Detecting the stepwise propagation of the Eastern Sicily thrust belt (Italy) insight from thermal and thermochronological constrains

An extensive dataset of vitrinite reflectance, FTIR parameters on organic matter, illite content in mixed layers illite-smectite, apatite fission tracks and U-Th/He dating has been used to reconstruct the Eastern Sicily fold-and-thrust belt propagation during Late Paleogene and Neogene times. Results indicate that the fold-and-thrust belt is divisible into two levels of thermal maturity. These levels consist of a less evolved level of thermal maturity that records limited sedimentary burial and minor heating, and a more evolved level tectonically buried and exhumed at different times. Deformation and exhumation of shallow buried units are linked to wedge forward propagation by low-angle thrusts, whereas the evolution of deeply buried units is associated with tectonic imbrications by duplex formation and steep thrusts. The two tectonic styles alternate throughout the fold-and-thrust belt evolution under low erosion rates.