The limnology, science about lakes, classifies lakes by different parameters including by origin. On this sign they are divided into nine groups - glacial, tectonic, kraterny, mountain, zavalnye-dammed, failure, seaside, river and artificial.
Instruction
1. The considerable part of lakes has tectonic origin. Because of the movement and deformation of a lithosphere in earth crust there are cracks and hollows which quickly are filled with water. Distinctive feature of such lakes - big size. The largest lakes of the world - Baikal, Tanganyika, the Great Lakes of North America - have tectonic origin. Tectonic lakes usually are located around lithospheric boards or along breaks in bark.
2. Volcanic lakes are formed after eruption of volcanoes. Water can fill either a crater of an extinct volcano, or deepening in the stiffened lava streams. A set of such lakes are in places of vigorous volcanic activity, for example on Kamchatka.
3. The lakes formed owing to the movement of glaciers carry to exogenous lakes, that is formed on external causes. During Ice Ages on a surface the mass of ice of the improbable sizes moves, they press through some fragile terrestrial breeds and after the leaving leave hollows. It is possible to look at the lakes formed by glaciers in Karelia.
4. Seaside lakes, so-called lagoons, are formed when the part of the sea separates from water bulk a tongue of sand. One of the most known lagoons - Venetian.
5. Often the small flat rivers which have too strong bends form lakes. Gradually the current straightens a bend, and a curved part it is necessary to exist separately from the river. Such lakes are called staritsa.
6. It is a lot of lakes in mountains. Here they can be formed for various reasons: - because of the movement of glaciers which leave chashepodobny deepenings on slopes below a zone of thawing of snow; - because of collapses which can partition off the mountain river and create a natural dam on its way.
7. The person often constructs artificial lakes which are called ponds and reservoirs. Such artificial reservoirs are necessary for irrigation, sanitary needs, cultivation of fish.