Microfacies and Diagenesis of Setul Formation, Pulau Langkawi

Setul Formation is the oldest limestone dated from Ordovician to Silurian in Langkawi. It shows variation of facies from the base of the formation to the top which comprises interbedded of limestone with sandstone and siltstone. This project mainly focuses on the part of Setul Formation around Kisap area and Pulau Langgun. The purpose is to study the microfacies characteristic of the Setul Limestone and investigate the diagenetic processes and depositional environment of the limestones in Setul Formation. Sampling process has been done on six different outcrops within my study area. Extensive petrography analysis was done to evaluate the minerals, fossils, microfacies and diagenetic features. Additional analysis such as X-Ray Fluorescence (XRF), Energy Dispersive of X-Ray (EDX) and chemical staining were carried out to further support the results. From the findings, five types of microfacies have been distinguished including of dolomite, calcitic dolomite, bioclastic mudstone, bioclastic wackestone and crystalline limestone. Setul Formation limestones had mostly undergone micritization, compaction, cementation and dolomitization which took place in low energy shelf lagoon to shallow to deep burial diagenetic environment.