CONTINENTAL AND OCEANIC CORE COMPLEXES

Extension in the continents and oceans leads to exhumation of deep crust and upper mantle in core complexes. Core-complex formation is therefore a major process in lithospheric differentiation and stabilization, element cycling, and heat and mass transfer. Over the past 40 years, interest in core complexes has remained high because these structures are ubiquitous in extending orogens and along slow-spreading oceanic divergent zones, they have been identified in the geologic record from the Precambrian to the present, and they record fundamental thermomechanical processes in extending lithosphere. Understanding uplift and exhumation of ductile rocks below low-angle normal faults, as well as the dynamics of the faults, is relevant to crustal evolution and seismogenesis in extending lithosphere. The pressure-temperature-time-fluid-deformation history of core complexes, investigated via field and modeling-based studies, reveals the magnitude, rate, and mechanisms of advection of heat and material from deep to shallow levels. In our review of core complex formation and consequences for the chemical and physical evolution of the lithosphere, we survey the core-complex literature, discuss processes and questions relevant to the formation and evolution of core complexes in continental and oceanic settings, highlight the significance of core complexes for lithosphere dynamics, and propose a few possible directions for future research.