New constraints for indentation mechanisms in arcuate belts from the Jura Mountains, France

The mechanism of indentation in arcuate belts is discussed using the Jura M ountains as an example. Using fault-inversion analysis from numerous sites, the Miocene-Pliocene stress pattern is reconstructed. Two superimposed com pressional stress fields have been recognized, Considering the theoretical distribution of compression in front of a rigid indenter, we interpret the complex stress pattern in the Jura Mountains as a result of a major change in the mechanism of indentation of the Jura by its hinterland. Initially, t he indenter was narrower and limited in the southwest by the Vuache transfe r fault. With time, it expanded to the southwest and included the entire Mo lasse basin. This evolution highlights the importance of decoupling along f aults, which here controlled the indenter shape.