Deformation of Diopside Single Crystal at Mantle Pressure, 1, Mechanical Data

Journal Article · Thu Jan 01 04:00:00 EST 2009 · Physics of the Earth and Planetary Interiors

DOI:https://doi.org/10.1016/j.pepi.2009.08.010· OSTI ID:1019981

Amiguet, E; Raterron, P; Cordier, P; Couvy, H; Chen, J

Steady-state deformation experiments were carried out in a deformation-DIA (D-DIA) high-pressure apparatus on oriented diopside single crystals, at pressure (P) ranging from 3.8 to 8.8 GPa, temperature (T) from 1100 to 1400 C, and differential stress ({sigma}) between 0.2 and 1.7 GPa. Three compression directions were chosen in order to test the activity of diopside dislocation slip systems, i.e., 1/2<1 1 0>{l_brace}1 {bar 1} 0{r_brace} systems activated together, both [1 0 0](0 1 0) and [0 1 0](1 0 0) systems together, or [0 0 1] dislocation slip activated in (1 0 0), (0 1 0) and {l_brace}1 1 0{r_brace} planes. Constant applied stress and specimen strain rates ({var_epsilon}) were monitored in situ using time-resolved synchrotron X-ray diffraction and radiography, respectively. Transmission electron microscopy (TEM) investigation of the run products revealed that dislocation creep was responsible for sample deformation. Comparison of the present high-P data with those obtained at room-P by Raterron and Jaoul (1991) - on similar crystals deformed at comparable T-{sigma} conditions - allows quantifying the effect of P on 1/2<1 1 0>{l_brace} 1 {bar 1} 0{r_brace} activity. This translates into the activation volume V* = 17 {+-} 6 cm{sup 3}/mol in the corresponding creep power law. Our data also show that both 1/2<1 1 0> dislocation slips and [0 0 1] have comparable slip activities at mantle P and T, while [1 0 0](0 1 0) and [0 1 0](1 0 0) slip systems remain marginal. These results show that P has a significant effect on high-T dislocation creep in diopside, the higher the pressure the harder the crystal, and that this effect is stronger on 1/2<1 1 0> slip than on [0 0 1] slip.

• Research Organization: Brookhaven National Laboratory (BNL) National Synchrotron Light Source
• Sponsoring Organization: DOE - OFFICE OF SCIENCE
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1019981
• Report Number(s): BNL--95827-2011-JA
• Journal Information: Physics of the Earth and Planetary Interiors, Journal Name: Physics of the Earth and Planetary Interiors Journal Issue: 3-4 Vol. 177; ISSN 0031-9201; ISSN PEPIAM
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
COMPRESSION
CREEP
DEFORMATION
DIOPSIDE
DISLOCATIONS
MONOCRYSTALS
SLIP
STRAIN RATE
SYNCHROTRONS
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION
national synchrotron light source