Morphotectonic Development of the Southern Black Sea Region and the Bosphorus Channel

Abstract

The southern coast of the Black Sea is bounded by the east-west trending Pontides and Strandjas mountain ranges and between them flows the Bosphorus a narrow channel representing the only seaway connecting the Black Sea with the Aegean-Mediterranean system. All of these morphological entities are young formed during the Plio-Quaternary period. A major force in the formation of the Pontides has been north-south compression generated in eastern Anatolia by the progressive northward advance of the Arabian Plate. At its western end the Pontides terminate in the Marmara region where north-south extension has been deforming the land since the Late Miocene producing a number of grabens and horsts aligned east to west. The Strandjas represent one of these horsts that extends westward along the trend of the Pontides to form the Black Sea's southwestern margin. Located between the Pontides and the Strandjas are the lowlands around Istanbul where deep erosion has produced a flat-lying surface. Beginning in the Pliocene when the North Anatolian Fault (NAF) extended into the Marmara Sea basin the Istanbul horst began to be deformed under a dextral shear stress regime. This regime generated conjugated pairs of oblique faults which caused the Bosphorus to take shape as a zigzagging channel. © 2007 Springer.