西藏扎西康铅锌银矿床含矿走滑断裂地球物理特征及找矿方向

扎西康铅锌银矿床位于北喜马拉雅大陆边缘褶冲带内,是西藏扎西康整装勘查区中大型铅锌锑银共生矿床之一。矿床赋存于下侏罗统日当组,容矿岩石为含碳钙质板岩、钙质板岩和构造角砾岩,矿体严格受近SN向和NE向断裂控制,呈脉状、透镜状产出。通过岩石物性分析,认为矿体具有中低电阻和中低极化的物性特征。在矿集区开展了音频大地电磁法(AMT)和激发极化法试验,结合地质地球物理初始模型,从地质背景、勘查模型角度分析,含矿走滑断裂的围岩具有中低极化率、断裂走向与极化率条带一致的特征;认为在中低极化率区域存在断裂,且断裂走向的垂直方向存在高极化、低电阻区,赋矿可能性较大。

The geophysical characteristics of the ore-hosted strike slip fault and the prospecting direction in Zhaxikang Pb-Zn-Ag deposit, Tibet

Zhaxikang polymatallic deposit is one of large Pb-Zn-Ag-Sb deposits located at the marginal fold thrust belt of the northern Himalayas and discovered in the Zhaxikang equipped exploration area.It occurs in Lower Jurassic Ridang formation and is hosted by Ca-bearing calcareous slate and calcareous slate and tectonic breccia.The ore body is in vein,lens controlled by roughly SN,NE trending faults. The research and analysis of physical property of the typical rock samples regionally collected and from drill holes show that ore body is characterized by middle and low resistance and low polarization.In the ore-deposit-clustered area we carry out AMT and IP survey.Combined with the initial geological and geo-physical model,geological background and analysis of prospecting model of the area the result of ore body is characteristic of middle and low polarization and coincidence of polarization girdle and strike of the ore-hosted strike slip fault,thus we consider that ore possibly occur at places where fracture is located in the middle and low polarization area and there are high polarization and low resistance area in the direction perpendicular to strike of the fault.Based on ore prospecting workings and geological and geochemical da-ta the prospecting direction is put forward.