いわゆる物見山層の礫組成と現河床礫との比較研究 : 物見山礫層の起源について

We measured magnetic susceptibility on matrix of gravels obtained from the Hanno formation, the Monomiyama conglomerate and the recent fluvial deposits around studied area for study on correlation and on origin of sediment of these formations. The Hanno formation and the Monomiyama formation are fluvial sediments distributed discontinuously along the eastern edge of the Kanto Mountains, northwest of Tokyo, Japan. The age of these sediments are considered as Plio-Pleistocene. In addition, these sediments became decayed gravel bed. Horiguchi et al. (1987) considered that the sediments of these formations were the same age and the same origin, which were fluvial deposits of the ancient Arakawa River. However, gravel compositions of two formations are very different. Component of gravels of the Monomiyama formation is almost chert. On the other hand, that of the Hanno formation is variable, such as chert, sandstone, mudstone, schist, green rock and diorite. Magnetic susceptibility of matrix of gravels obtained from two formations is similar to each other. According to the study of magnetic susceptibility, sediments of the Hanno formation and the Monomiyama formation are concluded to be same origin. They are fluvial deposits of the ancient Arakawa River. Difference between compositions of these gravels, are cause of weathering. The Monomiyama formation is more weathered than the Hanno formation, so, many gravels of the Monomiyama formation except chert gravels, assimilate into matrix.

大東文化大学紀要. 自然科学

AA1256185X

09122346

45

17

27

2007-03-31

日本語

紀要論文

紀要論文

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