投稿时间：2013-01-11
修订日期：2013-11-04
网络发布日期：2013-12-29
中文摘要:黑龙江省岔路口超大型斑岩钼矿床位于大兴安岭北部，是目前中国东北地区最大的钼矿床，矿体赋存于中酸性杂岩体及侏罗系火山-沉积岩内，其中，晚侏罗世花岗斑岩、石英斑岩、细粒花岗岩与钼矿化关系密切。6件辉钼矿样品的铼-锇等时线年龄为（148±1）Ma。中侏罗世二长花岗岩属钾玄岩系列，w（SiO2）为69.48% ~ 74.98%，w（Al2O3）为12.35%~14.48%，w（K2O+Na2O）为7.67%~10.42%，K2O/Na2O比值介于1.07~2.81。轻、重稀土元素分馏较强，具有较弱的铕负异常，HFSE和LILE分异明显，Rb、K等元素富集，Ta、Nb、P、Ti等元素亏损，显示正εHf（t）值；晚侏罗世花岗斑岩、石英斑岩属钾玄岩系列，而细粒花岗岩属高钾钙碱性系列，w（SiO2）为73.87%~78.95%，w（Al2O3）为10.35%~13.47%，w（K2O+Na2O）为8.06%~10.02%，K2O/Na2O比值介于1.03~8.20。轻、重稀土元素分馏较强，具有明显的铕负异常，HFSE和LILE分异明显，Rb、K、Th等元素富集，P、Ti、Ba、Sr等元素亏损，显示正εHf（t）值。二长花岗岩、花岗斑岩、石英斑岩及细粒花岗岩均为高硅、富碱的高分异I型花岗岩，岩浆源区组成类似，主要来自于新元古代期间亏损地幔增生的年轻下地壳物质。岔路口斑岩钼矿床是晚侏罗世大陆内部构造-岩浆活化的产物，形成于蒙古-鄂霍次克造山带后碰撞伸展环境，同时，可能受到古太平洋板块俯冲诱发的弧后伸展作用的叠加。
Abstract:Located in northern Da Hinggan Mountains, the Chalukou superlarge porphyry Mo deposit is the largest Mo deposit in Northeast China. Its ore bodies are mainly hosted in the intermediate-acid complex and Jurassic volcanic sedimentary rocks, of which Late Jurassic granite porphyry, quartz porphyry and fine grained granite are closely associated with Mo mineralization. The Re-Os isochronic age of six molybdenite samples is (148±1) Ma. The Middle Jurassic monzogranites are of shoshonite series. Their w(SiO2)and w(Al2O3) values are 69.48%~74.98% and 12.35%~14.48%, respectively. The total alkali w(K2O+Na2O) content ranges from 7.67% to 10.42%, with K2O/Na2O ratios being from 1.07 to 2.81. REE analyses demonstrate intense fractionation between LREE and HREE, with weak negative Eu anomalies. The trace element analyses show clear fractionation between HFSE and LILE, and the rocks are strongly enriched in Rb and K but depleted in Ta, Nb, P and Ti, indicating clear positive εHf(t). The Late Jurassic granite porphyry, quartz porphyry and fine grained granite are of shoshonite or high-K calc-alkaline series. Their w(SiO2)and w(Al2O3)content ranges 73.87%~78.95% and 10.35%~13.47%, respectively. The total alkali w(K2O+Na2O) content ranges 8.06%~10.02%, with K2O/Na2O ratios varying from 1.03 to 8.20. The REE analyses demonstrate intense fractionation between LREE and HREE, with clear negative Eu anomalies. The trace element analyses show clear fractionation between HFSE and LILE, and the rocks are strongly enriched in Rb, K and Th but depleted in P, Ti, Ba and Sr, indicating clear positive εHf(t). The monzogranite, granite porphyry, quartz porphyry and fine grained granite are silicon-high and alkali-rich highly fractionated I-type granite, derived from the juvenile lower crust materials originating from the Neoproterozoic depleted mantle. The mineralization of the Chalukou deposit took place in the Late Jurassic, and the mineralization occurred in an extension tectonic setting at the post-collision stage of the Mongolia-Okhotsk orogeny, followed by the back-arc extension related to the subduction of the Paleo-Pacific Plate.
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中图分类号：P618.52
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基金项目:本文得到国家自然科学基金项目（编号：41202058和41172081）、云南驰宏资源勘查开发有限公司科研项目（编号：201107ZKJS-01）和中国地质调查局地质调查项目（编号：1212011085260和12120113093600）的联合资助
引用文本：
刘军,武广,王峰,罗大锋,胡妍青.2013.大兴安岭北段岔路口斑岩钼矿床成矿年代学、岩石地球化学及其地质意义[J].矿床地质,32(6):1093~1116LIU Jun,WU Guang,WANG Feng,LUO DaFeng,HU YanQing.2013.Geochronology and petrogeochemistry of Chalukou porphyry Mo deposit in northern Da Hinggan Mountains[J].Mineral Deposits32(6):1093~1116
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