Cardiff University | Prifysgol Caerdydd ORCA
Online Research @ Cardiff 
WelshClear Cookie - decide language by browser settings

Sediment recycling by continental subduction indicated by B-Hf-Pb-Nd isotopes from Miocene?Quaternary lavas in the northern margin of Tibet

Zhang, Xiu-Zheng, Wang, Qiang, Kerr, Andrew C. ORCID: https://orcid.org/0000-0001-5569-4730, Wei, Gang-Jian, Qi, Yue, Liu, Ying and Yang, Yu-Cheng 2023. Sediment recycling by continental subduction indicated by B-Hf-Pb-Nd isotopes from Miocene?Quaternary lavas in the northern margin of Tibet. Lithos 444-44 , 107109. 10.1016/j.lithos.2023.107109

[thumbnail of Zhang et al. Lithos.pdf]
Preview
PDF - Accepted Post-Print Version
Download (1MB) | Preview

Abstract

Although it has been argued that sediment recycling plays an important role in the differentiation of the continental crust, boron (B) isotopic data does not support a direct input of subducted sediments into arc magmas. This raises questions about the viability of sediment recycling as a process in the differentiation of continental crust. Here, we report B isotopic data from Miocene–Quaternary lavas derived from different sources in the northern margin of Tibet. These lavas have high B contents and negative δ11B values close to those of continental sediments. Strongly peraluminous rhyolites have the highest B (93 to 1559 ppm) contents with negative δ11B (−9.7 to −17.9) values. Adakitic dacites and trachyandesites exhibit the lowest B (18 to 29 ppm) contents with markedly negative δ11B (−12.0 to −35.7) values whereas olivine leucitites have B (37.2 to 59.3 ppm) contents with negative δ11B (−8.3 to −15.6) values. These lavas also have enriched Hf-Pb-Nd isotopic compositions similar to those of sediments. This data, combined with numerical modelling and geophysical and tectonic data for Cenozoic continental subduction in the northern margin of Tibet, indicates that: (1) the strongly peraluminous rhyolites were generated by partial melting of mica-bearing continental sedimentary rocks subducted to the depth of mid-to-lower crust; (2) adakitic lavas were derived by partial melting of sediment-bearing thickened lower crust underwent dehydration and eclogites-facies metamorphism; and (3) olivine leucitites were generated by partial melting of enriched mantle metasomatized by sediment-bearing eclogite-facies crust-derived melts. Thus, at continental convergent margins, continental subduction is an important mechanism for sediment recycling and the evolution of continental crust.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Earth and Environmental Sciences
Publisher: Elsevier
ISSN: 0024-4937
Date of First Compliant Deposit: 10 March 2023
Date of Acceptance: 1 March 2023
Last Modified: 05 Mar 2024 17:05
URI: https://orca.cardiff.ac.uk/id/eprint/157659

Citation Data

Cited 2 times in Scopus. View in Scopus. Powered By Scopus® Data

Actions (repository staff only)

Edit Item Edit Item

Downloads

Downloads per month over past year

View more statistics