Extensive crustal extraction in Earth’s early history inferred from molybdenum isotopes

McCoy-West, Alex J.; Chowdhury, Priyadarshi; Burton, Kevin W.; Sossi, Paolo; Nowell, Geoff M.; Fitton, J. Godfrey; Kerr, Andrew C.; Cawood, Peter A.; Williams, Helen M.

doi:10.1038/s41561-019-0451-2

Extensive crustal extraction in Earth’s early history inferred from molybdenum isotopes

McCoy-West, Alex J.; Chowdhury, Priyadarshi; Burton, Kevin W.; Sossi, Paolo; Nowell, Geoff M.; Fitton, J. Godfrey; Kerr, Andrew C.; Cawood, Peter A.; Williams, Helen M.

Authors

Alex J. McCoy-West

Priyadarshi Chowdhury

Professor Kevin Burton kevin.burton@durham.ac.uk
Professor

Paolo Sossi

Dr Geoffrey Nowell g.m.nowell@durham.ac.uk
Associate Professor

J. Godfrey Fitton

Andrew C. Kerr

Peter A. Cawood

Helen M. Williams

Abstract

Estimates of the volume of the earliest crust based on zircon ages and radiogenic isotopes remain equivocal. Stable isotope systems, such as molybdenum, have the potential to provide further constraints but remain underused due to the lack of complementarity between mantle and crustal reservoirs. Here we present molybdenum isotope data for Archaean komatiites and Phanerozoic komatiites and picrites and demonstrate that their mantle sources all possess subchondritic signatures complementary to the superchondritic continental crust. These results confirm that the present-day degree of mantle depletion was achieved by 3.5 billion years ago and that Earth has been in a steady state with respect to molybdenum recycling. Mass balance modelling shows that this early mantle depletion requires the extraction of a far greater volume of mafic-dominated protocrust than previously thought, more than twice the volume of the continental crust today, implying rapid crustal growth and destruction in the first billion years of Earth’s history.

Citation

McCoy-West, A. J., Chowdhury, P., Burton, K. W., Sossi, P., Nowell, G. M., Fitton, J. G., …Williams, H. M. (2019). Extensive crustal extraction in Earth’s early history inferred from molybdenum isotopes. Nature Geoscience, 12, 946-951. https://doi.org/10.1038/s41561-019-0451-2

Journal Article Type	Article
Acceptance Date	Aug 19, 2019
Online Publication Date	Sep 23, 2019
Publication Date	Dec 1, 2019
Deposit Date	Sep 12, 2019
Publicly Available Date	Mar 23, 2020
Journal	Nature Geoscience
Print ISSN	1752-0894
Electronic ISSN	1752-0908
Publisher	Nature Research
Peer Reviewed	Peer Reviewed
Volume	12
Pages	946-951
DOI	https://doi.org/10.1038/s41561-019-0451-2