

QUATERNARY

In Iran, Quaternary deposits are widespread and include alluvium of valleys and plains, marine terraces and beach sediments, fans, mud and salt flats, sand dunes and loess. Quaternary lava flows are of basaltic and andesitic type.

In Afghanistan, the lower part of the Quaternary is represented by Pleistocene variegated and drab clays, sands, conglomerates and siltstones, developed in some intermontane depressions (Mazar-i- Sharif, Kabul, etc.). The younger deposits in the depressions consist of fluvial and talus sediments, loess and some tuff. Recent deposits generally include unconsolidated continental deposits of different origin, mostly alluvium. In the southwest, there are eolian deposits and sand dunes. In the southern regions, the Quaternary sediments are associated with some volcanic rocks; dacitic and andesitic flows and tuffs occur over a large area north of the Chagai Hills in southernmost Afghanistan.

In West Pakistan, the Pleistocene includes clastic sediments of molasse type, laid down in depressions and reflect'ng the Himalayan Orogeny. These are poorly consolidated or unconsolidated deposits, including shales, sandstone, conglomerates, sands, clays and pebbles. They also include some littoral marine formations, older alluvial deposits of river valleys and plains, and some loess and eolian sands. Pleistocene volcanic rocks in Chagai (Baluchistan) consist of agglomerate, tuff and andesitic lava. Recent deposits are represented by alluvium, coastal, deltaic and tidal deposits, dune sands and other unconsolidated superficial material. The Pleistocene &posits of the Karewa Formation in Kashmir and the Himalayas are of freshwater origin at the basal part and lacustrine at the top and they contain several interbedded glacial deposits. The flora includes Trapa, Vullisnsria and Garophyta, and the fauna comprises Equus, Elephas namadicus, Sivatherium, etc.

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The Pleistocene of India includes glacial andfluvioglacial deposits in the Himalayan region, laterite deposits in the Deccan peninsula and loess and the Older Alluvium of the Indus-Ganges plain. Recent deposits include coral reefs, the Younger Alluvium, coastal deposits, young glacial deposits, sand dunes and other surficial sediments.

In Nepal, the unsorted glacial and alluvial sediments of the Kali- Gandak River are of Pleistocene and Recent age (shown on the map as Neogene-Quaternary) whereas the alluvium of the Ganges plain is shown as Recent.

Pleistocene deposits in Ceylon include mottled gravel, the Red Earth deposits (red sands and clays) and laterite. The Recent deposits consist of alluvium, residual deposits, coastal sands and some lateritic earths.

In Burma, the Pleistocene deposits are represented by the Plateau Gravels (mainly ferruginous sands with pebbles) and associated Red Earth of the Plateau Region, the Uru Boulders, some laterite and the Older Alluvium, The Recent includes surficial alluvium and coastal deposits.

The Quaternary deposits of Thailand, the Khmer Republic, Laos and Viet-Nam consist mostly of alluvium, lacustrine deposits and some laterite. The thickest alluvial deposits are in the Mekong and Tonkinese deltas, and the Chao Phraya River basin. Much of the central and western parts of the Khmer Republic are covered by the alluvium of the Tonle Sap basin. Coastal deposits and beach sands are developed along the sea shores of Thailand, the Khmer Republic and Viet-Nam.

In West Malaysia, the Quaternary consists predominantly of Recent river alluvium inland, and this alluvium is admixed with marine coastal deposits along the shore-line.

In Borneo, the Quaternary includes mainly Recent alluvium, covering extensive alluvial plains, and coastal deposits. The Quaternary volcanic rocks comprise mainly andesitic and some basaltic lava flows and pyroclastic deposits.

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In the islands of Indonesia., Quaternary sediments include alluvium, terrace and coastal deposits and coral reefs; the latter are an important feature in the eastern half of the archipelago. In Java, the Pleistocene terrestrial deposits have yielded the hominid fossils Meganthropus paleojavanicus, Pithecanthropus sp, Homo soloensis, etc; Stegodon trigonocephalus flwensis is known from Flores. Quaternary volcanic activity was almost continuous from Pleistocene to Recent and was widespread over the whole Indonesian archipelago. The Quaternary volcanic products, ranging in composition from basaltic to dacitic- rhyolitic in most islands, were derived from a calc-alkali magma of Pacific type. Although some areas with predominantly basic, intermediate-basic, or basic volcanic rocks may be distinguished, a more or less gradual change from basic eruption products to acidic within one volcanic cycle may be observed inmany localities. The unclassified volcanic rocks in Java, Bali, Lombok, Sumbawa, Sulawesi and Halma- hera comprise normal intermediate basic volcanic rocks of the calc- alkali Pacific type, associated with potash-bearing volcanic rocks of the Mediterranean type, including leucite basanites, tephrites, trachytes and syenite-porphyries. In West Irian, Recent alluvial deposits cover large areas in coastal plains and valleys. Mud volcano deposits are known in the Van Rees mountains, east of Geelvink Bay. On Noemfoor and Biak Islands, north of Geelvink Bay, the youngest rocks consist of sub-Recent uplifted coral reefs.

