Nemrut Caldera and Eastern Anatolian Volcanoes: Fire in the Highlands

Abstract

Volcanism is one of the main actors in the formation of the Eastern Anatolian landscape. Quaternary volcanism covers a significant area in Eastern Anatolia where Holocene and historical activity have been reported. Nemrut Caldera is one of the youngest volcanoes in the region, with a small-size collapse caldera forming a spectacular landscape. Mount Nemrut is characterized by extension-related peralkaline volcanism in this well-known continental-collisional setting. Following the collapse of the Quaternary caldera, the activity continued within the caldera and at the northern fissure zone. Post-caldera activity shaping the intra-caldera region is represented by domes, lava flows and phreatic/phreatomagmatic explosions. While the products of this activity cover the eastern part of the caldera, the western half of the caldera is filled with a fresh volcanic lake. Hydrothermal activity is marked with fumaroles and hot springs in the caldera. The northern fissure zone produced the youngest effusive activity in Anatolia. Bimodal fissural activity is characterized by successive rhyolite and basalt flows. Historical and mythological records of the Nemrut volcanism are scattered in a wide historical time span. During the Quaternary, Mount Nemrut and Süphan have contributed to the gradual enclosure of Van Lake Basin. They are located on the divide separating the Van Lake Basin from the Murat-Euphrates drainage basin. Products of explosive volcanism of Nemrut Caldera filled the Bitlis and Güzeldere valleys, separating the Van Lake Basin from the Dicle-Tigris hydrosystem.