大阪府千里山丘陵の大阪層群から多量のオーソコーツァイト質礫の発見

抄録

Abundant orthoquartzitic gravels were found in the basal part of the Osaka Group in the Senriyama Hills, Osaka Prefecture. The gravels which contain orthoquartzite are mostly composed of chert, accompanied with numerous acidic pyroclastic rocks and acidic igneous rocks. On the other hand, the gravels without orthoquartzite are poor in acidic pyroclastic rock. Abundance and limited distribution of orthoquartzitic gravels accompanied with many acidic pyroclastic rocks suggest that the source area of them may be restricted within narrow limits.