Abstract: Integrated Biostratigraphic Zonation for the Malay Basin

Azmi Mohd Yakzan, Bahari Md. Nasib, Awalludin Harun, Robert J. Morley

This study presents a detailed biostratigraphic scheme for the Malay Basin based on the examination of 10 wells by PRSS, and the review of data from 12 wells, which were previously studied by service companies. For each of the wells reviewed, foraminiferal, nannofossil, and quantitative palynological data were available. This paper demonstrates that through the integration of data from all three biostratigraphic disciplines and through taking careful accounts of lithologies, it is possible to make accurate correlations within the Malay Basin, which would not be possible using data from a single discipline.

Stratigraphic relationships within upper Oligocene fluvial and lacustrine sediments are best determined from their rich miospore and freshwater algal content. Miospores are also of importance for correlation in the paralic lower Miocene, but in

addition, marine flooding surfaces may be characterized by benthic foraminifera, which although not age diagnostic, may permit accurate correlations. These marine pulses sometimes contain age-diagnostic nannofossils, which permit palynological and foraminiferal events to be dated.

The lower/middle Miocene boundary is represented by a marine transgressive unit, which can be dated by nannofossils; benthic foraminiferal and palynological events again provide a basis for detailed correlations.

The remainder of the middle Miocene, and most of the upper Miocene, consists of paralic sediments for which correlations can be achieved using benthic foraminifera and miospores. Again age-diagnostic nannofossils may be associated with marine flooding surfaces.

The upper part of the upper Miocene and the Pliocene-Pleistocene is marine and readily dated using planktonic foraminifera and nannofossils.

AAPG Search and Discovery Article #90982©1994 AAPG International Conference and Exhibition, Kuala Lumpur, Malaysia, August 21-24, 1994