Lakes of the world
Lake – a mass of water or other liquid of considerable size, situated on the land. The large number of lakes on Earth is freshwater, and most lie in the Northern hemisphere at higher latitudes. In the ecology of the surrounding lake environment is referred to as lacustrine deposits. Large lakes are sometimes referred to as “inland seas” and small seas are sometimes referred to as lakes. Small lakes tend to put the word “lake” after the name, as in Green Lake, while larger lakes often invert the word order, as in Lake Ontario, at least in North America.
Most lakes have a natural outflow in the form of a river or stream, but some have not, and lose water solely by evaporation and/or underground leakage. They are called internal lakes.
The term “lake” is also used to describe such a feature as lake Eyre, which is a dry basin most of the time, but can be filled with seasonal heavy rains.
Many lakes are artificial and constructed for hydro-electric power, regional purposes, industrial use, agricultural use or domestic water supply.
Evidence of extraterrestrial lakes exists. The testimony of lakes filled with methane, was approved by NASA to return the automatic research station “Cassini” – observing satellite Titan, which moves around the planet Saturn.
The origin of natural lakes
Geologically speaking, most lakes are young. Natural results of erosion will wash one of the basin sides containing the lake, like lake Baikal in Russia, which is estimated to 25 – 30 million years. There are many natural processes that can form lakes. Recent architectural rise of mountain ranges can create bowl-shaped depressions that accumulate water and form lakes. The advancement and retreat of glaciers can excavate depressions in the surface where lakes accumulate; such lakes are common in Scandinavia, Patagonia, Siberia and Canada. Lakes can also be formed by landslides or by glacial blockages. An example of the latter occurred during the last ice age in Washington state, USA, when a huge lake formed behind a glacial flow. When the ice melted, the result was a huge flood that created the Dry Falls at Sun Lakes in Washington.
Salt lakes (also called saline lakes) can form where there is no natural outlet or where the water evaporates rapidly and the drainage surface of the groundwater is higher than normal salt content. Examples of salt lakes include Great Salt lake, Caspian sea, Aral sea and Dead sea.
Small, half-moon shaped lakes, called oxbow lakes. They may form in river valleys as a result of the bends of the channel. Lazy river forms a sinuous shape as the outer side of bends is destroyed more quickly than the inside. Ultimately, the bend of the “horseshoe” is formed and the river cuts a narrow isthmus. This new passage forms a main passage for the river, and the ends of the bend become silted up, thus forming bow-shaped lake.
Lake Vostok is a subglacial lake in Antarctica, possibly the largest in the world. The pressure from ice and the internal chemical composition shows that, if the lake started to drill, this could lead to a crack, which gushed forth like a geyser.
Some lakes, like lake Baikal and lake Tanganyika that lie along continental rift zones and are created lower crust in place of the partition plates. These lakes are the oldest and the deepest in the world, and it may take more millions of years to become oceans. The red sea is believed to have occurred as a lake of the East African fault zone.
The Crater lake in Oregon, USA – this lake located within the Caldera of the volcano Mazama. The Caldera was created in a massive volcanic eruption, which led to the lowering of mount Mazama approximately 4860 BC Since that time, all the eruptions at Mazama ogranichivat the Caldera.
Some lakes, like lake Jackson, USA was the result of the activities of sinkholes.