AHe datasets from the Eastern Balkan Belt, (Bulgaria)

The intraplate eastern Balkans fold-and-thrust belt marks the boundary between the Moesian Platform to the north and a series of accreted lithospheric terranes to the south. This major lithospheric boundary has undergone a complex evolution, with multiple reactivations and contrasting kinematics that have not been completely understood. This paper provides the first low-temperature thermochronologic data [fission-track and (U-Th)/He analyses on apatite] on the eastern Balkans. Statistical inverse modeling of the dataset indicates a phase of cooling/exhumation of the frontal portion of the orogenic wedge starting in the middle Eocene and also points to an older, Late Cretaceous unroofing phase resulting from the structural inversion of the Srednogorie rift basin to the south. To the north, the flexed and partly deformed lower (Moesian) plate and the associated foredeep sediments have remained thermally unreset, retaining the Late Cretaceous provenance signature of the eroded hinterland. These findings imply relatively limited shortening/exhumation along the main frontal thrust system of the eastern Balkans and point to a significant proportion of strike-slip deformation, likely the result of far-field stress transmission related to the oblique closure of the Vardar Ocean to the west.