Geochemistry and Zircon U-Pb and Hf Isotopes of Early Devonian Hardawu Granites in the Eastern Segment of the Ultrahigh-Pressure Metamorphic Belt, Northern Qaidam Basin

IF 4.1 2区 地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY
Hua Li, Ming Wang, Jiqing Li, Haikui Tong, Jiaxiang Dong, Minggang Tian, Xiaolin Chen, Leguang Li, Ting Xie, Xiong Li, Yuying Che
{"title":"Geochemistry and Zircon U-Pb and Hf Isotopes of Early Devonian Hardawu Granites in the Eastern Segment of the Ultrahigh-Pressure Metamorphic Belt, Northern Qaidam Basin","authors":"Hua Li, Ming Wang, Jiqing Li, Haikui Tong, Jiaxiang Dong, Minggang Tian, Xiaolin Chen, Leguang Li, Ting Xie, Xiong Li, Yuying Che","doi":"10.1007/s12583-022-1791-1","DOIUrl":null,"url":null,"abstract":"<p>The Hardawu granites in the eastern segment of the ultrahigh-pressure metamorphic belt, the northern Qaidam Basin, were studied by whole-rock major and trace elements and <i>in-situ</i> zircon U-Pb geochronology and Hf isotopes to discuss the petrogenesis and tectonic evolution. Geochronological results show that the granites have a crystallization age of 401 ± 3 Ma, suggesting that they were formed in the Early Devonian. The granites have SiO<sub>2</sub> contents of 75.32 wt.%–76.05 wt.%, total alkali contents of 8.23 wt.%–8.36 wt.%, and K<sub>2</sub>O/Na<sub>2</sub>O ratios of 1.62–1.91. They were rich in K<sub>2</sub>O, poor in TiO<sub>2</sub>, MnO, MgO, and P<sub>2</sub>O<sub>5</sub>, and have A/CNK values of 1.05–1.07, Rittmann index <i>δ</i> values of 2.05–2.14, and differentiation index (DI) values of 92.85–94.18. They are high potassium calc-alkaline, weak-peraluminum, and highly differentiated I-type granites. The granites also show enrichment of large ion lithophile elements (LILE) such as Rb, Ba, and Th, and depletion of high field strength elements (HFSE) such as Nb, Ta, and Ti. The total REE concentrations range from 169 ppm to 232 ppm, with enrichments of light rare earth elements and negative Eu anomalies (δEu = 0.39–0.55). The zircon <i>ε</i><sub>Hf</sub>(<i>t</i>) values range from −0.65 to −2.29, and the two-stage model ages (<i>t</i><sub>DM2</sub>) changed within a small range of 1.44 to 1.54 Ga, indicating that the magma of the Hardawu granites was originated from the partial melting of Mesoproterozoic lower crustal materials. Combined with previous studies, we suggest that the Hardawu granites were formed in the extensional tectonic setting after the collision between the Qaidam Block and the central and southern Qilian Block in the Early Devonian.</p>","PeriodicalId":15607,"journal":{"name":"Journal of Earth Science","volume":"137 1","pages":""},"PeriodicalIF":4.1000,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Earth Science","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1007/s12583-022-1791-1","RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0

