鉱物の水とレオロジイ [in Japanese] H_2O and Rheology of Minerals [in Japanese]
Access this Article
Search this Article
Rheology of rocks and minerals in the earth interior is strongly controlled by temperature, pressure, grain size and H<SUB>2</SUB>O contents. Activation energies for creep of silicates range from 100 to 530 kJ/mol, and activation volumes seem to range from less than 1 cc/mol for Si to 7 cc/mol for O. The effect of H<SUB>2</SUB>O on rheology of silicates depends on the defect structure of H in the lattice. Considering that the dominant defect of H is 3Hsi showing 3H replacing Si, solubility limits of H in quartz, forsterite, modified spinel, spinel, pyroxene, and perovskite are calculated as a function of water fugacity by means of defect chemistry. Compared with the experimental results, the author obtained their solubility limits under excess H<SUB>2</SUB>O condition at very high pressures. It shows that olivine may contain 20000ppm(=H/106Si) at 15GPa and modified spinel and spinel may contain 220000ppm at 15GPa and 300000ppm at 24GPa. On the other hand, it seems that perovskite may contain at most 1000ppm under 100GPa. Combined with dislocation motion and diffusivity of defects, flow laws for above minerals are deduced as the function of f<SUB>H2O</SUB> and f<SUB>O2</SUB> in this paper.
- Journal of the Mineralogical Society of Japan
Journal of the Mineralogical Society of Japan 25(4), 181-187, 1996-10-01
Japan Association of Mineralogical Sciences