河南板厂铜钼多金属矿床钻孔原生晕地球化学特征及找矿预测

Geochemical characteristics of the primary haloin boreholes and prospecting prediction of the BanchangCu-Mo polymetallic deposit in Henan Province

板厂铜钼多金属矿区处于秦岭造山带东段的北秦岭褶皱带内,位于区域深大断裂朱阳关—夏馆断裂带中段,为河南省发现的第一个大型铜矿床。为增储开展了预查、普查工作,先后投入2.36万m的钻探工作量,将板厂铜矿带的找矿深度延伸了近千米,主矿体最大厚度达285.95 m。通过系统采集板厂铜钼多金属矿床220~76勘探线共23个钻孔的岩矿样品,初步分析了矿床原生晕的分布特征,重点对施工钻孔最多的172勘探线开展了典型构造流体运移通道的解剖研究,印证流体运移成矿具有前铜后钼的分带特征,并采用格里戈良分带指数方法建立了矿区原生晕垂向分带序列为Sb-As-Pb-Bi-Zn-Ag-Sn-Cu-W-Au-Mo,总结了矿床异常元素的分带规律,结合172勘探线矿体空间展布情况,进一步建立4个分带指数作为评价隐伏矿体空间位置的指标,为深部找矿预测提供了地球化学依据。在172典型勘探线研究的基础上,全区钻孔原生晕并结合CSAMT剖面地球物理特征进行了地质、物探和化探综合分析,预测成矿母岩(燕山期花岗斑岩)赋存位置,认为深部存在可能比目前主矿体规模更大的矿体,圈定了找矿预测靶区,为后期深部及外围勘查工作指明了方向。

The Banchang Cu-Mo polymetallic deposit is located in the middle section of the Zhuyangguan-Xiaguan regional fault,the North Qinling fold belt of the eastern Qinling orogenic belt.It is the first large copper deposit discovered in Henan Province.In the presurvey and general prospecting,a drilling workload of 23600 meters was invested successively,extending the prospecting depth of the copper belt in Banchang by nearly kilometers,and the maximum thickness of the main ore body is 285.95 m.By systematical samples from 23 drilling holes of the No.220 to No.76 exploration line in the Banchang Cu-Mo polymetallic deposit,the primary halo characteristics were preliminarily studied.The geochemical primary halo obtained from the No.172 exploration line with the most construction drilling holes reveal the fluid transport channels.The study confirmed the zoning characteristic of fluid migration and mineralization—"Cu first and then Mo",and the vertical primary superimposed halo established by the Gregorian zoning index method is Sb-AS-Pb-Bi-Zn-Ag-Sn-Cu-W-Au-Mo in the mining area.Combined with the spatial distribution of ore bodies in the No.172 exploration line,four zonal indexes were further established as indicators for evaluating the spatial location of concealed ore bodies.All these factors provide a geochemical basis for deep prospecting.