L=A  -r Dynamic recrystallization

Some Applications Dewatering due to partial melting and the lithosphere-asthenosphere structure (Karato (1986); Hirth and Kohlstedt (1996); Karato and Jung (1998)) Strength and deformation of subducted slabs (Riedel and Karato (1997); Karato et al. (2001))

Partial melting results in depletion of trace elements including hydrogen leading to hardening.

Karato and Jung (1998)

Hirth and Kohlstedt (1996)

Karato et al. (1998) Karato et al. (2001) A model of rheological structure of a descending slab in the transition zone

Unresolved Problems in Rheology Rheological stratification: rheology of deep mantle minerals Lattice-preferred orientation in deep mantle minerals What controls the grain-size? What controls the water distribution? Shear localization –Deformation of a two-phase material