Sedimentological Study of a Turbidite Cycle, Kii Peninsula, Japan

Abstract

A typical turbidite cycle from rocks of the middle Miocene Kumano Group of the southeastern Kii Peninsula, Japan was studied to determine in particular distinguishing features of the pelite interval. Grain-size and mineralogical composition data are inconclusive in distinguishing the turbidite E-division from the inter-turbidite F-division. However, fabric information revealed by scanning electron microscope study, varies for the two divisions. The sandstone and turbiditic siltstone have random clay flake orientation (suggestive of rapid deposition of flocculated sediments), while preferred orientation exists in the interturbidite unit. The latter fabric may have been produced by deposition of the clay in the dispersed state.