Transmission electron microscopy characterization of dislocations and slip systems in K-lingunite: Implications for the seismic anisotropy of subducted crust

A. Mussi (1) , P. Cordier (1, 2) , D. Mainprice , D.J. Frost (2)

1 Université Lille Nord de France (COMUE)
2 Universität Bayreuth

In order to estimate the seismic anisotropy of subducted crust, polycrystalline samples of KAlSiO K-lingunite (25% of the total subducted transformed sediments), have been synthesized and deformed under the temperature and pressure conditions of the subducted slabs. Transmission Electron Microscopy (TEM) characterizations of the recovered samples reveal that the microstructures are clearly dominated by [001] glide involving screw dislocations. For this reason, only {100} could be identified as glide planes, the question of [001] slip on {110} remains open. Few ½<111> dislocations were observed gliding on {110} planes, which implies that ½<111>{110} is a harder slip system than those involving [001] slip. The occurrence of sub-grain boundaries suggests that diffusion and climb might be active under these conditions.

Mots clés: K-lingunite; dislocation; slip systems; crystal preferred orientations; seismic properties

Domaines: Sciences de la Terre

A. Mussi, P. Cordier, D. Mainprice, D.J. Frost. Transmission electron microscopy characterization of dislocations and slip systems in K-lingunite: Implications for the seismic anisotropy of subducted crust. Physics of the Earth and Planetary Interiors, 2010, 182 (1-2), pp.50. ⟨10.1016/j.pepi.2010.06.013⟩. ⟨hal-00675799⟩