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Weak cubic CaSiO₃ perovskite in the Earth's mantle

Titelangaben

Immoor, Julia ; Miyagi, Lowell ; Liermann, H.-P. ; Speziale, S. ; Schulze, K. ; Buchen, Johannes ; Kurnosov, Alexander ; Marquardt, Hauke:
Weak cubic CaSiO₃ perovskite in the Earth's mantle.
In: Nature. Bd. 603 (2022) . - S. 276-279.
ISSN 1476-4687
DOI: https://doi.org/10.1038/s41586-021-04378-2

Abstract

Cubic CaSiO3 perovskite is a major phase in subducted oceanic crust, where it forms at a depth of about 550 kilometres from majoritic garnet. However, its rheological properties at temperatures and pressures typical of the lower mantle are poorly known. Here we measured the plastic strength of cubic CaSiO3 perovskite at pressure and temperature conditions typical for a subducting slab up to a depth of about 1,200 kilometres. In contrast to tetragonal CaSiO3, previously investigated at room temperature, we find that cubic CaSiO3 perovskite is a comparably weak phase at the temperatures of the lower mantle. We find that its strength and viscosity are substantially lower than that of bridgmanite and ferropericlase, possibly making cubic CaSiO3 perovskite the weakest lower-mantle phase. Our findings suggest that cubic CaSiO3 perovskite governs the dynamics of subducting slabs. Weak CaSiO3 perovskite further provides a mechanism to separate subducted oceanic crust from the underlying mantle. Depending on the depth of the separation, basaltic crust could accumulate at the boundary between the upper and lower mantle, where cubic CaSiO3 perovskite may contribute to the seismically observed regions of low shear-wave velocities in the uppermost lower mantle, or sink to the core–mantle boundary and explain the seismic anomalies associated with large low-shear-velocity provinces beneath Africa and the Pacific.

Weitere Angaben

Publikationsform: Artikel in einer Zeitschrift
Begutachteter Beitrag: Ja
Institutionen der Universität: Forschungseinrichtungen > Forschungszentren > Bayerisches Forschungsinstitut für Experimentelle Geochemie und Geophysik - BGI
Graduierteneinrichtungen > Bayreuther Graduiertenschule für Mathematik und Naturwissenschaften - BayNAT
Forschungseinrichtungen
Forschungseinrichtungen > Forschungszentren
Graduierteneinrichtungen
Titel an der UBT entstanden: Ja
Themengebiete aus DDC: 500 Naturwissenschaften und Mathematik > 500 Naturwissenschaften
500 Naturwissenschaften und Mathematik > 510 Mathematik
Eingestellt am: 11 Mai 2022 08:18
Letzte Änderung: 29 Sep 2022 12:06
URI: https://eref.uni-bayreuth.de/id/eprint/69591