Geology and Ore Deposits of the Ryushoden Mine, Hokkaido

Abstract

The Ryushoden Mine is located in the northern part of the Hidaka range, Hokkaido.
The mine area consists of sandstone and shale of the Pliocene formation (Yasoshi formation) unconformably overlying black slate and hard sandstone of the Cretaceous formation.
The ore minerals are cinnabars and a small amount of native mercury impregnated in sandstone.
The writer believes that ore shoot is controlled by porosity and breccia zone of the Yasoshi formation.
The existence of pre-ore fault is important for the genesis of these deposits.