MORPHOTECTONIC DEVELOPMENT OF THE ISTANBUL REGION

The Istanbul region is a narrow strip of land between the two seas namely the Black Sea and the Marmara Sea. These two seas are connected by the Bosphorous strait. The Marmara Sea is a rather small sea surrounded by the land and, is situated to the south of the Istanbul. It is connected to the Mediterranean- Aegean system by another narrow strait; the Dardanelle.

The Black Sea is an ancient basin. The Marmara Sea, on the other hand is a young basin which began to develop after the latest Miocene- Early Pliocene. The narrow strip of land, the Istanbul region began to shape up morphologically in connection with the development of the Marmara- Thrace regions.

Three district phases may be differentiated in the morphotectonic development of the region. a. The old phase: This corresponds to the Oligocene period. During this time the morphology and the controlling tectonics were distinctly different from the following phases. b. The Early Phase, this begins with the Early Pliocene, and is related closely with the extensional Tectonics of the western Turkey c. The late phase; this begins with the entrance of the NAF to the Marmara region and, since then it has become the major controlling factor in the development of the present morphology of the region.

In this presentation sequential morphological development of the Marmara and Istanbul regions will be outlined.