Sedimentological Study of the Okazaki Group on Mt. Ushinori in the Southern Part of Okazaki City, Central Japan: Clast Fabric Measurements

摘要

We present a sedimentological study of the lowermost conglomerate beds of the Okazaki Group, cropping out on the summit of Mt. Ushinori (Ushinori-yama) located in the southern part of Okazaki City, Aichi Prefecture. Our purpose in this study was to infer the depositional condition and paleogeography of the study area from analysis of the preferred orientation and imbrication of clasts in the conglomerate beds, but it has not yet been achieved. The studied conglomerate section is about 5 m thick, shows an upward-fining trend, and contains trace fossils of Ophiomorpha isp. In the upper part of the section, we found preferred orientations of granules and pebbles that are similar to each other at six stratigraphic sites, and also an ESE-dipping imbrication at one site. We also present clast fabric measurements from modern foreshore and fluvial lateral bar deposits.