Abstract

Devonian rocks in South China are characterized by widespread shallow platform carbonate facies (Xiangzhou facies) and pelagic facies (Nandan facies) deposited in a submarine trough system originated by synsedimentary faults and modified by current circulation. Reef development and distribution were mainly controlled by current circulation and configuration of the platform. Reef development began in the Shipaian (Emsian) and continued until the Upper Devonian (Xikwangshanian or Famennian). Two major phases of reef development and one phase of renalcid micrite mound development are recognized, each starting in a shallow, clear water condition which occurred during a tectonically calm period and ending with a rapid terrigenous supply caused by revival of tectonic movements which coincided with regional transgression or regression. The regional paleogeographic setting and evolution are described for each of the intervals in terms of sedimentation, location of the shoreline, platform edges and pattern of the trough system. Sites of reef growth were initially controlled by paleogeographic setting, bathymetry, pre-existing topographic features and currents circulating along the trough system. According to whether they were on a shallow stable platform, along a platform margin, on a relatively deeper platform, on a ramp or in a shallow submarine trough there are four main depositional environments in which biostromes, platform margin reefs, patch reefs, bioherm complexes and micrite mounds were developed. The sites of potential reef development in the subsurface are also discussed.