物化探综合方法在西藏普则铜多金属矿区成矿预测中的应用

Application of comprehensive geophysical and geochemical exploration method in metallogenic prediction of Puze copper polymetallic mining area in Xizang

研究区位于冈底斯成矿带东段的拉抗俄—吹败子铜(钼)矿集区内,成矿条件十分优越。在以往研究中发现,该区铜多金属矿产的形成与喜山期中酸性岩浆的侵入活动关系密切,现有矿床分布比较集中的区域,深部都有隐伏岩体赋存。但是与成矿关系密切的隐伏花岗斑岩体赋存特征及其深部成矿预测研究成果有限,制约了该区深部找矿工作。为了实现区内找矿突破,开展了11万高精度磁测及11万土壤地化测量相结合的物化探综合勘查工作,圈定了“一带(中部构造蚀变带)三区(Ⅰ、Ⅱ、Ⅲ异常)”为成矿最有利区段,认为中部构造蚀变带有寻找中低温热液—构造蚀变岩型的金矿的潜力;在Ⅰ区隐伏岩体较深有寻找斑岩型铜矿的潜力;在Ⅱ区具有寻找浅部矽卡岩型铜矿及中深部斑岩型铜钼矿的潜力;在Ⅲ区地质勘查程度相对较高,浅部具有寻找矽卡岩型铜,深部仍有寻找斑岩型钼金铜矿的潜力。通过对磁异常与组合元素异常特征分析,初步建立起该区矽卡岩—斑岩复合型铜多金属矿床的物化探找矿模式。

The research area is located at the Laguo-Puwanzi copper(molybdenum)deposit concentration area in the east section of Gangdisi metallogenic belt,and the metallogenic condition is very favorable.It has been found in previous studies that the formation of copper polymetallic mineral resources in this area is closely related to the intrusion of acidic magma in the alpine period,and there are hidden rock masses in deep areas where the existing deposit distribution is relatively concentrated.However,the occurrence characteristics of the buried granite porphyry are closely related to mineralization and the research result of deep mineralization prediction is limited,which restricts the deep prospecting work in this area.In order to achieve a prospecting breakthrough in the area,the comprehensive geophysical and chemical exploration work of 110000 high-precision magnetic survey and 110000 soil geochemical survey is carried out,and three areas(I,II,III anomaly)of"One Belt(central tectonic alteration zone)"are identified as the most favorable metallogenic section,and it is considered that the central tectonic alteration zone has the potential to find gold deposit of medium and low temperature hydrothermal and tectonic alteration rocks.There is the potential to find porphyry copper deposit in the deep buried rock mass in area I.It has the potential to search for shallow skarn type copper deposit and medium-low temperature hydrothermal gold deposit in area II.The geological exploration degree of area III is relatively high,the shallow part has the potential to find skarn type copper,and the deep part still has the potential to find porphyry type molybdenum gold copper deposit.By analyzing the characteristics of magnetic anomaly and combined element anomaly,the geophysical and geochemical prospecting model of the skarn porphyry composite copper polymetallic deposit in this area is preliminarily established.