Lake Vanis the largest lake in Turkey, located in the far east of the country. It is a saline and soda lake, receiving water from numerous small streams that descend from the surrounding mountains. Lake Van is one of the world's largest endorheic lakes (having no outlet). The original outlet from the basin was blocked by an ancient volcanic eruption.
Hydrology and chemistry Lake Van is 119 km across at its widest point, averaging a depth of 171 metres. The lake surface lies 1,640 metres above sea level and the shore length is 430 kilometres. Lake Van has an area of 3,755 km2 and a volume of 607 cubic kilometers. 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 eastern arms of the lake are shallower. The Van-Ahtamar portion shelves gradually, with a maximum depth of about 250 m on its northwest side where it joins the rest of the lake. The Ercis arm is much shallower, mostly less than 50 m, with a maximum depth of about 150 m. The lake water is strongly alkaline (pH 9.7–9.8).
GeologyThe lake's outlet was blocked at some time during the Pleistocene, when lava flows from Nemrut volcano blocked westward outflow towards the Mus Plain. Now dormant, Nemrut Dagi is close to the western shore of the lake, and another dormant stratovolcano, Süphan Dagi dominates the northern side of the lake. The water level of the lake has often altered dramatically: near Tatvan, Oswald noted a raised beach high above the present level of the lake as well as recently drowned trees. Investigation by Degens and others in the early 1980s determined that the highest lake levels (72m above the current height) had been during the last ice age, about 18,000 years ago. About 9,500 years ago there was a dramatic drop to more than 300m below the present level. This was followed by an equally dramatic rise around 6,500 years ago. Similar but smaller fluctuations have been seen recently. The level of the lake rose by at least three metres during the 1990s, drowning much agricultural land, and (after a brief period of stability and then retreat) seems to be rising again. The level has risen about two meters in the ten years immediatey prior to 2004. As a deep lake with no outlet, Lake Van has accumulated great amounts of sediment washed in from surrounding plains and valleys, and occasionally deposited as ash from eruptions of nearby volcanoes. This layer of sediment is estimated to be up to 400m thick in places, and has attracted climatologists and vulcanologists interested in drilling cores to examine the layered sediments. In 1989 and 1990, an international team of geologists led by Dr. Stephan Kempe from the University of Hamburg (now Professor at the Technische Universität Darmstadt) retrieved ten sediment cores from depths up to 446 m. Although these cores only penetrated the first few meters of sediment, they provided sufficient varves to give climate data for up to 14,570 years BP. A team of scientists headed by palaeontologist Professor Thomas Litt at the University of Bonn has applied for funding from the International Continental Scientific Drilling Program (ICDP) for a new, deeper drilling project to examine the lake's sediments. Litt expects to find that "Lake Van stores the climate history of the last 800,000 years an incomparable treasure house of data which we want to tap for at least the last 500,000 years. A test drilling in 2004 detected evidence of 15 volcanic eruptions in the past 20,000 years.
Ecology103 species of phytoplankton have been recorded in the lake including Diatome, Bacteriophyta, Cyanophyta, Chlorophyta, Flagellata and Phaeophyta. 36 species of zooplankton have also been recorded including Rotatoria, Cladocera and Copepoda in the lake. In 1991, researchers reported the discovery of 40 m tall microbialites in Lake Van. These are solid towers on the lake bed created by mats of coccoid cyanobacteria that create aragonite in combination with calcite precipitating out of the lake water. The Lake Van region is the home of the rare Van Kedisi breed of cat, noted for among other things its unusual fascination with water. Since about 1995 there have been reported sightings of a 'Lake Van monster' about 15 metres in length named Van Canavari ("Monster of Van"). The lake is surrounded by fruit and grain-growing agricultural areas.
TransportationThe railway connecting Turkey and Iran built in the 1970s uses a train ferry across Lake Van between the cities Tatvan and Van, rather than building railway tracks around the rugged shore line. Transfer from train to ship and back again limits the total carrying capacity. In May, 2008 talks started between Iran and Turkey to upgrade the ferry to a double track electrified railway.
Van Citadel The Fortress of Van also known as Van Citadel is a massive stone fortification built by the ancient kingdom of Urartu, overlooking Tushpa, the Urartu Capital. It is the largest of a number of similar fortifications built throughout the kingdom, where modern Armenia, Turkey and Iran meet, usually cut into hillsides and outcrops. The lower parts of the wall were built out of unmortared basalt, the rest out of mud-brick. Such fortresses were usually used for regional control, rather than for defense against foreign armies. The ruins of this building sit outside the modern city of Van, Turkey, Turkey, where they support walls built in the medieval era. See my spoiler!
1. Describe the shape of Lake Van.
2. What is the maximum recorded depth of the lake?
3. What is the Turkish name of Lake Van?
4. The lake water is strongly alkaline, why?
5. What does Chalcalburnus tarichi mean?
Please attach your photo at the location (see the spoiler).
E-mail your answers via the profile; subject: „Lake Van and Citadel“.
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