Structural and magnetic record of superposed non-coaxial deformation in the Lagonegro thrust nappe, Southern Apennines of Italy

Structural analysis of a short segment of the Lagonegro thrust nappe in the Lucania region (Southern Apennines, Italy), revealed two episodes of non-coaxial folding and thrusting (D1, D2). The best developed mesoscopic structures found in the region trend NNW-SSE and are attributed to Miocene shortening (D1). Minor distortion of earlier fold traces developed WSW-ENE trending tectonic fabrics and possibly occurred during Pliocene-Pleistocene(?) deformation (D2). Two different structural sheets of Mesozoic Lagonegro basinal rocks occur in the area. Upper Triassic cherty limestones which are part of the lower imbricate exhibit a variable anisotropy of low field magnetic susceptibility (AMS) from 5% to 40%. The AMS ellipsoids show a lack of correlation in orientation with the pervasive tectonic structures formed during the regional shortening episode (D1). On the contrary, they are consistent with structures developed during the younger deformational episode (D2), casting doubt on the commonly accepted spatial correlation between major mesoscopic structures and AMS ellipsoids.