塔里木东北部中坡山北层状镁铁-超镁铁质岩体成因及成矿作用

项目名称： 塔里木东北部中坡山北层状镁铁-超镁铁质岩体成因及成矿作用

项目编号： No.40872070

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 矿业工程

项目作者： 姜常义

作者单位： 长安大学

项目金额： 44万元

中文摘要： 中坡山北岩体是我国境内目前已知出露面积最大的镁铁-超镁铁质层状岩体之一。岩体中存在两类层状岩系，含有两种类型的岩浆型矿床。构成岩体主体的是以镁铁质岩石为主的层状杂岩体，堆晶韵律是橄榄辉长苏长岩-辉长岩-淡色辉长岩±石英闪长岩或斜长岩，其中存在与堆晶层理整合的磁铁矿层。在镁铁质层状岩系下部和磁铁矿层中具有较好的铂族元素成矿前景。岩浆镍铜硫化物矿床赋存于晚期侵入的、以超镁铁质岩石为主体的小型层状侵入体中。其中，坡一和坡十小侵入体中均有工业品位的铜镍硫化物矿体产出。研究显示坡一和坡十侵入体中堆晶结构与韵律性堆晶层理非常发育，岩浆经历了充分的分异演化过程。岩浆演化过程遭受了较强的同化混染作用。原生岩浆为苦橄质岩浆，岩浆源区属洋岛型，源岩物质应该是石榴石辉石岩。此外，岩浆经历了早阶段硫化物熔离，现存的硫化物矿体形成于岩浆阶段，硫化物过饱和及分凝是岩浆自身演化和同化混染共同作用的结果，此类侵入体深部找矿潜力巨大。中坡山北岩体与塔里木板块东北部二叠纪幔源岩浆岩的生成与地幔柱活动有关，应该是塔里木大火成岩省的组成部分。

中文关键词： 成矿作用；岩石成因；层状岩体；中坡山北

英文摘要： The Zhongposhanbei intrusion is one of the largest layered mafic-ultramafic intrusions in China. It comprises two layered rock series with different type magmatic sulfide deposit. The layered intrusion, which is mainly composed of mafic rocks, show the rhythmic layering characteristic of olivine gabbro norite-gabbro- leucocratic gabbro±quartz diorite or plagiocasite. There are lots of magnetite layers in the intrusion. and the magnetite layers are conformable contact with rhythmic layering. and the lower part of the mafic layer and the magnetite layer are hosts of PGE mineralization.However, Magmatic Ni-Cu sulphide deposits mainly host in small layered ultramafic intrusions by late invaded. for example Poyi and Poshi intrusions have industrial copper-nickel sulfide ore body. The studies indicate that they develop cumulate texture and rhythmic layering and the magma differentiated thoroughly. At the same time, contamination promoted magmatic differentiation. And the primary magma is picritic and the main rock of magmatic source should be garnet-pyroxenolite. In addition, sulphide formed during magmatic stage, and the metallogenetic magma had gone through segregation of sulfide, which was the result of magmatic evolution and contamination. Therefore, exploration potential is better in deep.and Lots of research also show Zhongposhanbei intrusion and the other Permian magmatite in northeastern Tarim Plate should be part of the Tarim large igneous province (LIP).

英文关键词： Mineralization；Petrogenesis；layered intrusions；Zhongposhanbei