觉罗塔格造山带阿奇山花岗岩地球化学、锆石U-Pb定年、Lu-Hf同位素及构造意义  

Geochemistry, Zircon U-Pb Chronology, Lu-Hf Isotopes and Their Tectonic Significance of the Aqishan Granite in the Jueluotage Orogen

作　　者：王晓丹 蔡宏明 吴兆宁 宫相宽 谢子航 WANG X iao-dan;CAI Hong-ming;WU Zhao-ning;GONG Xiang-kuan;XIE Zi-hang(School of Geology and Mining Engineering,Xinjiang University,Urumqi S30046,China;Key Laboratory of Central Asian Orogenic Belt Continental Dynamics and Metallogenic Prediction Autonomous Region,Urumqi 830046,China)

机构地区：[1]新疆大学地质与矿业工程学院,乌鲁木齐830046 [2]中亚造山带大陆动力学与成矿预测自治区重点实验室,乌鲁木齐830046

出　　处：《矿物岩石地球化学通报》2019年第5期977-988,共12页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：新疆中亚造山带大陆动力学与成矿预测自治区重点实验室开放课题(2016D03002);国家自然科学基金项目(41562010)

摘　　要：为确定觉罗塔格造山带阿奇山花岗岩的成因和构造背景,并为觉罗塔格造山带在海西期-印支期发生了由后碰撞向板内转化的过程提供证据,对阿奇山地区的正长花岗岩和黑云母二长花岗岩进行了锆石U-Pb定年、Hf同位素和岩石地球化学研究。结果表明,两类花岗岩的形成时代分别为(271.7±3.1)Ma和(251.0±3.7)Ma;锆石^176Hf/^177Hf值分别为0.282785~0.282952和0.282761~0.282918,εHf(t)值分别为6.00~11.65和4.63~10.20;岩体属高钾钙碱性系列,准铝质-弱过铝质的I型花岗岩。综合分析认为,花岗岩体形成于板内构造环境,且觉罗塔格造山带在海西期-印支期发生了由后碰撞向板内转化,这对深入了解天山造山带碰撞后及陆内构造演化过程、板内岩浆活动起源以及区域动力学背景等具有重要意义。In order to determine the genesis and tectonic setting of the Aqishan granite,and to provide evidence for the tranisition from the post-collision to intraplate of the Jueluotage orogenic belt,zircon U-Pb dating,Hf isotopes and petrogeochemistry of the syenite and biotite monzonitic granites in the Aqishan area have been performed.The formation ages of the two granites are(271.7±3.1)Ma and(251.0±3.7)Ma,respectively.They have zircon^176Hf/^177Hf ratios of 0.282785~0.282952 and 0.282761~0.282918,respectively,yieldingεHf(t)values of 6.00-11.65 and 4.63-10.20,respectively.These granites belong to high-potassium calc-alkaline series,metaluminous to weak peraluminous I-type granite that were formed in the intraplate tectonic environment.Therefore,the Jueluotage orogenic belt was transformed from post-collision to intraplate setting during the Hercynian-Indosinian period.It is of great significance to understand the evolution process of intra-continental tectonics,the origin of intraplate magmatic activity and the regional geodynamics of the Tianshan orogenic belt.

关 键 词：觉罗塔格造山带 阿奇山花岗岩 地球化学特征 HF同位素 

分 类 号：P597.3[天文地球—地球化学]