Benthic fossil assemblages and depositional facies of the Middle Triassic (Anisian) Yuqing Member of the Qingyan Formation, southern China

Abstract

The Middle Triassic (Anisian) Yuqing Member of the Qingyan Formation crops out in Guizhou Province, southwestern China, and consists of storm-dominated inner and outer shelf deposits. It contains Tethyan benthic fossils that are grouped into two fossil assemblages. The allochthonous Mentzelia multi-costata-Mentzelia mentzeli assemblage is characterized by brachiopods in the inner shelf facies. The par-autochthonous and allochthonous Posidonia wengensis assemblages, composed mainly of epifaunal bivalves, dominate in the inner and outer shelf facies, although some species of Posidonia generally are characteristic of deep-sea environments or low-oxygen conditions. © by the Palaeontological Society of Japan.