Geological Evolution of South-East Asia Second Edition CHARLES S. HUTCHISON Geological Society of Malaysia 2007 Geological Evolution of South-east Asia Second edition CHARLES S. HUTCHISON Professor emeritus, Department of geology University of Malaya Geological Society of Malaysia 2007 Geological Society of Malaysia Department of Geology University of Malaya 50603 Kuala Lumpur Malaysia All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior permission of the Geological Society of Malaysia ©Charles S. Hutchison 1989 First published by Oxford University Press 1989 This edition published with the permission of Oxford University Press 1996 ISBN 978-983-99102-5-4 Printed in Malaysia by Art Printing Works Sdn. Bhd. This book is dedicated to the former professors at the University of Malaya. It is my privilege to have collabo­ rated with Professors C. S. Pichamuthu, T. H. F. Klompe, N. S. Haile, K. F. G. Hosking and P. H. Stauffer. Their teaching and publications laid the foundations for our present understanding of the geology of this complex region. I also salute D. ]. Gobbett for having the foresight to establish the Geological Society of Malaysia and Professor Robert Hall for his ongoing fascination with this region. Preface to this edition The original edition of this book was published by known throughout the region of South-east Asia. Oxford University Press in 1989 as number 13 of the Unfortunately the stock has become depleted in 2007. Oxford monographs on geology and geophysics. It It is too important a book to let go. A thorough was originally planned by me to include a section on revision would be beyond my time constraints. I have economic deposits. However, the editor in Oxford revised only those sections that have become instructed that this should be more comprehensively absolutely necessary because of important new data. covered in a subsequent book. It appeared under the Petaling jaya CSH title 'South-East Asian oil, gas, coal and mineral 2007 deposits' in 1996 as number 36 of the Oxford mono­ graphs on geology and geophysics. Number 36 is still available from Oxford because it has been included in their new 'print when required' system. Number 13, ACKNOWLEDGEMENTS unfortunately preceded this new system, and it is no longer available from Oxford. I am grateful to the former President, Professor Lee With the permission of Oxford University Press, Chai Peng, for support and considerable help in the 'Geological Evolution of South-East Asia' was bringing this new edition into publication, and to reprinted in Kuala Lumpur, without any revision, and Mrs Anna Lee for her friendly assistance. Many published by the Geological Society of Malaysia in thanks are due to Dr. Ng Tham Fatt for designing 1996. This blue paper-back edition became well the book cover. Preface to the original Oxford book My in volvement in South-east Asian geology began in Earth history of Australia, edited by J. J. Veevers 1957 with systematic studies on the granite and (1984), and No. 3 The Geology of China, by Yang gabbro-norite of Singapore Island. Gradually, these et al. (1986). studies were extended throughout the Malay Penin­ The present volume will I hope appeal to regional sula and into Thailand and South China. My interests stratigraphers and students of the great Tethyan broadened to the volcanic rocks, stratigraphy, struc­ province. The inclusion of Tertiary oil and gas basins ture, and economic deposits of the region. may result in the use of this book by exploration After completing the Geology of the Malay companies. Unfortunately, mineral deposits have been Peninsula with D. ]. Cobbett in 1973, it became my excluded due to length constraints. desire to write a book on the greater region, for no This volume is the outcome of courses I have regional geology had ever been written on South-east taught to my students at the University of Malaya Asia. Warren Hamilton completed his landmark over the past 5 years. By the time it is published, Tectonics of the Indonesian region in 1979, pavi ng I will have closed my own books and- with regret­ the way for the present book. have left the region after 30 enjoyable years of Professor P. H. Stauffer and I made initial plans for involvement in the geology of South-east As ia. It is a book under the title South-east Asia: geology and my earnest hope, however, that this volume will environment. Unfortunately, the compilation of this remain open on the desks of my graduates and future book had to be abandoned in 1983 when Professor generations of geology students to stimulate their Stauffer left the region. better understanding of th is complex and fascinating An enquiry from the Oxford University Press for a region. book under my sole authorship conveniently arrived Exeter C.S.H. in 1984, and was readily formalized. 