Evaluation on the accuracy of the degree of graphitization, and the boundary between the shuffled-cards along a route at the Sanbagawa metamorphic belt, Kanto Mountains.

Abstract

We evaluated the accuracy of the degree of graphitization on the basis of the repeated experiments on pelitic schist, and of the analysis on ten pelitic schists collected from an out crop. The experimental accuracy of the degree of graphitization is ±1 in both experiments at GD=31 and GD=26. This evaluation strongly suggests that the difference over GD=6 between closely neighboring two samples is derived from a discontinuous metamorphic condition. Based on the samplings in 20 cm and in 25 cm interval along the direction normal to the strike, we found this difference at two places, at a stream of the Sanbagawa-river and at an out crop of the Arakawa-river, Kanto Mts. Miyashiro(1994) called its geologic relation the shuffled-cards structure. In the first case, serpentinitic greenschist forms the boundary between the shuffled-cards. In the second case, the thrust plane in pelitic schists divides the shuffled-cards. However, a continuous pile also exists in the Sanbagawa metamorphic terrain such as the Kamabuse-yama boringcore of 280m depths.