Zircon U-Pb age and Sr-Nd-Hf isotope geochemistry of I-type granites in the Jiangda-Weixi region, Eastern Tibet: Implications for the tectonic evolution of the Paleo-Tethyan orogen

Gao, Rui, Wu, Tao, Kerr, Andrew C. ORCID: https://orcid.org/0000-0001-5569-4730, Lui, Han, Xiao, Long and Huang, Wan 2025. Zircon U-Pb age and Sr-Nd-Hf isotope geochemistry of I-type granites in the Jiangda-Weixi region, Eastern Tibet: Implications for the tectonic evolution of the Paleo-Tethyan orogen. Journal of Earth Science 10.1007/s12583-024-0144-7 Item availability restricted.

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Abstract

Permian—Triassic granitoids are widely distributed along the Jinshajiang suture belt, eastern Tibet, and are regarded as the result of the tectonic-magmatic activity associated with the evolution of Paleo-Tethys Ocean. This paper focuses on the high-K calc-alkaline I-type Rennong (~ 235 Ma) and Jiaduoling (~232 Ma) granitoid plutons, eastern Tibet, which are enriched in light rare earth elements (LREEs) and large ion lithophile elements (LILEs), but depleted in high field strength elements (HFSEs) with moderate-weak negative Eu anomalies (0.61–0.90). The Rennong granites are characterized by uniform zircon εHf(t) values (-7.3 to-3.5) and negative εNd(t) values (-7.6 to-5.7), with old two-stage Nd model ages (TDM2 = 1.51-1.46 Ga) and was likely formed by partial melting of the basement rocks, whereas the Jiaduoling rock samples have variable zircon εHf(t) values (-5.7 to +5.5) but negative εNd(t) values (-7.6 to-7.7) and are proposed to be formed by hybridization of mantle-derived mafic magma, Rennong felsic magma and sediments. Mafic microgranular enclaves (MMEs) in the Jiaduoling granitic rocks, have similar zircon U-Pb ages (~237 Ma) and zircon εHf(t) values (-4.4 to +6.3) to the host rocks, indicating that zircons in the MMEs were actually xenocrysts that formed at an early stage in the granitic magma chamber. These results reveal that the break-off of the Jinshajiang oceanic slab beneath Changdu (Qamdo)-Simao Block was in a post-collisional setting, resulted in the upwelling of asthenosphere in the Late Triassic, and then, generated the wide-spread intermediate-felsic magmatism along the Jinshajing belt, including the Rennong and Jiaduoling plutons.

Item Type:	Article
Date Type:	Published Online
Status:	In Press
Schools:	Schools > Earth and Environmental Sciences
Publisher:	Springer
ISSN:	1674-487X
Date of First Compliant Deposit:	7 March 2025
Date of Acceptance:	14 December 2024
Last Modified:	30 Sep 2025 11:15
URI:	https://orca.cardiff.ac.uk/id/eprint/176716

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