Seismic responses and distribution characteristics of the Miocene carbonate platforms in the Beikang Basin of southern South China Sea

Seismic reflection characteristics, as well as the distribution pattern and evolution history of the carbonate platforms in the Beikang Basin are systematically studied in this paper, based on the high resolution 2D seismic data acquired so far. The study filled the gap in the research of carbonate platforms in the Beikang Basin, having great significance for revealing the evolutionary history of carbonate platforms and prediction of carbonate reservoirs. The carbonate platforms in the Beikang Basin started from Early Miocene, extended in Middle Miocene, and declined and drowned in Late Miocene. The Miocene carbonate platforms are mostly isolated by faults on the edge of platforms. In seismic sections, the top of the carbonate platform always has two parallel or sub-parallel strong reflection axes and the inside is characterized by blank and disordered reflection or sub-parallel weak reflection axes sometimes.While the bottom of the platform is a smooth parallel or sub-parallel weak reflection axes. The Miocene carbonate platforms in the Beikang Basin can be subdivided into three stages.The platforms in the first stage were wide laterally, but thin in thickness. In the second stage, the platforms were controlled by faults obviously with smaller lateral extension. In the third stage, however, the platforms were submerged gradually and disappeared finally. The Miocene carbonate platforms were mainly north-east and north-west in direction, similar to the platforms in other basins adjacent and present platforms in the South China Sea. The distribution of these carbonate platforms are possibly controlled by structural highs and faults.