Syn-convergence extension and exhumation in the internal Dinarides

As part of his Ph.D. research, Gabriele [Gabe] Casale made a field-based study of the external and internal Dinarides in Croatia and Bosnia-Herzegovina. The Dinarides orogen resulted from eastward subduction of continental crust of the Adria microplate—it is a mirror image of the Apennine chain in Italy, beneath which the western edge of the microplate is being consumed. The external Dinarides are a west-facing thin-skinned fold-thrust belt composed chiefly of Mesozoic carbonate-platform strata. In the upper photo, carbonate strata on the Peljesac Peninsula on the mainland crop out impressively east of the village and island of Korcula.

During his field work in the internal Dinarides, Gabe discovered a core complex in the Mid Bosnian Schist Mountains [MBSM]. He used field mapping, kinematic analyses, and thermoshronometry to conclude that the Paleozoic metamorphic rocks in the core were exhumed by denudation along a system of core-bounding normal faults in mid-Tertiary time. The extension was synchronous with the convergence recorded in the external Dinarides. The lower image illustrates the location of the MBSM relative to the external fold-thrust belt.

Click on the images for larger versions.