Deformation-enhanced reaction in experimentally deformed plagioclase-olivine aggregates

摘要: The effects of deformation on the kinetics net-transfer reaction anorthite + forsterite → cpx opx spinel ± gt were studied using static and shear experiments. Experiments performed dry anorthite-olivine (An92–Fo93) samples at 900°C pressures between 1,000 1,600 MPa in a Griggs apparatus. Deformed (‘non-hydrostatic’) undeformed (‘static’) are compared terms phase petrology, rate mechanisms. Anorthite olivine reactions diffusion-controlled as seen from rim structures. In samples, delayed onset low rates demonstrate sluggish nucleation products slow diffusion conditions, even 700–900 MPa confining pressure overstepping. is enhanced deformed An–Fo samples. higher mainly attributed to combination high stresses viscous processes reactants products, which cause an increase products. results imply that alone can be responsible for initiation localisation metamorphic rocks absence fluid infiltration.