Late Eocene shoreline volcanism along the continental margin:the volcanic succession at Kabuki Iwa, Oga Peninsula, NE Japan

Abstract

    Kabuki Iwa (Rock) at the northwestern shore of Oga Peninsula is composed of Late Eocene basaltic andesite aa lava flows and pillowed lava flows, dacitic pyroclastic flows, debris flows and other epiclastic rocks. This close association of the subaerial and subaqueous volcanic products demonstrates a transitional environment between land and shallow water. NE-SW-trending parallel dikes and normal faults are also associated with these rocks in the surrounding areas, and the volcanic succession at Kabuki Iwa is interpreted to have accumulated in an extensional basin which slowly subsided with volcanism before the rapid opening of the Japan Sea.