Three-dimensional numerical models of flat slab subduction and the Denali fault driving deformation in south-central Alaska

摘要: Abstract Early theories of plate tectonics assumed plates were rigid with deformation limited to within a few tens kilometers the boundary. However, observations indicate most continental defy such behavior extending over 1000 inboard. We construct three-dimensional (3D) numerical models boundary between Pacific and North American in Alaska investigate relative controls flat slab subduction, scale faulting, non-linear rheology on overriding plate. The incorporate realistic shape based seismicity seismic tomography variable thermal structure for both subducting geologic geophysical observables. inclusion Denali fault allows portion south-central trench partially decouple from rest America, forming an independently moving region that correlates what has been described geodetic studies as Wrangell block. motion block tracks subsurface indicating is driving Models using composite (Newtonian non-Newtonian) viscosity predict compressional along northern bend fault, consistent thermochronologic data show significant late Neogene exhumation central Range, including at Mt. McKinley, tallest mountain America. These 3D Pacific–North margin main driver combined can reproduce several first order tectonic features block, uplift subsidence Cook Inlet-Susitna Basins, upwelling edge beneath volcanics.