Turkey’s largest lake is a soda sea 451 metres deep
Lake Van in eastern Anatolia is Turkey’s largest lake—a saline soda basin spanning 3,755 square kilometres at 1,640 metres elevation. It averages 171 metres deep and reaches 451 metres, with water so alkaline (pH 9.7–9.8) that evaporation ponds harvest detergent salts.
At its widest the lake stretches 119 kilometres; shoreline runs about 430. The deepest trough, the Tatvan basin between Tatvan and Ahlat, is almost entirely hemmed in by faults and drops below 400 metres, while the Van-Ahtamar arm to the east shelves gently to about 250. Formed more than 600,000 years ago by tectonic subsidence along major faults, its southern edge meets the Bitlis Massif. Mount Süphan dominates the north shore; a broad crater volcano also shapes the skyline near the Karlıova triple junction.
Until the Pleistocene the lake had a south-western outlet to the Murat River and on to the Euphrates, but lava from Nemrut volcano repeatedly dammed that exit. Old shorelines survive above the water: in 1898 geologist Felix Oswald noted raised beaches 5, 15 and 30 metres up, as well as recently drowned trees. Sodium carbonate–rich chemistry supports small-scale salt works.
Acoustic surveys began in 1974, mapping lacustrine shelves that cover about twenty-seven percent of the floor. Kempe and his colleague Degens later divided the bed into provinces, including that shelf and a flat deep basin covering about a tenth of the floor in the west centre. In 1989 and 1990 a Hamburg-led team pulled ten sediment cores from as deep as 446 metres, whose annual layers yielded climate records. The PALEOVAN project has since used seismic surveys and deep drilling to reconstruct 600,000 years of the lake’s climate and sediments.
Source: Lake Van
