Phase Relations in the MgSiO₃ System Associated With Hot Mantle Upwelling Across the 660 km Depth

DOI zum Zitieren der Version auf EPub Bayreuth: https://doi.org/10.15495/EPub_UBT_00009133
URN to cite this document: urn:nbn:de:bvb:703-epub-9133-4

Title data

Chanyshev, Artem ; Purevjav, Narangoo ; Bondar, Dmitry ; Tang, Hu ; Fei, Hongzhan ; Wang, Lin ; Wang, Fei ; Kim, Eun Jeong ; Liu, Dan ; Ishii, Takayuki ; Bhat, Shrikant ; Farla, Robert ; Katsura, Tomoo:
Phase Relations in the MgSiO₃ System Associated With Hot Mantle Upwelling Across the 660 km Depth.
In: Geophysical Research Letters. Vol. 52 (2025) Issue 17 . - e2025GL115385.
ISSN 1944-8007
DOI der Verlagsversion: https://doi.org/10.1029/2025GL115385

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Abstract

The phase transformations of MgSiO3 bridgmanite control the structure, dynamics and chemistry of the Earth's mantle. Formation of bridgmanite occurs at a depth of about 660 km causing the strong and abrupt seismic discontinuity. Previous experimental studies have revealed that this discontinuity is caused by ringwoodite dissociation in the average mantle. However, the cause of the 660-km seismic discontinuity beneath hotspots remains unclear. Here we determine the phase relations in the MgSiO3 system near the 660-km seismic discontinuity conditions. At 2,200–2,350 K with decreasing pressure, MgSiO3 bridgmanite first transforms to akimotoite and then to garnet. The akimotoite-bridgmanite boundary has almost no temperature dependence, whereas the garnet–akimotoite transition has a very steep positive boundary slope. Based on these slopes, we calculated the garnet–bridgmanite boundary slope. Depending on the temperature regime, the akimotoite-bridgmanite or the garnet–bridgmanite transition may occur in ascending plume beneath hotspots near the 660 km depth.

Further data

Item Type:	Article in a journal
Keywords:	experimental; high-pressure; in situ X-ray diffraction; bridgmanite; geodynamics; phase relations
DDC Subjects:	500 Science > 550 Earth sciences, geology
Institutions of the University:	Research Institutions > Central research institutes > Bavarian Research Institute of Experimental Geochemistry and Geophysics - BGI Research Institutions Research Institutions > Central research institutes
Language:	English
Originates at UBT:	Yes
URN:	urn:nbn:de:bvb:703-epub-9133-4
Date Deposited:	17 Apr 2026 07:37
Last Modified:	17 Apr 2026 07:38
URI:	https://epub.uni-bayreuth.de/id/eprint/9133

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