Correlation of Middle Pleistocene tephra between Sempoku Area, Northeast Japan and 1151C core drilled by ODP off Sanriku Coast and its application for geomorphic chronology

Abstract

This study showed correlation of Middle Pleistocene tephra between Sempoku Area, Northeast Japan and 1151C core drilled off Sanriku Coast. We recognized volcanic sand in the top of terrace deposit distributed in Sendai City and in sample No.2 of 1151C core. The volcanic sand in Sendai is correlated with Kozo Tephra (Kzo) (near 8/7 boundary of marine isotope stage (MIS)). 1151C-No.2 sample contains Kzo and Ata-Torihama Tephra (Ata-Th) (near 8/7 boundary of MIS). These correlations improve chronology of geomorphic evolution, such as Aobayama Ⅰ Surface formed in MIS 9-8.5 and Mt. Aoso erupted before MIS 11.