A clockwise-deflected paleomagnetic direction of a Paleogene formation in the Aizu district, Fukushima Prefecture, Northeast Japan

摘要

Paleomagnetic results from a Middle Eocene felsic pyroclastic formation in the Aizu district, Fukushima Prefecture suggest a clockwise block rotation. By means of stepwise thermal demagnetization and principal component analysis, site-mean directions of high-temperature magnetization components were determined at four sites, yielding an overall mean direction of normal polarity characterized by a clockwise-deflected declination (67.9°). Comparison of the direction with that of a Paleogene formation in the Oga Peninsula indicates that the clockwise rotation reaches ～100°.