Fig. 1
a Creep curves of wet olivine as functions of stress and temperature at strain rates of 10−14 (black lines) and 10−17 (gray lines) s−1. These creep curves were calculated from the Peierls mechanism (Katayama and Karato 2008) and power-law creep (Karato and Jung 2003). Solid lines indicate the dominant mechanism and stress required to achieve the assumed strain rate at each temperature. At high temperature, power-law creep was the dominant deformation mechanism, although the stress of the power-law creep exceeded that of the Peierls mechanism below ~1000 K. This suggests that the Peierls mechanism becomes dominant at low temperature and high stress. The shaded section shows variations in the temperature of the Moho at the North Pole (Fig. 4). b Deformation mechanism map for wet olivine. Stress is plotted as a function of temperature at P = 1.0 GPa and grain size of 1.0 mm. The thick solid line represents the transition of the deformation mechanism, and the dashed lines show different strain rates at 10−5, 10−10, and 10−15 (s−1). The transitions between the deformation mechanism of olivine were calculated for diffusion creep (grain boundary diffusion; Hirth and Kohlstedt 2003), power-law creep (Karato and Jung 2003), and the Peierls mechanism (Katayama and Karato 2008)