Recycling of subducted continental crust: geochemical evidence from syn-exhumation Triassic alkaline mafic rocks of the southern Liaodong Peninsula
Syn-exhumation mafic magmatism during continental collision provides insights into the crust-mantle reaction during deep subduction and the nature of orogenic lithospheric mantle in collisional orogens. In this study, we present a comprehensive data set of zircon U-Pb ages and whole-rock major-trace...
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| Autores principales: | , , , , , , , |
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| Formato: | Article (Journal) |
| Lenguaje: | inglés |
| Publicado: |
10 July 2021
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| In: |
Lithos
Year: 2021, Volumen: 400/401, Pages: 1-13 |
| ISSN: | 1872-6143 |
| DOI: | 10.1016/j.lithos.2021.106353 |
| Acceso en línea: | Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1016/j.lithos.2021.106353 Verlag, lizenzpflichtig, Volltext: https://www.sciencedirect.com/science/article/pii/S0024493721003893 
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| Notas de Autor: | Zhaoping Hu, Lingsen Zeng, Michael W. Förster, Linghao Zhao, Lie Gao, Huan Li, Yizeng Yang, Shuangqing Li |
| Sumario: | Syn-exhumation mafic magmatism during continental collision provides insights into the crust-mantle reaction during deep subduction and the nature of orogenic lithospheric mantle in collisional orogens. In this study, we present a comprehensive data set of zircon U-Pb ages and whole-rock major-trace elements as well as Sr-Nd-Pb isotopes of alkaline mafic rocks from the southern Liaodong Peninsula, eastern China. Zircon U-Pb analyses yield Late Triassic age of 213 ± 3 to 217 ± 3 Ma, younger than the Middle Triassic ultrahigh-pressure metamorphic rocks of the Dabie-Sulu orogen. Thus, the alkaline mafic rocks are products of syn-exhumation magmatism during continental collision of the South and North China blocks. The rocks show shoshonitic affinities with high K2O (3.78-5.23 wt%) and K2O/Na2O (0.71-1.22). They are characterized by arc-like trace-element patterns with enriched LILE, Pb, and LREE, and depleted HFSE. They exhibit enriched Sr-Nd isotopic compositions with high initial 87Sr/86Sr isotopic ratios of 0.7058-0.7061 and negative εNd(t) values of −13.0 to −15.1. These results suggest involvement of recycled continental crust in their mantle source. The mantle source likely formed by the metasomatic reaction of subducted continental crust-derived melts with the overlying subcontinental lithospheric mantle during the Triassic continental collision. Decompressional melting of this metasomatized mantle formed syn-exhumation mafic magmas during the transition from convergent to extensional tectonics in the Late Triassic. Accordingly, mafic rocks from the southern Liaodong Peninsula provide a geochemical record of the subduction and recycling of continental crust into the mantle and melt-mantle reaction induced metasomatism within the orogen. |
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| Notas: | Gesehen am 02.12.2021 |
| Descripción Física: | Online Resource |
| ISSN: | 1872-6143 |
| DOI: | 10.1016/j.lithos.2021.106353 |