东天山云海铜镍矿地球化学特征及成因分析

云海铜镍矿位于觉罗塔格构造带西段,成矿岩体为多期次侵入的杂岩体,岩体分异演化充分,镁铁质和超镁铁质岩石均有发育,主要岩石类型为角闪辉石岩、橄榄苏长岩、辉长岩、闪长岩。主量元素化学组成表明,该杂岩体属拉斑玄武岩系列,岩石具同源演化特征,显示高铁、高镁、低钛、低铝特征,富集大离子亲石元素Rb,Ba,亏损Nb,Ta,轻稀土富集。岩浆源区有部分熔融而交代的岩石圈地幔,岩浆在上升过程中受到地壳物质混染,发生橄榄石、斜方辉石、斜长石的分离结晶。岩体形成于早二叠世,为构造活动和地幔柱双重作用下的产物。

Geochemical Characteristics and Genesis of Yunhai Cu-Ni Deposit in Eastern Tianshan

s:Yunhai copper nickel deposit is located in the western part of Jueluotage structural belt,The ore-forming rocks are multi-stage intrusive complexes,and the differentiation and evolution of the rock mass is full.Mafic and ultramafic rocks are developed..The main rock types of the complex include hornblende pyroxene,olivine norite,gabbro and diorite.The major elements composition indicates that the complex belongs to the tholeiitic series.The rocks have the characteristics of homologous evolution,it is characterized by high iron,high magnesium,low titanium and low aluminum.They are enriched in large ion lithophile elements Rb and Ba,depleted in Nb and Ta,and enriched in LREE.The magma source area is the lithospheric mantle with partial melting and metasomatism.The magma was contaminated by crustal materials during the rising process,and the fractional crystallization of olivine,orthopyroxene and plagioclase occurred.The pluton was formed in the early Permian and it is the product of tectonic activity and mantle plume.