安徽小紫山地区铜多金属矿土壤地球化学特征及找矿前景

繁昌县小紫山地区位于安徽省南部,区内铜多金属矿处于安徽沿江成矿带中段,繁昌成矿区东南缘。结合该区1∶5 000地质测量、1∶5 000土壤地球化学测量成果,分析了区域成矿地质背景,并对Cu、Pb、Zn、Mo、As、Sb、Bi、Au等元素的土壤地球化学特征进行了如下分析:首先运用迭代法计算出了测区各元素的地球化学背景值和异常下限,并圈定了区内单元素的异常范围;然后应用多元统计分析方法厘定了区内成矿元素组合,圈定了3处综合异常带作为找矿靶区,即位于测区东北端以Cu、Pb、Zn、Mo为主的Ⅰ#综合异常带和以Cu、Pb、Zn、As、Sb、Bi为主的Ⅱ#综合异常带以及位于测区中部以Cu、Pb、Zn、Mo为主的Ⅲ#综合异常带。研究表明:区内Cu、Pb、Zn、Mo异常浓集中心明显,套合程度高,主要沿NE向呈带状展布,异常强度东高西低,与区内构造蚀变带和地表矿化体对应较好,为后续找矿工作提供了丰富完整的地球化学找矿信息。在上述分析的基础上,综合区内成矿物质来源条件、成矿地质条件以及类比邻近同类型铜多金属矿床,认为区内形成中—低温热液脉型和矽卡岩型铜多金属矿床的潜力较大。

Soil Geochemical Characteristics and Prospecting Potential of Cu-polymetallic Deposit in Xiaozishan Area,Anhui Province

The Xiaozishan area in Fangchang County is located in the south of Anhui province,the Cu-polymetallic deposit of Xiaozishan area is located in the southeast margin of Fanchang metallogenic province,middle of the Yangtze River metallogenic belt of Anhui province.Combing with the 1 ∶ 5 000 geological measurement and 1 ∶ 5 000 soil geochemical measurement results of the area,the regional metallogenic geological background is analyzed,the soil geochemical characteristics of Cu、Pb、Zn、Mo、As、Sb、Bi、Au is analyzed as following:firstly,the geochemical background values and anomaly thresholds of the eight elements are calculated by using the iterative method,and the anomaly range of the single elements are delineated respectively;then,the multivariate statistical analysis method is used to determine the combinations of metallogenic elements within the area,three comprehensive anomaly zones are delineated as the prospecting target ares in the area,they are Ⅰ #comprehensive anomaly zone (mainly for Cu,Pb,Zn,Mo) and Ⅱ # comprehensive anomaly zone (mainly for Cu,Pb,Zn,As,Sb,Bi),which are located in the northeast end of the area,the third one is Ⅲ # comprehensive anomaly zone (mainly for Cu,Pb,Zn,Mo),which is located in central part of the area.The research results show that the anomaly concentration centers of the Cu,Pb,Zn,Mo are obviously as well as overlap well and zonal distributed along the northeast direction,the abnormal intensities are higher in the west and lower in the east,they are consistent with the regional structural alteration zones and surface mineralized bodies,which provides the rich and complete geochemical information for the subsequent prospecting work in the area.Based on the above analysis results,combing with the metallogenic material source conditions,metallogenic geological conditions and analogy to the nearby Cu-polymetallic deposit,it is show that the metallogenic potentials of the medium-low temperature hydrothermal vein type Cu-polymetallic deposit and skarn type Cu-polymetallic deposit of the area are both great.