铁橄榄石高温高压流变性的实验研究

The high temperature and high pressure rheology of fayalite olivine was studied in this paper. Tri-axial compressive creep experiments were performed on anhydrous as well as hydrous fine-grained fayalite olivine samples. Samples were deformed in a gas-medium apparatus at a confining pressure of 300MPa, a temperature between 1273 and 1423K, a differential stress 10 ∼250MPa, a strain rate 10^-7 ∼ 10^-4s^-1, and the maximum accumulative strain 20%, respectively, for each sample. The samples were deformed both in the diffusion and the dislocation creep regime. From three dimensional global non-linear fitting of the test data, the stress exponent was determined as 5.4 for anhydrous fayalite olivine and 3.4 for hydrous fayalite olivine samples in dislocation creep regime, respectively, and the activation energy is 781kJ/mol for dry fayalite and 516kJ/mol for wet fayalite olivine samples, respectively. These hydrous samples creep at a rate over a factor of 10 faster than those anhydrous samples under the same deformation conditions. Therefore, this paper gives a preliminary test result of effect of temperature and water on the viscosity of fayalite olivine aggregates.