Calcareous nannofossil biostratigraphy of the Temburong Formation in Batu Luang, Klias Peninsular, Sabah.

Calcareous nannofossils were used as the key components for biostratigraphy indicators integral for age control in either academic settings or the petroleum industry. However, the age of the Batu Luang sediments has still been debated and revised continuously, especially for the Temburong Formation. Previously, calcareous nannofossil has not been used as a tool to indicate the accurate stratigraphic age determination and paleo- environment of the research area specifically for academic purposes. Therefore, the research thesis is aimed to identify the assemblages of the calcareous nannofossil species in the lithostratigraphy sequences. Also, a thorough systematic identification of taxonomy and the classification of the calcareous nannofossils has been done to understand their abundance. Then, their assemblages were used for biozonation identification and paleo-environment analysis. The study area was in the southwestern part of the Sabah, at the shoreline of Batu Luang, Klias Peninsula. All 28 samples were collected and analysed quantitatively across to three different facies, resulting in the determination of the distribution on biostratigraphy resolution. SHE analysis, Diversity Indices Graph, H index and Principal Component Analysis (PCA) were used to examine the biozonation identification and paleoenvironmental gradients. The methods used were the most influenced by the distribution of species and their abundances. Plus, the H index analysis was used to recognise the biomarkers index and correlate them with the previous biostratigraphy schemes. As many as 73 species have been identified, and seven of them were used as the biomarkers index for Temburong Formation sediments. This study research has distinguished into three different intervals of Paleogene/Neogene age which are Late Oligocene to Early Miocene (NP24, NP25 and NN1-NN4). This research has shown that the study area was observed as the lower shoreface environment due to warm-water taxa (K mode species) abundances. There was diverse paleo-productivity with high constituents of nutrients consumed by the light exposure and less contribution of cold-water taxa (Coccolithus pelagicus) in the formations. Besides, the Shanon Diversity and the abundance per cent of the taxa correlate significantly to PCA2, suggesting that the r-K specialist classification was an important secondary controlling factor during the Late Oligocene. The correlation between the coefficient of PC1 and PC2 resulting Sphenolithus belemnos, Sphenolithus conicus, Furcatolithus ciperoensis and Furcatolithus distentus covered the K mode taxa (warm-water), while Cyclicargolithus abisectus and Triquetrorhabdulus carinatus covered the r mode taxa (cold-water).