Map analysis techniques and fold kinematics in the Umbrian Apennines, Italy

The structure of southeastern Umbria (Central Apennines. Italy), as obtained with the use of map analysis techniques, integrated with observations on mesoscopic structures, is described. The strike of major fold and thrust structures is remarkably parellel. both at frontal and lateral or oblique ramps, suggesting a common origin for folding and thrusting. Folds at all scales strike parallel even when the minor structures are not consistent with the shearing sense expected for flexural-slip fold mechanisms: this indicates a multistage, progressive compressional deformation, resulting in a coaxial overprinting fold geometry. The complex structural evolution can be interpreted as due to simple breaching during the Neogene compression.