Transition from slab roll-back to slab break-off in the central Apennines, Italy: Constraints from the stratigraphic and thermochronologic record

ABSTRACT Stratigraphic and thermochronologic data are used to study the processes that shaped topography of central Apennines Italy. These part a major, active mountain belt in center Mediterranean area, where several subduction zones control complex topography. The were by contraction at front accretionary wedge overlying subducting Adria microplate followed extension rear response eastward slab roll-back. In Apennines, intermontane extensional basins on western flank rise toward summit. We contribute with new consisting 28 (U-Th-Sm)/He 10 fission track ages apatites resolve pattern thermal histories time space, which we interpret as reflecting transitional state orogen, undergoing two-phase evolution related initial retreat, detachment. Along Tyrrhenian coast, document cooling from depths ≥3–4 km occurring between 8 5 Ma opening marine basins. Post–5 Ma, broader region exhibits variable depths, <2 most areas northeast, different onset times: ca. 4 west, 2.5 1 southeast. Between exhumation is associated modest topographic growth during late stages thrusting. Since has concurred west east, regional erosion, be locally detaching slab.