Department of Geography, Tokyo Metropolitan University
Abstract
Three widespread Early Pleistocene tephras were identified in a sediment core drilled at Fuchu in the central part of the Musashino Uplands of the West Kanto Plain, the central Japanese Islands. Characteristic properties such as geochemical composition and refractive indices of glass shards correlate these unknown tephras to three well-characterized tephras formed by calderaforming eruptions. Ebs-Fkd (1.70 Ma), Nyg (1.75 Ma) and Sgn-Kd44 (2.0-1.8 Ma) tephras, all inthe Kazusa Group, early Quaternary strata, are compared to Fuchu core samples and other boring cores from the Musashino Uplands area. Changes in altitudes of those tephras found in other cores under the upland reveal changes to the Kazusa Group’s sedimentary environment and landform at the time of the tephra’s deposition