A Neoproterozoic appinite rock suite records the early tectonic evolution of the northern margin of the Yangtze Block during convergence with Rodinia

Li, Haiquan, Wei, Yunxu, Zhou, Wenxiao, Chi Fru, Ernest ORCID: https://orcid.org/0000-0003-2673-0565, Drüppel, Kirsten, Xu, Daliang, Deng, Xin, Liu, Hao and Tan, Mantang 2024. A Neoproterozoic appinite rock suite records the early tectonic evolution of the northern margin of the Yangtze Block during convergence with Rodinia. Precambrian Research 409 , 107448. 10.1016/j.precamres.2024.107448 Item availability restricted.

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Abstract

Appinite rock suites generally consist of bimodal mafic–silicic hornblende-bearing igneous rocks, mostly generated by post-subduction processes along ancient convergent plate margins. In this study, we investigated the Neoproterozoic Duanfangxi appinite rock suite from the south Kongling terrane, South China, which is key to understanding the tectonic evolution of the Yangtze Block and for the reconstruction of its association with Rodinia. Based on field observations, mineralogical and whole-rock geochemical analyses, the appinites are divided into the early Zhaibao and Yazikou and the late Taipingxi sub-series. Zircon U–Pb dating constrains the age of formation of the early Zhaibao and Yazikou and the later Taipingxi sub-series to 890–870 Ma and 870–865 Ma, respectively. The three successions are characterised by high hornblende, biotite, and Mg calc-alkaline compositions, and low Th, Nb, and Zr content. While the early sub-series is rich in large-ion lithophile elements, the late sub-series is enriched in high-field-strength elements. Collectively, the geochemical composition of the three rock units is typical of arc-related rocks, with slightly positive to negative εHf(t) values spanning 11.5 to –14.8 for the Zhaibao and –1.2 to –18.1 for the Yazikou sub-series, indicating an asthenospheric mantle source that interacted with subducted slab-derived fluids and hydrous melts. Together, the appinite suites suggest a switch from subduction to a post-subduction depositional setting between 890–865 Ma. Our results, supported by previous lines of evidence, indicate that formation of the northern margin of the Yangtze Block was associated with a complete Wilson cycle during the late Mesoproterozoic to early Neoproterozoic.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Earth and Environmental Sciences
Publisher:	Elsevier
ISSN:	0301-9268
Date of First Compliant Deposit:	12 July 2024
Date of Acceptance:	23 May 2024
Last Modified:	09 Nov 2024 11:00
URI:	https://orca.cardiff.ac.uk/id/eprint/170564

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