Global reef recovery after the end-Ordovician extinction: evidence from late Aeronian coral-stromatoporoid reefs in South China

摘要

After the end-Ordovician mass extinction, reef recovery (size and biotic diversity) took several million years. On the Upper Yangtze Platform, South China Block, the initial reef reconstruction episode is recorded in limestone of middle Aeronian age in northern Guizhou Province. By late Aeronian, reefs were widespread on the Yangtze carbonate platform, today represented by patch reefs cropping out in a 10-km~2 large area near Shuibatang, Tongzi County, where two stratigraphic intervals with reefs are recognized. Late Aeronian reefs constitute a complex and diverse reef community dominated by corals, and to a lesser extent stromatoporoids. They contain an accessory fauna of abundant bryozoans and crinoids and some brachiopods, trilobites, molluscs and calcimicrobes. These reefs correlate in time with similar reefs in Anticosti, Laurentia, palaeogeographically very distant from South China. Thus, there is good evidence that recovery and geographic expansion of reefs after the end-Ordovician extinction occur simultaneously in at least two continents.