Effect of water on the rheology of iron rich olivine

Yong Hong Zhao, Xu Shi, Mark E Zimmerman, David L Kohlstedt

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

We have undertaken an experimental investigation of the effect of water on the viscosity of iron rich olivine aggregates. Tri-axial compressive creep experiments were performed on hydrous fine-grained olivine samples of Fo50, Fo70, and Fo90. Two drops of water were added for hot-pressing using a telescoping can to prevent the water from escaping during the hot-press. Samples were deformed in a gas-medium apparatus at a confining pressure of 300MPa, a temperature between 1323 and 1473K, a differential stress 10 ∼ 300MPa, a strain rate 10-7 ∼ 10-4s-1, and the maximum accumulative strain 20% for each sample. The samples were deformed both in the diffusion and the dislocation creep regime. From three dimensional global non-linear fitting of the test data, the stress exponent for wet iron rich olivine aggregates Fo50, Fo70, and Fo90,were determined as 3.8, 3.7 and 3.6 in dislocation creep regime, respectively, and the activation energy for wet Fo50, Fo70, and Fo90, as 444kJ/mol, 479kJ/mol and 514kJ/mol, respectively. These hydrous samples creep at a rate over a factor of 10 faster than those anhydrous samples with the same iron content and under the same deformation conditions. Therefore, this paper gives a preliminary test result of effect of water on the viscosity of iron rich olivine aggregates.

Original languageEnglish (US)
Pages (from-to)2381-2386
Number of pages6
JournalActa Petrologica Sinica
Volume22
Issue number9
StatePublished - Sep 2006

Keywords

  • Experimental study
  • High temperature creep
  • Hydrous iron rich olivine
  • Three dimensional compression
  • Viscosity

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