A Study of Devonian Reefs from Southern China

Three Devonian reefs (bioherms) from Yunnan and Guangxi, southern China, are studied in detail. Six microfacies types are differentiated. Colonial rugose corals (Columnaria, Disphyllum and Hexagonaria) at Qujing, tabulate corals (Alveolites) with massive stromatoporoids (Actinostroma and Stromatoporella) and sponges at Panxi, and massive stromatoporoids (Actinostroma, Trupetostroma and Stromatoporella) at Yangshuo belong to the most important reef builders. All the three reefs studied clearly reveal a successive evolution history. They developed on the carbonate banks, shallow carbonate platforms and platform margins in the Late Givetian and terminated in the Frasnian due to sea-level falls related to local uplifts of platforms. This coincides with a eustatic fall of relative sea level at the Frasnian/Famennian transition.