西昆仑都扎哈达绕英云闪长岩年代学、地球化学特征及其意义  

Geochemical characteristics,chronology of Duzahadarao tonalite in West Kunlun Orogen and the significance

作　　者：张伟豪 ZHANG Weihao(School of Earth Sciences,Chengdu University of Technology,Chengdu 610059,Sichuan,China)

机构地区：[1]成都理工大学地球科学学院,四川成都6100590

出　　处：《矿产与地质》2022年第5期981-990,共10页Mineral Resources and Geology

摘　　要：都扎哈达绕岩体位于新疆塔身库尔干县东部,侵入于中元古界库浪那古岩群地层,岩性主要为英云闪长岩。LA-ICP-MS锆石U-Pb测年结果显示该岩体206Pb/238U加权平均年龄为(244.1±1.8) Ma (MSWD=0.47),属于中三叠世的岩浆活动产物。岩石地球化学特征显示其具有富钠、贫硅钾、稀土总量较低的特征,轻重稀土元素分馏明显,富集Rb、Th、Zr、Hf等元素,强烈亏损Ba、Sr、P和Ti元素,相对亏损Nb元素,具有活动大陆边缘的岩浆岩的特征。结合区域地质资料,并通过岩石学、岩石地球化学和年代学研究,认为都扎哈达绕岩体属于慕士塔格复式岩体的一部分,后者由中三叠世和晚三叠世两期岩浆岩组成。都扎哈达绕岩体的英云闪长岩形成于古特提斯洋闭合碰撞向后碰撞伸展环境转换的构造背景,具有壳幔混源的特征。Duzhahadarao pluton, mainly composed of tonalite, is located at the south of Tashikuergan County in Xinjiang, which intrudes into Kulangnagu group in Proterozoic. LA-ICP-MS zircon U-Pb dating age indicates that it is formed in the Early Triassic(244.1±1.8Ma). Geochemical analysis data show that the granite is characterized by high Na2O, low SiO2and K2O, and low ∑REE. The enrichment trace elements are Rb, Th, Zr, Hf and impoverished elements are Ba, Sr, P, Ti. It belongs to the product of middle Triassic magmatic activity. On the basis of the study of petrology, petrogeochemistry and chronology, and the regional and geological data, it is considered that the Duzahada pluton belongs to one part of the Mustage composite rock body, which is composed of two magmatic rocks of the Middle Triassic and the Late Triassic. The tonalite of the Duzahada rock body is formed in the tectonic background of the transformation from closed collision of the Paleo Tethys Ocean to the post collision extension environment, with the characteristics of mixed crust and mantle sources.

关 键 词：英云闪长岩 锆石U-PB测年 岩石地球化学 壳幔混源 西昆仑 

分 类 号：P597[天文地球—地球化学]