The Preliminary Study of Late Oligocene to Early Miocene Calcareous Nannofossil in Klias Peninsula, Sabah

Abstract

Klias Peninsula comprises of five different lithostratigraphic units which are, Temburong, West Crocker, Setap Shale, Belait, and Liang formations. The study area is one of the onshore outcrops of the western side of Sabah mainland which contributed to the high potential of hydrogen exploration within the Temburong Formation. There is still a lack of calcareous nannofossils study in terms of academic purposes, hence a systematic preliminary research study had been conducted to find the taxonomic diversity of the calcareous nannofossils within the age of late Oligocene to early Miocene. This study aims to identify the taxonomy classification of the calcareous nannofossil based on the morphology features. Coccosphere has been distinguished by two different taxonomic classifications of coccoliths and nannoliths. Coccoliths are the most discussed for their morphology and classified into two basic mode holococcoliths and heterococcoliths. Nannolith morphology feature is complex and classified as a heterogeneous group. Thirty-four samples from Kuala Penyu to Menumbok areas of Sabah were collected. A simple smear method used to prepare all the samples. Light microscope (LM) observations used to identify the taxonomy and calcareous nannofossil classification aided by plane-polarized (PPL) and cross-polarized (XPL) nicols with 800x magnification. Apart from that, there were diverse taxa that had been discovered such as, Braararudosphaera bigelowii, Discoaster deflandrei, Cyclicargolithus abisectus, Cyclicargolithus bukryi, Coccolithus pelagicus, Thoracosphaera saxea, Alisphaera sp. and Reticulofenestra bisecta.