甘肃北山拾金滩岩体与邻区超基性岩体岩石地球化学特征对比及成矿潜力浅析

摘要

Shijintan basic-ultrabasic rock body is a small copper-nickel mineralization rock that was recently discovered. The rock body is in the volcano stone tectonic melange zone and mineralized,it was composited of serpentinized dunite, olive two eclogite,gabbro,mafic to diabase;Metal mineral in pentlandite,chalcopyrite, pyrrhotite,magnetite ore rock;Com-parison to the other ultrabasic rock body,Shijintan rock body has a low SiO2;high MgO,low TiO2,low magnesium iron characteristics;Aluminum supersaturation ANK greater than 1 and lower than the other body;Mg# value between79.99%~81.19%,generally higher than Guaishishan and Heishan copper-nickel ore rock;Rare earth elements content was lower than the other body;Through analysis of geophysical and geochemical anomalies and surface mineralization body,con-clude that Shijintan rock body has good mineralization potential.%　　拾金滩基性超基性小岩体,是最近发现的铜镍矿化岩体.该岩体处于火山岩构造混杂岩带内,全岩矿化,超基性岩露头有：蛇纹石化纯橄岩、橄榄二辉岩、二辉橄榄岩,基性岩有辉长岩、辉绿岩脉；矿化岩体中金属矿物以镍黄铁矿、磁黄铁矿、黄铜矿、磁铁矿为主；与该地区其它含矿岩体相比,拾金滩岩体具常量元素差别不大、低SiO2、高MgO、低TiO2、低镁铁比特点；铝过饱和度ANK大于1,普遍低于该地区其它岩体；Mg#值介于79.99%~81.19%,普遍高于怪石山和黑山铜镍矿岩体的Mg#值；稀土元素总量较低的特点.通过构造环境对比、地质特征对比及物化探特征研究,认为拾金滩岩体具形成铜镍矿的良好潜力.