茨木花崗岩体の古地磁気

その他

The Ibaragi granitic complex is devided into two units of the Nose and Myoken plutons. The directions of remanent vector at each sampling site are well grouped and fall into two groups. The normal remanent vectors of the Nose pluton are almost northeasterly and the reversed ones are southwesterly. It is expected that some of these intermediate directions of magnetization was acquired at the time of a field transition. All samples from the Myoken pluton are normally magnetized and the directions of remanent vector are slightly northeasterly. A significant difference in direction of remanent vector between the Nose and Myoken plutons was found. This suggests that the directions of remanent vector have been affected by some tectonic movement after the intrusion of the plutons. Although there are a few restoring methods to find an original position of the plutons, we concluded that the Ibaragi complex has been tilted by a rotation about an axis in a tilted plane of about 15 ゜upward from the horizontal plane.