安徽宣城马尾山硫铁矿床地质特征及胶状黄铁矿成因研究

Mineralogical Characteristics Genetic Analysis of Colloidal Pyrite of Maweishan Pyrite Deposit in Xuancheng,Anhui Province

在马尾山硫铁矿床的开发过程中,发现矿床中黄铁矿矿体严格受地层控制,多呈层状-似层状产出,而矿体中大量存在胶状结构黄铁矿。为了确定马尾山硫铁矿矿床成因及胶状黄铁矿形成机制,通过对马尾山硫铁矿床地质特征和黄铁矿物特征进行研究,并与铜陵新桥硫铁矿床中胶状黄铁矿矿物特征进行对比研究。结果表明:黄铁矿体普遍发育于石炭系上统黄龙、船山组地层中,且胶状黄铁矿环带裂隙充填黄铜矿及外围包裹黄铁矿、闪锌矿;对比发现胶状黄铁矿矿物特征、成矿条件均与铜陵新桥硫铁矿相类似,推测马尾山硫铁矿床胶状黄铁矿成因与新桥硫铁矿相似,为生物化学沉积形成。马尾山硫铁矿矿床成矿期次分别为原生沉积期、岩浆—热液期、表生风化期3个成矿期次,而胶状黄铁矿形成于成矿早期的原生沉积期。

With the development of Maweishan pyrite deposit,it is found that pyrite ore bodies in the deposit are strictly controlled by strata,and most of them are layered-like,while there are a large number of colloidal pyrite in pyrite ore bodies.In order to determine the genesis of Maweishan pyrite deposit and the formation mechanism of colloidal pyrite,the geological characteristics of Maweishan pyrite deposit and the mineral characteristics of pyrite ore were studied,and the mineral characteristics of colloidal pyrite ore in Xinqiao pyrite deposit in Tongling were compared.It is determined that pyrite orebodies are generally devel⁃oped in the strata of Huanglong and Chuanshan Formation in the upper Carboniferous system,and the band⁃ed fissures of colloidal pyrite are filled with chalcopyrite,and pyrite and sphalerite are wrapped around them.By comparing the mineral characteristics and metallogenic conditions of colloidal pyrite with those of Xinqiao pyrite in Tongling,it is speculated that the genesis of colloidal pyrite in Maweishan pyrite deposit is similar to that of Xinqiao pyrite,and it is formed by biochemical deposition.It is proved that Maweishan py⁃rite deposit has three metallogenic stages:primary sedimentary stage,magma-hydrothermal stage and super⁃gene weathering stage,and colloidal pyrite was formed in the primary sedimentary stage at the early metallo⁃genic stage.