摘要
长期以来东沟—金龙山金矿床被认为是典型的卡林型金矿床,其成矿时代不明。控矿构造为褶冲带短轴背斜。短轴背斜为东西向紧闭背斜与北东向宽缓背斜叠加形成的穹隆构造,成矿作用主要受后期北东向脆性构造及东西向岩性不整合界面的控制;区内Au、As、Sb异常套合较好,异常沿北东向呈串珠状分布并与穹隆构造、遥感解译环形构造套合明显;获得成矿期绢云母40 Ar/39 Ar坪年龄为（142.34±0.83）Ma,等时线年龄为（141.6±2.8）Ma,成矿为晚中生代早期;黄铁矿具有3期形成特征,晚期含金黄铁矿,主要与毒砂、辉锑矿共生。结合区域资料认为成矿作用与深部隐伏岩体有关,矿床类型为与深部岩浆期后热液作用有关的远程低温热液矿床,成矿作用发生在141～142 Ma晚中生代早期的挤压-伸展转变期,显示挤压伸展转变期的减压增温环境是该矿床最为有利的成矿地球动力学背景。
Donggou-Jinlongshan gold deposit located in flysch folded-thrust belt brachyanticline in southern Qinling orogen is considered to be a typical Carlin-type gold deposit and its metallogenic epoch yet to be determined.The regional tectonic system analysis showed that the brachyanticline is a dome structure which was formed by the superposition of east-west closed dome and north-east broad top anticline;the mineralization was mainly controlled by the late north-east brittle structure and east-west heterolithic facies unconformity interface.The geochemistry result of regional exploration shows that the anomalies of Au,As,and Sb register better,and that the anomalies distribute along north-east in beaded presentation and register obviously with the dome structure and the annular structure of remote sensing interpretation.The 40Ar/39 Ar plateau age of sericite is 142.34±0.83 Ma,and the isochron age is 141.6±2.8 Ma,which shows that the mineralization happened in the early stage of the Late Mesozoic.The formation of pyrite has the characteristics of three periods;the auriferous pyrite has a symbiotic relationship with arsenopyrite and stibnite.Combining with regional date that the mineralization has a relationship with deep buried rock,and the deposit type is a remote epithermal deposit which is related to the deep hydrothermal fluid after the magmatic stage;the mineralization occurred in the squeeze-extended transition period at 141-142 Ma in the early Late Mesozoic;it suggests that the decompression and warming environment at the squeeze-extended transition period is the most favorable metallogenic geodynamic background.
出处
《地学前缘》
EI
CAS
CSCD
北大核心
2016年第4期81-93,共13页
Earth Science Frontiers
基金
中国地质调查局项目(12120114007401,121201130868400)
中央高校基金项目(310827153407)
