新疆谢米斯台山乌图顺岩体地球化学特征及其与金成矿关系

Geochemical characteristics of Wutushun intrusives in Xiemistai mountain of Xinjiang and its relationship with gold mineralization

新疆西准噶尔盆地北缘的谢米斯台山发现了众多产于岩体外接触带的金矿床(点),尤以乌什加嘎衣提金矿床最为典型。乌什加嘎衣提金矿床产于乌图顺岩体北部的内凹部位,由52条金矿体组成,矿石可分为石英大脉型,蚀变岩型和石英复脉型3种。乌图顺岩体主要岩性为二长花岗岩,其地球化学特征显示出高钾(K_(2)O=4.09%~4.86%),准铝质(A/CNK=0.90~1.01),轻重稀土明显分异(LREE/HREE=7.88~8.28),铕异常不明显(δEu=0.77~0.86),富集大离子亲石元素K、Rb、Ba、Th,亏损高场强元素Ti、Nb和重稀土元素Gd、Dy、Y、Er的特征,为高钾钙碱-钾玄岩系列,属I型花岗岩,形成于俯冲背景。结合前人对乌图顺岩体与乌什加嘎衣提金矿床研究获得的地球化学、年代学、氢、氧、硫同位素数据,综合分析岩体与金成矿之间的时空和成因联系,认为岩浆作用是金矿床形成的主要因素。在此基础上,尝试建立了乌什加嘎衣提式岩浆热液型金成矿模式,以期指导谢米斯台山地区与侵入岩相关的金矿床勘查和研究。

Many gold deposits or gold points have been found in the contact zone outside the intrusives in the Xiemisitai Mountain in the northern margin of west Junggar Basin of Xinjiang.The typical deposit Wushenjiagayiti gold deposit.The gold deposit of Wushenjiagayiti is produced in the concave part of the northern Wutushun intrusives,which is composed of 52 gold ore bodies.The ore bodies can be divided into three types:quartz large vein gold mineralization,altered rock type and quartz complex vein type.The main lithology of Wutushun intrusives is monzonitic granite,and its geochemical characteristics show high-K(K_(2)O=4.09%-4.86%),quasi-aluminums rocks(A/CNK=0.90-1.01),significant differentiation of light and heavy rare earths(LREE/HREE=7.88-8.28).The Eu anomaly is not obvious(δEu=0.77-0.86),enrichment of LILE(K,Rb,Ba,Th),loss of HFSE(Ti,Nb)and HREE(Gd,Dy,Y,Er),which has the characteristics of high-potassium calc-alkaline-basalt series and I-type granite,generated in the subduction subduction context.A comparative study the geochemistry,chronology,hydrogen isotopes,oxygen isotopes and sulfur isotopes obtained from the Wutushun intrusives and the Wushenjiagayiti gold deposit by the previous researchers.and a comprehensive analysis of the spatial,temporal and genetic links between intrusives and gold mineralization suggests that magmatism is the main factor in the formation of gold deposits.On this basis,a tentative model of Wushenjiagayiti-type magmatic-hydrothermal gold mineralization was established to guide the exploration and study of gold deposits associated with intrusives in the Xiemistai Mountain.