| Abstract: | The Shuswap metamorphic core complex of the southeast Canadian Cordillera, which is allochthonous with respect to a fixed reference frame beneath the Plains of the North American craton, evolved and became consolidated prior to major development of thrust faulting in the Rocky Mountains.Polyphase deformation of the infrastructure of the complex beneath a weakly compressed suprastructure is probably due to shear strains generated by underthrusting of marginal lithosphere rather than to gravitational upwelling and lateral spreading.Pre-metamorphic to early metamorphic strain of the complex may be related to eastward underthrusting from the west. Late metamorphic strain may be related to westward underthrusting of the North American craton from the east. Continued underthrusting of the craton led to uplift and northeastward translation of the consolidated metamorphic complex together with development of thrust faults in the Rocky Mountains. |
