The Geomorphological Regions of Turkey

Abstract

The core of Turkey’s land is the Anatolian Peninsula, which is surrounded by several seas (Mediterranean, Aegean, Marmara and Black Sea). Offering a high variety of morphological landscapes, Anatolia is an orogenic plateau bordered to the north by one of the world’s most seismically active strike-slip faults, the North Anatolian Fault Zone (NAFZ), to the south by the Cyprus and Hellenic subduction margins, to the west by the Aegean extensional zone, and to the east by the East Anatolia Fault Zone (EAFZ) and Bitlis–Zagros collision zone. In this context, first-order morphotectonic features are primary contributors to complex and unique landscapes both in and around the peninsula. This role appears first in the citadel-like relief of Anatolia, whose hill and mountain slopes steepen quickly from the coastal zones in direction of the plateau. From the west–eastward, the relief rises also steadily but less abruptly. Anatolian highlands thus form a barrier capturing the humidity generated by the seas. In return, its springs and rivers deliver abundant water to the lowlands around. Interacting with the relief organization, river paths and networks are thus impacted, not only by tectonic movements but also by several other geomorphological processes which are at work in shaping of the Anatolian landscapes. While relief generates hydrography and landscape contrasts, climate and lithology control hydrology and vegetation as well as weathering processes. In the meantime, volcanic activity and karst development produce some of the most outstanding landscapes in the country. This chapter aims to present the richness of these landforms, as well as to explain how and when they were formed. To that end, six regions are identified, each of them corresponding to a specific mix of landscapes and land-forming factors. These six regions are: Northern Anatolia (Black Sea), Western Anatolia (Aegean), Mediterranean Anatolia, Central Anatolia, Eastern Anatolia and South-eastern Anatolia. We define each region on the basis of first, physiographic description (relief, climate, phytogeography, hydrography), allowing the identification of (i) subregions corresponding to a certain group of landforms and (ii) the spatial distribution of these landforms within the region. This first task is followed by the presentation of the structural background, insisting on tectonics and dominant lithologies as well as the stratigraphic data pointing to the differential erosional context inscribed in ancient morphologies. Based on this geologic information, the third part exposes landforms resulting from morphological processes acting through time. This task groups the regional landforms according to the main geomorphological agents and processes that produced them. It underlines the importance, in the formation of the present landscapes, of the interplay between different factors, whether tectonic or climatic, karstic or volcanic, hydrographic or hydrologic… and the importance of time in the preservation and transformation of landscapes. The human action is evoked when its influence has been important in today’s landscapes, either because of duration, or because of specific cultural or historic contribution. This evocation is especially critical for areas where human’s action has transformed landscapes throughout the Holocene period, or where it has been studied thoroughly.