Magnetostratigraphic Study for Quaternary in Japan

By the paleomagnetic measurements on sediments of both on land and lake bottom, it is obtained vary detailed magnetostratigraphic sections of the middle and late Pleistocene. Especially, the studies carried out in the northern part of the Miyagi Prefecture where many stone implements of the early paleolithic age were excavated gave an almost complete magnetostratigraphic sequence of the Brunhes Normal Polarity Epoch. Ten big geomagnetic fluctuations such as reversals and excursions are found in the sequence. Brunhes/Matuyama Boundfary is also found in the lowermost horizon of the sequence. This result revealed that the history of the human beings who dwelled and made stone implements in the Japanese Islands, trace back to 60 ka at the oldest. And also it will highly contribute on the magnetostratigraphic age dating in the Brunhes Normal Polarity Epoch.