摘要
海沟金矿为大型贫硫化物的石英脉型金矿床受NE—NNE向构造控制。该金矿有3种类型控矿构造:①NNE向脆韧性剪切带构造控矿,主要控制43号矿脉,矿脉发育在中元古界色洛河群变质岩系与花岗岩之间的接触带,其控制矿体金的品位高,规模不大;②脆性复合叠加构造带控矿,矿体发育在二长岩和二长花岗岩体中,控制矿体规模大,品位高,是矿区内最主要的控矿构造;③层间虚脱构造控矿,矿体发育在中元古界色洛河群大理岩层之间,碳酸盐为有利的控矿围岩,矿体的规模小,向北倾伏的褶皱构造倾没端是最有利的找矿远景区。在区域挤压应力背景下,深大断裂的多次活动导致色洛河群变质岩系中金的活化,富金的岩浆热液沿壳断裂上侵。在145 Ma左右,由于地壳的拆沉作用,造成岩石圈减薄,形成区域性伸展动力学背景,含成矿流体向NE—NNE向次级断裂系统扩溶带迁移,在一定的物理化学条件下使金沉淀,形成了海沟金矿。
Haigou gold deposit, a large quartz vein type one with poor sulphur is controlled by tectonic direction of NE-NEE. There are three kinds of ore controlling structures in the gold deposit： （1） ore-control of brittle-ductile shear zone in direction of NNE, mainly controlled No.43 vein developed in the contact strip between the metamorphic rocks and granite in Middle Proterozoic Seluohe Group, and the grade of the gold ore is high but the ore body is small; （2） the brittle compound superimposed tectonic belt, controlled ore body in granite mass with large scope and high grade, as the main structure in the mining area; （3） interlayer detachment structure, making the ore body occurred between marble layers, small in scope, with the dip end of fold as the beneficial place of ore finding mine. Under the regional extrusion stress setting, the activities of deep and big faults for many times resulted in activation of gold in the metamorphic series. Au-rich magma intruded along the crust faults ascendingly. The gold deposits were formed in 145 Ma transitional period from compression to extension, corresponding to the period of large-scale delamination of the lithosphere. Under the regional background of geologic structure, the magma containing ore-forming fluids moved up to the sub-faults. In some conditions of physics and chemistry the gold precipitated and formed the Haigou gold deposit.
出处
《世界地质》
CAS
CSCD
2007年第3期275-281,共7页
World Geology
关键词
控矿构造
脆-韧性剪切带
脆性复合叠加构造
层间虚脱构造
挤压应力
海淘金矿
ore controlling structure
brittle-ductile shear zone
extrusion stress
brittle compound super imposed tectonic belt
inlerlayer detachment structure
Haigou gold deposit
