Geochronology and petrogenesis of the early Silurian Zeluo mafic-ultramafic intrusion, eastern Tibet: implications for the tectonic setting and evolution of the eastern Proto-Tethys Ocean

Zhou, Hang, Zhou, Wenxiao, Chi Fru, Ernest ORCID: https://orcid.org/0000-0003-2673-0565, Sheldrick, Thomas C., Li, Haiquan, Huang, Bo, Fu, Dong and Xu, Yadong 2022. Geochronology and petrogenesis of the early Silurian Zeluo mafic-ultramafic intrusion, eastern Tibet: implications for the tectonic setting and evolution of the eastern Proto-Tethys Ocean. International Geology Review 10.1080/00206814.2022.2151050

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Abstract

The Tibetan Plateau is a key region to understand the evolution of the Tethys Oceans. To better constrain the tectonic evolution of the Proto-Tethys Ocean on the western margin of the Yangtze plate, we present an integrated petrography, geochemistry, and zircon U-Pb-Lu-Hf isotope study on newly recognized early Silurian gabbro and serpentinite rocks from the eastern Yidun terrane of the Tibetan Plateau. Zircon U-Pb dating of the gabbro yields an Early Silurian age of 438.2 ± 2.8 Ma. Zircon εHf(t) values of 5.4 to 8.5 suggest a single-stage model age (TDM1) ranging from 729 to 858 Ma. The gabbros exhibit low total rare earth element abundances but are moderately enriched in the light rare earth elements and the large-ion lithophile elements (e.g. Rb, Ba, and Sr), and display representative negative high-field strength elemental anomalies for Nb, Ta, Zr, and Hf on spidergrams. The gabbro and serpentinites were derived from a depleted mantle-like source made of garnet-spinel lherzolite composition, from a sub-arc mantle wedge that was metasomatized by slab dehydration. Thus, the gabbro and serpentinites record an Early Silurian subduction event of the Proto-Tethys Ocean under the Yangtze plate. Furthermore, this study confirms that the Yidun terrane on the western margin of the Yangtze plate is underlined by a Precambrian crystalline basement.

Item Type:	Article
Date Type:	Published Online
Status:	Published
Schools:	Earth and Environmental Sciences
Publisher:	Taylor and Francis Group
ISSN:	0020-6814
Date of First Compliant Deposit:	3 January 2023
Date of Acceptance:	20 November 2022
Last Modified:	05 Dec 2023 02:30
URI:	https://orca.cardiff.ac.uk/id/eprint/155357

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