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ABSTRACT: Origin of Izu-Bonin Forearc Submarine Canyons

Kantaro Fujioka, Haruko Yoshida

Submarine canyons on the Izu-Bonin forearc are morphologically divided from north to south into four types based on their morphology, long profiles, and seismic profiles: Mikura, Aogashima, Sofu, and Chichijima types, respectively. These types of canyons are genetically different from each other. Mikura group is formed by the faults related to bending of the subducting Philippine Sea Plate. Aogashima type genetically relates to the activity of large submarine calderas that supply large amounts of volcaniclastic material to the consequent forearc slope. The third, Sofu group, is thought to be formed by the large-scale mega mass wasting in relation to the recent movement of the Sofugan tectonic line. The last, Chichijima group, is formed by collision of the Uyeda Ridge and he Ogasawara Plateau on the subducting Pacific Plate with Bonin Arc. Long profiles of four types of submarine canyons also support this.

AAPG Search and Discovery Article #90097©1990 Fifth Circum-Pacific Energy and Mineral Resources Conference, Honolulu, Hawaii, July 29-August 3, 1990