Biostratigraphy of conodonts and foraminifers across the boundary between permian and Triassic Systems in calcareous facies.

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Recent study of the boundary problem of the Permian and Triassic-Systems in Japan has been initiated in strata which were deposited in the off-shore pelagic to semipelagic environments. The study in calcareous facies, however, was remained the result of investigations until 1960's and insufficient compared with the research in foreign countries. The present study was planed and conducted to obtain more advanced knowledge concerning the boundary problems between permian and Triassic Systems.We tried to establish the complete sections in calcareous facies including the P/T boundary in the following areas such as Kamura, Takachiho of Miyazaki Prefecture ; Taho Limestone, Shikoku ; Akasaka Limestone, Ogaki of Gifu Prefecture ; Gozen-yama Limestone, Okutama of Tokyo ; Kuzu Limestone, Aso county of Tochigi Prefecture ; Kamiiso Limestone, Hakodate of Hamatonbetsu of Hokkaido ; and Menashidomari near Hokkaido. In these sections, we establish hiostratigraphy of microfossils (mainly smaller foraminifers, fusulinacean foraminifers, conodonts, calcareous algae, and others) and analyzed vertical change of microfacies of carbonate rocks. As a result, we confirmed the intercalation of dolomitized facies and carbonaceous limestone in strata contain the P/T boundary.This stratigraphic and sedimentological evidence shows that the world-wide geochemical change of the sea water related with eustatic regression occurred at the boundary.