乌兰茶卡北山含矿伟晶岩地球化学特征及地质意义  

Geochemical Characteristics and Geological Significance of Ore-bearing Pegmatites in the Wulan Chakabeishan Area

作　　者：王建国[1,2] 张世珍 邢佳 王志男 魏生云 胡建 WANG Jianguo;ZHANG Shizhen;XING Jia;WANG Zhinan;WEI Shengyun;HU Jian(Department of Geological Engineering,Qinghai University,Xining 810016,Qinghai,China;State Key Laboratory of Mineral Processing Science and Technology,Beijing 102628,China;The Third Institute of Geology and Minerals Exploration,Gansu Provincial Bureau of Geology and Minerals Exploration and Development,Lanzhou 730050,Gansu,China)

机构地区：[1]青海大学地质工程系,青海西宁810016 [2]矿物加工科学与技术国家重点实验室,北京102628 [3]甘肃省地质矿产勘查开发局第三地质矿产勘查院,甘肃兰州730050

出　　处：《黄金科学技术》2022年第6期809-821,共13页Gold Science and Technology

基　　金：国家自然科学基金项目“基于微观层面分析的岩矿电阻率耦合机理及其模型:以查藏错铜铅锌矿床为例”(编号:42164007);青海省应用基础研究计划项目“柴北缘地区铍矿床成矿约束条件、地质意义及靶区优选”(编号:2019-ZJ-7022);矿物加工科学与技术国家重点实验室开放基金项目“典型金属矿物标型特征及其对可选性的影响”(编号:BGRIMM-KJSKL-2020-04)联合资助。

摘　　要：伟晶岩型矿床是稀有金属矿产的主要来源之一,我国西部地区的稀有金属矿床也以伟晶岩型为典型。柴达木盆地北缘乌兰茶卡北山地区岩浆活动频繁,伟晶岩体发育,具有形成稀有金属矿床的良好条件。为了进一步了解伟晶岩的地球化学特征,加深对区域构造演化以及稀有金属成矿和控矿条件的认识,选择该地区含矿伟晶岩作为研究对象,通过分析岩石矿物组合、岩相学特征、主微量及稀土元素组成,解释了侵入古元古界达肯大坂岩群中的伟晶岩地球化学特征。研究发现样品全碱含量较高,这与形成于大陆弧或板块碰撞环境下的成岩特征相似。稀土配分曲线为右倾型,轻重稀土分馏明显,具有Eu中等负异常,推测含矿伟晶岩源区不仅与地壳有关,而且还具有幔源镁铁质岩浆参与的可能性。研究结果表明:研究区内含矿伟晶岩属于亚碱性岩石类型,轻稀土元素富集,重稀土元素亏损,分馏程度较高,反映出在岩浆演化及伟晶岩成岩过程中幔源物质可能参与了稀有稀土金属的成矿作用。研究认为伟晶岩的物质来源不仅与地壳有关,而且还有幔源物质的参与,推断含矿伟晶岩的地质构造环境可能为后碰撞或碰撞后伸展环境。Rare,scattered and rare earth non-ferrous metals is new strategic key mineral resources.At present,some research understandings and breakthroughs have been made in the mineralization and prospecting of key metal deposits in China.Pegmatite type deposit is one of the main sources of rare metal mineral resources,and the rare metal deposits is the most typical of pegmatite types in western China.The magmatic activities are very frequent,and the magmatic rocks are widely distributed,mainly medium-acidic rocks,and very few basite and ultrabasic rock in the Wulan Chakabeishan area of the northern margin of the Qaidam Basin.The main types of rocks with good conditions for forming rare metal deposits,which include syenite granite,monzonitic granite,granodiorite,quartz diorite,tonalite,diorite,gabbro,etc. In order to further understand the geochemical characteristics of the ore-bearing pegmatites in the research area and deepen the understanding of regional tectonic evolution,the mineralization of rare metals and the ore-controlling conditions,the ore-bearing pegmatite was taken as the research object,and the rock mineral features,main trace and rare earth elements composition were analyzed.In the study area,pegmatite vein was band-distributed,outputed in clusters,various types,morphological pulse,beads,lens,and under obvious structural control.The types of pegmatite that closely related to the mineralization of rare metals include mainly muscovite-biotite granite,syenite granite pegmatite,monzonitic granite pegmatite,quartz diorite pegmatite and granodiorite pegmatite.The study found that the orebearing pegmatites have high total alkali content,which is similar to the diagenesis characteristics formed in the continental arc or plate collision environment.The partition curve of rare earth is right-leaning,and the light and heavy rare earth fractionation is obvious,and the Eu with medium negative anomaly,it is speculated that the orebearing pegmatite source area is not only related to the crust,but also has the possibility

关 键 词：伟晶岩 地球化学 物质来源 构造环境 稀有金属矿床 柴北缘 

分 类 号：P618.6[天文地球—矿床学]