Microfacies and diagenesis in the Setul Limestone in Langkawi and Perlis

Abstract

The Setul limestone outcrops in Langkawi and Perlis show a variety of facies consisting of thickly bedded mudstone, wackestone, packstone, grainstone and dolomitic limestone. Seven microfacies have been recognized comprising of dolomicritic mudstone, bioclastic wackestone, peloidal wackestone, intraclastic wackestone, pelloidal packstone, pelloidal grainstone and dolomitic limestone. The presence of bioclasts such as brachiopods, trilobites, ostracods, bivalves, crinoids and the microfacies spectrum reflect that the sediments were deposited in broad environments ranging from tidal flats to lagoon and shallow subtidal of a carbonate ramp. The diagenetic processes that have taken place include cementation, dolomitization, stylolitization, neomorphism, dissolution, compaction and micritization. Petrographic studies show that diagenesis took place in wide digenetic environments including freshwater phreatic zone, marine phreatic zone, mixing zone and deep burial zone.