泉南層群 : 領家帯南部における後期中生代酸性火山作用

概要

論文の詳細を見る
The Sennan Group, hitherto called the Sennan Acid (Pyroclastic) Rocks, crops out in the Sennan district, south of Osaka City, western Japan, showing a narrow but elongated distribution for 25 km or more in an E-W direction in the southern Ryoke Belt. Stratigraphically, it is divided in to the Ogawa Andesite (about 300 m thick), the Sobagawa Conglomerate (about 200 m thick), and the mainpart of the group (3,000 m or more thick), in ascending order, the last being further subdivided into a large number of rhyolite to rhyodacite welded tuff with a subordinate amount of non-welded tuff, clastic sediment and rhyolite lava. Granite porphyries, granodiorite porphyries and quartz porphyries are intruded into the group, as many stocks or dikes. The Sennan Group has generally a high-angle or almost vertical structure, and is covered by the latest Cretaceous (Hetonaian) Izumi Group with a marked unconformity. On the other hand, it is intruded by the Late Cretaceous Takijiri Adamellite, one of the Younger Ryoke Granitic Rocks, along its northern margin and suffered from distinct thermal metamorphism. It seems very significant that the Sennan Group, composed principally of acid pyroclastic flow deposits, had been highly disturbed prior to the intrusion of one of the Younger Ryoke Granitic Rocks. Such the tectonic disturbance might have been caused by the rapid upheaval of the northern-adjacent area, where the older Ryoke Granitic Rocks and associated high-grade metamorphic rocks are now extensively cropped out.
日本地質学会の論文
1979-09-20

泉南層群 : 領家帯南部における後期中生代酸性火山作用

スポンサーリンク

概要

著者

関連論文

スポンサーリンク