Early Paleogene (?) Tectonics of Northern Pirin Mt., SW Bulgaria (Based on Preliminary Photogeological Observations)

Abstract

Carbonatic clastics of probable Early Paleogene age are recognized for the first time in the highest (Vihren) part of Pirin Mountain. They exhibit a complex fold structure: recumbent folds refolded by normal folds, intersected and displaced by shear zones with thrusting movement, and a later generation of uplift, extensional detachment and normal faulting. Fractures and normal faults were superimposed later, too. Several first-order structures may be recognized in the Vihren area: the Vihren Complex Fold, the Main Vihren Shear Zone, and the Vihren Fold Cascade. The whole northern periform of the Sinanitsa Antiform exhibits an interference pattern: a series of SSW-NNE antiforms along the main ridges of the same direction are crossing WNW-ESE folds as the Koncheto Antiform and the Vihren Synform. Issued from preliminary photogeological observations, the regional interpretations should be verified by field and laboratory sedimentological, stratigraphic, and structural studies. Photogeological and remote sensing research on a modern methodological basis is needed, too.