Interference Folding of the Southern Slope of the Greater Caucasus

Abstract

As a result of the detailed geological-structural researches within the Southern Slope of the Greater Caucasus there have been established the development of the interference folding. It builds up southern marginal part of separate areas of North-West, Central and South-East Caucasus. The 85 km long and 25km wide stripe of development of the interference folding in general has sublatitudional directions in distinction from NW orientation of main linear folding of the region. All areas are characterized with development of uniform intersecting folded structures of nearly identic morphology. They are represented by linear folds as well as by brachiform folds and nonlinear rounded structures. Individual folds in the plane have NW, sublatitudional and submeridional orientation. It’s built up with multi-order structures of folds of different shape and size, from first hundred meters to several kilometers and first tenth kilometers. In short linear lens-shaped folds bending of fold hinges in plane and section are observed. Sometimes brenching of the structures, festoon morphology of their pericline and wedge-shaped forms are recorded. Domes, pit-like (cuppy) and brachiform structures in plane have rounded, oval, drop-shaped, four-sided (quadrangular), horseshoe shapes. It occurred due to the transformation of the primary linear plicative structures, formed at the Early-Middle Alpine and Early Orogenic stages during the NW tangential compression of the Greater Caucasus. At the Late Orogenic collision stage, the orientation of the previous stress in this region was replaced by the submeridional stress. It caused the northward movement of certain block-schols of the Black Sea-Transcaucasian micro-continent and its intrusion into the folded system of the Greater Caucasus. Such deformation caused the oblique superposition of submeridional strains and the repeated compression of the structures on the local areas of development of the previous folding of submeridional strains. In the result of combination of these processes of different orientation typical interferential structure was formed in the southern edge zone of the Greater Caucasus. Thus, mechanism of the formation of interferential folding represents manifestation of external unilateral, but diversified (in plane) tangential deformations occurred during the Alpine cycle in the Greater Caucasus.