• 首页|本刊简介|在线投稿|过刊浏览|高级检索|专家风采|学习园地|期刊论坛|联系我们
喜马拉雅造山带亚东地区多期构造热事件——锆石和独居石U-Th-Pb年代学证据
Multistage tectono-thermal events in the Yadong area of the Himalayan orogenic belt: Evidence from zircon and monazite U-Th-Pb geochronology
投稿时间:2019-01-08  
中文关键词:锆石和独居石  U-Th-Pb定年  多期构造热事件  亚东  喜马拉雅造山带
英文关键词:zircon and monazite  U-Th-Pb dating  multistage tectono-thermal event  Yadong  Himalayan orogenic belt
基金项目:国家自然科学基金项目(41872070);国家留学基金项目(201809110024);中国地质调查局地质调查项目(12120114022801,12120115026801,DD20160022,DD20160201)
作者单位E-mail
董昕 自然资源部深地动力学重点实验室, 中国地质科学院 地质研究所, 北京 100037  
田作林 自然资源部深地动力学重点实验室, 中国地质科学院 地质研究所, 北京 100037 zuolin.tian@gmail.com 
摘要点击次数: 300
全文下载次数: 236
中文摘要:
      喜马拉雅造山带是研究板块构造的天然实验室,位于造山带核心部位的大喜马拉雅岩系是揭示碰撞造山过程和造山带演化的关键。本文主要对亚东地区大喜马拉雅岩系中的花岗质片麻岩进行了岩相学、锆石和独居石U-Th-Pb年代学以及全岩主微量地球化学研究。野外和显微结构特征观察表明,花岗质片麻岩的矿物组合为斜长石+钾长石+石英+黑云母+石榴石,岩石发生了部分熔融,经历了高角闪岩相至麻粒岩相的变质作用。年代学和全岩地球化学研究表明,花岗质片麻岩的原岩包括新元古代(~800 Ma)的花岗闪长岩和志留纪(~440 Ma)的花岗岩,二者均在中新世(~16 Ma)发生了变质作用。新元古代花岗闪长岩具有负的εHf(t)值(-16.4~-12.2),地壳Hf模式年龄为3.11~2.79 Ga,说明其起源于古老下地壳物质的部分熔融。新元古代花岗闪长岩和志留纪花岗岩具有相似的弧花岗质岩石地球化学特征,即具有高场强元素Nb、Ta、P和Ti的负异常。本次研究表明大喜马拉雅岩系经历了多期构造热事件,其不仅记录了新生代的碰撞造山作用,还记录了与新元古代与罗迪尼亚超大陆演化相关的岩浆热事件以及古生代冈瓦纳大陆拼合后的周缘安第斯型造山作用。
英文摘要:
      The Himalayan orogenic belt is a natural laboratory for studying plate tectonics. Located at the core of the Himalayan orogen, the Greater Himalayan Sequence (GHS) is the key to revealing the collisional orogenesis and orogenic evolution. This paper presents the petrography, zircon and monazite U-Th-Pb chronology and geochemistry of the GHS granitic gneisses from the Yadong area. The field survey and microstructure show that these rocks have the mineral assemblage of plagioclase + K-feldspar + quartz + biotite + garnet, and have experienced a metamorphism of the upper-amphibolite to granulite facies with partial melting. Chronology and geochemistry indicate that the protoliths of granitic gneisses include the Neoproterozoic (~800 Ma) granodiorite and the Silurian (~440 Ma) granite, both of which experienced metamorphism in Miocene (~16 Ma). The Neoproterozoic granodiorite has negative εHf(t) values of -16.4~-12.2, and crust model ages tDMC of 3.11~2.79 Ga, suggesting that the rock was derived from partial melting of the ancient lower crust. The Neoproterozoic granodiorite and Silurian granite have similar geochemical characteristics to arc granitic rocks, with negative anomalies of high field strength elements Nb, Ta, P and Ti. The present study reveals that the Greater Himalayan Sequence has experienced multistage tectono-thermal events, including not only the Cenozoic collisional orogeny but also the Neoproterozoic magmatism associated with the evolution of the supercontinent Rodinia as well as the surrounding Andean orogeny after the Paleozoic formation of Gondwana.
董昕,田作林,2019,喜马拉雅造山带亚东地区多期构造热事件——锆石和独居石U-Th-Pb年代学证据[J].岩石矿物学杂志,38(4):431~452.
查看全文  查看/发表评论  下载PDF阅读器
关闭
您是本站第 6058996位访问者  京ICP备05032737号-8
版权所有:《岩石矿物学杂志》编辑部
主管:中国科学技术协会 主办:中国地质学会岩石学专业委员会 中国地质学会矿物学专业委员会 中国地质科学院地质研究所
技术支持:北京勤云科技发展有限公司

京公网安备 11010202007772号