Ancient lake

Source: Wikipedia, the free encyclopedia.
Lake Zaysan in Kazakhstan is one of the oldest lakes in the world.

An ancient lake is a lake that has consistently carried water for more than one million years. 12 of the 20 ancient lakes have existed for more than 2.6 million years, the full

Quaternary period. Ancient lakes continue to persist due to plate tectonics in an active rift zone. This active rift zone creates lakes that are extremely deep and difficult to naturally fill with sediment. Due to the prolonged life of ancient lakes, they serve as models for isolated evolutionary traits and speciation. Most of the world's bodies of water are less than 18,000 years old. There are only 20 ancient lakes over 1 million years old.[1]

Lake Baikal is often considered the oldest, as clear evidence shows that it is 25–30 million years old.[2][3] Lake Zaysan may be even older, of Cretaceous origin and at least 66 million years old[4] (most likely around 70 million years[5]), but its exact age is controversial and labelled with some uncertainty.[6] Another contender for oldest is Lake Maracaibo, estimated to be 20–36 million years old. In ancient times it was indisputably a true lake, but today it is saline and directly connected to the sea, leading many to consider it a large lagoon or bay.[7]

Ancient lakes vs. younger lakes

There are six major types of lakes (listed below). The majority of lakes dry up as the result of the filling with

rift zones and subsided sections of land called grabens
.

For example, Lake Baikal in Russia, the deepest lake in the world, is an ancient lake created by the Baikal Rift Zone which is 25–30 million years old and 5,387 feet (1,642 m) deep. This is compared to the North American Great Lakes, which were formed by the last glacial period by glacial scouring and the pooling of meltwater which are 14,000 years old and have maximum depths ranging from 200–1,300 feet (60–400 m) deep.

Formation of ancient lakes

Ancient lake formation is similar to that of a rift valley. Formation occurs within a graben that is located on an active rift zone. Grabens are sections of land, formed along divergent plate boundaries, which have subsided between two parallel plates. The location of the graben above the active rift zone results in a lake bottom that is constantly dropping in depth and walls increasing in height.

Importance to evolution

Ancient lakes allow scientists to study the mechanisms of environmental changes over glacial-interglacial timescales. Evolutionary characteristics including

fluctuating profundal and evaporative facies
.

List of ancient lakes

These are the 20 ancient lakes in the world that have existed for more than 1 million years.[1]

Name Origin Type Age Area
(km2) 		Volume
(km3) 		Depth max Depth average Countries Notes
Lake Pingualuk
 meteor impact fresh, permanent, crater 1.5 million 8 267 Canada
Lake Tahoe tectonic fresh, permanent 1–2 million 499 156 505 313 United States
Lake Bosumtwi meteor impact soda, permanent, crater 1–2 million 49 2.24 81 45 Ghana
Lake Lanao volcanic fresh, permanent 2 million 375 112 60.3 Philippines
Lake Titicaca tectonic fresh, permanent 3 million 8372 893 281 107 Bolivia, Peru
Lake Prespa tectonic fresh, permanent 1.5-5 million 259 4.8 54 18.7 Albania, Greece, North Macedonia
Lake Ohrid tectonic fresh, permanent 1.5-5 million 358.18 53.63 286.7 163.71 Albania North Macedonia
Lake Malawi tectonic fresh, permanent 2–5 million 29600 8400 705 292 Malawi, Mozambique, Tanzania
Lake Hovsgol tectonic fresh, permanent 2–5 million 2770 381 267 138 Mongolia
Kati Thanda–Lake Eyre tectonic saline, intermittent, endorheic 2.5-5 million 9690 30.1 6 3 Australia
Lake Tanganyika tectonic fresh, permanent 3–6 million 32000 17800 1471 572 Burundi, Congo, Tanzania, Zambia
Caspian Sea tectonic saline, permanent, endorheic 5.5 million 374000 78200 1025 182 Azerbaijan, Iran, Kazakhstan, Russia, Turkmenistan
Aral Sea tectonic saline, permanent 5.5 million 64500 625 67 16 Kazakhstan, Uzbekistan Formerly the fourth
largest lake
in the world with an area of 68,000 km2 (26,300 sq mi). By 1997, it had shrunk to 10% of its original size due to water that was diverted in the Soviet Era. It is now split into 4 smaller lakes. As of 2023, the Aral Sea has become mostly desert.
Lake Biwa tectonic fresh, permanent 5–6 million 674 27.5 104 41 Japan
Lake Tule tectonic fresh, permanent 3–15 million 53 40 United States
Lake Maracaibo tectonic saline, permanent, coastal bay 20+ million 13010 280 60 25.9 Venezuela Historically it was an ancient lake. Now a large tidal bay / inlet rather than a lake in the traditional sense. It is saline and directly connected to the Caribbean Sea, leading many to consider it a large lagoon or bay.
Lake Baikal tectonic fresh, permanent 25+ million 31500 23000 1741 740 Russia
Issyk-Kul tectonic saline, permanent 25 million 6236 1738 668 270 Kyrgyzstan
Lake Vostok subglacial fresh, permanent, subglacial 15–35 million 12500 5400 510 432 Antarctica
Lake Zaysan tectonic fresh, permanent 65+ million 5510 53 10 5 Kazakhstan The construction of the Bukhtarma dam inundated the lake, thus, in some sources the lake is considered a reservoir.[8]

References

  1. ^ a b Free, Christopher (April 23, 2016). "Ancient lakes of the world". Christopher M. Free. Archived from the original (website) on February 9, 2020. Retrieved 20 January 2024. Most of the hundreds of thousands of inland water bodies on our planet are less than 18,000 years old, but a few lakes and inland seas have existed continuously for more than 1 million years. I present a database of the 20 ancient lakes of the world.
  2. ^ "Lake Baikal – UNESCO World Heritage Centre". 1992–2024. Retrieved 20 January 2024. Situated in south-east Siberia, the 3.15-million-ha Lake Baikal is the oldest (25 million years) and deepest (1,700 m) lake in the world. It contains 20% of the world's total unfrozen freshwater reserve.
  3. ^ "Lake Baikal: Protection of a unique ecosystem". ScienceDaily. 26 July 2017. Retrieved 8 March 2018.
  4. doi:10.1016/j.proenv.2011.09.220
    .
  5. doi:10.1016/j.proenv.2011.09.220
    .
  6. ^ "The Oldest Lakes in the World". World Atlas. 25 August 2017. Retrieved 8 March 2018.
  7. ^ "Lake Maracaibo – Lakes of the World". World Atlas. Retrieved 8 March 2018.
  8. ^ Soviet Encyclopedic Dictionary, Moscow, 1980, p. 451.

External links
Retrieved from "https://en.wikipedia.org/w/index.php?title=Ancient_lake&oldid=1216835234"