Structural evolution of the Vardar root zone, northern Greece

Abstract

Allochthonous alpine ophiolites in northern Greece are related to destruction of an ocean basin during Late Cretaceous time. Associated plate interaction caused regional-scale flexure of the internal portions of obducted thrust sheets composed of continental and oceanic rocks. This flexure, the Vardar root zone, is characterized by at least four successive phases of mesoscopic folding accompanied by development of mylonites and rotation of s surfaces from a subhorizontal to a vertical or near-vertical attitude. Earlier fold sets (F 1 and F 2 ) in a number of lithologic units have been rotated and flattened in the core of the root flexure during its formation (F 3 ), which suggests that this deformation phase represents a single tectonic event. Subsequent collision of Rhodopian zone basement with the root zone may have caused renewed southwest-directed thrusting and F 4 kink folds. The Olympus window through late Paleozoic Pelagonian basement rocks into Eocene flysch suggests that the Vardar root zone and other major tectonic units in north-central Greece may be allochthonous.