In the Phi I ippines, Quaternary sediments are re2resented by Recent alluvium, fluviatile, lacustrine and beach deposits, raised coral reefs and atolls. The Quaternary volcanic rocks consist mainly of active volcanoes and their products, mostly andesitic and basaltic lava flows and tuffs.

In Japan, the Pleistocene comprises predominantly continental, but also marine deposits, composed mainly of coarse sediments but containing in places some lignite beds and often associated with volcanic material and Recent deposits in alluvial and coastal plains. The Quaternary vulcanism in Japan is recorded in the same areas as during the Neogene. More than two hundred volcanoes were developed in Quaternary times and fifty of them have been active in historic

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times. The products are mainly calc-alkaline and range in composition from acidic to intermediate-basic,

The Pleistocene in China is represented by alluvium in plains and valleys, loess, moraines, drift and fluvio-glacial deposits, some cave deposits, eolian deposits and sand dunes. In northern China, the Choukoutien deposits of the fourth erosion cycle contain remains of Sinanthropus pekinensis, Elephas, Rhinoceros, etc., of early Pleisto- cene age, which have been found in isolated caves. The fifth cycle recognized in northern China began with the Chingshui Stage of erosion, which was followed by the deposition of the Malan Loess covering vast areas in northern China. It contains Helix, Mastodon, Boss etco The loams of the high (20m) terrace inthe lower Yangtse valley have yielded Traumotophora, Ganesella, Opeas, etc. At least three successive glaciations, separated by interglacial periods, are represented by glacial and fluvio-glacial deposits, The Recent deposits are represented by alluvium of lower terraces in valleys and lowland plains, eolian deposits, sand dunes and other surficial material. Volcanic activity during the Pleistocene resulted in the extrusion of basalt flows which occupy fairly large areas in southern Kwangtung and the island of Hainan.

In Taiwan, Pleistocene post-orogenic deposits formed after the early Pleistocene orogeny include gravels and lateritic deposits, with marine deposits along the coast. Active vulcanism during the Pleisto- cene resulted in the formation of andesitic lavas and pyroclastic deposits in Taiwan and plateau basalts in the Penghu Islands, west of Taiwan. Recent deposits are mainly alluvium, beach deposits and reef limestones.

In Mongolia., the Quaternary deposits include alluvium in valleys, glacial and fluvio-glacial deposits in mountain regions, lacustrine sediments, loess and sand dunes in southern Mongolia. Quaternary basaltic flows are scattered through central and northern Mongolia.

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3. Intrusive rocks

PRECAMBRIAN

Precambrian metamorphic and crystalline rocks, particularly of the Precambrian C (generally Archean) andPrecambrianB (generally Lower Proterozoic) divisions in most of the region, are generally granitized, migmatized and intruded with great masses of granitic rocks also of Precambrian age. They also contain embedded bodies of metamorphosed basic and ultrabasic rocks of Precambrian age. O n the map, most or all of these are not separated from Precamhrian metamorphic and crystalline rocks, but, in some places, some Pre- cambrian granites occupy sufficiently large areas to warrant separate representation.

Large intrusions of Precambrian basic and ultrabasic rocks are known in Kashmir and the northeastern part of peninsular India. In the peninsula, the Precambrian basic and ultrabasic rocks comprise anorthosites, labradorite-pyroxene rocks, anorthosite gabbro, norite, diorite, etc., of post-Dharwar age. The Dharwar System itself includes metamorphosed and folded basic igneous and metavolcanic rocks. The earliest acidic intrusions include the Champion Gneiss (gneissic granites and granite-porphyry stocks and bosses) and the Peninsular Gneiss (granites, gneissic granites, granodiorites), and their equivalents. The later Precambrian granites are represented by the Closepet Granite, Mylliem Granite, Erinpurna Granite, Singhbhum Granite, etc.

