Synconvergent exhumation of metamorphic core complexes in the northern North American Cordillera

Abstract

Continental metamorphic core complexes of the northern North American Cordillera were exhumed during the early Paleogene while the Farallon–North American plate convergence rate remained high. Such convergent boundary conditions can excite localized mid-crustal exhumation in numerical simulations of collisions of softer accreted terranes with a rigid, irregular craton margin. Resulting simulated temperature-time ( T - t ) paths match T - t paths interpreted from observed footwall exposures in several core complexes of the northern North American Cordillera, including variability of maximum temperatures, duration of exhumation, and exhumation velocities among individual complexes.