中条山铜矿峪铜矿含矿岩系地球化学特征及矿床成因

中条山铜矿峪斑岩型铜矿床位于秦岭造山带北端,矿体主要赋存于变质花岗闪长斑岩、黑云母片岩和变质基性火山岩中。矿区内含铜岩系的全岩地球化学分析显示,主量元素表明矿区的含铜岩系均表现出富钾、富铝的特征;微量元素表明所有样品均显示出相对富集大离子亲石元素(K、Rb、Ba等),亏损高场强元素(P、Y、Ti、Nb、Ta等),反映岩浆源区可能遭受过俯冲带流体的交代作用,具有岛弧玄武岩的地球化学特征;稀土元素特征显示出明显的轻重稀土分馏,轻稀土富集,所有样品都表现出弱的铕负异常。研究认为,变质花岗斑岩、黑云母片岩和绢英岩的原岩初步定为钙碱性玄武岩或拉斑玄武岩,铜矿峪铜矿床形成于挤压与拉张构造环境的转换阶段,其成因类型应属于斑岩型铜矿床。

Geochemical characteristics of ore-bearing rock series and ore genesis of Tongkuangyu copper deposit in Zhongtiao mountains

Tongkuangyu copper deposit of Zhongtiao mountains is located in the northern Qinling ogenic zone.The ore bodies mainly occurred in the metamorphic granodiorite porphyry,biotite schist and metamorphic basic volcanics.According to the geochemical analysis of ore-bearing rock series from the Tongkuangyu copper deposit,the characteristics of major elements indicated that copper-bearing rock series is rich in K and Al.The trace elements indicated that all the samples showed a relative enrichment of LILE （K,Rb,Ba,etc） and depletion of HFSE （P,Y,Ti,Nb,Ta,etc）,reflecting that the magma source may have suffered metasomatism of the fluids in subduction zones,which has the geochemical characteristics of arc basalt.Characteristics of REE showed the obvious fractionation of LREE and HREE,slight negative Eu anomalies and enrichment in light REE.It is considered that the original rocks of metamorphic granodiorite porphyry,biotite schist and sericitolite belonged to calc-alkaline basalt or tholeiite.Tongkuangyu copper deposit was formed in the conversion stage of extension-compression,and the genetic type of Tongkuangyu copper is defined as porphyry copper deposit,in general.