著者

飯島 静男 大河原 恵子 大崎 小夜子 神沢 憲治 木崎 喜雄 久保 誠二 黒岩 繁 篠原 婦美江 関口 孝 高橋 武夫 田島 順子 玉田 淳子 角田 寛子 中村 庄八 服部 幸雄 武藤 斉 村山 昭夫 矢島 博 高島 和美 田中 淳子 萩原 哲 堀沢 勝

出版者

日本地質学会

雑誌

地質学論集 (ISSN:03858545)

巻号頁・発行日

no.13, pp.251-260, 1976-12-30

被引用文献数

1

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The Green tuff formations are widely distributed in the southern Joetsu district, and are divided into two groups, namely the Sarugakyo group and the Minakami group. The former overlies the latter unconformably. The area studied is surrounded by the River Akaya-gawa, the River Sukawa-gawa and the River Nishi-kawa, of which the latter two are the tributaries of the former. In this area the Sarugakyo group and the welded tuff formation with some related intrusive bodies are extensive. The Sarugakyo group is overlain unconformably by the welded tuff formation, and is divided, in descending order, into the following formations: Daido formation, Kassezawa formation, Hara formation, Akaya formation. The relation between each formation of the Sarugakyo group, generally, is conformable, but partial unconformity can be observed between the Hara formation and the Kassezawa formation. The structure of the Sarugakyo group is generally monoclinic with a NWW-SEE strike and low-angle dips toward SE. The Sarugakyo group is considered, from fossils, to belong to the middle Miocene. Some intrusive bodies, such as the Izumi-yama andesite, the Kasse andesite, the Amami-yama andesite, porphyrite and quartz diorite, are found in this area.