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Title: Pressure-Induced Slip-System Transition in Forsterite: Single-Crystal Rheological Properties at Mantle Pressure and Temperature

Abstract

Deformation experiments were carried out in a Deformation-DIA high-pressure apparatus (D-DIA) on oriented Mg2SiO4 olivine (Fo100) single crystals, at pressure (P) ranging from 2.1 to 7.5 GPa, in the temperature (T) range 1373-1677 K, and in dry conditions. These experiments were designed to investigate the effect of pressure on olivine dislocation slip-system activities, responsible for the lattice-preferred orientations observed in the upper mantle. Two compression directions were tested, promoting either [100] slip alone or [001] slip alone in (010) crystallographic plane. Constant applied stress ({sigma}) and specimen strain rates (Formula) were monitored in situ using time-resolved X-ray synchrotron diffraction and radiography, respectively. Transmission electron microscopy (TEM) investigation of the run products reveals that dislocation creep assisted by dislocation climb and cross slip was responsible for sample deformation. A slip transition with increasing pressure, from a dominant [100]-slip to a dominant [001]-slip, is documented. Extrapolation of the obtained rheological laws to upper-mantle P, T, and {sigma} conditions, suggests that [001]-slip activity becomes comparable to [100]-slip activity in the deep upper mantle, while [001] slip is mostly dominant in subduction zones. These results provide alternative explanations for the seismic anisotropy attenuation observed in the upper mantle, and for the 'puzzling' seismic-anisotropy anomaliesmore » commonly observed in subduction zones.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
959614
Report Number(s):
BNL-82600-2009-JA
Journal ID: ISSN 0003-004X; AMMIAY; TRN: US1005760
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Journal Article
Journal Name:
American Mineralogist
Additional Journal Information:
Journal Volume: 92; Journal ID: ISSN 0003-004X
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANISOTROPY; ATTENUATION; COMPRESSION; CREEP; DEFORMATION; DIFFRACTION; DISLOCATIONS; EXTRAPOLATION; MAGNESIUM SILICATES; MONOCRYSTALS; OLIVINE; PRESSURE RANGE GIGA PA; SLIP; STRAIN RATE; SUBDUCTION ZONES; TEMPERATURE RANGE 1000-4000 K; TRANSMISSION ELECTRON MICROSCOPY; national synchrotron light source

Citation Formats

Raterron, P, Chen, J, Li, L, Weidner, D, and Cordier, P. Pressure-Induced Slip-System Transition in Forsterite: Single-Crystal Rheological Properties at Mantle Pressure and Temperature. United States: N. p., 2007. Web. doi:10.2138/am.2007.2474.
Raterron, P, Chen, J, Li, L, Weidner, D, & Cordier, P. Pressure-Induced Slip-System Transition in Forsterite: Single-Crystal Rheological Properties at Mantle Pressure and Temperature. United States. https://doi.org/10.2138/am.2007.2474
Raterron, P, Chen, J, Li, L, Weidner, D, and Cordier, P. 2007. "Pressure-Induced Slip-System Transition in Forsterite: Single-Crystal Rheological Properties at Mantle Pressure and Temperature". United States. https://doi.org/10.2138/am.2007.2474.
@article{osti_959614,
title = {Pressure-Induced Slip-System Transition in Forsterite: Single-Crystal Rheological Properties at Mantle Pressure and Temperature},
author = {Raterron, P and Chen, J and Li, L and Weidner, D and Cordier, P},
abstractNote = {Deformation experiments were carried out in a Deformation-DIA high-pressure apparatus (D-DIA) on oriented Mg2SiO4 olivine (Fo100) single crystals, at pressure (P) ranging from 2.1 to 7.5 GPa, in the temperature (T) range 1373-1677 K, and in dry conditions. These experiments were designed to investigate the effect of pressure on olivine dislocation slip-system activities, responsible for the lattice-preferred orientations observed in the upper mantle. Two compression directions were tested, promoting either [100] slip alone or [001] slip alone in (010) crystallographic plane. Constant applied stress ({sigma}) and specimen strain rates (Formula) were monitored in situ using time-resolved X-ray synchrotron diffraction and radiography, respectively. Transmission electron microscopy (TEM) investigation of the run products reveals that dislocation creep assisted by dislocation climb and cross slip was responsible for sample deformation. A slip transition with increasing pressure, from a dominant [100]-slip to a dominant [001]-slip, is documented. Extrapolation of the obtained rheological laws to upper-mantle P, T, and {sigma} conditions, suggests that [001]-slip activity becomes comparable to [100]-slip activity in the deep upper mantle, while [001] slip is mostly dominant in subduction zones. These results provide alternative explanations for the seismic anisotropy attenuation observed in the upper mantle, and for the 'puzzling' seismic-anisotropy anomalies commonly observed in subduction zones.},
doi = {10.2138/am.2007.2474},
url = {https://www.osti.gov/biblio/959614}, journal = {American Mineralogist},
issn = {0003-004X},
number = ,
volume = 92,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}