BIOMARKERS AS PALAEOENVIRONMENT AND THERMAL MATURITY INDICATORS OF THE SANDAKAN FORMATION (LATE MIOCENE) EAST SABAH, MALAYSIA

Authors

  • Tarek Abubaker Department of Geology, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
  • Wan Hasiah Abdullah Department of Geology, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
  • Abdul Hadi Abd. Rahman Geophysics Group, School of Physics, University of Science Malaysia, 11800 USM Penang, Malaysia

Keywords:

Biomarkers, Sandakan Formation, depositional conditions, thermal maturity, vitrinite reflectance (%Ro)

Abstract

This paper discusses biomarker distributions and their application as thermal maturity and palaeoenvironmental indicators for the Late Miocene Sandakan Formation. Parameters such as CPI (carbon preference index) and transformation of $C_3_1$ and/or $C_3_2$ 22S/ (22S+22R) hopane ratios, suggest that the samples analysed are thermally immature for oil generation. Very low ratios of $C_3_1$ and/or $C_3_2$ 22S/ (22S+22R) hopanes and very high CPI values are typical of low maturity. Vitrinite reflectance (%$R_0$) supports the low thermal maturity and an absence offeatures indicative of hydrocarbon generation. The dominance of n-$C_3_1$ over n-$C_1_7_$ alkanes, $C_2_9$ over $C_3_0$ hopane and oleanane over $C_3_0$ hopane suggest a high input of terrestrially-derived organic matter. The wide spread in parameters such as pristane/n-$C_1_7$ phytane/n-$C_1_8$, and Pristane/ Phytane ratios may, however, reflect variation in depositional conditions and/or source input within the Sandakan Formation. These samples appear to have been deposited in varying depositional conditions of oxic to sub-oxic to reducing conditions of deposition; of peat-swamp environments to alternating brackish swamps to more open-water conditions. A low relative abundance of tricyclic terpanes suggests only slight marine influence in the depositional setting, with perhaps slightly saline conditions based on minor occurrence of $C_2_4$ tetracyclics and $C_2_3$ tricyclics.

Downloads

Download data is not yet available.

Downloads

Published

26-08-2004

How to Cite

Abubaker, T., Hasiah Abdullah, W., & Abd. Rahman, A. H. (2004). BIOMARKERS AS PALAEOENVIRONMENT AND THERMAL MATURITY INDICATORS OF THE SANDAKAN FORMATION (LATE MIOCENE) EAST SABAH, MALAYSIA. Malaysian Journal of Science (MJS), 23(2), 165–174. Retrieved from https://jml.um.edu.my/index.php/MJS/article/view/8456

Issue

Section

Original Articles