Potential field modelling of the Atlas lithosphere
(reproduced from Teixell et al. 2005)
Potential-field modelling of the NW African lithosphere defines the geometry of a NE-trending, 400 km wide asthenosphere high beneath the Moroccan Atlas Mountains. Based on a 2D finite element algorithm developed by Zeyen and Fernāndez (1994) and Zeyen et al. (2005), the modelling approach searches a good fit to heat flow, gravity, geoid and topography data and assumes conditions of thermal steady-state and local isostasy. The compensation depth is located at the deepest point reached by the lithosphere-asthenosphere boundary. More details can be found in Zeyen et al. (2005) and Teixell et al. (2005).
Modelling suggests that the Saharan cratonic lithosphere, some 160-180 km thick, thins to ~80 km beneath the Atlas fold-thrust belts, in contrast with the shortening regime prevailing there since the early Cenozoic. This implies density compensation within the mantle, and explains singular features of the Atlas region as high topography with modest tectonic shortening and crustal thickening, the occurrence of alkaline magmatism synchronic to compression, and a scarce foreland basin record. The modeled lithosphere thinning is related to a thermal upwelling constrained between the Iberia-Africa convergent plate boundary and the Saharan craton.