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Intrusive rocks

The chamockites widely developed in the Precambrian of peninsular India and Ceylon include a suite of rocks ranging in composition from acidic to ultrabasic and characterized by the presence of hyper- sthene. There is considerable difference of opinion on the origin of these rocks; although they were originally considered to be of igneous origin, many workers regard them as being the metamorphosedand recrystallized products of different rock types.

In Burma, Precambrian acidic intrusions are mainly granites

In Laos and Viet-Nam, Precambrian igneous rocks associated with the gneisses of the basement complex are exposed over large areas in the north; they are mainly foliated plagioclase granites, granite-gneisses and granites.

Precambrian granitic intrusions are extensively exposed in China, although they are not separated on the map from Precambrian metamorphic and crystalline rocks. The oldest granitic plutons include the Taishan granite, mainly biotite gneissic granites and granite- gneisses, invading the metamorphic rocks of the Taishan Complex in northern China and its equivalents in other regions. The younger granitic rocks intruded into the Wutai Series have yielded absolute age datings of 1,800 f 100 m.y.; some radiometric dates show the presence of older granitic migmatites (2,560 m.y.) in the lower part of the Wutai Series. The absolute age of the pre-Sinian older rapakivi- granite in northeastern China is 1,320 m.y. The acidic plutonic intrusions disrupting the Precambrian supracrustal rocks are mainly granites, plagioclase granites and minor granodiorites, commonly with gneissic texture; they are accompanied by pegmatites and aplites and gsnerally form extensive zones of migmatites and granitized rocks. Younger metamorphic rocks of the Hut0 Series in Shansi and Hopei are also intruded by gneissic graniteso Other intrusive rocks of pre-Sinian (Proterozoic) age include large granite intrusions and small bodies of granite, syenite and diorite.

with associated pegmatites and some earlier syenites.

In Mongolia., rhe Precambrian intrusive rocks are mostly con- centrated in the northern and northeastern parts of the country. Small pods, lenses and stocks of ultrabasic and basic rocks (mainly peridotites, pyroxenites and gabbros) are exposed in the north, west of the

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Intrusive rocks

Hobsogol lake, and are classified as Precambrian A (Upper Protero- zoic) in age. Connected with an unconformity between Middle and Upper Proterozoic rocks are intrusions of granites, granite-gneisses and binary granites, which form large batholiths as well as small dispersed massifs with extensive migmatite zones.

The Granite Gneiss System of Korea is shown on the map as Pre- cambrian intrusive rocks; it consists of granites, gneissic granites, granite-gneisses and intensely migmatic and granitized metamorphic rocks, including gneisses and crystalline schists, which are equivalent in age to rocks of the Precambrian C subdivision.

PRECAMBRIAN-PALEOZOIC

In Iran, the most ancient intrusive rocks are dated as Precambrian- Paleozoic and they comprise Precambrian and possibly Cambrian intrusions; these are mainly biotite and two-mica granites, ranging from granodiorite to alkali-granite and coarse-grained pegmatitic granite rich in feldspar. Their age is uncertain; however, they are certainly younger than the Precambrian metamorphic rocks but older than some Cambrian and Eo-Cambrian rocks.

The Jalor and Siwaria granites and their equivalents in Rajasthan, India, compose the Malani Igneous Suite of probable late Precambrian - early Cambrian age.

PA LE OZOlC

Paleozoic basic rocks in the Khmer Republic, Laos and Viet-Nam are confined to the areas of Paleozoic-Triassic volcanic activity and include intermediate basic intrusive and associated extrusive types (andesite, dolerite, porphyrite, gabbro, micro-gabbro, etc.) occurring in the form of dykes, sills, small laccolithic intrusions, lava flows, etc., emplaced mostly during late Carboniferous, Permianandearly Triassic times. The Paleozoic intrusions in most areas of the Khmer Republic, Laos and Viet-Nam consist of widespread granitic-granodioritic intrusions of the Hercynian orogenic cycle, most probably emplaced in mid-Carboniferous times. In western Laos (southwest of L u n g Prabang), this group also includes Permian-(?) early Triassic intrusive rocks composed of granodiorite-tonalite, with monzonitic and dioritic

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Intrusive rocks

affinities, which were formed during an early phase of the Endosinian orogeny.

In Japan, late Paleozoic-early Mesozoic intrusions are represented by granitic gneisses and some granites in the metamorphic complex in the Hi& and Abakuma Mountains, and also include some granodiorites with cataclastic texture. Some of the intrusions of this group are considered to be Permian or pre-Permian in age.

