丹沢トーナル岩複合岩体の残留磁化

The main part of the tonalite complex are mostly reversely magnetized and normally magnetized in part. It is therefore concluded that the complex encountered with a polarity transition of the geomagnetic field during a cooling process after the intrusion. However, paleomagnetic results from the complex did not provide a continuous record of the field reversal. Only part of transitional pole positions is obtained from the data. The positions of virtual north pole fall in a region between Africa and the Antarctic Continent such as those from the Japanese rocks of various types and ages. The timing of intrusions of each rock body was also estimated by examining directions of the remanent magnetization from the intrusive rocks measured.