Basaltic reservoirs in the Earth’s mantle transition zone

Tauzin, Benoit, Waszek, Lauren, Ballmer, Maxim D., Afonso, Juan Carlos, and Bodin, Thomas (2022) Basaltic reservoirs in the Earth’s mantle transition zone. Proceedings of the National Academy of Sciences of the United States of America, 119 (48). e2209399119.

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Abstract

The formation and preservation of compositional heterogeneities inside the Earth affect mantle convection patterns globally and control the long-term evolution of geochemical reservoirs. However, the distribution, nature, and size of reservoirs in the Earth’s mantle are poorly constrained. Here, we invert measurements of travel times and amplitudes of seismic waves interacting with mineralogical phase transitions at 400–700-km depth to obtain global probabilistic maps of temperature and bulk composition. We find large basalt-rich pools (up to 60% basalt fraction) surrounding the Pacific Ocean, which we relate to the segregation of oceanic crust from slabs that have been subducted since the Mesozoic. Segregation of oceanic crust from initially cold and stiff slabs may be facilitated by the presence of a weak hydrated layer in the slab or by weakening upon mineralogical transition due to grain-size reduction.

Item ID: 77587
Item Type: Article (Research - C1)
ISSN: 1091-6490
Keywords: mantle composition, mineral physics, seismology
Copyright Information: Copyright © 2022 the Author(s). Published by PNAS. This article is distributed under Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND).
Date Deposited: 18 Apr 2023 02:22
FoR Codes: 37 EARTH SCIENCES > 3706 Geophysics > 370609 Seismology and seismic exploration @ 100%
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