新疆卡拉麦里蛇绿混杂岩带北侧英云闪长岩年代学、地球化学特征及地质意义  

Geochronology,Geochemistry of Tonalite from North Karamaili Ophiolite Melange Belt in Xinjiang and Its Geological Significance

作　　者：肖鸿[1] 王璐 郭振军 王响元 Xiao Hong;Wang Lu;Guo Zhenjun;Wang Xiangyuan(No.1 Geological Party of Xinjiang Bureau of Geology and Mineral Exploration and Development,Changji,Xinjiang,831100,China)

机构地区：[1]新疆维吾尔自治区地质矿产勘查开发局第一地质大队,新疆昌吉831100

出　　处：《新疆地质》2023年第2期141-146,共6页Xinjiang Geology

基　　金：新疆阿尔泰成矿带地质矿产调查评价项目《新疆东准噶尔地区1∶5万L46E018003、L46E018004、L46E018005、L46E018006、L46E018007、L46E018008六幅区调》(1212011120511)资助。

摘　　要：以出露于卡拉麦里蛇绿混杂岩带北侧元湖一带英云闪长岩为研究对象,在野外地质调查基础上,结合锆石LA-LCP-MS U-Pb年龄测试、岩石地球化学分析,对该岩体侵入时代及成因进行讨论。英云闪长岩锆石LA-ICPMS U-Pb年龄为(342.3±2.8)Ma(MSDW=0.49)。岩石SiO_(2)含量73.21%~77.15%,Al2O_(3)含量10.66%~13.00%,属偏铝质,A/CNK为0.89~0.98、富钠,Na_(2)O/K_(2)O值为6.99~22.31,低钾(拉斑)系列。稀土元素总量较低,∑REE=40.95~55.01,轻重稀土分馏较弱,(La/Yb)_(N)=0.47~0.72,Eu负异常明显,δEu=0.15~0.25。Sr/Y比值为3.07~4.36,Nb/Ta比值为3.61~9.86。岩石具较低的Sr初始值,(^(87)Sr/^(86)Sr)i=0.704485和正的Nd初始值,ε_(Nd)(t)=9.45~10.295。认为卡拉麦里蛇绿混杂岩带北侧英云闪长岩不属于蛇绿岩套组成部分,是由亏损地幔演化的新生低钾拉斑玄武岩部分熔融形成。In this paper,the tonalite outcropped in Yuanhu area on the northern side of the Karamaili ophiolite melange belt is taken as the object of study,based on Zircon LAICPMS U-Pb dating and geochemistry analysis,the intrusive age and genesis of the intrusion are discussed.LA-ICP-MS U-Pb zircon dating of the intrusive is(342.3±2.8)Ma(MSDW=0.49).These rocks are characterized by high SiO_(2)(73.21%~77.15%)and low Al_(2)O_(3)(10.66%~13.00%),metaluminous(A/CNK=0.89~0.98),sodium-rich(Na_(2)O/K_(2)O=6.99~22.31),which are belong to tholeiitic series.The REE patterns are char-acterized by low content ofΣREE(40.95~55.01)and significantly Eu negative anomalies(δEu=0.15~0.25).The value of Sr/Y is 3.07 to 4.36 and Nb/Ta is 3.61 to 9.86,these rocks have low initial ^(87)Sr/^(86)Sr values 0.704485 and positive ε_(Nd)(t)values vary from 9.45 to 10.295.In this paper,It is considered that the tonalite is not a part of the ophiolite mélange.The granites melts were probably derived from partial melting of low potassium tholeiitic from lower crust,which evolved form depleted mantle.

关 键 词：卡拉麦里蛇绿混杂岩带 锆石U-PB年龄 地球化学 英云闪长岩 

分 类 号：P588.12[天文地球—岩石学]