Lake Nemrut on the southern slope of the caldera in 2007. The main thread in terms of ecology is overgrazing. Lake Nemrut Lake Nemrut () is a freshwater crater lake in Bitlis Province, eastern Turkey. It is part of Nemrut Caldera (), a volcanic caldera atop Volcano Nemrut. The caldera is a registered natural monument and the wetlandsis registered as a Ramsar site of the country. The caldera is located west of Lake Van in the Tatvan, Ahlat and Güroymak districts of Bitlis Province. It is named after the biblical figure King Nimrod. The caldera is far from Tatvan, and from Ahlat.
Nemrut (volcano) the city Tatvan, in the north-western shore of Lake Van. Nemrut was probably formed in the early Quaternary Period, about 1 million years ago. It showed the greatest activity in the Pleistocene, with regular eruptions occurring in the Holocene. In the middle Pleistocene, about 250,000 years ago, a major eruption formed a lava flow over 60 km long, which blocked the water discharge from the Van basin and formed Lake Van, the world's largest alkali endorheic lake. In the same period, the conical top of the volcano collapsed inward, forming an 8.3×7 km caldera. Later, the freshwater Lake Nemrut formed