Kinematics of the Helminthoid Flysch-Marguareis Unit tectonic coupling: consequences for the tectonic evolution of Western Ligurian Alps

We investigated the kinematics of the coupled Helminthoid Flysch-Marguareis Unit outcropping in the High Tanaro Valley in order to constraint the tectonic evolution of the Western Ligurian Alps. Field mapping highlights a tectonic pile composed of, from top to bottom: the MarguareisUnit (Briançonnais Domain); the Helminthoid Flysch Unit (Ligurian Domain) and several continentalderived tectonic slices (Chambeuil Slices) showing affinity to the Briançonnais Domain. Each unitrecorded different deformation histories represented by pre-, syn- and post-stacking structures. Thesyn-stacking structures are represented by thrusts and folds, both responsible for the coupling of theunits and for their current structural relationships. In other sectors of the Alpine chain previous authors have highlighted similar structural architectures. We maintain that syn-stacking deformationevents played a key role in the tectonic evolution of the Western Ligurian Alps.