近畿・中国地方の後期中生代酸性火山岩類と＂領家花崗岩類＂との一，二の地域における関係

A Relation of the Ryôke Granites to the Late Mesozoic Acidic Volcanics in Chûgoku and Kinki Provinces.

YOSHIDA Hironao

廣島大學地學研究報告

Geological report of the Hiroshima University

Vast tracts of the inner zone of Southwest Japan are occupied by so-called Ryôke rocks consisting of granites and metamorphics and by other Cretaceous igneous rocks consisting of granites and volcanics. In the volcanics are contained large amount of rhyolitic rocks named the Takada rhyolitic rocks belonging to those of the Middle Cretaceous in age. The Takada rhyolitic rocks are found intruded by some Cretaceous granites such as the Hiroshima granitic complex and the Naegi-type granites, both being the most important members of the Cretaceous granites. The Ryôke rocks have been thought by predecessors as those produced in certain stage 1) from the Late Palaeozoic to the Early Mesozoic, 2) from the Jurassic to the Lower Cretaceous, and 3) of the Cretaceous. To clarify the geologic relation between the Ryôke rocks and the Takada rhyolitic rocks, the author has surveyed the island of Ôsakishimojima in Hiroshima Prefecture and the southern part of Osaka Prefecture. As a result of the work it has become claer that some Ryôke granites might have been covered unconformably by the Takada rhyolitic rocks.

jpn

廣島大學理學部地學教室

[ISSN] 0073-2303

[NCID] AN00213676