Cover photograph by Patrick Gou, currently with Shell Sarawak. 'Angular unconformity separating the underlying Beloit Formation fram the younger sediments/soil horizon above it. Note the pebbles on the unconformity surface. SMK Kubong, Limbang Sara wok. " This photograph was awarded the Grand Prize in the 2004 GSM Photo Competition
Geological Society of Malaysia Council 2005/2006 President Vice President Secretary Assistant Secretary Treasurer Editor Immediate Past President Councill ors Yunus Abdul Razak Abdul Rasid Jaapar Askmy Abd. Kadir Ahmad Nizam Hasan Liew Kit Kong Mohd. Shafeea Leman Samsuddin Taib Tan Boon Kong Mohd. Rozi Umor Juhari Mat Akhjr Lau Yin Leong Safarudin Mat Tahir PERSIDANGAN TAHUNAN 2005 Annual Conference 2005 Organizing Committee Askury b. Abd. Kadir (Chairman) Ismail b. Ahmad Rosni bt. Lokmannul Hakim Anna Lee Haniza bt. Zakri Mohd. Noor A izad Morad Asminah bt. Rajuli Editorial Committee K.K. Liew John Kuna Raj Zainol Abidin Sulaiman Robert Tate Tajul Anuar Jamaluddin Che Noorli za Lat Ismail Yu soff l amaluddin Othman Samsudin Hj. Taib Mustafa Kamal Shuib Askury Abd, Kadir (Chairman) Reviewers Chow Weng Sum Tee Ai Teng Kamaluddin Hassan H.D. Tjia Ng Tham Fatt Mazlan Madon Wan Hasiah Abdullah Abd. Hadi Abd. Rahman Wan Fuad Wan Hassan T.F. Ng Tan Boon Kong S. Paramananthan Ibrahim Komoo Joy J. Pereira Yunus Abd. Razak Ahmad T~uddin Hj. Ibrahim Azman Abd. Ghani Charles S. Hutchison
GEOLOGICAL SOCIETY OF MALAYSIA Cover photograph by Patrick Gou, currently with Shell Sarawak. "Angular unconformity separating the underlying Belait Formation from the younger sediments/soil horizon above it. Note the pebbles on the unconformity surface. SMK Kubong, Limbang Sarawak. " This photograph was awarded the Grand Prize in the 2004 GSM Photo Competition Bulletin of the Geological Society of Malaysia
Copyright Geological Society of Malaysia, 2005 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, without prior permission in writing from the Geological Society of Malaysia. Published in June 2005 by the Geological Society of Malaysia c/o Depart of Geology, University of Malaya, 50603 Kuala Lumpur, Malaysia Tel: 6-03-79577036 (voice) 6-03-79563900 (fax) Email: geologi@po.jaring.my Printed by Art Printing Works Sdn. Bhd. 29 Jalan Riong, 59100 Kuala Lumpur Malaysia ii
PREFACE This is the 51 51 volume of the Geological Society of Malaysia bulletin, printed in conjunction with the 19 th Annual Geological Conference, to be held in Seremban, on the 4th and 5 th of June. Inside this volume you will find 23 papers, which were the papers we managed to get reviewed and corrected in time for the printer's deadline, which was the 16 th of May. Papers that are still in the process of being reviewed and corrected will be published in a subsequent volume. You will notice that some of the diagrams and maps in this volume are sub-optimal in terms of readability. We apologize for this. Two years ago, the Society decided that the Bulletin was to be published in black and white, since the previous policy of printing in color was proving to be very expensive. Unfortunately, a lot of the diagrams and illustrations are still being submitted in color. When converted to greyscale, it becomes difficult to differentiate between different shades of grey. The other problem we encountered was a number of low resolution scans and photographs. For printing, photos and scans should be a true 300 d.p.i. or better at the size it is to be printed. Pictures that look O.K. on the screen may be of too Iowa resolution to print. Given the short deadlines, there was no time to send the articles back to the authors for redrafting. We shall be making changes to prevent this problem from recurring. We shall be soliciting papers much earlier than was the case in the past. A call for papers for next year's June issue will go out soon after the Conference. We will adhere strictly to deadlines - papers received after the submission deadline (probably February 28 th ) will not be published in that issue. Papers that contain artwork that does not conform to the stated guidelines will immediately be returned to the authors for redrafting. Hopefully, these steps will help make a better, more readable Bulletin. We will print an article in an upcoming Warta on this subject, complete with examples of acceptable and unacceptable diagrams. On the brighter side, we were, for the first time, able to make use of computer networks to put a volume together. The files were kept on a central file server (with frequent backup). This allowed several people to work on the files simultaneously. The final files were transferred to the printers using the Web, which made frequent trips there unnecessary. We wish to thank the authors, and all who have made this issue of the Bulletin possible. The Geology Department at UM allowed us the use of their computer equipment and network. The list of reviewers is quite long, several of them reviewed a great many papers. The folks at Art Printing Works have been a great help, especially Mr. Choo Tik Ho. And special thanks go to Mrs. Anna Lee, who kept everything organized and in order; and Mohd. Aizad Morad, who spent many hours formatting the articles. Chairman Editorial Committee GSM Bulletin vol. 51 iii