Barium isotope evidence for pervasive sediment recycling in the upper mantle

Sune G. Nielsen, Tristan J. Horner, Helena V. Pryer, Jerzy Blusztajn, Yunchao Shu, Mark D. Kurz, Véronique Le Roux

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)

Abstract

The upper mantle, as sampled by mid-ocean ridge basalts (MORBs), exhibits significant chemical variability unrelated to mechanisms of melt extraction at ridges. We show that barium isotope variations in global MORBs vary systematically with radiogenic isotopes and trace element ratios, which reflects mixing between depleted and enriched MORB melts. In addition, modern sediments and enriched MORBs share similar Ba isotope signatures. Using modeling, we show that addition of ~0.1% by weight of sediment components into the depleted mantle in subduction zones must impart a sedimentary Ba signature to the overlying mantle and induce low-degree melting that produces the enriched MORB reservoir. Subsequently, these enriched domains convect toward mid-ocean ridges and produce radiogenic isotope variation typical of enriched MORBs. This mechanism can explain the chemical and isotopic features of enriched MORBs and provide strong evidence for pervasive sediment recycling in the upper mantle.

Original languageEnglish
Article numbereaas8675
JournalScience Advances
Volume4
Issue number7
DOIs
Publication statusPublished - Jul 11 2018
Externally publishedYes

ASJC Scopus subject areas

  • General

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