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

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。

Search for hidden rock bodies using geological, geophysical, and geochemical methods: An example from the West Damingshan area of Guangxi Province

Based on the data from field outcrops, drilling wells and fine seismic data interpretation, combined with analysis on the paleogeography, this paper presents a detailed study on late Cenozoic tectonic evolution and reservoir generation process in the west section of the northern margin of Qaidam Basin. The results suggest that this section consists of a series of arc-shaped thrust faults and folds along the front of the range. Since late Cenozoic, its tectonic evolution is featured by spreading from range-front to interior of the basin and propagating from either side to the middle. The hydrocarbon accumulation coupled well with the tectonic evolution process. Both sides of each arc-shaped tectonic zone formed earlier, with good combination of generation, storage, and cover as well as the background of ancient tectonics. These places indicate long-term direction of hydrocarbon migration and accumulation, which should be the priority of exploration targets in the future.