In China, Paleozoic intrusions, mainly granitic rocks generally associated with ultrabasic and basic rocks of mafic phases, are extensive in all the foldbelts; they occur as large batholiths and smaller plutons in the form of concordant to massive discordant bodies. Most batholiths are complex and have a wide range of structure, composition and age. In central (Nan Shan) and southeastern China the oldest Paleozoic intrusive rocks are peridotites and gabbros of Cam- brian age; synorogenic intrusions in that area include granites and granodiorites of pre-Silurian age. Late orogenic pre-Devonian biotite- hornblende granites, granodiorites and some diorites form large concordanc batholiths. In Tsirding Shan, Kunlun and eastern Tien- Shan, in central and northwestern China, Paleozoic granitic intrusions are nlvnerous and widespread, in t!he form of large plutons and small linear bodies. The main emplacement took place in late Paleozoic time, although early Paleozoic (Cambrian-Silurian) granites and ultramafic and mafic rocks are also known. The synorogenic granites of Carboniferous age in places are characterized by gneissic and cataclastic texture. Permian granitic rocks comprise late-orogenic medium- and coarse-grained biotite and hornblende-biotite granites, granodiorites and some diorites. In Manchuria, northeastern China, Paleozoic granitic rocks form a huge batholith nearly continuous for more than 1,000 km in a north-east direction and several hundred k m wide. Geologic relations indicate a prolonged time for the emplacement of these granitic rocks, which consist of fine- to coarse-grained biotite granites, hornblende granites, biotite-hornblende granites, granodiorites and two-mica granites; they are accompanied by pegmatites, aplites, quartz diorites, gneissic granites and granite porphyries. The main assemblage of rocks is probably of late Paleozoic age although some parts may be older.

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Intrusive rocks

In Mongolia, Paleozoic granitic rocks are extensively ewosed, but the largest exposures and probably the greatest volumes of granitic rock occur in central northern Mongolia and in the Altai Range in the west, where they form large batholiths as well as smaller bodies. The Paleozoic batholiths have been shown by recent detailed study to be internally complex in both age and composition, and ta be composed of many discrete plutons, which according to their age can be divided into three main groups: early, middle and late Paleozoic. The main assemblage of early Paleozoic granitic rocks in northern, northwestern and central Mongolia consists of middle-late Cambrian plagioclase granites, granodiorites and some granites, in places with gneissic and cataclastic texture, but there are also smaller bodies of Ordovician rocks, mainly leucocratic biotite and binary granites. In the Altai Range in the west, and in some parts of southernMongolia, Ordo- vician granites and some granodiorites form quite large batholithic bodies.

Lower Paleozoic ultramafic and mafic intrusions, mainly pods, dykes and stocks, are in part related to the middle-late Cambrian granitic phase, but some intrusions are connected with a Lower Cambrian spilite-diabase suite. The middle Paleozoic plutonic rocks range in age from Silurian to early Carboniferous and exhibit a wide variety of form, structure and composition and most of them have several mafic phases. There are also some discrete smallplutons of peridotites, pyroxenites, gabbros and gabbro-diorites which are either contemporaneous with the granitic @ m e or slightly earlier in age.

The main emplacement of middle Paleozoic granitic rocks took place during the Devonian (middle and late Devonian granites, granodiorites, tonalites, some leucocratic granites and granite-syenites), but there are also granitic bodies of late Silurian, post-Devonian and early Carboniferous age. In the northeast, some batholithic intrusions of middle Devonian age are composed of granite-syenites, syenites, and some alkali-syenites with nepheline. Late Paleozoic plutonic rocks also include mafic intrusions, in part related to the dominant granitic rocks; the latter, complex in age and composition, are most extensive in central Mongolia, where they form large batholiths,

90

intrusive rocks

although smaller plutons are widely scattered over mostof the country. The major granitic emplacement occurred in late Carboniferous time; most granitic intrusions of this age comprise mainly medium- and coarse-grained granites and granodiorites, with biotite or both biotite and hornblende, sometime with poqhyritic texture. The granitic rocks of Permain age are mainly granites and granodiorites with some diorites, which form shallow intrusions associated with volcanic rocks.

MESOZOIC

In Iran, Mesozoic intrusions include biotite-granodiorite ranging to granite of probable late Jurassic age, sometimes porphyritic, and late Cretaceous diorites.

Extensive igneous activity commenced towards the end of the Cretaceous in the Himalayas, and granites and particularly basic rocks of this period may form part of the undifferentiated granites of the Himalayas.

