Lake Van

Lore & Background

Lake Van is primarily a tectonic lake, formed more than 600,000 years ago by the gradual subsidence of a large block of the Earth's crust due to movement on several major faults. The lake's southern margin demarcates a metamorphic rock zone of the Bitlis Massif and volcanic strata of the Neogene and Quaternary periods. The lake's proximity to the Karlıova triple junction has led to molten fluids of the Earth's mantle accumulating in the strata beneath, still driving gradual change. Dominating the lake's northern shore is the stratovolcano Mount Süphan. The broad crater of a second, dormant volcano, Mount Nemrut, is close to the western tip of the lake. There is hydrothermal activity throughout the region. For much of its history, until the Pleistocene, Lake Van had an outlet towards the southwest into the Murat River and eventually into the Euphrates river. However, the level of this threshold has varied over time, as the lake has been blocked by successive lava flows from Nemrut volcano westward towards the Muş Plain. This threshold has then been lowered at times by erosion.

Reader's Guide

Lake Van is 119 kilometres across at its widest point. It averages 171 metres deep. Its greatest known depth is 451 metres. The surface lies 1,640 metres above sea level and the shore length is 430 kilometres. It covers 3,755 km² and contains 607 cubic kilometres. The western portion of the lake is deepest, with a large basin deeper than 400 m lying northeast of Tatvan and south of Ahlat. The lake water is strongly alkaline (pH 9.7–9.8) and rich in sodium carbonate and other salts. Some is extracted in salt evaporation ponds alongside, used in or as detergents. Despite the high altitude and winter averages below 0 °C, high salinity usually prevents it from freezing; the shallow northern section can freeze, but rarely. The PALEOVAN project studied the lake's paleolimnology, paleoclimatology, and sedimentology over the last 600,000 years using seismic reflection and continuous cores. They found that the lake level has varied by as much as 600 m during the past 600,000 years, with five major lowstands circa 600, 365–340, 290–230, 150–130, and 30–14 ka BP. The level of the lake rose by at least 3 m during the 1990s, drowning much agricultural land, and rose approximately 2 m in the 10 years immediately prior to 2004. But in the early 2020s it fell.

Did You Know?

• Lake Van is one of the world's few endorheic lakes of size greater than 3,000 square kilometres.
• The lake holds 38% of Turkey's surface water, including rivers.
• The only fish known to live in the brackish water was Alburnus tarichi (Pearl Mullet) until a new species, Oxynoemacheilus ercisianus, was discovered inside a microbialite in 2018.
• Researchers reported 40 m tall microbialites in the lake in 1991, formed by coccoid cyanobacteria.
• The PALEOVAN project found that the lake level has varied by as much as 600 m over the past 600,000 years.