中期中新世における南部フォッサマグナ北西部櫛形山ブロックの衝突  [in Japanese] Collision of the Kushigatayama block during the Middle Miocene, northwestern part of South Fossa-Magna, central Japan  [in Japanese]

This paper represents collision tectonics of South Fossa Magna, central Japan during the Middle Miocene. The Kushigatayama block, which is a member of the paleo-Izu-Bonin arc, is mainly composed of pyroclastic rocks and lavas named the Kushigatayama Subgroup. Paleo-trench was situated between the Honshu arc and the Kushigatayama block. This trench was filled up with hemipelagic sediments and turbidites (Momonoki Subgroup). The Kushigatayama block is situated near the Honshu arc about 16-15 Ma. The block collided with the Honshu arc owing to the northward moving of the Izu-Bonin arc and the opening of the Sea of Japan about 15 Ma. Severe contractive deformation was occurred with in the Momonoki Subgroup. The bend of the pre-Middle Miocene terrane of the Honshu arc can be assumed to be formed by this collision.