Japan Trench and tectonics of the Japanese Island Arcs

Seven chronostratigraphic stages were established based on the correlation of magneto-biostratigraphic marker horizons within the Deep Sea Drilling Project and Ocean Drilling Program cores from the forearc of the Japan Trench. Because the stages are coeval with changes in the rate of sedimentation, lithofacies, magnetic intensity and composition of fossil assemblages, they probably reflect the tectonic situation in the Japan Trench forearc and also in the arc-trench system. The stages correlate to the tectonic events of the Japanese Island Arcs; for example, evolution of the Boso triple junction, initiation of Philippine Sea Plate subduction and the Japan Sea opening.