ABSTRACT: Evolution and controls on isolated Cenozoic carbonate platforms in SE Asia

Wilson, Moyra E. J. , Dept. of Geological Sciences, Durham University, Durham, United Kingdom

Extensive carbonate platforms formed during the Cenozoic as isolated platforms or land attached shelves on microcontinental blocks or basins margins throughout SE Asia. This study evaluates platform evolution and controls on development and diagenesis of a number of Cenozoic carbonate platforms around the Makassar Straits in Central Indonesia. These deposits provide a good analogue for evaluating similar subsurface platforms in SE Asia, comprising major hydrocarbon targets, but for which there is often little data.

The location and initiation of all the Cenozoic platforms studied in western Sulawesi and eastern Borneo was controlled by pre-existing structures and basement highs. In Sulawesi an Eocene to middle Miocene isolated carbonate platform developed on a faulted high just 60 km to the west of a volcanic arc. In Borneo, Eocene to early Miocene, and Oligo-Miocene carbonate platforms formed on faulted highs away from major clastic input at the western margin of the extensional Makassar Straits. In all examples tectonic subsidence controlled accommodation space for the platforms. Faulting variously resulted in segmentation of the platforms, localised drowning and uplift, tilting and subaerial exposure of carbonates in basinal grabens and footwall highs respectively. Facies distribution and types of lithologies were controlled by water depth, variations in biota and depositional energy. Diagenetic features were often facies specific, and porosity occluding and enhancing processes related to marine, meteoric and burial processes were active on many of the platforms.

AAPG Search and Discovery Article #90913©2000 AAPG International Conference and Exhibition, Bali, Indonesia