The geology of Turkey is the product of a wide variety of tectonic processes that have shaped Anatolia over millions of years, a process which continues today as evidenced by frequent earthquakes and occasional volcanic eruptions. Background Turkey's terrain is structurally complex. A central massif composed of uplifted blocks and downfolded troughs, covered by recent deposits and giving the appearance of a plateau with rough terrain, is wedged between two folded mountain ranges that converge in the east. True lowland is confined to the plain of the Ergene river in Thrace, extending along rivers that discharge into the Aegean Sea or the Sea of Marmara, and to a few narrow coastal strips along the Black Sea and Mediterranean Sea coasts. Nearly 85% of the land is at an elevation of at least 450 meters; the median altitude of the country is 1,128 meters. In Asiatic Turkey, flat or gently sloping land is rare and largely confined to the deltas of the Kızıl River, the coastal plains of Antalya and Adana, and the valley floors of the Gediz River and the Büyük Menderes River, and some interior high plains in Anatolia, mainly around Tuz Gölü (Salt Lake) and Konya Ovası (Konya Basin). Moderately sloping terrain is limited almost entirely outside Thrace to the hills of the Arabian Platform along the border with Syria. More than 80% of the land surface is rough, broken, and mountainous, and therefore is of limited agricultural value. The terrain's ruggedness is accentuated in the eastern part of the country, where the two mountain ranges converge into a lofty region with a median elevation of more than 1,500 meters, which reaches its highest point along the borders with Armenia, Azerbaijan, and Iran. Turkey's highest peak, Mount Ararat (Ağrı Dağı)—about 5,166 meters high—is situated near the point where the boundaries of the four countries meet. Geological history The earliest geological history of Turkey is poorly understood, partly because these oldest rocks in the region are involved into younger deformation phases that hindered their evolution. This created problem of reconstructing how the region has been tectonically assembled by plate motions. Turkey can be thought of as a collage of different continental pieces and remnants of oceanic lithospheric rocks amalgamated together by younger tectonic processes that involve accumulation of igneous (both plutonic and volcanic) and sedimentary rocks. Plate tectonics Except for a relatively small portion of its territory along the