Early Jurassic S-type granitoids in the Nyainqêntanglha Range, South Tibet: A record of slab roll-back of subducted Neo-Tethyan Ocean
Early Jurassic S-type granitoids in the Nyainqêntanglha Range, South Tibet: A record of slab roll-back of subducted Neo-Tethyan Ocean
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藏南念青唐古拉山早侏罗世S型花岗岩：俯冲新特提斯洋板片回滚的记录
DOI：
10.1016/j.gr.2021.07.030
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发表时间：
2022
影响因子：
6.1
通讯作者：
Yue Ya-Hui
中科院分区：
文献类型：
--
作者：
Wang Chao;Ding Lin;Zhang Li-Yun;Li Jin-Xiang;Yue Ya-Hui
然而，冈底斯带北部s型花岗岩的年代学和地球动力学存在争议。根据野外关系、岩石学和地球化学，花岗岩类有三种不同的类群。粗粒的第一类和第二类花岗岩类为大片状体，不相容元素含量高，Eu呈负异常。细粒III类花岗岩形成小的漆膜岩，稀土元素含量低，Eu呈正异常。负的εNd(t)和εHf(t)值，丰富的继承锆石，中度轻REE和LILE富集，HFSE亏缺，表明当雄花岗岩主要由变质长岩源部分熔融形成。进一步研究表明，具有高不相容元素含量和负Eu异常的I组和II组样品为分馏熔体，而具有低REE含量和正Eu异常的III组样品为堆积体。继承锆石的年龄分布模式支持拉萨地体从印度板块北缘裂离的解释。结合拉萨地体已有资料，我们认为早侏罗世岩浆活动可能与一段俯冲洋板回滚期有关，这为新特提斯海洋领域的演化过程提供了新的认识。
The Gangdese orogenic belt in southern Tibet records a succession of arc-trench-basin assemblages formed by the Neo-Tethyan subduction and the subsequent India-Asian collision. However, the geochronology and geodynamics of S-type granites in the northern part of the Gangdese belt are disputed. This paper describes ~190 Ma S-type granitoids outcropped in the Nyainqêntanglha Range, South Tibet, focusing on their petrogenesis and their relationship with contemporaneous magmatism. There are three distinct groups of granitoids, based on field relationships, petrology, and geochemistry. The coarse-grained Group I and II granitoids are large, sheet-like bodies and exhibit high contents of incompatible elements and negative Eu anomalies. The fine-grained Group III granites form small laccoliths and have low REE contents and positive Eu anomalies. The negative εNd(t) and εHf(t) values, abundant inherited zircons, moderately light REE and LILE enrichment, and HFSE depletion indicate that the Damxung granitoids were derived mainly by the partial melting of a metapelitic source. Further studies proposed that group I and II samples with high contents of incompatible elements and negative Eu anomalies represent fractionated melts, whereas group III samples with low REE contents and positive Eu anomalies represent cumulates. The age distribution pattern of inherited zircons supports the interpretation that the Lhasa terrane rifted away from the northern margin of the Indian plate. Considering previously published data in the Lhasa terrane, we suggest that the Early Jurassic magmatism could be related to a period of subducted oceanic slab roll-back, which provides new insights into the evolution process of the Neo-Tethyan ocean realm.
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影响因子：
5
作者：
Hoskin, PWO
通讯作者：
Hoskin, PWO
影响因子：
2.6
作者：
Guochun Zhao;San-zhong Li;M. Sun;S. Wilde
通讯作者：
Guochun Zhao;San-zhong Li;M. Sun;S. Wilde
影响因子：
3.5
作者：
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Chao Wang;L. Ding;Liyun Zhang;P. Kapp;A. Pullen;Yahui Yue
影响因子：
3
作者：
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通讯作者：
Jingsui Yang;Zhiqin Xu;Zhaoli Li;Xiangzhen Xu;Tianfu Li;Yufeng Ren;Huaqi Li;Songyong Chen
影响因子：
3.8
作者：
Xin Dong;Zeming Zhang;Y. Niu;Z. Tian;L. Zhang
通讯作者：
Xin Dong;Zeming Zhang;Y. Niu;Z. Tian;L. Zhang