 A fold-thrust belt may contain other detachments above the décollement—an imbricate fan of thrust faults and duplexes as well as other detachment horizons.In compressional settings, the layer directly above the décollement will develop more intense deformation than other layers, and weaker deformation below the décollement.Décollements are responsible for duplex formation, the geometry of which greatly influences the dynamics of the thrust wedge.