青海东部查明一大型微细浸染型金矿床

加吾金矿位于青海省东部同德县境内,是武警黄金部队近年来发现的又一处具大型规模的金矿床。该矿床在大地构造位置上处于西秦岭与东昆仑的衔接部位。矿体赋存于中下三叠统中,在平面上呈舒缓波状,在剖面上为脉状、似层状。矿石中金属矿物主要为黄铁矿和毒砂,金主要以微细粒分布于石英裂隙和毒砂、黄铁矿等矿物粒间。区内中下三叠统隆务河群板岩中的金丰度值和有机碳含量高,是有利的赋矿层位。矿体产于北西向和近东西向构造蚀变带内,受区内断裂带控制明显。矿体在空间上与印支期中酸性岩浆岩相伴产出。研究表明,该矿床为受构造蚀变带控制的、与沉积作用和岩浆活动有成因联系的微细浸染型金矿床。截止目前,该矿共计探明金矿脉22条,累计提交金资源量超过20t。该矿的发现和评价对指导青海东部微细浸染型金矿找矿具有重要的示范意义。

The discovery of a large-size fine disseminated gold deposit in eastern Qinghai

Located in Tongde County of eastern Qinghai, the Jiawu gold deposit is another large-size gold deposit discovered by Gold Prospecting Armed Police in recent years. The ore deposit is situated between western Qinling and eastern Kunlun. Ore bodies occur in Middle-Lower Triassic strata, and are horizontally in the gentle wave form and vertically in the veinlike or layered form. The main metallic minerals include pyrite and arsenopyrite, and gold is disseminated in fissures of quartz and intergranule space between arsenopyrite and pyrite in the microgranular form. The high organic-C content suggests that the ore bodies are obviously controlled by the regional fracture belt and lie in NW-and EW-trending structural alteration zones. Due to its high Au and organic-C content, the slate in Middle-Lower Triassic Longwuhe Group is considered to be the favorable host rock. Ore bodies are spatially accompanied by Indo-China medium-acid magmatic rock. A preliminary study reveals that this deposit is a kind of fine disseminated gold deposit directly controlled by the structural alteration zone and has a genetic relationship with sedimentation and magnetic activity. Until now, the proven reserves of the total 22 ore bodies have reached over 20 tons.