地质通报2011，Vol.30Issue(7)：1066-1076,11.
北阿尔金构造带红柳沟钾长花岗岩地球化学特征、LA-ICP-MS锆石U-Pb定年和Hf同位素组成
Geochemistry, zircon LA-ICP-MS U-Pb ages and Elf isotopes of Hongliugou moyite from north Altyn Tagh tectonic belt
摘要
Abstract
Hongliugou moyite outcropped in western Hongliugou-Lapeiquan complex belt belongs to high K cal-alkalire granites,characterized by SiO2＞69.0％, A12O3＞13.0％, (K2O+Na2O)＞7.0％, K2O/Na2O＞1, 1＜A/CNK＜1.1, enrichment of LILE and depletion of HFSE (Nb, Ta, Sr, P and Ti). The REE distribution patterns show features of low ΣREE (128.47×10-6～150.67×10-6), negative anomaly of Eu, relative enrichment of LREE, and obvious fractionation between HREE and LREE. The Nb/Ta and Zr/Hf ratios are close to ratios of the upper crust, the εH (t) values of zircon range from -7.13～-5.12, with TDM2 ages between 1786～1912Ma. These characteristics suggest that the source rock might have been derived fr-om ancient crust. Diagrams for discriminating compositions of source rocks and the feature Al2O3/TiO2＜100 imply that the rock came from partial melting of arenitic metasediments in the middleupper crust. The LA-ICP-MS in situU-Pb age is 500.3±1.2Ma for zircons characterized by oscillatory zoning and Th/U＞0.4, and hence this age can be regarded as the formation age of the moyite. Combined with regional geological characteristics, the authors consider that the formation of the rock was related to the subduction of the oceanic crust, with the tectonic setting being continental margin arc.关键词
北阿尔金构造带/钾长花岗岩/地球化学/锆石LA-ICP-MS/U-Pb定年/Hf同位素Key words
northern Altyn Tagh tectonic belt/ moyite/ geochemistry/ zircon LA-ICP-MS U-Pb ages/ Hf isotopes分类
天文与地球科学引用本文复制引用
康磊,刘良,曹玉亭,王超,杨文强,朱小辉..北阿尔金构造带红柳沟钾长花岗岩地球化学特征、LA-ICP-MS锆石U-Pb定年和Hf同位素组成[J].地质通报,2011,30(7):1066-1076,11.基金项目
中国地质调查局项且《西昆仑-阿尔金成矿带基础地质综合研究》、国家重点研究发展规划"973"项目《深俯冲地壳的化学变化与差异折返》的二级课题《陆壳超深俯冲和折返的岩石学记录》(编号:2009CB825003)、国家自然科学基金项目《阿尔金山南缘碰撞后花岗岩的岩浆混合作用及其动力学意义》(批准号:40902022)、陕西省自然科学基金项目《岩浆混合作用过程中长石和锆石微结构和微区元素分析及其对岩浆动力学的指示)(编号:2010JM5007)、西北大学大陆动力学国家重点实验室创新基金项目《南阿尔金高压-超高压变质岩石中流体包裹体及其地质意义研究》(编号:10DZSY020)和西北大学研究生自主创新项目《阿尔金高压-超高压泥质岩石的相平衡关系与p-t演化轨迹--来自PT视剖面图的证据》(编号:09YZZ40) （编号:2009CB825003）
