南部北上山地荷沢地域の下部石炭系

概要

論文の詳細を見る
The Lower Carboniferous System developed in the Nisawa district, Southern Kitakami Mountains, is divided into two formations : Karoyama Formation and Onimaru Formation. The former, here newly proposed, is 500m + thick and mainly composed of tuff and slate, with intercalations of limestone, sandstone and conglomerate. It yields the following fossils : Shizophoria resupinata (Martin), Marginicinctus sp., Fluctuaria cf. undata (Defrance), Striatifera cf. striata (Fischer), Gigantoproductus sp., Martinia aff. glabra (Sowerby), Diphyphyllum hochangpingense Yu and Arachnolasma irregulare Yu. The fossil evidence indicates that the Karoyama Formation is Visean in age, being highly different from previous views. The Karoyama Formation is conformably overlain by the limestone of the Upper Visean Onimaru Formation which is about 30m in thickness. The facts support the view that there is no stratigraphic break between the Onimaru Series and its underlying rock sequences, showing no evidence on the Shizu Folding, even in this district.
東北大学の論文
1981-03-28