Flow-law for ringwoodite at subduction zone conditions Article

Xu, Y, Weidner, DJ, Chen, J et al. (2003). Flow-law for ringwoodite at subduction zone conditions . PHYSICS OF THE EARTH AND PLANETARY INTERIORS, 136(1-2), 3-9. 10.1016/S0031-9201(03)00026-8

cited authors

  • Xu, Y; Weidner, DJ; Chen, J; Vaughan, MT; Wang, Y; Uchida, T

authors

abstract

  • The plastic properties of ringwoodite, a high-pressure modification of olivine, are experimentally determined at the pressure of 20 GPa and temperatures up to 1350 °C. Stress relaxation experiments have been carried out on fine-grained samples using a two-stage T-cup multiple anvil high-pressure apparatus with synchrotron-generated X-rays. We observe the presence of a significant weakening of the shear strength with a decrease from 2.5 to 0.2 GPa between 600 and 1000 °C. In this region, the activation energy, U, is about 275 kJ/mol and it decreases with increasing stress, reaching a value of about 200 kJ/mol when the shear stress attains 2.5 GPa. We propose that the plasticity is associated with vigorous dislocation glide controlled by short-range lattice resistance forces. At lower temperatures, the shear strength is mildly dependent on temperature reaching 3 GPa at room temperature, while above 1000 °C, the flow may be governed by a power-law relation with n about 3.5. © 2003 Elsevier Science B.V. All rights reserved.

publication date

  • April 15, 2003

published in

Digital Object Identifier (DOI)

start page

  • 3

end page

  • 9

volume

  • 136

issue

  • 1-2