西藏扎西康铅锌多金属矿床原生晕特征

Primary halo characteristics of the Zhaxikang lead-zinc polymetallic deposit,Tibet

原生晕法在长期大量的勘探实践中,已被证明是一种能有效研究异常分布、地球化学特征、剥蚀程度,推测隐伏矿体,评价深部潜力,进行找矿预测的地球化学勘探方法。在西藏扎西康铅锌多金属矿床的实际勘查基础上,研究矿体的元素分带性特征,即原生晕轴向分带特征,可为研究控矿因素、成矿物质来源、围岩蚀变、成矿期次、矿床成因等方面提供地球化学依据。本文通过采集扎西康矿区0号线剖面ZK006、ZK007、ZK009、ZK010等4个钻孔的岩石样品,选取Cu、Pb、Zn、W、Mo、Sb、Bi、Ga、Sn、In、Au、Ag等成矿元素进行分析,来研究该矿床的原生晕地球化学特征及规律。结果表明,元素异常及原生晕集中分布在4400m以下,成矿物源不仅由周围地层提供,还可能来自于深部的隐伏岩体,成矿过程可能经历了多期次的叠加作用。这些研究成果暗示扎西康的工业矿体在深部还有继续下延的良好前景。

In previous exploration, researchers commonly considered that the primary halo method is an effective geochemical means for studying the distribution, geochemistry and denudation of the anomaly, and this method can also help predict concealed orebodies and assess mineral resource potential in the depth. Based on previous exploration of the Zhaxikang lead-zinc polymetallic deposit in Tibet, the authors studied vertical zoning of the deposit, and the results achieved can provide reliable geochemical information in such aspects as factors affecting mineralization, metal source, wall rock alteration, metallogenic stages and ore genesis. Primary halo study was carried out by analyzing Cu, Pb, Zn, W, Mo, Sb, Bi, Ga, Sn, In, Au, Ag and some other metallogenic ele- ments in rock samples from four selected drill holes of ZK006, ZK007, ZK009 and ZK010 along No. 0 explo- ration line in the mining area. It is shown that the element anomalies and primary halos mainly occur below the altitude of 4 400 m, metal sources might have been derived from both strata and concealed rock mass in the depth,and mineralization might have experienced multiple-stage superposition. The authors hold that the economic ore- bodies of the Zhaxikang deposit might have a good prospect o{ downward extension in the depth.