The Llavorsí syncline is made up of devonian and silurian rocks. This unit has a structure, which is consecuence of a hercinian polifasic deformation with thrusts, folds and tectonic foliation. The most recents studies of Llavorsi syncline reveals that the main foliation of ESE- WNW trending, is associated to tight folds whose axis are dispersed, not showing main trending because of the interference with previous structures. The southern limb of the Llavorsí syncline is cut by a set of E-W trending nortward dipping thrusts. These thrusts have their "décollement" level located in the silurian ampelites. These thrusts are cutting the Devonian rocks folds.