Conference Proceedings

Remnants of early Earth differentiation in the deepest mantle-derived lavas

Andrea Giuliani, Matthew G Jackson, Angus Fitzpayne, Hayden Dalton

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA | NATL ACAD SCIENCES | Published : 2021

Abstract

The noble gas isotope systematics of ocean island basalts suggest the existence of primordial mantle signatures in the deep mantle. Yet, the isotopic compositions of lithophile elements (Sr, Nd, Hf) in these lavas require derivation from a mantle source that is geochemically depleted by melt extraction rather than primitive. Here, this apparent contradiction is resolved by employing a compilation of the Sr, Nd, and Hf isotope composition of kimberlites-volcanic rocks that originate at great depth beneath continents. This compilation includes kimberlites as old as 2.06 billion years and shows that kimberlites do not derive from a primitive mantle source but sample the same geochemically deple..

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Grants

Awarded by Swiss National Science Foundation Ambizione Fellowship


Awarded by NSF


Funding Acknowledgements

We thank Jon Woodhead, Janet Hergt, Rick Carlson, Paolo Sossi, Brad Peters, and Andreas Stracke for discussions and Matteo Desiderio for proofreading this manuscript. Comments from the editor and two anonymous reviewers have improved the clarity of this contribution. This research was funded by Swiss National Science Foundation Ambizione Fellowship PZ00P2_180126/1 (to A.G.) and NSF Grant NSF EAR-1900652 (to M.G.J.).