In India and Burma, late Cretaceous igneous activity is known in Assam and the Arakan-Andaman belt where intrusions of basic and ultrabasic rocks, mostly peridotites and serpentines locally containing chromite, are found. In northern Burma, these are largely serpentinized peridotites, dunites, pyroxenites and amphibolites. In the Andaman and Nicobar Islands, gabbros, serpentines and enstatite- peridotites form a zone which continues southeastwards into Sumatra and Java.

Mesozoic intrusions in the southwestern and northern parts of the Khmer Republic consist of stock-like batholithic bodies of coarse porphyritic adamellite, biotite granite and granodiorite. Previously considered as late Cretaceous, these intrusions at present are classified as early Jurassic in age.

Age determinacions made recently of intrusive rocks in norEhern Viet-Nam have indicated a period of magmatic activity in Jurassic- early Cretaceous time (gabbros, granites) and another in late Cre- taceous-Paleogene time (granites); these rocks are exclusively con- centrated in the extreme north of Viet-Nam and are shown on the map as Paleozoic.

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Intrusive rocks

In Thai land, Mesozoic basic and ultrabasic intrusions (dykess plugs and stocks) occur in the north and northeast. This group consists of diorite, gabbro and pyroxenite, partly serpentinized. The age of the rocks is uncertain, but geologic relationships suggest they may be Mesozoic and post-Triassic in age.

in Japan, Cretaceous acidic intrusions are the most widespread and they are the most important in connexion with ore mineralization; they are developed along north-south tectonic lines in northeastern Japan and form large batholiths in the southwest. The main rocks are granites and granodiorites.

In Korea., Mesozoic plutonic rocks are generally represented by granites of Jurassic age, and granites, granodiorites, some diorites and related porphyritic hypabyssal rocks of Cretaceous age.

Mesozoic granicic rocks in China are moscly confined CO an intrusive belt which lies along the eastern and southeastern margin of the continent and extends from the southeastern coastal region of China including the islard of Hainan, through Shantung and Korea to the Sikhota Alin Range in che eastern USSR. Appendages to the main belt occur in Tsinling Shan ana Inshan (eastern China). The belt is characterized by numerous shallow stocks and batholiths of Mesozoic granitic rocks associated with small bodies of gabbros and gabbro- diorites of probable Jurassic age. The main emplacement of granitic intrusions probably occurred in early Cretaceous time, although, in some places, there was some emplacement of granite and granodiorite in late Jurassic time. The major assemblage of early Cretaceous rocks consists of granodiorites and leucocratic biotite granites, generally coarse-grained, succeeded by aplitic granites, granite-porphyries, granodiorite-porphyrites, etc., representing younger phases of the early Cretaceous intrusive activity. In places, granites and granodiorites are associated with felsitic granites, syenites and diorites, and sometimes grade into porphyritic granites and granite-porphyries. The younger rocks of late Cretaceous age are commonly represented by shallow intrusions of leucocratic granites, felsitic granites, granite- porphyry and quartz-porphyry, as well as granodiorite-porphyrite and syenite-porphyry in some places.

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Intrusive rocks

In Mongolia, Mesozoic mafic rocks form small bodies (stocks, plugs, etc.) emplaced mainly in Triassic-early Jurassic times. The Mesozoic granitic rocks are post-orogenic and commonly more alkalic than earlier ones. They form mostly discordant bodies of different size and shape and are largely confined to fault zones. Triassic granitic rocks, mainly leucocratic granites, granodiorites, grano- syenites and some diorites, form large plutons in northern and northeastern Mongolia and smaller bodies in the south. The middle Jurassic intrusive phase resulted in the formation of alkalic leucocratic granites, coarse hornblende-biotite granites with porphyritic texture, some granodiorites, and related felsic plutonic rocks. The younger intrusive rocks form stocks, dykes, plugs, laccoliths and other shallow intrusions, composed of late Jurassic (in places probably early Cretaceous) granites, granite-syenites, granite-porphyries and other porphyritic rocks.

PRE-TERTIARY

Pre-Tertiary intrusive rocks are exposed in western and central Borneo where they form a batholithic massif occupying a large area, with some isolated relics of the former roof, made up of metamorphosed Carboniferous-Permian rocks. In the northern part of the island, this massif is composed mostly of diorite, quartz diorite, some syenite, and aplitic and alkali granites. The southern part is occupied by granite, granodiorite, tonalite and quartz porphyry.

