Desiderio, Matteo;
Ballmer, Maxim D;
(2024)
Ancient Stratified Thermochemical Piles Due To High Intrinsic Viscosity.
Geophysical Research Letters
, 51
(14)
, Article e2024GL110006. 10.1029/2024GL110006.
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Geophysical Research Letters - 2024 - Desiderio - Ancient Stratified Thermochemical Piles Due To High Intrinsic Viscosity.pdf - Published Version Download (1MB) | Preview |
Abstract
The two Large Low Velocity Provinces (LLVPs) in the lowermost Earth mantle are thought to affect large-scale heat and material transport, governing mantle evolution. LLVPs have been interpreted as thermochemical piles of recycled oceanic crust (ROC) and/or other dense rock types. However, the role of ROC intrinsic viscosity in pile formation and related effects on mantle evolution remain poorly understood. Using mantle convection models, we show that, while ROC intrinsic density controls pile formation, intrinsic viscosity determines whether piles are internally convecting or stratified. Only high-viscosity, stratified piles can preserve material over several billions of years. Pile stratification is therefore required to reconcile geochemical evidence for the survival of ancient reservoirs. Compositionally layered piles are also consistent with geophysical observations that point to vertical gradients in LLVP properties. As mineral physics constraints point to low-viscosity ROC, our results suggest that LLVPs may be partly formed by early basal-magma-ocean cumulates.
| Type: | Article |
|---|---|
| Title: | Ancient Stratified Thermochemical Piles Due To High Intrinsic Viscosity |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1029/2024GL110006 |
| Publisher version: | https://doi.org/10.1029/2024GL110006 |
| Language: | English |
| Additional information: | © The Author(s), 2025. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licence (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. https://creativecommons.org/licenses/by/4.0/ |
| Keywords: | deep mantle, large low shear velocity provinces (LLSVPs), viscosity, oceanic crust, mantle convection, thermochemical piles, |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Earth Sciences |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10204882 |
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