Lake Baikal

Lake Baikal (Russian: о́зеро Байка́л,  Ozero Baykal; IPA: [ˈozʲɪrə bəjˈkɑl]; Buryat: Байгал нуур, Mongolian: Байгал нуур, Baygal nuur, meaning "nature lake") (Байкол - in kyrgyz translates as Rich lake) is the world's oldest lake, at 25 million years (possibly older), and deepest, averaging 744.4 metres (2,442 ft).

Located in the south of the Russian region of Siberia, between Irkutsk Oblast to the northwest and the Buryat Republic to the southeast, it is the most voluminous freshwater lake in the world, containing roughly 20% of the world's unfrozen surface fresh water.

At 1,642 metres (5,387 ft), Lake Baikal is the deepest and among the clearest of all lakes in the world. Similar to Lake Tanganyika, Lake Baikal was formed as an ancient rift valley, having the typical long crescent shape with a surface area of 31,722 km² (12,248 sq mi), less than that of Lake Superior or Lake Victoria. Baikal is home to more than 1,700 species of plants and animals, two thirds of which can be found nowhere else in the world and was declared a UNESCO World Heritage Site in 1996. It is also home to Buryat  tribes who reside on the eastern side of Lake Baikal, rearing goats, camels, cattle and sheep, where the regional average temperatures vary from a minimum of −19 °C (−2 °F) in winter to maximum of 14 °C (57 °F) in summer. Lake Baikal is nicknamed "Older sister of Sister Lakes (Lake Khövsgöl and Lake Baikal)"

The first European to reach the lake is said to be Kurbat Ivanov in 1643.

In the past, the Baikal was respectfully referred to by many Russians as the "Baikal Sea" (Russian: Море Байкал, More Baikal), rather than merely "Lake Baikal" (Russian: Озеро Байкал, Ozero Baikal). This usage is attested already on the late-17th century maps by Semyon Remezov. To these days, the strait between the western shore of the Lake and the Olkhon Island is called Maloye More (Малое Море), i.e. "the Little Sea".

According to 19th century traveler T. W. Atkinson, locals in the Lake Baikal Region had the tradition that Christ visited the area:

The people have a tradition in connection with this region which they implicitly believe. They say "that Christ visited this part of Asia and ascended this summit, whence he looked down on all the region around. After blessing the country to the northward, he turned towards the south, and looking across the Baikal, he waved his hand, exclaiming 'Beyond this there is nothing.'" Thus they account for the sterility of Daouria, where it is said "no corn will grow."

Lake Baikal is in a rift valley, created by the Baikal Rift Zone, where the Earth's crust pulls apart. At 636 kilometres (395 mi) long and 79 km (49 mi) wide, Lake Baikal has the largest surface area of any freshwater lake in Asia (31,722 km²/12,248 sq mi) and is the deepest lake in the world (1,642 m/5,387 ft). The bottom of the lake is 1,186.5 metres (3,893 ft) below sea level, but below this lies some 7 km (4.3 mi) of sediment, placing the rift floor some 8–11 kilometres (5.0–6.8 mi) below the surface: the deepest continental rift on Earth. In geological terms, the rift is young and active—it widens about two cm per year. The fault zone is also seismically active; there are hot springs in the area and notable earthquakes every few years. The lake is divided into three basins: North, Central, and South, with depths of about 900, 1600, and 1400 m, respectively. Fault-controlled accommodation zones rising to depths of about 300 m separate the basins. The North and Central basins are separated by Academician Ridge while the area around the Selenga Delta and the Buguldeika Saddle separates the Central and South basins. The lake drains into the Angara tributary of the Yenisei.

Its age is estimated at 25–30 million years, making it one of the most ancient lakes in geological history. It is unique among large, high-latitude lakes, in that its sediments have not been scoured by overriding continental ice sheets. U.S. and Russian studies of core sediment in the 1990s provide a detailed record of climatic variation over the past 250,000 years. Longer and deeper sediment cores are expected in the near future. Lake Baikal is furthermore the only confined fresh water lake in which direct and indirect evidence of gas hydratesexists.