Evolution of the Permian and Triassic reef ecosystems in South China

This paper reviews the spatio-temporal distributions of Permian-Triassic reefs of South China. We have recognised two Permian reef-building cycles, corresponding respectively to the Maokouan and the Changhsingian. Both cycles went through a similar process of settlement-diversification-destruction. In comparison, the Changhsingian reef ecosystems appear to have evolved faster and reached a wider palaeogeographical distribution than the Maokouan reef ecosystems. The onset of the two Permian reef-building cycles appears comparable respectively with, and thus presumably related to, the end-Maokouan and end-Changhsingian mass extinctions. The Early Triassic is an epoch of eclipse in reef construction, interpreted to be a direct consequence of the end-Permian mass extinction which may have eliminated all of the major extant Permian reef-building organisms. However, algae as the reef binders seem to have survived the extinction crisis and persisted well into the Triassic. Succeeding the Permian-Triassic extinction events, reef ecosystems did not return to South China until the Middle Triassic when binding organisms such as algae played a major role in reef building rather than frame-builders.