Home | Contact Us | Sitemap | 中文 | CAS | Director's Email
 
Location:Home > Papers > Recent Papers
Oceanic lithosphere heterogeneity in the eastern Paleo-Tethys revealed by PGE and Re-Os isotopes of mantle peridotites in the Jinshajiang ophiolite TEXT SIZE: A A A
Platinum group elements (PGE) and Re-Os isotopes of mantle peridotites in the Jinshajiang ophiolite (SWChina) were investigated in this study, in order to constrain the evolution of the lithospheric mantle beneath the Jinshajiang-Ailaoshan Ocean, which was a branch of the eastern Paleo-Tethys. The Jinshajiang peridotites have whole-rock compositions (e.g., MgO = 32.7-38.1 wt.%; Al2O3 = 0.67-1.30 wt.%) and spinels with moderate Cr# values (0.4-0.6) similar to those of abyssal peridotites, which indicate moderate degrees of partial melting (15%-20%). These peridotites exhibit U-shaped chondrite-normalized REE patterns that could be caused by hydrothermal alteration or melt-rock interaction after mantle melting. In addition, Pd concentrations and (Pd/Ir) N ratios of the Jinshajiang peridotites increases with decreasing Al2O3 concentrations. These negative correlations cannot be explained by simple partial melting but record a melt-rock reaction event after mantle melting. This study therefore demonstrates the efficiency of PGE in detecting themelt-rock reaction process relative to whole-rock major and trace elements. The suprachondritic Os-187/Os-188 ratios (0.1272-0.1374) further indicate that the later percolating melt derived from a mantle domain with distinct Os-187-enriched isotopic compositions. In comparison with peridotites in the Ailaoshan ophiolite belt, which were not significantly affected by melt percolation, this study further highlights that the lithosphericmantle compositions beneath different segments of the same ocean basin are highly variable and might be controlled by distinct mantle processes in response to different rifting mechanisms. (C) 2021 China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V.
 

Publication name

 GEOSCIENCE FRONTIERS Volume: 12 Issue: 3 Article Number: 101114 DOI: 10.1016/j.gsf.2020.11.011 Published: MAY 2021

Author(s)

 Wang, Yan-Jun; Hu, Wen-Jun; Zhong, Hong; Zhu, Wei-Guang; Bai, Zhong-Jie

Corresponding author(s) 

 HU Wenjun 
 huwenjun170@163.cOm  
 Chinese AcademyofSci, Inst Geochem, State Key Lab Ore Deposit Geochem, Guiyang 550081, Peoples R China.

View here for the details 

Copyright © Institute Of Geochemistry, Chinese Academy of Sciences All Rights Reserved.
Address: 99 West Lincheng Road, Guanshanhu District, Guiyang, Guizhou Province 550081, P.R.China
Tel: +86-851-85895239 Fax: +86-851-85895239 Email: web_en@mail.gyig.ac.cn