Abstract

The Hardawu granites in the eastern segment of the ultrahigh-pressure metamorphic belt, the northern Qaidam Basin, were studied by whole-rock major and trace elements and in-situ zircon U-Pb geochronology and Hf isotopes to discuss the petrogenesis and tectonic evolution. Geochronological results show that the granites have a crystallization age of 401 ± 3 Ma, suggesting that they were formed in the Early Devonian. The granites have SiO2 contents of 75.32 wt.%–76.05 wt.%, total alkali contents of 8.23 wt.%–8.36 wt.%, and K2O/Na2O ratios of 1.62–1.91. They were rich in K2O, poor in TiO2, MnO, MgO, and P2O5, and have A/CNK values of 1.05–1.07, Rittmann index δ values of 2.05–2.14, and differentiation index (DI) values of 92.85–94.18. They are high potassium calc-alkaline, weak-peraluminum, and highly differentiated I-type granites. The granites also show enrichment of large ion lithophile elements (LILE) such as Rb, Ba, and Th, and depletion of high field strength elements (HFSE) such as Nb, Ta, and Ti. The total REE concentrations range from 169 ppm to 232 ppm, with enrichments of light rare earth elements and negative Eu anomalies (δEu = 0.39–0.55). The zircon εHf(t) values range from −0.65 to −2.29, and the two-stage model ages (tDM2) changed within a small range of 1.44 to 1.54 Ga, indicating that the magma of the Hardawu granites was originated from the partial melting of Mesoproterozoic lower crustal materials. Combined with previous studies, we suggest that the Hardawu granites were formed in the extensional tectonic setting after the collision between the Qaidam Block and the central and southern Qilian Block in the Early Devonian.

北柴达木盆地超高压变质带东段早泥盆世哈达乌花岗岩的地球化学及锆石U-Pb和Hf同位素
通过全岩主要元素、微量元素、原位锆石U-Pb地质年代学和Hf同位素研究了位于超高压变质带东段、柴达木盆地北部的哈达乌花岗岩,探讨了其成岩和构造演化过程。地质年代结果表明,花岗岩的结晶年龄为 401 ± 3 Ma,表明它们形成于早泥盆世。花岗岩的二氧化硅含量为 75.32 重量%-76.05 重量%,总碱含量为 8.23 重量%-8.36 重量%,K2O/Na2O 比率为 1.62-1.91。它们富含 K2O,贫含 TiO2、MnO、MgO 和 P2O5,A/CNK 值为 1.05-1.07,Rittmann 指数 δ 值为 2.05-2.14,分异指数 (DI) 值为 92.85-94.18。它们属于高钾钙碱性、弱铝、高分化 I 型花岗岩。这些花岗岩还显示出Rb、Ba和Th等大离子亲岩元素(LILE)的富集和Nb、Ta和Ti等高场强元素(HFSE)的贫化。稀土元素的总浓度在 169 ppm 到 232 ppm 之间,轻稀土元素富集,Eu 负异常(δEu = 0.39-0.55)。锆石εHf(t)值在-0.65至-2.29之间,两阶段模型年龄(tDM2)在1.44至1.54 Ga的小范围内变化,表明哈达乌花岗岩的岩浆来源于中新生代下地壳物质的部分熔融。结合以往的研究,我们认为哈达乌花岗岩形成于早泥盆世柴达木块体与祁连块体中南部碰撞后的伸展构造环境中。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
求助全文
约1分钟内获得全文 求助全文
来源期刊
Journal of Earth Science
Journal of Earth Science 地学-地球科学综合
CiteScore
5.50
自引率
12.10%
发文量
128
审稿时长
4.5 months
期刊介绍: Journal of Earth Science (previously known as Journal of China University of Geosciences), issued bimonthly through China University of Geosciences, covers all branches of geology and related technology in the exploration and utilization of earth resources. Founded in 1990 as the Journal of China University of Geosciences, this publication is expanding its breadth of coverage to an international scope. Coverage includes such topics as geology, petrology, mineralogy, ore deposit geology, tectonics, paleontology, stratigraphy, sedimentology, geochemistry, geophysics and environmental sciences. Articles published in recent issues include Tectonics in the Northwestern West Philippine Basin; Creep Damage Characteristics of Soft Rock under Disturbance Loads; Simplicial Indicator Kriging; Tephra Discovered in High Resolution Peat Sediment and Its Indication to Climatic Event. The journal offers discussion of new theories, methods and discoveries; reports on recent achievements in the geosciences; and timely reviews of selected subjects.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
copy
已复制链接
快去分享给好友吧!
我知道了
右上角分享
点击右上角分享
0
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信