湖北双河硒矿地质特征及成因浅析

PRELIMINARY ANALYSIS ON THE GEOLOGICAL CHARACTERISTICS AND ORIGIN OF THE SHUANGHE SELENIUM ORE BEDS,HUBEI

本文介绍了双河硒矿地质特征、分布规律;阐述了成矿与碳酸盐台地海盆浅部沼泽(主要为藻沼)环境中局部出现的黑色炭质硅质岩相有关;矿质来源与火山活动有关;探讨了成矿机制;提出了该硒矿属于沉积-成岩-表生层控成因。

The Shuanghe selenium deposit is situated within the middle part of a selenium anomaly area(selenium abundance area) in South western of Hubei. It is a dispersed selenium deposit for the first time discovered in 1970’s and associated with V, Mo, etc. which can be compre-hensively utilized. The selenium deposit occurs in the stratum of carbonaceous silliceous rocks in upper part of Maokou formation of Permian. The ore bodies are beded and. lensoid which controlled by stratigraphic-horizon. There is no obvious boundary between orebody and country rock. The host rock includes carbonbearing silliceous rock, carbonaceous siliceous rock, etc. The mineralization is mainly connected with carbonaceous material and secondly with sulphide originated in sedimentary diagenesis. The orebodies generally occured with enclosing rock in conformity and both are controlled by specific lithostratic unit. The orebearing bed is a litological assemblage, which consists of a set of rocks and ores, i. e. sele-niumbearing black carbonaceous siliceous rock interlaid with dolomitite. The ores consits of essential minerals of quartz, chalcedony, carbonaceous material, hydromica and of auxiliary minerals of pyrite, hematite, limonite, etc. Industrial type of the selenium ores is a type of carbonaceous adsorption. According to composition, texture and structure, the selenium ores can be divided into three natural types , i. e. carbonaceous siliceous rock type, siliceous carbonaceous argillite type and the type of carbonaceous siliceous rock interlayered with mineralized and thin bedded semidull-sapro-pelic coal. The selenium occurs principally in the carbonaceous as a form of adsorption, sec-ondly in the sulphide minerals as isomorphism and rarely as the berzelianite-achavalite. Mineralization is related to the selenium-bearing black carbonaceous siliceous rock facies, which is partially present in the swamp environment of shallow part of the carbonate plat-form sea basin. The mineral-forming materials come from volcanic activity. The selenium deposit was formed through supergene enrichment of souce bed which was formed by sedi-mentary diagenesis. Therefore, the genetic type of selenium deposit is type of stratabound originated in sedi-mentation-diagenesis-supergene enrichment.