In Japan, pre-Tertiary basic and ultrabasic intrusions include peridotites, pyroxenites, hornblendites, gabbros and gabbro-diorites, which were emplaced during a long period in connexion with late Paleozoic-early Mesozoic, Jurassic-Cretaceous and probably late Mesozoic phases of igneous activity in Japan.

CRETACEOUS -TERTIARY

In Iran, ultrabasic intrusions of the "Coloured Melange" assemblage of rocks (basic lava flows and serpentine intrusions associated with marls, calcareous shales and radiolarian cherts) form part of the Upper Cretaceous-Paleogene @ossible Upper Cretaceous) Ophiolite Formation.

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Intrusive rocks

In West Pakistan, basic and ultrabasic rocks in the Axial Belt, occupying the mountain ranges between Baluchistan and the lower Indus basin, range in composition from diorite and gabbro to serpentinized peridotite, and, in places, are associated with volcanic rocks; the age of these intrusions appears to be either late Cretaceous or early Paleocene. In Baluchistan (Chagai), mafic intrusions of the same age are mostly sills, dykes and boss-like bodies. In this region, the granitic intrusions were emplaced at various times from the Cretaceous period onward, probably ending during Oligocene time; these rocks range in composition from granite to granodiorite and diorite, and include some monzonite. The younger rocks (post-Eocene) are more alkalic than those of the Cretaceous.

In the Phi 1 ippines, undifferentiated Cretaceous-Paleogene ultramafic and mafic plutonic rocks are predominantly peridotites associated with late gabbro and diabase dykes. In some places (Zambales Moun- tains, western Euzon) they form complex layered intrusions generally thrust or upfaulted into Tertiary and older rock formations.

TERTIARY

In Iran, Tertiary granites and granodiorites form rather small intrusive bodies, mainly in northern Iran; some of these intrusions are post-Eocene and may be as young as Pliocene in age.

In the Himalayan region of Afghunistan, India and West Pakistun, considerable igneous activity commenced towards the end of Cretaceous time and especially during the earlier part of the Tertiary; basic rocks and large masses of granites, mostly tourmaline granites, were intruded at that time in the northern and central Himalayas.

Tertiary intrusions in northeastern and central Thai land, represented by bosses, stocks and small batholiths of diorite and quartz- diorite, intrude the Khorat Series and older rocks.

In West Irian, Indonesia., Tertiary granitic to quartz-dioritic intrusions occur mainly in the northwest (Vogelkop); they consist of granites, granodiorites, monzonites, and locally quartz diorites, accompanied in some places by dykes of posrphvritic rocks. The age of most of these intrusions is certainly post-Mesozoic and possibly post-early Miocene.

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In the Philippines, the Tertiary intrusions comprise Paleogene and Neogene dioritic rocks. The Paleogene intrusive rocks consist mainly of quartz diorites, but also include granodiorite in eastern Luzon and quartz monzonite in Palawan. The Neogene intrusions consist mainly of intra-Miocene quartz diorite in the form of batholiths, stocks, some laccoliths, sills and dykes, but diorite-porphyry and late Miocene dacites are also found.

NON-DATED OR UNDIFFERENTLATED

In Iran, most of the non-dated basic and ultrabasic intrusions are most probably associated with ophiolites of late Cretaceous- Paleocene age, while granitic rocks of uncertain age may iary in age from Precambrian to Tertiary.

The basic and ultrabasic intrusions in southern and southeastern Afghanistan represent the initial magmatism, in the form of ophiolites, lasting from late Cretaceous through Paleocene time. It is likely that many of the granites in central Afghanistan and the volcanic activities in the western part of central Afghanistan may have occurred at this stage. In the Indus-Baluchistan geosyncline within Afghanistan, however, the presence of granite has not yet been proved. In eastern Afghanis- tan (Hindu Kush), the Paleozoic granitic rocks may be connected with the Hercynian Orogeny. In northern Afghanistan, granitic rocks of unknown age intrude a highly deformed and metamorphosed basement complex of Paleozoic age.

In the northern mountainous areas of West Pakistan (Hazara, Hindu Kush) undifferentiated acidic intrusions include granites and gneiss-granites of possible Precambrian age, and granodiorite, syenite and diorite of probable early Tertiary age.

The Himalayan granites of India and Nepal consist of undifferentiated products of igneous activities in several different periods. The main part may comprise the tourmaline and hornblende granites introduced during late Eocene and Miocene times. Some of the granites are probably of Cretaceous or earlier age, as they contributed material to Paleogene conglomerates in the Kara Koram and Trans-Himalayan Ranges.

