Viscosity of bridgmanite determined by in situ stress and strain measurements in uniaxial deformation experiments

Noriyoshi Tsujino, Daisuke Yamazaki, Yu Nishihara, Takashi Yoshino, Yuji Higo, Yoshinori Tange

Research output: Contribution to journalArticlepeer-review

Abstract

To understand mantle dynamics, it is important to determine the rheological properties of bridgmanite, the dominant mineral in Earth’s mantle. Nevertheless, experimental data on the viscosity of bridgmanite are quite limited due to experimental difficulties. Here, we report viscosity and deformation mechanism maps of bridgmanite at the uppermost lower mantle conditions obtained through in situ stress-strain measurements of bridgmanite using deformation apparatuses with the Kawai-type cell. Bridgmanite would be the hardest among mantle constituent minerals even under nominally dry conditions in the dislocation creep region, consistent with the observation that the lower mantle is the hardest layer. Deformation mechanism maps of bridgmanite indicate that grain size of bridgmanite and stress conditions at top of the lower mantle would be several millimeters and ~105 Pa to realize viscosity of 1021–22 Pa·s, respectively. This grain size of bridgmanite suggests that the main part of the lower mantle is isolated from the convecting mantle as primordial reservoirs.

Original languageEnglish
Article number1821
JournalScience Advances
Volume8
Issue number13
DOIs
Publication statusPublished - Apr 2022

ASJC Scopus subject areas

  • General

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