The interaction of viscous heating with grain-size dependent rheology in the formation of localized slip zones

Masanori Kameyama, David A. Yuen, Hiromi Fujimoto

Research output: Contribution to journalArticlepeer-review

87 Scopus citations

Abstract

The formation of localized shear zones is important for understanding many local and global processes in geodynamics. We have developed a self-consistent thermal-mechanical model together with a rheology which depends on temperature, strain-rate and grain-size distribution. The grain-size distribution has contributions from both dynamic recrystallization and grain-growth processes, and is governed locally by a nonlinear ordinary differential equation. A one-dimensional model with 104 points is employed to resolve all of the scales involving grain-size and temperature. We found that grain-growth inhibits the development of shear zones, and that there is a delicate interplay between viscous heating and grain-growth process in determining whether narrow fault zones are developed quickly. For realistic parameters of rheology and grain-boundary processes for wet olivine, the magnitude of the rate of grain-growth is crucial to determine whether shear zones are stable or unstable at temperature T ≃ 1000 K or shear stress a ≃ 100 MPa.

Original languageEnglish (US)
Article number97GL02648
Pages (from-to)2523-2526
Number of pages4
JournalGeophysical Research Letters
Volume24
Issue number20
DOIs
StatePublished - 1997

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