东疆图拉尔根铜镍矿的岩石矿物学研究

发布时间：2018-02-20 22:40

本文关键词： 图拉尔根橄榄石母岩浆成矿过程　出处：《中国地质大学(北京)》2015年硕士论文　论文类型：学位论文

【摘要】：中亚造山带为全球最大的显生宙陆壳增生造山带,也是重要的岩浆铜镍硫化物矿床成矿带之一,一直备受地质工作者的研究与关注。在中亚造山带南缘,广泛分布着大量的镁铁质-超镁铁质的铜镍硫化物含矿岩体,分布一系列大中型铜镍硫化物矿床,如东天山地区(黄山、黄山东、葫芦、图拉尔根、香山等),北山地区(黑山、笔架山、红石山等)。图拉尔根铜镍矿大地构造上位于觉罗塔格构造杂岩带北东端,该带遭受强烈的韧性剪切作用,分布着众多的镁铁质-超镁铁质含矿岩体。图拉尔根铜镍矿有3个含矿岩体,其中Ⅰ号岩体出露面积较小,但全岩矿化,品位较富,也是目前正在开采的对象。铜镍矿上部矿石品位高而下部低,与其他铜镍矿相比具有较大的差别,有违铜镍矿底部富集的一般规律。论文选取Ⅰ号岩体为研究对象,在大量搜集前人研究的基础上,运用岩石学、矿物学、地球化学等方法,取得了以下几点认识:①Ⅰ号岩体出露面积较小,矿体岩相分带明显,系同源岩浆经过深部分异多期次侵入形成的复式岩体。从内而外依次为角闪橄榄岩、角闪橄辉岩、橄榄辉石岩、辉石岩、辉长岩,各岩相之间呈渐变过渡形式。海绵陨铁状矿石及块状矿石主要产在角闪橄榄岩中,主要造岩矿物有辉石、橄榄石、角闪石、长石、黑云母。②图拉尔根铜镍矿岩体中造岩矿物橄榄石中的Ni含量较高,Fo值81.08~84.53。为贵橄榄石。橄榄石成分受晶间残余熔浆影响较大,Fo值从边部到核部呈升高的趋势。③通过模拟计算得到图拉尔根原始岩浆是由原始地幔经过14%的部分熔融后形成的,成矿过程中,首先橄榄石发生了3%的结晶分异,然后S达到饱和,硫化物开始熔离。④部分橄榄石中Ni含量异常偏高,一方面是造山碰撞后伸展阶段,软流圈岩浆上涌,H2O的加入提高了氧逸度,其证据是矿区中发现大量的富水矿物-角闪石。另一方面是源源不断上涌的岩浆为成矿体系提供大量的Ni,增加的Ni足以抵消因硫化物熔离,橄榄石结晶分异造成的Ni含量减少。
[Abstract]:The Central Asian orogenic belt is the largest Phanerozoic continental crust accretion orogenic belt in the world. It is also one of the important metallogenic belts of magmatic copper-nickel sulfide deposits. A large number of mafic-ultramafic copper-nickel sulphide ore bodies are widely distributed, and a series of large and medium-sized Cu-Ni sulphide deposits are distributed, such as the East Tianshan area (Huangshan, Huangshan, Shandong, Hulu, Tulargen, Xiangshan, etc.), the Beishan region (Montenegro, China). Bijiashan, Hongshi, etc. Tulargen copper-nickel ore deposits are located in the northern eastern end of the Chuolatag structural complex belt, which is subjected to strong ductile shear. There are many magnesia-ultramafic ore-bearing rock bodies. There are three ore-bearing bodies in Tulargen copper-nickel ore deposit, among which the No. 1 orebody has a small exposed area, but the whole rock is mineralized and has rich grade. The ore grade of the upper part of the copper and nickel ore is high but the lower part is low, which is different from other copper and nickel ores, which is contrary to the general law of enrichment at the bottom of the copper and nickel ore. In this paper, the No. 1 rock mass is chosen as the research object. On the basis of a large number of previous studies and by using petrology, mineralogy, geochemistry and other methods, the authors have obtained the following conclusions: the exposed area of the No. 1 ~ (-1) rock mass is relatively small, and the lithofacies zoning of the orebody is obvious. The homologous magma is a complex rock mass formed by deep partial heterodyne intrusions. The order from inside to out is hornblende, hornblende, olivine pyroxenite, pyroxenite, gabbro, etc. The spongy meteorite iron ore and massive ore mainly occur in hornblende peridotite, and the main rock-forming minerals are pyroxene, olivine, hornblende, feldspar, etc. Biotite .2 the content of Ni in the lithogenic olivine in Tulargen copper-nickel ore body is higher than that in the lithogenic mineral olivine. It is an expensive olivine. The composition of olivine tends to increase from the edge to the nucleus by the intergranular residual slurry. The simulation results show that the primitive magma was formed by the partial melting of the primitive mantle in 14%. During the process of mineralization, first of all, 3% crystal differentiation occurred in olivine, then S reached saturation, and the Ni content of olivine began to melt away from 4.4. on the one hand, the extensional stage after orogenic collision occurred, on the one hand, the content of Ni in olivine was abnormally high. The addition of H _ 2O to the magma upwelling in the asthenosphere increases the oxygen fugacity. The evidence is that a large number of water-rich minerals, hornblende, are found in the mining area. On the other hand, the rising magma provides a large amount of Ni for the ore-forming system, and the increase of Ni is enough to counteract the decrease of Ni content caused by the crystallization differentiation of olivine due to sulfide melting.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.41;P618.63

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