Sedimentary Event Recorded in Pelagic Sediments in the Circum-Pacific Mesozoic Accretionary Complexes

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1. We have made field surveys in the Inner zone of Southwest Japan (Mino, Tamba and Ultra-Tamba terranes) and in Northeast Japan (Kitakami terrane), and collected samples of event-related rocks already found and looked for the new event-related rocks. We could find event-related rocks in chert distributed in Gujo-Hachiman, and estimated it to be Permian in age on the basis of the accompanied rocks.2. We have characterized the clastic grains in event-related rocks. The methods we used include observation by microscope, chemical analysis by EPMA,and chemical mapping by XGT.We could find glauconite-like minerals in the event-related rocks in the Hisuikyo area and dolomite clasts in the Ozaki area. These findings constraint the origin of the event-related rocks.3. Mesozoic accretionary complexes similar to those in Southwest Japan widely occur in Far East Russia. We examined the event-related rocks in the Samarka terrane, Jurassic accretionary complex, in Sikhote-Alin. As the result the event-related rocks are very similar to those in the Jurassic accretionary complex in Southwest Japan in composition, age, occurrence and depositional processes.