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Intrusive rocks

In Nepal, the undifferentiated granitic rocks comprise biotite granites, probably of Cretaceous or early Tertiary age, and tourmaline granites (the Mustang Granite and Manasulu Granite in the Kathmandu area) associated with late phases of the Alpine Orogeny during the Tertiary (most probably late Eocene and Miocene).

In Burma, non-dated basic intrusions include gabbro and other basic crystalline rocks, generally associated with Precambrian metamorphic rocks.

Non-dated altered peridotite and serpentine intrusions are exposed in the extreme northeastern part of Laos, where they are aligned along a major northwest-southeast structural trend which extends into Viet-Nam.

Undifferentiated acidic intrusive rocks exposed in southern Viet- Nam include undifferentiated granite-gneisses and gneissic granites of Precambrian or possibly Paleozoic age, probable early Paleozoic alkaline granites, and locally some syenites, early-middle Carboni- ferous granites, granodiorites with associated monzonites, tonalites, diorites and some minor basic rocks.

The undifferentiated granites of eastern Thai land (east of the Chao Phraya basin), which contain no tin in significant quantity, consist of Carboniferous granite, Triassic granite and granodiorite, and granites of probable Tertiary age. Recent radio-isotopic age determi- nations have shown that the granites northeast of the Gulf of Thailand are mainly Triassic or older (190-198 million years) while some smaller granitic intrusive bodies are possibly Tertiary, with an age of 72 plus or minus 3 m.y.

A distinctive feature of southeast Asia is a belt of stamserous granitic intrusions which extend southward from southern China (Y unnan), through eastern Burma, western and peninsular Thailand, and West Malaysia to the "tin islands" of Indonesia, of which the largest are Bangka and Billiton. .This belt, forming the well-known Southeast Asian metallogenic province, is the most important tin producing region in the world. Exposed within this belt are mainly highly-differentiated granitic rocks which form dispersed elongated

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Intrusive rocks

plutons. Both the geologic relations and radiometric dates indicate that they were emplaced in various phases during a prolonged period from Paleozoic into Tertiary time. The main assemblages of granitic rocks are of Carboniferous (300-285 m.y.), Triassic (230-175 m.y.) and late Cretaceous-early Tertiary (85-48 m.y.) age. Recent investiga- tions have yielded evidence indicating that, locally, there are granites of late Jurassic-early Cretaceous age (145-120 m.y.) and that two phases of granitic emplacement occurred in the Triassic, one in the early (230 plus or minus 6 m.y.) and the other in the late Triassic (199 plus or minus 2 may.). The presence of granite pebbles in some Silurian-Carboniferous sediments suggests the possible occurrence of older granites in or close to thearea. The granites vary in composition from alkaline and monzonitic to calc-alkaline and may differ in chemical and modal composition within the same granitic mass. Locally, some of the granitic rocks have mafic phases; these are not separated on the map from the main granitic phases. Carboniferous granites intruding Lower Paleozoic rocks are in places gneissic with planar foliation marked by prolific biotite and prominent feldspar phenocrysts. The Triassic granites are usually hornblende-biotite granite with hornblende more abundant than biotite, while the younger late Cretaceous-early Tertiary rocks are generally binary or biotite granites, often with a coarsely porphyritic texture.

According to the concept of age relationship between the primary tin deposits and the granitic rocks in Thailand, the late Cretaceous- early Tertiary granites are the main source of economic tin deposits, although older granites are also stanniferous. O n the other hand, in West Malaysia, according to recent data, many primary tin deposits appear to be connected with Triassic granite intrusions, although Carboniferous granites have also yielded stanniferous pegmatite.

Ultrabasic intrusions in Borneo occur mainly in the northern and southeastern regions. They consist for the greater part of serpentinized peridotites and serpentinites, but comparatively fresh peridotites, together with dunite and pyroxenite, are present in a few scattered localities. The basic intrusions of Borneo are composed largely of

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gabbros and intimately related diorites, with some dunite and pyroxenites. Some of the ultrabasic and basic intrusions were apparently emplaced at an earlier date, possibly in late Paleogene time, although part of them may belong to the mafic phases of pre-Tertiary granitic and dioritic intrusions. Some large batholiths and dykes in southeastern Kalimantan are composed of granite and quartz-porphyry, locally with some alkaline tendencies; these batholiths were most probably formed during different intrusive phases in Paleogene and probably pre-Tertiary zimes.

