Sequential development of selected Pyrenean thrust faults

New mapping, structural analysis and magnetostratigraphy reveal a polyphase deformational history at the leading edge of the Spanish Pyrenean foreland fold-and-thrust belt. The present structural architecture is the consequence of three discrete periods of deformation. Map relationships between four syntectonic units and major structures provide tight geometric and age constraints for each deformational period (D1: 55 to 42 Ma; D2: 30.1 to 28.0 Ma; D3: 27.9 to < 25.8 Ma). Most of the shortening in the area accumulated during D2 thrusting at rates which varied from 0.7 mm y −1 to 2.8 mm y −1 along strike from northwest to southeast, respectively. Removal of D2 and D3 displacement on thrust faults restores folds formed during D1. A sequential kinematic history during which an individual structure accommodates shortening by folding, tightening of the fold and subsequent truncation by thrust faulting is inferred. Sequential restoration of three serial cross-sections demonstrates that nearly every structure active during D1 was also active during D2. Distributed deformation characterizes the temporal and spatial pattern on all time scales, from structures active during each individual deformational period to the long-term history encompassed by the total deformation.