DOI | 10.1016/j.gsf.2023.101534
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| A greenstone belt in southeast Tibet: An accreted middle-late Permian oceanic plateau |
| Wang, Bin; Xie, Chao-Ming; Yakymchuk, Chris; Dong, Yong-sheng; Song, Yu-hang; Duan, Meng-long
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发表日期 | 2023
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ISSN | 1674-9871
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卷号 | 14期号:3 |
英文摘要 | Studies of accreted oceanic plateau sections provide crucial information on their structures, composi-tions, and origins. We investigate the petrogenesis of ultramafic-mafic rocks in the Tangjia-Sumdo greenstone belt of southeast Tibet using petrography, whole-rock geochemistry, and U-Pb zircon geochronology. These rocks are divided into four groups based on geochemical characteristics that include depleted and tholeiitic mafic rocks, transitional mafic rocks, enriched and alkaline mafic rocks, and picritic ultramafic rocks. Depleted and tholeiitic mafic rocks have the oldest crystallization ages (-272 Ma), followed by picritic ultramafic rocks (-270 Ma), transitional mafic rocks (267-254 Ma), and enriched and alkaline mafic rocks (252-250 Ma). Hafnium and neodymium isotope ratios of depleted and tholeiitic mafic rocks (eHf(t) = +13.1-+16.9; eNd(t) = +6.9-+7.1), transitional mafic rocks (eHf(t) = +1.8- +16.9; eNd(t) = +0.8-+5.5), enriched and alkaline mafic rocks (eHf(t) = +0.5-+5.4; eNd(t) =-1.5 to +1.9) and picritic ultramafic rocks (eHf(t) = +14.9-+17.2; eNd(t) = +7.8-+9.0) are similar to those of N-MORB, E-MORB, OIB and depleted-type picritic mafic rocks in other oceanic plateaus, respectively. The geochem-ical characteristics of the depleted and tholeiitic mafic rocks suggest that they formed by partial melting of depleted spinel lherzolite in a mid-ocean ridge setting, whereas the picritic ultramafic rocks suggest a high degree of partial melting of depleted lherzolite in a hot mantle plume head. The transitional mafic rocks formed by partial melting of moderately enriched garnet lherzolite. The youngest rocks (enriched and alkaline mafic rocks) formed by partial melting of a more enriched garnet lherzolite (compared to transitional mafic rocks) at relatively low temperatures. We propose that the depleted and tholeiitic mafic rocks represent normal oceanic crust of the Sumdo Paleo-Tethys Ocean and the transitional mafic rocks, enriched and alkaline mafic rocks and picritic ultramafic rocks are the fragments of the oceanic pla-teau, which were related to middle-late Permian mantle plume activity in the Sumdo Paleo-Tethys Ocean. We further suggest that the majority of the Tangjia-Sumdo greenstone belt represents a mid-dle-late Permian oceanic plateau that reflects a previously unrecognized middle-late Permian mantle plume.(c) 2023 China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/). |
关键词 | Oceanic plateauMantle plumePaleo-TethysTibetGreenstone belts |
英文关键词 | LARGE IGNEOUS PROVINCES; MINO-TAMBA BELT; LHASA TERRANE; GEOCHEMICAL EVIDENCE; SUBDUCTION INITIATION; CONTINENTAL-CRUST; OROGENIC BELT; FLOOD BASALTS; MAFIC ROCKS; U-PB |
WOS研究方向 | Geosciences, Multidisciplinary
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WOS记录号 | WOS:000923089500001
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来源期刊 | GEOSCIENCE FRONTIERS
(IF:4.16[JCR-2018],4.516[5-Year]) |
文献类型 | 期刊论文
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条目标识符 | http://gcip.llas.ac.cn/handle/2XKMVOVA/282776
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作者单位 | Jilin University; Ministry of Natural Resources of the People's Republic of China; Jilin University; University of Waterloo
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推荐引用方式 GB/T 7714 |
Wang, Bin,Xie, Chao-Ming,Yakymchuk, Chris,et al. A greenstone belt in southeast Tibet: An accreted middle-late Permian oceanic plateau[J],2023,14(3).
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APA |
Wang, Bin,Xie, Chao-Ming,Yakymchuk, Chris,Dong, Yong-sheng,Song, Yu-hang,&Duan, Meng-long.(2023).A greenstone belt in southeast Tibet: An accreted middle-late Permian oceanic plateau.GEOSCIENCE FRONTIERS,14(3).
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MLA |
Wang, Bin,et al."A greenstone belt in southeast Tibet: An accreted middle-late Permian oceanic plateau".GEOSCIENCE FRONTIERS 14.3(2023).
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