Tectonics of the Miocene volcanism in E Hokkaido

认为北海道东部中新世火成岩带向下延伸至日本西南外缘。DSDP 438孔和439孔22马英质火山砾岩等火成岩可能是连接两个中新世火成岩带的热源。中新世NE火山带则穿过大岛半岛，直达日本海。中中新世至上新世火成岩带沿日本列岛由内（弧后）侧向外（海沟）侧呈带状排列：弧、单源和弧前火山带。这一时期的海沟位于距弧前火山带不到100公里的地方。

It is proposed that the Miocene igneous belts in eastern Hokkaido extends down to the outer zone of Southwest Japan. Igneous rocks, such as 22 Ma-dacitic volcanic conglomerate in Holes 438 and 439, DSDP,and as a heat source for Jyouban hot spring, may connect both Miocene igneous belts. On the contrary the Miocene NE volcanic belt passes through the Oshima Peninsula and attains to the Sea of Japan. There was the zonal arrangement of middle Miocene to Pliocene igneous belts along the Japanese islands from the inner (back-arc) side to outer (trench) one : the arc, monogenic and forearc volcanic belts. The trench during this period was located less than about 100 km far from the forearc volcanic belt.