Low-temperature thermochronology of the Bukulja-Brajkovac area (central Serbia): new constraints on the Cenozoic exhumation of the Internal Dinarides

The Bukulja Mts. and its surroundings in the Internal Dinarides of central Serbia, provide an important record of post-collisional tectonic and thermal events during Oligocene-Miocene time. This is expressed by intense extensional deformation characterized by core complex geometry and the presence of granitoid intrusions of different ages and composition. The Oligocene I-type Brajkovac intrusion records an earlier stage of post-collisional magmatism, probably related to detachment of the Neotethyan slab beneath the Dinarides. In contrast, the Miocene S-type Bukulja granite reflects a later extensional stage that caused lithospheric thinning and crustal melting likely associated with the opening of the Pannonian back-arc basin. To improve the understanding of thermal history of the Bukulja-Brajkovac area and its relationship with extensional deformation, we performed fission-track analysis of apatite grains from magmatic and meta-sedimentary rocks, combined with kinematic analysis of the observed structures.

Such an approach enables us to define the main phases of exhumation and associated deformation, and to examine differences in thermal histories of the Brajkovac and Bukulja intrusions. The obtained results improve the understanding of the Cenozoic geodynamic evolution of the northern Internal Dinarides and the overall transition from collisional to post-collisional processes of orogens.

Keywords: apatite fission-track analysis, post-collisional extension, Internal Dinarides, core complex, Cenozoic exhumation