紫金山铜金矿床是我国东南沿海著名的高硫化型浅成低温热液矿床。通过对近几年紫金山铜金矿床深部发现的Ⅺ号铜矿带的铜矿石样品进行采样,利用显微镜观察、电子探针分析等方法,对铜矿石结构构造、矿物种类及矿物成分等进行了较深入和系统的研究。Ⅺ号铜矿带的主要金属矿物有黄铁矿、Cu-S体系矿物、硫砷铜矿,次要金属矿物有黄铜矿、斑铜矿、似黄锡矿、硫铋铜矿等,是一套高硫化型铜矿物组合,主要非金属矿物为石英、明矾石、地开石、绢云母。矿石结构以固溶体分离结构、交代残余结构、它形—自形粒状结构和包含结构为主。矿石构造主要为浸染状、脉状、网脉状、团块状和条带状构造,具典型的热液交代矿石特征。斜方蓝辉铜矿和久辉铜矿为形成温度低于63℃的矿物,因而推断Ⅺ号铜矿带属于紫金山高硫化低温热液型矿床的尾部,下部可能存在其他成因类型的矿床。
Zijinshan Cu-Au Deposit is a famous high sulfidation epithermal deposit located in the southeast coast of China.Based on the samples from No.Ⅺ copper ore zone which is found at the depth of Zijinshan Cu-Au deposit in recent years,a systematic study on the copper polymetallic ore texture and structure,mineral types and component by identification under microscope and EMPA.Research shows that metallic minerals at No.Ⅺcopper ore zone are a series of high sulfide copper minerals include mainly metallic minerals pyrire,Cu-S series minerals and enargite,minor metallic minerals chalcopyrite,bornite,stannoidite,wittichenite et al.Major non-metallic minerals are quartz,alunite and dickite,sericite.The exsolution texture,metasomatic relict texture,automorphic-xenomorphic granular texture and poikilitic texture are obvious.Such structures as vein,mesh-vein,nodular and disseminated structures are the main ore structure.These textures and structures perform the characteristics of hydrothermal metasomatic ore.Moreover,the anilite and djurleite turn into a matrix phase whose formation temperature less than63℃.Therefore,we speculated that No.Ⅺ copper ore zone has been presented in the empennage of Zijinshan high sulfidation epithermal deposit and it may be underlain by other type genesis deposits.