Ancient mantle in a modern arc: Osmium isotopes in Izu-Bonin-Mariana forearc peridotites

Parkinson, Ian; Hawkesworth, Chris J. and Cohen, Anthony (1998). Ancient mantle in a modern arc: Osmium isotopes in Izu-Bonin-Mariana forearc peridotites. Science, 281 pp. 2011–2013.

DOI: https://doi.org/10.1126/science.281.5385.2011

Abstract

Mantle peridotites drilled from the Izu-Bonin-Mariana forearc have unradiogenic ¹⁸⁷Os/¹⁸⁸Os ratios (0.1193 to 0.1273), which give Proterozoic model ages of 820 to 1230 million years ago. If these peridotites are residues from magmatism during the initiation of subduction 40 to 48 million years ago, then the mantle that melted was much more depleted in incompatible elements than the source of mid-ocean ridge basalts (MORB). This result indicates that osmium isotopes record information about ancient melting events in the convecting upper mantle not recorded by incompatible lithophile isotope tracers. Subduction zones may be a graveyard for ancient depleted mantle material, and portions of the convecting upper mantle may be less radiogenic in osmium isotopes than previously recognized.

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About

• Item ORO ID
• 29091
• Item Type
• Journal Item
• ISSN
• 1095-9203
• Project Funding Details

• Funded Project Name	Project ID	Funding Body
  Not Set	Not Set	NERC (Natural Environment Research Council)

• Academic Unit or School
• Faculty of Science, Technology, Engineering and Mathematics (STEM) > Environment, Earth and Ecosystem Sciences
  Faculty of Science, Technology, Engineering and Mathematics (STEM)
• Copyright Holders
• © 1998 American Association for the Advancement of Science
• Depositing User
• Ian Parkinson