In northern East Malaysia, the unclassified igneous rocks shown on the map are intrusive rocks which vary in composition from ultrabasic and intermediate types to acidic rocks. The ultrabasic rocks include serpentinite, and also unaltered peridotite, pyroxenite and dunite. The intermediate rocks are mainly dioritic, and the acidic rocks are granodiorites with minor granites. The age of the rocks is uncertain; some were probably emplaced in pre-Tertiary times, while others may be related to Tertiary and younger igneous activity.

In Sumatra, Indonesia, ophiolitic rocks, shown on the map as non-dated, are associated mainly with upper Mesozoic deposits. Large intrusive masses of peridotites, serpentines and gabbros occur in Sulawesi, Timor, and some other islands of eastern Indonesia. The main assemblage of ultrabasic and basic rocks is related to the ophiolitic suite which also includes extrusions of basalts (spilites). There is considerable difference of opinion concerning the age of these rocks; it is most probable, however, that the Intrusion of the ultrabasic masses took place at several intervals during Mesozoic- Tertiary times.

In Sumatra, a number of granite masses form a belt extending southeastwards along the northeastern part of the Barisan Range. The age of the oldest granites is probably Carboniferous or Carboniferous- Permian, but many of the intrusions are possibly of post-Triassic age. Some granodioritic and dioritic batholiths may have been emplaced during a phase of igneous activity at the end of Paleogene time. In Sulawesi, plutonic massifs of granitic and granodioritic rocks are exposed in the west central part of the island; these are mainly granites and granodiorites, some related microdiorites and quartz-diorites,

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with gneissic granites and gneisses, indicating a synorogenic or pre- orogenic time of intrusion. Geological relations indicate the presence of granitic intrusions of different ages, which are considered to be not older than late Mesozoic or Tertiary. The presence of dacitic lavas in the Pleistocene suggests the continued activity of acidic-intermediate intrusions up to Quaternary time.

Undifferentiated igneous rocks shown in northern Java, Sulawesi and some other islands in eastern Indonesia are of the Mediterranean Suite, comprising alkaline igneous rocks of Neogene-Quaternary age, associated with extrusive and intrusive products of potassic magmas of the Mediterranean type. They include flows of leucite-bearing lavas and hypabyssal stocks, bosses, necks and dykes of trachytes and syenite-porphyries.

In West Irian, basic and ultrabasic rocks shown on the map under this group consist of elongated plutonic massifs disposed in two parallel belts extending east-west in the northern part of the Central Range and the northern coastal region. They consist generally of peridotites, harzburgites, dunites, serpentinites and gabbros; the gabbros occur usually as small dykes or stocks in the ultrabasic rocks. The age of these rocks is uncertain; the major part may be older than late Creta- ceous, although some intrusions may have takenplace in Tertiary times.

In Korea, the basic rocks of uncertain age include mainly intrusions of gabbros in the Precambrian granite gneissic complex in the southern part of the country.

In China, the undifferentiated and non-dated basic and ultra-basic rocks shown on the map consist mostly of Paleozoic and minor Mesozoic intrusions emplaced during mafic phases of granitic magmatic activity, and also some Paleozoic ultrabasic rocks, connected with basic volcanic activity in Paleozoic foldbelts. In southern Tibet, basic and ultrabasic rocks include small ultramafic plutons of late Cretaceous(?) or late Cretaceous-early Tertiary age.

Granitic rocks of uncertain age or undifferentiated acidic intrusive rocks occur as intrusions of mainly late Precambrian, Paleozoic or Mesozoic age, and, in places, include large complex batholiths composed of many discrete plutons of different age, structure and

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composition. In northern China, these are mainly granites and granodiorites of late Paleozoic age, but locally early Paleozoic and Mesozoic. In northeastern China (northern Manchuria), a great batholith, shown on the map as undifferentiated, consists of pre-Jurassic granites and gneissic granites, some granodiorites, diorites and quartz diorites, and Mesozoic (mostly Cretaceous) leucocratic granites, porphyritic biotite and hornblende-biotite granites and granodiorites, felsitic granites, graphic granites, quartz porphyries, granite-porphyries, some syenites and aplites. In central China, undifferentiated intrusions range from granitic to dioritic bodies, mostly of late Paleozoic age. In Tibet, elongate granitic plutons, mainly biotite granites, are of probable late Mesozoic age. Tourmaline granites in southern Tibet were emplaced during Tertiary time. Granites in southernmost China and Hainan consist mainly of early Paleozoic and Mesozoic intrusions, with associated small bodies and dykes of basic and ultrabasic rocks.

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Documents

Geological Map of Asia and the Far East