Consideration on the Geological Structure in the Eastern Marginal Region of the Ou-Mountainland, Iwate Prefecture

Abstract

In the eastern marginal region of the Ou-Mountainland, Iwate Pref., the geological stage of the crustal disturbance which formed the depression zone along the backborn range is after the sedimentaion of Motohata-Lignite-bearing beds in the Pliocene age.
This crustal disturbance accompanied by the volcvolcanisms is considered as the direct forerunner of the recent one. And the dacite eruption took place as the first products of the volcanisms along the main tectonic lines caused by the crustal disturbance.
Sulphur and Pyrite deposits for instance Matsuo and Uguisuzawa are the only ore depositions in this region.