Paleoecological associations of middle Llandovery (Silurian) corals from Huaying Mountain, eastern Sichuan Province

Abstract

Corals are comparatively abundant in the upper member of the Baiyun’an Formation (upper Aeronian to lowerest Telychian, Llandovery, Silurian) of Huaying, eastern Sichuan Province, Southwest China. Three coral associations have been recognized, i.e., in ascending order, the Mesofavosites Association, the Dentilasma Association, and the Paraceriaster Association. The Mesofavosites Association occurs at horizons indicating a shallow and high-energy environment. It is dominated by large favositids accompanied by a few broken pieces of halysitids and small solitary rugose corals. The Dentilasma Association has a pretty high coral diversity, dominated by the solitary rugose coral Dentilasma meitanense, together with some subordinative heliolitids and favositids. The sedimentary evidence shows that this association might live in a quiet and nutritive shallow water environment. The Paraceriaster Association yields in the grayish green calcareous mudstone indicating a comparatively deep water environment. Systematically it contains abundant fasciculate Paraceriaster micropora and a few favositids. The distinction among these three coral associations shows that corals could adopt different adaptive strategies under different environments, which provide some new data for the investigation on the ecology of Silurian corals and further study on the “Lower Red Beds”.