 Thin-skinned tectonics was implied in that paper but the actual term was not used until Buxtorf's 1907 publication.Décollements are caused by surface forces, which 'push' at converging plate boundaries, facilitated by body forces (gravity sliding).Mechanically weak layers in strata allow the development of stepped thrusts (either over- or underthrusts), which originate at subduction zones and emerge deep in the foreland.