地物化综合方法寻找隐伏岩体—以广西西大明山隐伏岩体的发现为例

Search for Hidden Rock Bodies Using Geological,Geophysical and Geochemical Methods:An Example from the West Damingshan Area of Guangxi Province

广西西大明山地区是广西重要的整装勘查区之一。区内与岩浆活动密切相关的内生矿床丰富,然而仅在局部地表上发现少量的小型岩脉,区内隐伏岩体的预测研究一直是个热点。文章借助广西大规模地质矿产勘查项目,在成岩成矿理论的指导下,通过对区域地质、地球物理、地球化学及遥感等特征的系统分析,确定了西大明山地区深部隐伏岩体的大致分布范围和埋藏深度。在区内选定了埋藏较浅的隐伏岩体预测靶区,有针对性地采取了高精度的地、物、化等方法圈定隐伏岩体的具体位置,经验证有ZK31901、ZK40004两个钻孔分别在500m和960m以下发现了隐伏的黑云母花岗闪长岩,同时在隐伏岩体上部发现了具有工业价值的罗维钨铋矿床。预测靶区验证钻孔成功发现岩体,不仅为相邻地区的隐伏岩体预测工作提供了典型的范例,而且对西大明山地区成矿系统、矿床成因的研究乃至找矿勘查工作具有重要意义。

The West Damingshan district is one of the most important integrated exploration areas in Guangxi Province,which hosts many endogenetic deposits closely related to magmatic activity. While only a few of small dikes are found on the surface, and prediction of subsurface concealed magmatic bodies remains a difficult issue all the time. In this work, under the guidance of diagenetic mineralization theory and contributed by the project of Large- scale Geological and Mineral Recourse Exploration in Guangxi, we have made an integrated analysis of the regional features of geology, geophysics, geo- chemistry and remote sensing data of this area. The distribution ranges and buried depths of the concealed magmatic bodies in the study area are deter- mined. Shallow buried concealed magmatie bodies are selected as forecast targets to perform high-precision integrated geological, geophysical, and geochem- ical analysis with the purpose of confirming their specific locations and outlines. The concealed biotite granodiorite body was validated by two boreholes of ZK31901 and ZK40003 below depths 500 m and 960 m,respectively. Moreover,a tungsten bismuth deposit with industrial value was found in the upper level of this concealed magmatic body. In summary,successful finding of hidden rock bodies with drill-verifying in the predicted targets provides a typical example for similar work in adjacent regions, which is also of great significance to research on metallogenic systems, ore genesis and prospecting work in the future.