Development and controlling factors of Miocene carbonate platform in the Nam Con Son Basin, southwestern South China Sea

摘要

Miocene carbonate platforms are located on intrabasinal structural highs and along the southern margin of the Nam Con Son Basin (also referred to as the Wanan Basin by Chinese), southwestern South China Sea. These isolated platforms together cover a gross area of over 25,000 km2. We map the platforms, reconstruct their evolution, and evaluate the controls on platform growth and demise within the regional geological setting using available seismic and well data. The platforms initiated in the late Early Miocene and reached their widest extent during the Middle Miocene. The platform margins were controlled by synsedimentary faults, associated with carbonate slope failure deposits and/or reef talus. The platforms formed as isolated platform. Platform growth history involves six phases: start-up, second start-up, keep-up, exposure, renewal and drowning phases. Quantitative analysis of the basin evolution indicates that tectonism, eustasy, the supply of both terrigenous sediment and nutrients were the dominant controls on platform development and demise.