Spatial Distribution of Sedimentary Facies on Modern Carbonate Platforms Interpreted via Remote Sensing, Northwest Celebes Sea, Malaysia

Abstract

Remote-sensing analysis of high-resolution satellite imagery of modern carbonate platforms in the Celebes Sea, east of Sabah, Borneo, Malaysia, was used to map geomorphology and sediment. Unsupervised classification of satellite images was interpreted in the context of environmental facies of seven isolated carbonate platforms and calibrated using analyses of surface sediments. In total, 140 sediment samples were collected and analyzed for grain-size and sorting. The grain-size analysis showed that sediment varied among the geomorphic elements, which included island, island/volcano, reef complex, carbonate sand shoal, grass-covered sand shoal, shallow lagoon, and deep lagoon. To generate carbonate sediment texture maps, the proportion of mud and the grain-size attributes (mean grain size and sorting) of each sediment sample provided a basis to classify samples into rock-equivalent textures. Integration of remote-sensing, field, and sedimentological data provided a means to characterize texture distribution maps and depositional facies maps. These maps suggest that mudstone to wackestone occurs mainly in the deep lagoon; wackestone to packstone is dominant in the shallow lagoon; the carbonate sand shoal is characterized by packstone to grainstone; and the reef complex is made up of boundstone to rudstone. These results facilitate estimates of the proportions of potential reservoirs on these platforms and the heterogeneity in facies distribution, based on the size of various recent carbonate platforms. Diagenesis notwithstanding, ancient analogs indicate the Selakan and Maiga platforms could be potential reservoirs, whereas the Selakan and Gaya platforms display more facies classes and represent poor potential reservoirs.