Lakes can have a different origin
Lakes can have a different origin. Geographers classify lakes by the presence of life, salt content, and the way they are formed. There is no life only in the saltiest lakes. Most of the lakes formed as a result of volcanic eruptions or movements of the earth’s crust .
Lakes can also form in depressions that have arisen as a result of uneven distribution of glaciers in areas of continental icing (moraine and glacial lakes) ; during the melting of ice in subsidence dips (thermokarst lakes) ; in castra chasms and funnels (campfire lakes) ; in valleys blocked by landslide, glacier, or displacement (volcanic lakes of the island of Java, the Kuril Islands, etc.) , by applying a mule or sand (estuary lakes of the Crimean peninsula).
Many lakes were created by people. These lakes are called reservoirs, since they contain a reserve of water for hydroelectric power plants and other economic needs.
Tectonic lakes. These lakes are the most interesting. They occur in places of tectonic faults, as a rule, very deep and have an elongated shape. The deepest lake in the world is Baikal (max. Depth – 1620 m, average – 730 m), tectonic in origin. It arose as a result of a break in the block of the earth’s crust, as a result of which a hollow filled with water appeared.
Due to precipitation , a water mass of lakes is formed. Sometimes seawater, which in the geological past filled the basin, is replaced by fresh water. These are the so-called relict lakes , among which are the Onega, Ladoga lakes and the Aral with the Caspian seas.
Salt lakes. To one degree or another, the drainless lakes are mineralized, salts accumulate in them (from 1 to 24.7% are brackish lakes, and from 24.7 to 47% are salty), which are found even in the fresh water of their tributaries.
There are still mineral lakes (they place salts more than 47%), including flowing, they are formed due to the flow of saline water from the depths of the Earth. Salts from them can precipitate.
Volcanic lakes. The water-filled crater of the volcano is the most common form of a volcanic lake.
Some lakes were formed by blocking volcanic valleys by lava flows and the accumulation of water in them. Lake Kivu serves as such an example; it is a depression in the East African rift system on the border of Rwanda and Zaire.
Lakes can also be formed underground, in the voids of limestone rocks. Water dissolves limestone, creating huge caverns filled with water. Such lakes can form in areas of underground salt deposits.
Artificial lakes. The most famous example of artificial lakes is reservoirs. Among the largest are Lake Mead in the United States, which appeared after the damming of the Colorado River and Lake Nasser on the border of Sudan and Egypt, which was created by damming the Nile Valley.
All of them serve hydroelectric power plants. Also, many artificial lakes exist for industrial use and for providing water to large settlements. Another example of artificial lakes are decorative small lakes, created in parks or just at home in the yard.