Gzhelian-Asselian Palaeoaplysina reef in atoll carbonates ofthe Akiyoshi Terrane, SW Japan: A peculiar communityin the Panthalassan reef evolution

A Palaeoaplysina reef occurs in the Gzhelian-Asselian interval of the Panthalassan atoll carbonates, Akiyoshi Terrane, SW Japan. An alga, Palaeoaplysina was paleogeographically distributed mainly along the northern margin of Pangea and is regarded as a boreal element. Its distribution extended to the tropical or subtropical area of the Panthalassa Ocean caused by global cooling during an icehouse period. The Palaeoaplysina community was succeeded by a calcisponge community in the late Early Permian. This biotic turnover almost corresponds to the climatic change from icehouse to greenhouse conditions and coincides with the timing of a superplume activity in the mid-Panthalassa Ocean.