Fig. 1

Models for structure and evolution in the Western Alps. a, b illustrate the notion that the lateral variation in crustal structure inherited from the Mesozoic rift history, exerted a fundamental control on orogenic evolution, with a “necking zone” forming a buttress and preferred site of tectonic reactivation during orogeneisis (after Mohn et al. 2014). c, d illustrate the notion that Brianconnais stratigraphic units were taken into the Alpine subduction channel with little disruption so that thrusting and “nappe-stacking” only happened once these units were deeply buried (modified after Michard et al. 2004)