地质力学学报2025，Vol.31Issue(1)：156-168,13.DOI:10.12090/j.issn.1006-6616.2024020
新疆东天山哈尔里克山早二叠世超基性岩墙锆石U-Pb年龄、地球化学特征及其构造意义
Zircon U-Pb age,geochemical characteristics,and tectonic implications of the early Permian ultrabasic dykes in the Harlik Mountain,east Tianshan,Xinjiang
摘要
Abstract
[Objective]During multiple stages of magmatic activity in the Harlik Mountains of the east Tianshan,extensive granitic and mafic dyke swarms were formed.This study aims to constrain the closure time of the Paleo-Asian Ocean in this area and to elucidate the tectonic environment in which ultrabasic dykes were formed.[Methods]This study reports petrography,geochemistry,and zircon U-Pb ages of a particular type of ultrabasic dyke swarms(amphibolites)in Qincheng,Hami.[Results]The amphibolites have SiO2 contents from 39.00%to 45.48%,TiO2 contents from 1.60%to 3.01%,and Mg#values from 50 to 60.They are relatively weakly enriched in light rare earth elements(La/Yb)N=1.34～2.25)and show no Eu anomalies(δEu=0.76～1.12).They are enriched in large ion lithophile elements(LILEs:Rb,Ba,K,Sr)and depleted in high field strength elements(HFSEs:Nb,Zr,Hf).The amphibolites belong to the alkaline rock series.LA-MC-ICP-MS zircon U-Pb dating reveals that these three amphibolites crystallized at 298.4±1.7 Ma,297.7±1.6 Ma,and 295.5±1.6 Ma,respectively.Whole rock Sr-Nd analysis reveals initial 87Sr/86Sr ratios from 0.7047 to 0.7051 and εNd(t)values from-2.63 to 1.81.[Conclusion]Based on the comprehensive analysis of regional geology,chronology,geochemistry,and Sr-Nd isotopes,it is suggested that the primitive magma of the early Permian amphibolites in Qincheng may have been created by partial melting of the lithospheric mantle,and these rocks were formed in a post-collisional extensional tectonic setting.It is furthermore implied that the Paleo-Asian Ocean in the Harlik Mountains region closed before the early Permian.关键词
角闪石岩/LA-MC-ICPMS U-Pb测年/Sr-Nd同位素/地球化学特征/哈密Key words
hornblendite/LA-MC-ICP-MS U-Pb dating/Sr-Nd isotopes/geochemical characteristics/Hami分类
天文与地球科学引用本文复制引用
杜晓飞,王威,张传林,马华东,朱炳玉,邱林..新疆东天山哈尔里克山早二叠世超基性岩墙锆石U-Pb年龄、地球化学特征及其构造意义[J].地质力学学报,2025,31(1):156-168,13.基金项目
新疆维吾尔自治区自然科学基金项目(2022D01A144) （2022D01A144）
自治区公益性科研院所基本科研业务费(KY2024112) This research is financially supported by the Natural Science Foundation of Xinjiang Uygur Autonomous Region(Grant No.2022D01A144)and the Basic Research Business Expenses of Public Welfare Research Institutes in the Autonomous Region(Grant No.KY2024112). （KY2024112）
