Structural Evolution of the Apenninic-maghrebian Orogen in Eastern Sicily - Thermal and Thermochronological Constraints

Temperature-dependent clay mineral assemblages and vitrinite reflectance data have been used to investigate levels of diagenesis from the Sicilian-Maghrebian fold-and-thrust belt in Eastern Sicily at the footwall of the Kabilian-Peloritan-Calabrian Arc. Data are from units sampled between the Nebrodi Mountains to the north and Mt. Judica to the south. The integration of organic and inorganic thermal indicators allowed us to distinguish portions of the accretionary wedge with different thermal maturity and thermo-chronological evolution and to define the maximum temperature that thrust-top, foredeep basin deposits and accreted passive margin units experienced. VRo% values between 0.60-0.96% and illite content in mixed-layer I-S (60-85%) are found in trench-involved and in accreted passive margin units. Lower VRo% values (0.20-0.50%), and percentage of illite layers in I-S (30-60%) are found in thrust-top and foredeep basin deposits and in units back-thrust toward the hinterland and mainly gravity-mobilized toward the Hyblean Plateau. Apatite fission-track data from the trench-involved deep structural units were partially to totally annealed during wedge accretion and indicate that subsequent exhumation have occurred mainly in Burdigalian times. Shallow structural units of the wedge have been removed by tectonics and erosion.