东天山红包山—碱泉—带镁铁-超镁铁质岩体的地球化学特征与岩石成因  

Geochemical Characteristics and Petrogenesis of Hongbaoshan-Jianquan Mafic-Ultramafic Intrusions in East Tianshan,Xinjiang

作　　者：马方彬 郗国庆 王开虎 方福康[3] 白玉 刘文建 

机构地区：[1]中化地质矿山总局地质研究院,河北涿州072754 [2]中化地质矿山总局新疆地质调查院,新疆乌鲁木齐830000 [3]中国煤炭地质总局特种技术勘探中心,北京100073 [4]上海申丰地质新技术应用研究所有限公司,上海201702 [5]西安地质矿产勘查开发院,陕西西安710100

出　　处：《西北地质》2016年第2期176-188,共13页Northwestern Geology

基　　金：中国地质调查局"新疆觉罗塔格-拜城一带铁磷矿资源远景调查"(1212011220827)

摘　　要：红包山—碱泉一带镁铁-超镁铁质岩体位于东天山卡瓦布拉克地区,岩体呈脉状或透镜状产出,出露面积约8km^2。岩石类型主要为纯橄榄岩、橄榄岩、单辉橄榄岩等。地球化学数据表明,该区岩体具高Mg~#的特征,属镁质超基性岩。岩石稀土元素为平缓右倾型配分模式,稀土元素总量(0.96×10^(-6)~10.02×10^(-6))较低,轻重稀土元素组间分馏较强((La/Yb)_N=2.14~4.08),δEu变化于0.63~1.08,可能与斜长石的结晶有关。微量元素蛛网图表明,岩石具富集大离子亲石元素Rb、Sr和高场强元素U、Pb及LREE,而亏损高场强元素Nb(Ta)、Hf、Ti的特征。主微量元素等地球化学相关图解说明,红包山—碱泉一带岩体原生岩浆为幔源的钙碱性玄武质岩浆,成岩作用以岩浆结晶分异为主导,并受到壳源物质的同化混染作用。Located in the Kawabulake area of east Tianshan,the Hongbaoshan-Jianquan manficultramafic intrusions exhibit as vein and lenticular,with outcropped area of^8km^2.It mainly consists of dunite,peridotite and wehrlite.The geochemical data shows that these intrusions belong to magnesian ultramafic rocks,which are characterized by high Mg~#and gently LREE-rich pattern with low ∑REE values（0.96×10^（-6）~10.02×10^（-6））and enrichment of LREE（（La/Yb）_N=2.14~4.08）.Additionally,they are enriched LILE（Rb and Sr）and HFSE（U and Pb）,and depleted HFSE（Nb（Ta）,Hf and Ti）.TheδEu values vary from 0.63 to 1.08,which may be related with the crystallization of plagioclase.The geochemical diagrams of major and trace elements correlation indicate that the primary magma of Hongbaoshan-Jianquan intrusions is cal-alkaline basaltic magma that formed in mantle,their diagenesis are mainly controlled by the magmatic crystallization,and contaminated by the crust during upward of magma.

关 键 词：镁铁-超镁铁质 地球化学 结晶分异 同化混染 东天山 

分 类 号：P618.46[天文地球—矿床学] P618.31[天文地球—地质学]