Organic petrological characteristics of Iimnic and paralic coals of Sarawak

702001-100739-537-B
Author : Wan Hasiah Abdullah
Publication : Bulletin of the Geological Society of Malaysia
Page : 65-70
Volume Number : 45
DOI : https://doi.org/10.7186/bgsm45200210

Bulletin of the Geological Society of Malaysia, Volume 45, May 2002, pp. 65 - 70

 

Organic petrological characteristics of limnic and paralic coals of Sarawak

Wan Hasiah Abdullah

Department of Geology, University of Malaya, 50603 Kuala Lumpur

 

Abstract: An organic petrological study was performed on Tertiary coals from the Merit-Pila and the Mukah-Balingian coalfields of Sarawak. The main objective of this study was to determine the petrological characteristics of these coals in relation to their environment of deposition. The coals analysed were deposited in two distinct depositional settings. The Mukah-Balingian coals were deposited under paralic conditions of a lower coastal plain setting whilst the Merit Pila coals were deposited inland under limnic condition of a lacustrine setting. Differentiation of these depositional settings are based on the presence of diagnostic macerals, such as alginite, and on cross plots of gelification index (Gl) versus tissue preservation index (TPI). While both sets of coals possess TPI values < 1, the paralic origin coals generally possess GI values > 10 whilst limnic coals possess GI values < 10.

https://doi.org/10.7186/bgsm45200210

Abstrak: Suatu kajian petrologi organik dilakukan ke atas arang batu Tertiar dari Merit-Pila dan Mukah-Balingian, Sarawak. Objektif utama kajian ini ialah untuk menentukan ciri-ciri petrologi arang batu ini yang berkaitan dengan persekitaran pengenapan mereka. Arang batu yang dikaji telah dienapkan di dalam dua persekitaran pengenapan yang berbeza. Arang batu Mukah-Balingian dienapkan di bawah keadaan paralik di kawasan dataran pantai bawah sementara arang batu Merit-Pila dienapkan di kawasan daratan pendalaman di bawah keadaan limnik persekitaran lakustrin. Perbedaan di antara persekitaran pengenapan ini adalah berdasarkan kepada kehadiran maseral-maseral diagnostic seperti alginit, dan berdasarkan plot indeks gelifikasi (Gl) lawan indeks pengawetan tisu (TPI). Sementara kedua-dua set arang batu ini mempunyai nilai TPl < 1, arang batu asalan paralik biasanya mempunyai nilai Gl > 10 sementara arang batu limnik mempunyai nilai Gl < 10.