南秦岭东江口岩体中丰富金矿矿床特征与成因浅析

陕西省宁陕县丰富金矿产于南秦岭构造带东江口岩体内,为一中型规模金矿床,赋矿围岩为黑云母二长花岗岩。矿床形成于印支-燕山期秦岭造山过程中由碰撞向伸展构造体制转变的后碰撞构造环境,成矿时代限定为200Ma左右的燕山早期,矿床类型为硫化物石英脉型和破碎带蚀变岩型。金的赋存状态有包裹金、裂隙金及晶隙金三种,以裂隙金和晶隙金为主,具有多期成矿特征。围绕主岩浆期后超浅成-浅成侵入的中基性岩脉、岩枝、岩株呈环状展布的缓倾斜断裂是主要的控矿和赋矿构造,成矿作用与主岩浆期后火山-次火山作用或隐蔽爆破作用引发的热液作用有关。

An analysis of the Fengfu gold deposit in the Dongjiangkou granite of the South Qinling orogenic belt

The Fengfu gold deposit is a medium-scale mine hosted in biotite adamellite, which is located in the South Qinling orogenic belt in Shanxi province. It was formed in a post-collision environment during late Yanshan Epoch (about 200Ma). The main types of this deposit include reef-gold ore and rift-zone alteration-type ores. The occurrence forms of the gold minerals include enclosed, crevice and crystal-fissure gold, and the latter two are dominant. The deposit has experienced multi-stage mineralization. The gentle-dipping faults in the granite which encircle later intermediate-basic hypabyssal dikes, apophysis and stock are the ore-controlling structure. Based on the spatial affinity of ore-bodies and intermediate-basic congenetic rocks, it is suggested that the mineralization has genetic relationship with hydrothermal sub-volcanism and crypto-explosion caused by multiple intrusion of magmatic.