EVOLUTIONARY MODEL AND CONTROL FACTORS OF LATE CENOZOIC CARBONATE PLATFORM IN XISHA AREA

Based on newly acquired seismic and well data, the present study demonstrates that the carbonate platforms in the Xisha area initiated on some high points of structures in Early Miocene and have remained active up to the present. In the beginning of Middle Miocene, carbonate platforms were only developed on the southwest and west slope of the Xisha Uplift and small in size. The carbonate platforms flourished around the Xisha Uplift and Guangle Uplift during Middle Miocene, and expanded to an area of about 50000 km². Carbonate platforms began to migrate to topographic highs of the Xisha Uplift after Late Miocene. Many reefs, such as patch reefs and atoll reefs grew rapidly on the edge of carbonate platforms. Nowadays, only a few atoll reefs survived by the Xuande and Yongle Atolls in the area due to sea level change and tectonic subsidence, which have been the major forces controlling the evolution of Cenozoic carbonate platforms in the Xisha area.