青藏高原北羌塘盆地纳日贡玛铜钼矿床地质特征及控矿条件
Geological Features of Copper-Molybdenum Deposit in Narigongma Area of Qiangtang Basin in Qinghai-Xizang Plateau
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摘要: 纳日贡玛铜钼矿床属斑岩型铜矿,处于班公湖-怒江缝合带北侧、金沙江缝合带以南的羌北-昌都地块,与玉龙斑岩铜矿床同属一个成矿带。早中二叠世尕笛考组为主要赋矿地层,铜矿体主要产于靠近斑岩体上部的硅化绢云母化黑云母二长花岗斑岩和接触带部位的蚀变玄武岩中,形态复杂,矿石类型较简单。钼矿主要产于斑岩体内具弱蚀变的黑云母二长花岗斑岩、浅色花岗闪长斑岩和强蚀变的硅化绢云母化黑云母二长花岗岩斑岩中,少量分布于黄铁矿青磐岩化玄武岩中,沿走向及倾斜方向延伸比较稳定。矿石类型以细脉浸染型铜钼矿为主,其来源于陆内碰撞而加厚的下地壳。复合断裂是控制本区斑岩成矿带的主要因素,铜钼矿床即产于大断裂交汇部位。中酸性侵入体是内在控矿因素,裂隙构造系统也具有重要的控矿作用。Abstract: The copper-molybdenum deposit in Narigongma area lies in the Qiangbei-Changdu block,which is in the north of Bangonghu-Nujiang suture zone and the south of Jiangshajiang suture zone.This deposit and Yulong porphyry cupric deposit belong to the same mineral belt.The cupric ore bodies generally distribute in the upper porphyry and melaphyre,and are complicated in shape and simple in mineral type.The molybdenum ore bodies mostly lie in granide,diorite and black mica granide and a few in pyrite propy litization basalt.The fluid inclusion shows that the source of impregnating copper-moly bdenum deposit is from lower crust.The composite rupture is mainly factor for controlling the mineral deposit in this area,and the copper-molybdenum depo sitlies in the crossed area of large faults.The intermediate intrusive is inner controlling factor,and the fissure tectonic system also plays the important rule for controlling minerlization.