1987 This is not a standard regional geology, and the selection of the title allowed me to emphasize tectonic models, but at the same time to document the strati­ graphy and igneous events. I have always taught my ACKNOWLEDGEMENTS students that every aspect of geology involves inter­ pretation. From thi n sections to hand specimens, to The compilation of this book has benefitted from col­ maps, and thence to regions there is an increasing laboration and discussions with many colleagues. In order of interpretation. Although it has greatly particular, I would like to single out P. H. Stauffer, benefited from and has been influenced by numerous I. Metcalfe, K. R. Chakraborty, andY. G. Gatinsky. discussions with colleagues, the mistakes are mine Many of their ideas have been crystallized, albeit alone. imperfectly by me, in the pages of this book. Ian This book gives more of a bird's-eye view of the Metcalfe kindly critically read the manuscript. region, for much field and laboratory work remains Thanks are due to ]. K. Blake for help in compiling before a definitive account can be written. There Table 5.1. remains great scope for high-quality palaeomagnetic S. Srinivass, Ching Yu Hay, and Roslin Ismail research to refine the Phanerozoic plate motions formed my sketches into the final illustrations. Jaafar modelled in the fol lowing pages. The granites have Abdullah and Lee Kok Eng gave me photographic been reasonably well dated, but there is still a lack of assistance. Rujiraporn Polchai helped in compiling radiometric dates for volcanic and metamorphic for­ the index. Zaimah Ahmad Saleh and Fauziah Han.im mations in addition to granites in critical tectonic Saidi helped with the typing at various stages. My son regions. Good structural geological analysis is a lso Timothy helped in the final stages of the manuscript. lacking, but lack of continuous outcrops will severely I wish to thank the editors and staff of the Oxford hamQe.r: Qrogress. University Press for their help in producing this book. The present volume links two major regions A debt of gratitude is expressed to the University of included in the present Oxford Monographs on Malaya for facilities to carry out m y res-earch and Geology and Geophysics Series: No. 2 Phanerozoic writing throughout the years. Contents 1. INTRODUCTION 1.1 . General 1 1.2. History of geological studies 3 1.2. 1. Thailand 3 1.2.2 . M ya nmar 4 1.2.3. Indochina (Ca mbodi a, Laos, Vietnam) 4 1.2.4. Indones ia 5 1.2.5. Philippines 5 1.2.6. Peninsu lar Mala ys ia and Singapore 5 1.2.7. Sarawak, Saba h, and Brunei 6 1.3. T he Modern Era of Geologica l Co-operati on 6 2. LATE MESOZOIC AN D CAINOZOIC TECT ONIC FEATURES 2.1. General 8 2.2. Wall ace's Line and its mea ning 8 2.3. T he Indian Ocean and margin al seas 10 2.3.1. Okinawa Trough 10 2.3.2. Western Philippine Sea Basin 10 2.3.3. Pa lau Ridge and Ay u T rough 12 2.3.4. Banda Sea 13 2.3.5. Celebes Sea Basin 13 2.3.6. Su lu Sea Basin 13 2.3.6.1. North-west Sulu Sea 13 2.3.6.2. Cagayan Ridge 14 2.3.6.3. Sulu- Zamboanga- Negros subduction system 17 2.3.6.4. Related rift events on-land Sa bah 17 2.3.7. South China Sea Basin 20 2.3.7.1. Abyssa l plain 23 2.3.7.2. M iddle Eocene - ea rl y M iddle M iocene 23 2.3.7.3. Crustal nature and thickn ess 23 2.3.7.4. Sunda Shelf 26 2.3.7.5. Contin ental slope and ri se (Da ngerous Grounds) 28 2.3.7.6. Rock formatio n identification 28 2.3.7.7. Western Dange rous Grounds 30 2.3.7.8. Sea-fl oor edifices 33 2.3.7.9. M iddle M iocene to Recent 33 2.3.7.10. Tectonic interpretati on of the M id -Miocene unconformity 34 2.3.8. Indian Ocean Basin 36 2.3.9. Anda man Sea Basin 38 2.4. T he Bengal and N icoba r Abyssal Fans 38 2.5. G ravity Measurements 42 2.6. Active Plate Margins 43 2.6.1. R yuky u island arc 43 2.6.2 . Taiwa n 46 2.6.3. Philippin e sector 47 2.6.3.1. Region between Luzon and Taiwan 47 2.6.3.2. Manil a Trench sys tem 47 2.6.3.3.