安徽省无为县钱村铁矿床地质特征及成因

Geological Characteristics and Genesis of Qiancun Iron Deposit in Wuwei County,Anhui Province

钱村铁矿是宁芜矿集区西南部雍镇矿田内的代表性铁矿床,位于扬子板块北缘的宁芜盆地西南侧。矿区属汤沟-裕溪口复背斜,发育NE-NNE及NWW向两组断裂,NE向褶皱构造控制了岩浆侵入及成矿作用。区内发育明显的磁异常,钱村矿床是单一的磁铁矿床,共圈定了8条磁铁矿体,矿体赋存于闪长玢岩与黄马青组接触带地层中。结合矿区地质工作成果,详细分析了矿区地质及地球物理特征、矿床地质特征,总结了矿床成因。研究表明:①矿石矿物主要为磁铁矿,次为赤铁矿、穆磁铁矿,另有少量的黄铜矿、斑铜矿,矿石有块状、浸染状、脉状及角砾状等类型,钱村铁矿为一中高温岩浆热液型接触交代矿床;②通过磁铁矿的判别图解,可知磁铁矿大量落于斑岩型矿床区域,指示矿区具有一定的铜金矿床的找矿潜力,成矿岩体侵位和成矿时代为早白垩世。

Qiancun Iron Deposit is a representative deposit in Yongzhen ore field,southwest of Ningwu ore district.The deposit is located at the southwestern side of Ningwu basin in the northern margin of Yangtze plate.The mining area belongs to Tanggou-Yuxikou anticline,two groups of faults are developed in NNE-NNE and NWW directions,the magmatic intrusion and mineralizaation in the mining area are controlled by NE trending fold structure.The magmnetic anomalies are developed obviously in the mining area,the deposit is a single magnetite deposit.8 magnetite orebodies are delineated in the mining area,the orebodies are distributed in the contact zone between diorite porphyrite and Huangmaqing Formation.Based on the latest geological prospecting results of the mining area,the geological characteristics and geophysical characteristics of the mining area,geological characteristics of the deposit are discussed,besides that,the deposit genesis is also analyzed.The study results show that:①the ore minerals are mainly for magnetite,followed by hematite and mumagnetite,and a small amount of chalcopyrite and bornite,ore types can be divided into massive,disseminated,veined and brecciated,genesis of Qiancun deposit is medium-high temperature magmatic hydrothermal contact metasomatism deposit;②according to the discrimination diagram of magnetite,the magnetite samples has fallen heavily into the porphyry deposit area,which further indicated that the prospecting potential of Cu-Au deposit in the mining area is good,the emplacement and metallogenic age of metallogenic rock mass are Early Cretaceous.