铁格隆南铜金矿床(荣那矿段)是在西藏班公湖-怒江成矿带上多龙矿集区内发现的青藏高原首例高硫化型浅成低温热液型Cu(Au)矿床.文章通过对铁格隆南铜金矿床金属矿物、蚀变矿物组合、蚀变分带及流体包裹体地球化学特征的研究,初步确定了矿床类型,探讨了矿床成因.铁格隆南矿区存在硫砷铜矿、铜蓝、蓝辉铜矿等典型的高硫化态矿物组合和黄铜矿、斑铜矿等斑岩型矿床的典型矿物,此外,还识别出久辉铜矿、斯硫铜蓝、吉硫铜矿等少见的Cu-S二元体系矿物组合.矿床蚀变矿物组合以典型的强酸性环境下的明矾石-高岭石-地开石等黏土矿物组合为特征,并见金红石、锐钛矿、硬石膏、磷锶铝石、叶蜡石、水铝石等特征蚀变矿物.蚀变分带特征为石英-明矾石-高岭石/地开石带和高岭石-地开石带组成的高级泥化带叠加在绢英岩化带和钾化带的顶部和外围.矿区存在高温、高盐度(404~430℃,32.39% ~38.94%)的岩浆流体和中低温、低盐度(239~292℃,0.35% ~4.18%)的高硫化型矿化流体.高温、高盐度富气相(主要是H2O、HCl、SO2)的岩浆流体与大气降水的混合,形成的强酸性高氧逸度的中低温、低盐度流体,是高硫化型浅成低温热液矿床蚀变和矿化形成的关键.多龙矿集区具有较典型的斑岩型-浅成低温热液成矿系统的矿物组合、蚀变组合及成矿流体特征,因此预测矿集区内还能找到类似的斑岩型-浅成低温热液型矿床.
The Southern Tiegelong Cu (Au)deposit(Rongna)within the Duolong ore concentration area along the Bangong Co-Nujiang River metallogenic belt is the first discovered high sulfidation epithermal Cu(Au)deposit in the Tibetan Plateau.The authors studied ore minerals,alteration assemeblages,alteration distribution and fluid inclusions of this deposit to preliminarily determine the deposit type and the genesis.There are some typical high sulfidation minerals such as enargite,covellite and digenite and porphyry system minerals such as chalcopyrite and bornite.In addition,some rare Cu-S systematic minerals like djurleite,spionkopite and geerite were recognized.The allteration is characterized by such typical clay minerals as alunite,kaolinite and dickite in acid environment,and rutile,anatase,anhydrite,goyazite,pyrophyllite and diaspore as well.The alteration consists of quartz-alunite-kaolinite/dickite belt and kaolinite-dickite belt,superimposed upon the argillic alteration belt at its top and in its outskirts,with phyllic and potassic alteration located in the lower east place.Two different fluids exist in the deposit,which are the high temperature and high salinity fluid(404~430℃,32.39 %~ 38.94 %) from the magma and the middle-low temperature and low salinity fluid(239~292℃,0.35 %~ 4.18 %) of high sulfidation respectively.The mixture of the high temperature and high salinity magmatic hydrothermal fluid enriched in vapor (mainly H2O,HCl and H2S) and the meteoric water seems to have been the key to form acidic,high f(O2),middle-low temperature and low salinity fluid that contributed to the formation of high sulfidation epithermal alteration and mineralization.There is a typical porphyry-epithermal system in the Duolong ore concentration area which contains specific minerals,alteration and fluid,which indicates that some other similar porphyry-epithermal deposits could be discovered in this region.