Lasting mantle scars lead to perennial plate tectonics.
Mid-ocean ridges, transform faults, subduction and continental collisions form the conventional theory of plate tectonics to explain non-rigid behaviour at plate boundaries. However, the theory does not explain directly the processes involved in intraplate deformation and seismicity. Recently, damage structures in the lithosphere have been linked to the origin of plate tectonics. Despite seismological imaging suggesting that inherited mantle lithosphere heterogeneities are ubiquitous, their plate tectonic role is rarely considered. Here we show that deep lithospheric anomalies can dominate shallow geological features in activating tectonics in plate interiors. In numerical experiments, we found that structures frozen into the mantle lithosphere through plate tectonic processes can behave as quasi-plate boundaries reactivated under far-field compressional forcing. Intraplate locations where proto-lithospheric plates have been scarred by earlier suturing could be regions where latent plate boundaries remain, and where plate tectonics processes are expressed as a 'perennial' phenomenon.
Department of Earth Sciences, University of Toronto, 22 Russell St. Toronto, Ontario, Canada M5S 3B1.
Philip J
PJ
Heron
Department of Earth Sciences, University of Toronto, 22 Russell St. Toronto, Ontario, Canada M5S 3B1.
Russell N
RN
Pysklywec
School of Geosciences, University of Aberdeen, Aberdeen AB24 3UE, Scotland.
Randell
R
Stephenson