| 大陆弧岩浆幕式作用与地壳加厚:以藏南冈底斯弧为例 |
| |
| 引用本文： | 马绪宣,许志琴,刘飞,赵中宝,李海兵.大陆弧岩浆幕式作用与地壳加厚:以藏南冈底斯弧为例[J].地质学报,2021,95(1):107-123. |
| |
| 作者姓名： | 马绪宣 许志琴 刘飞 赵中宝 李海兵 |
| |
| 作者单位： | 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;南方海洋科学与工程广东省实验室,广州,511458;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;南京大学地球科学与工程学院,大陆动力学研究中心,南京,210046 |
| |
| 基金项目： | 本文为国家重点研发计划变革性技术关键科学问题项目(编号2019YFA0708601)、南方海洋科学与工程广东省实验室(广州)人才团队引进重大专项(编号GML2019ZD0201)、第二次青藏科考项目(编号2019QZKK0802)、国家自然基金委青年项目(编号41502198)、中国地质科学院自主基金(编号J2024)和中国地质调查项目(编号DD20190057、DD20190060)联合资助成果 |
| |
| 摘 要： | 大陆弧岩浆带位于汇聚板块的前缘,记录了洋陆俯冲过程和大陆地壳生长过程,是研究壳幔相互作用的天然实验室。越来越多的研究发现,大陆弧岩浆的生长与侵位并不是均一的、连续的过程,而是呈现阶段性、峰期性特征,即幕式岩浆作用。弧岩浆峰期与岩浆平静期相比,岩浆增生速率显著增强,易于发生岩浆聚集,继而形成大的岩基,如北美西部科迪勒拉造山带内华达岩基、半岛岩基等。藏南冈底斯岩浆带位于拉萨地体南缘,属于印度-亚洲碰撞带的上盘,其南侧与喜马拉雅地体以雅鲁藏布蛇绿岩带为界。冈底斯弧岩浆形成时代集中在240~50 Ma期间,其形成与演化与新特提斯洋壳岩石圈板片俯冲到拉萨地体之下密切相关。因此,对冈底斯弧型岩浆作用的研究,将很好地揭示大陆型弧岩浆的演化过程,继而反演洋-陆俯冲过程,以及壳幔相互作用过程。通过对冈底斯岩浆带岩浆岩锆石U-Pb及Lu-Hf同位素,以及弧前和前陆盆地碎屑锆石U-Pb和Lu-Hf同位素的收集和整理,结合已经发表的区域地质资料的总结,我们发现冈底斯弧型岩浆演化具有如下特点:1幕式侵位,岩浆峰期为100~80 Ma和65~40 Ma,中间为岩浆平静期;2峰期阶段岩浆聚集,形成巨大岩基;岩石同位素非常亏损,预示着地幔物质的显著参与;3在弧岩浆的峰期阶段,冈底斯地壳厚度有显著增加,说明弧岩浆的峰期侵位对地壳加厚有重大贡献。
|
| 关 键 词： | 大陆弧岩浆 岩浆幕式作用 岩浆爆发期 地壳加厚 冈底斯 西藏 |
| 收稿时间： | 2020/7/27 0:00:00 |
| 修稿时间： | 2020/9/15 0:00:00 |
Continental arc tempos and crustal thickening:a case study in the Gangdese arc,southern Tibet |
| |
| MA Xuxuan,XU Zhiqin,LIU Fei,ZHAO Zhongbao,LI Haibing.Continental arc tempos and crustal thickening:a case study in the Gangdese arc,southern Tibet[J].Acta Geologica Sinica,2021,95(1):107-123. |
| |
| Authors: | MA Xuxuan XU Zhiqin LIU Fei ZHAO Zhongbao LI Haibing |
| |
| Institution: | 1)Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resources,Institute of Geology,Chinese Academy of Geological Sciences,Beijing,100037;2)Southern Marine Science and Engineering Guangdong Laboratory,Guangzhou,511458;1)Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resources,Institute of Geology,Chinese Academy of Geological Sciences,Beijing,100037;3)State Key Laboratory for Mineral Deposits Research,School of Earth Sciences and Engineering,Nanjing University,Nanjing,210046 |
| |
| Abstract: | The continental arc belt,located at the frontier margin of convergent plate,records the subduction of oceanic lithosphere and the continental crustal growth processes.In addition, the continental arc is the best laboratory to address the interaction between crust and mantle.Increasing number of studies reveal that the growth and emplacement of continental arc magmatism shows episodic patterns,rather than a steady or continuous process.Compared with the magmatic lull,the magmatic flare-up is characterized by high magma addition rates (MARs) and magma focusing,which is favorable for the formation of big arc batholith,such as the Sierra Nevada and Peninsular Ranges batholiths in the Cordilleran orogen,western North America.The Gangdese arc belt is located along the southern margin of the Lhasa terrane, belonging to the overlying plate of the Indo-Asian collisional zone.The Gangdese arc belt is separated from the southern Himalayan terranes by the Indus-Yarlung Tsangpo suture zone.The arc magmatism of the Gangdese arc persisted from ~240 to ~50 Ma,and is closely related to northward subduction of the Neotethyan oceanic lithosphere beneath the southern margin of the Lhasa terrane.Thus,the on-going studies on the magmatism of the Gangdese arc will help us to better understand the Gangdese arc tempos,the subduction of the Neotethys,as well as the crust-mantle interaction.In the present study,we have collected manyzircon U-Pb ages and Lu-Hf isotopes of igneous rocks from the Gangdese arc,and detrital zircon U-Pb ages and Lu-Hf isotopes from forearc and foreland basins.Thiscompiled data,in combination with regional geology,leads to the following conclusions:1)the magmatism of the Gangdese arc shows episodic features,with magmatic flare-ups culminating at 100~80 Ma and 65~40 Ma,respectively;2)the magmatic flare-up is favorable for the formation of big batholiths with depleted isotopes,implying significant involvement of mantle material;and 3)the magmatic flare-ups are coincidently synchronous with the crustal thickening events,indicatingthat the magmatic flare-up contributed greatly to the crustal thickening. |
| |
| Keywords: | continental arc magmatism magmatic tempos magmatic flare-up crustal thickening Gangdese Tibet |
| 本文献已被 CNKI 维普 万方数据 等数据库收录！ |
| 点击此处可从《地质学报》浏览原始摘要信息 |
| 点击此处可从《地质学报》下载免费的PDF全文 |
|
