东天山地区铜镍矿找矿评价指标探讨

摘要

The magmatic Cu-Ni sulfide deposit is mainly hosted in mafic-ultramafic intru-sions which are generally small scales. The ore body is mainly hosted in the base of the intru-sion. This forms a large number of deposits which we call“mall intrusion forming large depos-it”. In the world,there are many mafic-ultramafic intrusions,but how to determine the metallo-genic potential of intrusion has been concerned all the time. In this paper,based on previous studies,we take eastern Tianshan as an example,compare and analyze the geological and geo-chemical characteristics of the economic mineralized mafic-ultramafic intrusions and the uneco-nomic mineralized mafic-ultramafic intrusions,in order to distinguish the metallogenic potential from theory. The prospecting evaluation indexes are gained from this study,mineralized mafic-ultramafic intrusions are generally characteristic by right incline in Chondrite normalized REE pattern diagrams;several stages of magma intruding are important;a certain amount of orthopy-roxene is contained in the rock;the mineral grains are obviously different,et al.%岩浆铜镍硫化物矿床主要赋存在镁铁-超镁铁质岩体中，赋矿岩体规模一般较小，矿体主要赋存在岩体的下盘，形成了很多小岩体大矿床的现象。世界上镁铁-超镁铁质岩体很多，如何判定岩体深部是否具有成矿潜力一直是大家关注的焦点。本文在前人大量研究的基础上，以东天山地区为例，对比剖析了成矿与不成矿镁铁-超镁铁质岩体的地质、地球化学特征，试图从理论上判别岩体的成矿潜力。提出成矿的超镁铁质岩体一般具有明显右倾的稀土配分曲线，岩体属于多期岩浆侵入形成，岩石中含一定量的斜方辉石，造岩矿物颗粒大小具有明显变化等找矿评价指标。