Making Space for Batholiths by Extrusion of Sub-Batholithic Crust

摘要

The long-standing space problem in the emplacement of orogenic batholiths may he solved by large-scale intracrustal flow toward the backarc, driven by the isostatic load of the batholith and its volcanic carapace. Isostatic compensation of modern magmatic arcs requires at least the volcanic cover to have settled relative to adjacent rocks. The kinematic pattern of wall rock deformation on the backarc side of the Sierra Nevada batholith indicates settling of the batholith relative to its surroundings. It appears likely that isostatic settling of the magmatic arc complex is accommodated at least partly by lateral extrusion of sub-batholithic crust, largely toward the backarc. Such lateral intracrustal flow may play an important role in the dynamics of backarc thrust belts and metamorphic core complexes.