Spatial correlation of deformation and mineral reaction in experimentally deformed plagioclase–olivine aggregates

摘要: Abstract Shear deformation of hot pressed plagioclase–olivine aggregates was studied in the presence and absence mineral reaction. Experiments were performed at 900 °C, 1500 MPa, a constant shear strain rate ∼5×10 −5 s −1 solid medium apparatus. Whether reaction between plagioclase olivine takes place or not is controlled by choosing appropriate composition; labradorite (An 60 ) does react, anorthite 92 does. Labradorite–olivine deformed without are very strong show hardening throughout experiment. Syndeformational causes pronounced weakening. The produces fine-grained opx–cpx–spinel aggregates, which accommodate large fraction finite strain. Deformation localised within 0.5-mm-wide sample. Three representative samples analysed for their fabric anisotropy R * shape-preferred orientation α (fabric angle with plane) using autocorrelation function (ACF). Fabric can be calibrated to quantify variations across sheared samples. In reacted anorthite–olivine aggregate, there correlation progress strain; regions correspond maximum progress. Within sample, derived range up almost one order magnitude.