The effect of aluminum and water on the development of deformation fabrics of orthopyroxene - Université Clermont Auvergne Accéder directement au contenu
Article Dans Une Revue Contributions to Mineralogy and Petrology Année : 2013

The effect of aluminum and water on the development of deformation fabrics of orthopyroxene

Résumé

The effect of alumina and water solubility on the development of fabric in orthopyroxene in response to simple shear deformation has been investigated at a pressure of 1.5 GPa and a temperature of 1,100 °C using the D-DIA apparatus. The microstructure observations at these conditions indicate that dislocation glide is the dominant deformation mechanism. In MgSiO3 enstatite and hydrous aluminous enstatite, partial dislocations bounding the stacking faults in [001] glide parallel to the (100) (or) the (100) [001] slip system. Electron backscattered diffraction analysis of anhydrous aluminous enstatite, however, indicates operation of the (010) [001] slip system, and microstructure analysis indicates dislocation movement involving [001] on both (100) and {210} planes. The strong covalent bonding induced by the occupation of M1 and T2 sites by Al could have restricted the glide on (100), activating slip on {210}. The resulting seismic anisotropies (~2 %) in orthopyroxene are weaker compared to olivine (~9.5 %), and reduced anisotropy can be expected if orthopyroxene coexists with olivine. Weak anisotropy observed in stable cratonic regions can be explained by the relatively high abundance of orthopyroxene in these rocks.

Dates et versions

hal-01066784 , version 1 (22-09-2014)

Identifiants

Citer

Geeth Manthilake, N. Miyajima, F. Heidelbach, V. Soustelle, D.J. Frost. The effect of aluminum and water on the development of deformation fabrics of orthopyroxene. Contributions to Mineralogy and Petrology, 2013, 165, pp.495-505. ⟨10.1007/s00410-012-0819-4⟩. ⟨hal-01066784⟩
94 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More