The crustal thickness in the Rhodope Metamorphic Complex area from the perspective of the present-day geological knowledge

Abstract

The crustal thickness in the area of the Rhodope Metamorphic Complex decreases from west to east from ~50 km to ~30 km. This regional-scale feature is mostly due to the different rates of extension that the basement rocks experienced in different parts of the complex. In our model, we postulate that the crustal thickness in the area is an effect of the late Eocene zipper-like or hinge-like extensional tectonics that caused a larger amount exhumation of high-grade metamorphic rocks in the eastern parts of the area and lesser one in the west. This zipper-like orogen parallel extension caused a vast tectonic erosion and progressive thinning of the crust from west to east.