甘肃肃北黑山镍铜矿床产出特征及对比研究  

Comparative Study on the Characteristic Occurrences of Heishang Ni-Cu Deposit in Subei County of Gansu Province

作　　者：张新虎 冯军 殷勇 孙金兰 

机构地区：[1]甘肃省地矿局,甘肃兰州730000 [2]甘肃省地调院,甘肃兰州730000 [3]甘肃省地矿局矿研院,甘肃兰州730000

出　　处：《西北地质》2012年第4期134-144,共11页Northwestern Geology

基　　金：2006~2010年甘肃省矿产资源补偿费(甘财建[2006]73号)项目"甘肃省1:100万地质矿产图";甘肃省重大科技专项(1002FKDA042)

摘　　要：黑山铜镍矿床位于哈萨克斯坦古板块马鬃山中间地块的南部边界黑山-碱泉子深大断裂上。构造属性属于古老地块边部的边缘裂谷性质。区域上断裂及岩体显示明显的重磁异常。含矿岩体侵位于青白口系大豁落山群白云石大理岩及寒武系西双鹰山组碳质硅质板岩、变质长石石英砂岩及重晶石岩中。岩体平面形态呈鸭梨形,北西方向略有拉长。长约800m,宽约470m,出露面积约0.25km2。属同源同期多次侵入形成的复式岩体,主体为斜长方辉橄榄岩、角闪橄榄岩、橄榄角闪辉长岩和角闪辉长岩。侵入顺序是第一期角闪辉长岩相,由角闪辉长岩及其内部的石英正长岩团块组成;主体第二期橄榄角闪辉长岩-斜长方辉橄榄岩相,由橄榄角闪辉长岩、角闪橄榄辉长岩、橄榄辉长岩和斜长方辉橄榄岩组成。岩体化学成分平均值与超基性岩化学成分相似。岩石的碱度指数σ值很低,平均为0.05;TiO2为0.28;m/f4.79(吴利仁);查氏数值b=56.00,s=39.77;m′=81.68;Na2O>K2O,碱度类型属极强太平洋型。原始岩浆具橄榄拉斑玄武岩性质,物质来源于上地幔。镁铁比值平均为4.79。铜镍矿体主要赋存于岩体的中部和下部,呈透镜状、脉状和似层状,成矿母岩和储矿岩石主要是方辉橄榄岩,其次为角闪辉长岩。矿体根据时间和成因又分为就地熔离矿体、晚期贯入矿体和接触交代矿体。矿石矿物有红砷镍矿、砷镍矿、黄铜矿、针镍矿、镍黄铁矿、磁黄铁矿和辉铜矿,其次有黄铁矿、紫硫镍矿和自然铜。金属氧化物有磁铁矿。伴生有益组分为Pt、Pd、Au、Ag、Os、Ir、Ru、Rh、Se、Te、Cr等。有害组分为:Pb、Zn、As、Bi。矿石的化学组分具有贫碱、低铝、低钙的特点。黑山铜镍矿和金川铜镍矿床在成岩成矿地质背景、重磁异常、含矿岩体的产出特征、矿体产出规律、岩石化学及矿化元素等方面具有相同之处,尽管在Heishan Ni-Cu deposit is situated on the Heishan-Jiznquanzi Fault which is the south margin of Mazongshan middle block within Kazakhstan paleo- plate. The fault has the characteristics of marginal rift on the edge of paleo- plate, and regionally, the fault and rock mass appear the obvious gravity and magnetic anomaly. The ore-bearing rock body intruded into dolomite marble of Qingbaikou Series Dahui- oluoshan Group, and Cambrian Shuanyingshan Formation carbonaceous-siliceous-slate, metamor-feldspar- quartz-sandstone and baritic rock. Viewing from the surface, the body is the pear shape with the outcrop area of nearly 0.25 km2 , slightly longer on the NW direction, about 800 m long and 470 m wide. It is a complex massif developed from multi-intrusive of the same source and period, mainly comprised of plagio- harzburgite, hornbtende-olivinite, olivine-hornblende-gabbro, and hornblende gabbro. The first phase is hornblende-gabbro facies which consist of hornblende-gabbro and quartz-syenite block within gabbro. The second phase is olivine-hornblende-gabbro and plagio-harzzburgite facies which consist of olivine- hornblende-gabbro, hornblende-olivine-gabbro, hornblende gabbro, and plagio-harzburgite. The average of chemical composition is similar with ultrabasie rock. The basicity index a is very low, average is 0. 05, TiO2 0.28, m/f （Wu Liren） 4. 79, Zavaritskiivalues b=56.00, s=39. 77; m＇= 81.68; Na2O〉K2O, the basicity type is Pacific type. The protomagma is characterized of olivine-tholeiite, came from the upper mantle. The average value of Mg/Fe is 4. 79. Ni-Cu orebody with appearance of len, vein and stratiform- like mainly exist the middle and lower part of rock mass. Mother rock and ore-bearing rock mainly consist of harzbeugite, secondly hornblende-gabbro. The ore body is classified into 3 types： insitu liquation, late period injection and contact metamorphic body. The ore minerals include niecolite, ehloanthite, chaleopyrite, millerite, magnetic pyrite, chaleocite, as well as some pyrite, violarite

关 键 词：黑山铜镍矿 地质背景 产出特征 金川铜镍矿 对比研究 

分 类 号：P611.1[天文地球—矿床学]