黔西南“断控型”金矿床的找矿模式与勘探评价方法——以丫他金矿床为例

Prospecting model and exploration evaluation method of “fault controlled” gold deposits in southwest Guizhou:a case study of Yata gold deposit

黔西南地区以丫他、烂泥沟、百地等为代表的"断控型"金矿床地处深水槽盆浊积岩沉积建造,其中烂泥沟金矿床埋深达1000 m且尚未圈闭,显示了该类型矿床巨大的深部隐伏矿找矿潜力。本文基于丫他幅1∶5万矿产地质调查和以丫他金矿为典型矿床的大比例尺找矿方法试验成果,分析了本区"断控型"金矿床的地质和成矿特征,对比研究了地质、物探、化探、遥感多尺度组合异常特征,总结了"断控型"金矿床的勘探找矿模式、靶区优选依据和定量预测评价要素,并利用成矿地质体参数法对丫他金矿床及外围0~2 km深度的潜在资源量进行了定量估算。研究结果认为区域性深切断层及其浅表贯通的次级断层、裂隙网络是该区重要的控矿要素之一,不同尺度、不同组合的物化遥异常对各级别构造的规模、产状等存在响应关系。对丫他金矿床外围及其深部的资源潜力进行了定量评价,预测0~2000 m空间仍存在约112.983 t的金资源潜力。化探、遥感浅表组合异常和区域重力、电法剖面相结合的勘查技术方法,能够为本区找矿靶区的优选提供多学科交叉证据支撑,其勘探技术、评价方法值得在黔西南其他找矿远景区推广,能够为后续商业性开发投入指明方向、减少风险。

The “fault controlled” gold deposits in the southwest Guizhou Province of China, represented by Yata, Lannigou and Baidi, are located in the turbidite sedimentary formation of deep flume basin. Among them, Lannigou Gold Deposit is buried 1000 m deep and has not been tapped, which shows that this type of gold deposit has great potential for deep concealed ore prospecting. Based on the 1∶50000 geological survey of mineral resources in Yata area and the large-scale prospecting method test results considering Yata gold deposit as a typical deposit, this paper analyzes the geological and metallogenic characteristics of the “fault controlled” gold deposit in this area. This investigation also compares and studies the geological, geophysical, geochemical and remote sensing multi-scale combination anomaly characteristics, and summarizes the exploration and prospecting mode, target optimization and quantitative prediction of the “fault controlled” gold deposit. This study also quantitatively estimates the potential resources of the Yata gold deposit and its periphery at a depth of 0~2 km using the metallogenic geological body parameter method. The results show that the regional deep fault and its secondary fault and fracture network are one of the important ore controlling factors in this area, and the geophysical and geochemical remote anomalies on different scales and combinations have a response relationship with the scale and occurrence of various metallogenic structures. Based on the quantitative evaluation of resource potential in the periphery and deep part of Yata gold deposit, it is predicted that there is still about 112.983 tons of gold resource potential in the space of 0~2000 m. The combination of geochemical exploration, remote sensing, shallow combined anomaly and regional gravity and electrical sounding profile can provide interdisciplinary evidence support for the optimization of prospecting targets in this area. Its exploration technology and evaluation method are worth promoting in other prospecting areas in southwest Guizhou, which can indicate the direction for subsequent commercial development investment and reduce risks.