Wang, W;
Liu, J;
Zhu, F;
Li, M;
Dorfman, SM;
Li, J;
Wu, Z;
(2021)
Formation of large low shear velocity provinces through the decomposition of oxidized mantle.
Nature Communications
, 12
, Article 1911. 10.1038/s41467-021-22185-1.
Preview |
Text
Wang_et_al-2021-Nature_Communications.pdf - Published Version Download (3MB) | Preview |
Abstract
Large Low Shear Velocity Provinces (LLSVPs) in the lowermost mantle are key to understanding the chemical composition and thermal structure of the deep Earth, but their origins have long been debated. Bridgmanite, the most abundant lower-mantle mineral, can incorporate extensive amounts of iron (Fe) with effects on various geophysical properties. Here our high-pressure experiments and ab initio calculations reveal that a ferric-iron-rich bridgmanite coexists with an Fe-poor bridgmanite in the 90 mol% MgSiO3-10 mol% Fe2O3 system, rather than forming a homogeneous single phase. The Fe3+-rich bridgmanite has substantially lower velocities and a higher VP/VS ratio than MgSiO3 bridgmanite under lowermost-mantle conditions. Our modeling shows that the enrichment of Fe3+-rich bridgmanite in a pyrolitic composition can explain the observed features of the LLSVPs. The presence of Fe3+-rich materials within LLSVPs may have profound effects on the deep reservoirs of redox-sensitive elements and their isotopes.
Type: | Article |
---|---|
Title: | Formation of large low shear velocity provinces through the decomposition of oxidized mantle. |
Location: | England |
Open access status: | An open access version is available from UCL Discovery |
DOI: | 10.1038/s41467-021-22185-1 |
Publisher version: | https://doi.org/10.1038/s41467-021-22185-1 |
Language: | English |
Additional information: | This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. |
Keywords: | Geodynamics, Geophysics, Mineralogy, Seismology |
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/10125389 |
Archive Staff Only
View Item |