Figure 4.
Images of numerical models to explain ultra-high pressure metamorphism in continental crust (UHP terranes) from a review by Hacker et al. (2013). Scale for all is in patterned box in B. (A) Subducted piece of the upper continental crust at a collisional margin detached at ~100–150 km depth and exhumed by buoyancy before slab breakoff. (B) Exhumation of a large block on a normal fault as motion reverses after slab breakoff. (C) UHP rocks rise through the mantle as a diapir, resulting in relamination. Modified from Anderson et al., 1991; Chemenda et al., 1995; Hacker et al., 2013; and Little et al., 2011.