The Genesis of the Horobetsu Sulphur Deposit

Abstract

(1) This deposit is an impregnation deposit of sulphur which occurs in both two-pyroxene andesite and the overlying pyroclastic rocks (agglomerate, tuff-breccia and shaly tuff).
(2) The flat shape of this deposit, inclining slightly northwards, depends on the geological structure of host rocks.
(3) The shaly tuff apparently behaved as a cap rock to the mineralizer.
(4) The existence of melnikovite associated with pyrite and marcasite in the ore has been ascertained.
(5) Native sulphur and iron sulphide minerals are impregnated and closely related with each other in host rocks.
(6) The ore usually contains a considerable amount of opaline-clay (clayey substance which consists mostly of opal).