Oxidation of Archean upper mantle caused by crustal recycling

Lei Gao, Shuwen Liu, Peter A. Cawood, Fangyang Hu, Jintuan Wang, Guozheng Sun, Yalu Hu

Research output: Contribution to journalArticleResearchpeer-review

27 Citations (Scopus)

Abstract

The redox evolution of Archean upper mantle impacted mantle melting and the nature of chemical equilibrium between mantle, ocean and atmosphere of the early Earth. Yet, the origin of these variations in redox remain controversial. Here we show that a global compilation of ∼3.8-2.5 Ga basalts can be subdivided into group B-1, showing modern mid-ocean ridge basalt-like features ((Nb/La)PM ≥ 0.75), and B-2, which are similar to contemporary island arc-related basalts ((Nb/La)PM < 0.75). Our V-Ti redox proxy indicates a more reducing upper mantle, and the results of both ambient and modified mantle obtained from B-1 and B-2 samples, respectively, exhibit a ∼1.0 log unit increase in their temporal evolution for most cratons. Increases in mantle oxygen fugacity are coincident with the changes in basalt Th/Nb ratios and Nd isotope ratios, indicating that crustal recycling played a crucial role, and this likely occurred either via plate subduction or lithospheric drips.

Original languageEnglish
Article number3283
Number of pages7
JournalNature Communications
Volume13
Issue number1
DOIs
Publication statusPublished - Dec 2022

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