豫西南老湾金矿原生晕地球化学特征及深部成矿预测

老湾金矿带位于桐柏山北麓,秦岭EW向复杂构造带东段,南阳盆地与吴城盆地之间,属中、低温蚀变岩型金矿床。近年来区内找矿取得了较大进展,新增金资源量突破150 t。为进一步扩大找矿成果,通过对老湾金矿Ⅱ-2-2矿体原生晕分带特征进行综合剖析,并采用相关分析、聚类分析、因子分析等方法对矿体组成元素的亲缘性特征进行研究,建立了地球化学找矿标志,并对深部隐伏矿体进行了成矿预测。研究表明:①矿体原生晕轴向分带序列为Ag→Zn→Hg→As→Au→Sb→Bi→Pb→Cu→Mo→W→Sn,近矿晕元素Ag、Zn出现在前缘晕元素Hg、As、Sb之前,尾晕元素Bi出现在Pb、Cu之前,表明-737 m标高以深存在隐伏矿体;②Mo、Bi、Cu、S与Au关联性较强,该类元素的地球化学异常可作为矿区找金标志;③元素分带指数比值显示下部矿体的前缘晕与上部矿体近矿晕叠加,F2因子得分的等值线在深部异常发育且未闭合,说明-740 m标高以深仍有较好的找矿潜力。在上述分析的基础上,认为E6勘探线钻孔ZKE608南部-740 m标高以深区域为矿区有利的找矿靶区。通过在E6线钻孔ZKE608南部布设深部钻探工程进行验证,在标高-794.18^-795.53 m处控制到真厚度为1.08 m的金矿化体,表明预测结果较为可靠,可为矿区后续深部找矿工作提供借鉴。

Geochemical Characteristics of Primary Halo and Deep Metallogenic Prediction of Laowan Gold Deposit in Southwestern Henan Province

Laowan gold mineralization belt is located at the north of Tongbai Mountain，the eastern part of east-west trending Qinling tectonic belt，and between Nanyang Basin and Wucheng Basin.It belongs to the mesothermal-epithermal gold deposit of alteration rock type.In recent years，great progress has been made in prospecting for gold in this region，with the amount of newly added gold resources exceeding 150 t.In order to expand prospecting results，the analysis of primary halo characteristics of No.Ⅱ-2-2 orebody was made，and the research of the related characteristics of ore-forming elements by correlation analysis，cluster analysis and factor analysis was carried out. Based on this study，the geochemical signs for prospecting were made and the concealed god orebodies were predicted.The research achievements have been obtained as follows:①the axial zoning sequence of orebodies can be described as Ag→Zn→Hg→As→Au→Sb→Bi→Pb→Cu→Mo→W→Sn.The near-ore hole elements Ag and Zn is before the head hole elements Hg，and As and Sb，the rear halo element Bi is before Pb and Cu.It may indicate that concealed orebodies are below -737 m；②Mo，Bi，Cu and S are strongly related to Au，and geochemical anomalies of such elements can be used as signs for gold prospecting in this region；③the ratios of elemental zoning index show that the head hole of the lower orebody is superimposed with the near-ore halo of the upper orebody，the contour of F2 factor score are abnormally developed and not closed in depth.It may indicate that the region below -740 m has good potential for prospecting.Based on the above analysis results，it is predicted that the target district is below -740 m in the south of ZKE608 drilling in exploration line E6.Drilling engineering were arranged in the south of ZKE608 drilling in exploration line E6 for verification，and the gold mineralized body whose real thickness is 1.08 m was found at the elevation from -794.18 m to -795.53 m，which further show that the prediction methods and prediction results in this paper are reliable and can provide reliable reference for the further deep prospecting work in the area.