京都, 深草地域に分布する大阪層群の堆積相

抄録

The Plio-Pleistocene Osaka Group distributed in Fukakusa, at the eastern part of the Kyoto basin, can be divide into four depositional facies. They are (1) fluvial channel gravelly sand with tabular and trough cross-stratifications, (2) inter-channel or abandoned channel sand and mud with inverse grading and rootlets, (3) massive gravel and ill-sorted gravelly mud of debris flow origin, and (4) bay floor mud with plant debris and burrows. The mud beds of (4), so called “marine clay beds” are repeatedly interbedded between fluvial deposits of (1) to (3). The fluvial deposits of (1) to (3) are in braided river system developed at the lowstand of sea-level, and in contrary the marine mud of (4) was deposited at the highstand during glacio-eustatic changes.