Characteristics of Coral Stratigraphic Reef of Lower Devonian Yujiang Formation in the Menggong, Guigang, Guangxi
摘要
The coral stratigraphic reef of Yujiang Formation in the Menggong, Guigang is a typical case of stratigraphic reef which existed in Tangding stage, Early Devonian. After the field measuring of columnar section, detailed indoor study of thin sections and geochemical analysis of trace elements, it is recognized that there has developed a large-scaled-reef complex composed of repeatedly appearing stratigraphic reef horizons vertically in the direction. The main reef-building organisms are Favosites and Xystriphylloides in the content of 70%~80% in the reef. The main reef-dwelling organisms are individual corals, brachiopods and gastropods. The growth and development of the reef appears to be in a positive correlation with the shifting of carbon and oxygen isotopes. Mudstones of the hybrid shelf deposits below the reef are of good hydrocarbon source rocks, which caused later charge of hydrocarbon in fissures of contemporaneous sandstones.