激电中梯和测深在柳树湾金矿勘查中的应用研究

Application of IP mid-ladder and IP sounding methods in the exploration of Liushuwan gold deposit

柳树湾金矿床位于汉南-碑坝元古代Fe-Cu成矿亚带内,为典型的黄铁矿化石英脉型金矿床。矿区前期的勘查仅限于地表圈定的矿化蚀变带周边的点对点找矿,对矿(化)体的延伸范围及垂向展布特征掌握不清,为进一步扩大矿体规模,加快找矿进度,选择了大功率激电测量对矿区进行勘查。通过激电中梯和测深方法在该矿床的应用研究表明:碑坝矿区内金矿体严格受NNE向或NS向断裂控制,呈脉状产出于断裂或岩性接触带部位,倾角较大。区内视极化率的ηs异常下限为5.00%,ηs值最高超过30.00%,电阻率值相对较低,表现为低阻高极化特征,激电异常多呈条带状展布,走向基本与构造走向一致。激电中梯及激电测深所圈定的IP1、IP2异常强度及规模都较好,且与地表已知矿化蚀变带对应性好,后经钻探查证,揭露了多层矿(化)石英脉体,脉体内赋存金矿(化)体,且与异常部位基本吻合,初步掌握了矿(化)体的发育位置和展布特征,取得了较好的地质找矿效果。认为该方法可以有效地指导钻探工作部署,是开展多金属矿勘查的重要技术手段之一,可作为该金矿床勘查的首选物探技术方法。

The Liushuwan gold deposit in southern Shaanxi is typical pyrite-quarta-vein type located in the Proterozoic Fe-Cu metallogenic sub-belt of Hannan-beiba.Eearly exploration in the mining area was constrained by the point-to-point method around the mineralized alteration zone delineated on the surface,and the extension range and vertical distribution characteristics of the mineralized body are not clear.In order to further expand the scale of the ore body and accelerate the prospecting progress,high-power IP measurement was selected to explore the mining area in this paper.The measurement result of IP mid-ladder and sounding methods in the deposit shows that the gold orebody in Beiba mining area is strictly controlled by NNE or NS faults,and vein-like production in the fault or lithologic contact zone with large dip angle.The lower limit of the apparent polarizationηs anomaly is 5.00%,the maximum value ofηs is over 30.00%,and the resistivity is relatively low,manifested as low resistivity and high polarization characteristics,the striking direction is basically consistent with that of the structure,and most of them are banding.The strength and scale of IP1 and IP2 anomalies delineated by IP mid-ladder and IP sounding are quite striking and correspond well with known mineralized alteration zones on the surface.After drilling verification,a multi-layer mineralized quartz vein body was exposed,and a gold mineralized body was endowed in the vein body,which basically coincided with the anomalous part,and the development location and spreading characteristics of the mineralized body were basically identified,and a better effect of geological prospecting was achieved.It is considered that this method can effectively guide the drilling deployment and is one of the important technical means for the exploration of polymetallic deposits,and can be used as the preferred geophysical prospecting method in the later exploration process of the gold deposit.