Paleobiogeographical study on the Permian brachiopods of the Akiyoshi Terrane

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In 1994 a huge number of collected materials on the Upper Carboniferous brachiopods from the Akiyoshi Limestone as well as the Lower Permian specimens from the Taishaku Limestone were examined. Permian brachiopods from the Tsunemori Formation have been collected with the detailed field survey. For the purpose of comparing the faunal character, Permian brachiopod faunas from Oman have been examined and described.In 1995 two species of early Late Carboniferous brachiopod Weiningia have been described and their paleobiogeographical significance was also discussed. A Lingula species was discriminated and discussed from the Triassic Mine Group, distiributed in the western neighboring region of Akiyoshi. The Triassic Lingula is very significant to consider the process of the largest mass extinction occured within marine invertebrates at the end of the Permian. The Middle Permian brachiopod from the Tsunemori Formation have been discussed. The preliminary research of them has been concluded as follows : The Tsunemori brachiopod fauna is closely related with that of the late Middle to early Late Permian of the Yangtze Platform in southern China. Elements of the Tsunemori brachiopod fauna are characterized by mixture of those in the warm water region of Tethys as well as the cool water in the high latitudal regions. This means that the Akiyoshi organic reef complex on a seamount probably collapsed the northern marginal region of the Yangtze Platform at the end of the Middle Permian or the begining of the Late Permian.These preliminary results have been presented and read in the 3rd International Brachiopod Congress held at the Laurentian University, Sudbury, Canada in 1995. The collected Carboniferous brachiopods from the Akiyoshi Limestone Group and the Permian brachiopods from the Tsunemori Formation will be described as soon as possible for the purpose of making clear the geologic history of the Upper Paleozoic of South west Japan.