Numerical study of continental collision: influence of buoyancy forces and an initial stiff inclusion

摘要: Summary. We study simple models of collision between two continental plates patterned after the geometry India-Asia collision, but which may be applicable to more general situations. The is modelled by indentation a viscoplastic plate (Asia) rigid punch (India). Although deformation three-dimensional in nature, thickness order 100 km permits 2-D approach for wavelengths longer than few hundred kilometres. assume an Airy compensation at crustmantle boundary throughout deformation. can then reduce problem one within context thin theory. This model makes it possible crustal thickening during collisions. opposition buoyancy forces, tend flatten topography, and viscous resistance, appears clearly we show existence relaxation mechanism associated with volumetric part asymptotic behaviour incompressible plane strain type thus tends maximum value. When this limit reached no distensive phenomena induced. Buoyancy effects described nondimensional parameter, Argand number Ar, ratio time characteristic flow. A finite element approximation, based on material description deformation, used investigate evolution process. role pre-existing heterogeneity (stiff inclusion) also considered. Lateral conditions are chosen approximate interactions that believed apply Asian plate, i.e.