Paleomagnetic Age-estimate of the Kamikayama and Sayama Surfaces along the Western Side of Kanto Plain, Central Japan

Abstract

The fluvial Kamikayama and Sayama surfaces with the Kamikayama and Imokubo Gravel Formations on the western side of the Kanto Plain, central Japan, underlie the air-laid 580- to 690-ka Kaisho-Kamitakara tephra (KMT). Paleomagnetic and rock-magnetic samples were taken from a flood loam facies at the uppermost strata of the Kamikayama Gravel Formation, tephric loess beds on the Kamikayama and Imokubo Gravel Formations, and the KMT. All the Kamikayama and Sayama samples hold normal paleomagnetic polarity. The magnetic carrier of primary remanence of these samples is titanomagnetite. Formation ages of the Kamikayama and Sayama surfaces are estimated to be the earliest Brunhes Chron.