Pb同位素剖面化探法在甘肃玛曲地区大水金矿深部找矿中的应用

攻深找盲是大水金矿矿山勘查的主要任务。根据Pb同位素示踪的有关理论和隐伏矿预测的方法,以甘肃玛曲大水金矿区为例,利用Pb同位素剖面化探法在大水金矿典型剖面70、72勘探线采集Pb同位素样品78个,进行成矿截止深度预测。取本区域的成矿V2截止值在22.4～234.36之间,70、72勘探线在3450m标高左右V2值分别为49.11、64.83,预测70～72勘探线深部及以西成矿截止深度在3000～3100m之间,还有400～500m的勘查空间,找矿潜力大,是今后矿区勘查的重点地段。

Application of geochemical exploration by Pb isotopes to deep ore-prospecting in the Dashui gold deposit of Maqu County, Gansu Province, China

As an important method, lead isotopic research not only is used for tracing ore material origin and calculating Pb model age, but also for applications to geochemical exploration and evaluation of deposits. Deep prospecting for Dashui gold deposit is the predominant task after exploration and development for 20 years. Geochemical exploration by Pb isotopes is applied in the Dashui gold deposit of Maqu County, Gansu Province, along the typical No.70 and 72 exploration lines, based on previous studies of the Pb isotopes. There are 78 Pb isotopic samples both rocks and ores collected for analysis and prediction for the mineralized depth. Based on the regional geochemical background, the cut-off V2 value of mineralization is established in a range of 22.42~34.36, Along the No.70 and 72 exploration line at the 3450m elevation, the V2 values are 49.11 and 64.83 respectively. Pb isotope forecast indicate that the cut-off depth of mineralization at No.70 to 72 and westward mineralized district is from 3000m to 3100m. Thus there is 400~500m great exploration potential in the depth, which is the focus of future mining exploration and deep exploration work should be strengthened.