Lakes formed by fracture depressions caused by crustal movements

Lake Baikal, Qinghai Lake, Lake Tanganyika, Lake Malawi in Africa, etc.

Tectonic lake: It is a lake formed by water storage in a tectonic basin formed by the action of internal forces in the earth's crust. It is characterized by a long and narrow lake shape, deep and clear water, such as Dianchi Lake, Erhai Lake and Fuxian Lake on the Yunnan Plateau; Qinghai Lake, Xinjiang Kanas Lake, etc.

For example, the famous Lake Malawi, Lake Tanganyika, and Lake Victoria along the Great Rift Valley) tectonic lakes generally have very distinct morphological characteristics, that is, the lake shore is steep and developed along the tectonic line, and the lake water is generally very deep. At the same time, there are often a series of tectonic lakes arranged according to the tectonic line.

Lakes formed by fault depressions created by crustal movements are called tectonic lakes; Lakes formed by landslides, glacial river valleys are called dammed lakes.

Glacial lakes: These are the five connected lakes between the United States and Canada that are formed by the sand and rocks carried by the glaciers after the glaciers have carved out the trenches on the surface. There are many such lakes on the Qinghai-Tibet Plateau in China, where the land is sparsely populated, the weather is cold, the lake water is very clean, and the snow-capped mountains are reflected in it like a fairyland.

Tectonic lake: It is a lake formed by the movement of the earth's crust that causes the ground to break and depression, form depressions, and accumulate water. For example, Tanganyika Lake in the Great Rift Valley of East Africa, Qinghai Lake in China, and Lake Baikal in northern Asia.

Aeolian lake: It is a lake formed by wind erosion and then the water of the depression is formed, this kind of lake is small in area, the lake water is not deep, and it is mostly distributed in arid desert areas. River into a lake:

It is formed by the erosion of the river, Haicheng Lake: It is a lake formed by the impact plain and the bay sandbar to close the bay, this kind of lake is also called a lagoon, and the famous West Lake of Hangzhou in China is a lagoon. Karst Lake:

It is a waterlogged depression formed by the long-term dissolution of soluble rocks by flowing water. Dammed lake: It is a lake formed by molten Qingyan intercepting the river valley.

For example, Jingpo Lake in the northeast and Wudalianchi volcanic lake: as the name suggests, lakes are lakes where water accumulates in extinct volcanic craters, and these lakes are generally very deep. Changbai Mountain Tianchi.

Broadly divided into six types:

1. Glacial lakes, such as the Great Lakes at the junction of the United States and Canada;

2. Tectonic lakes, such as Qinghai Lake and Baikal Lake;

3. The dammed lake was formed in Wenchuan**;

4. The river becomes a lake;

5. Haicheng Lake (lagoon);

6. Blind karst lakes.

1. Tectonic lake: The tectonic lake basin generated by the internal forces of the earth's crust, including the crustal faults, depressions and subsidence generated by geological tectonic movements, and the lakes formed by water storage are called tectonic lakes. Tectonic lakes have a very distinct morphological characteristic, that is, the shores are steep and develop along the tectonic line, and the water is generally very deep.

At the same time, there are often a series of tectonic lakes arranged according to the tectonic line.

2 Fault lake: refers to a lake formed by the fault and subsidence of internal forces. It is a type of lake formed by internal forces, and this type of lake can also be called a tectonic lake.

3 There are many factors in the formation of lakes, such as volcanic activity can form crater lakes and dammed lakes; The movement of the earth's crust can form tectonic lakes, which are collectively known as internal force lakes, which are the result of the action of the earth's internal forces. There is also an external force lake, which is formed under the condition that flowing water, wind, glaciers, etc. play a dominant role, such as glacial lake, sea lake, river lake, wind lake, karst lake, etc.

tectonic lakes Dianchi Lake and Erhai Lake on the Yunnan Plateau; Qinghai Lake, Xinjiang Kanas Lake, etc.

Crater Lake, Baektu Mountain Tianchi;

Hecheng Lake, Dongting Lake;

Haicheng Lake, Caspian Sea, West Lake of Hangzhou;

Dammed Lake: Wudalianchi, Jingpo Lake;

glacial lake, Yao Pond;

Karst Lake, Caohai in Weining County, Guizhou Province;

A lake is a continuum of a basin, its water, and the substances contained in it – minerals, dissolved matter, organic matter, and aquatic organisms. Lakes can be formed in many forms, such as crustal movements, natural erosion, accumulation, and man-made forces, all of which turn the surface of the earth into a depression. However, no matter how a lake is formed, it must meet two basic conditions:

One is the depression, that is, the lake basin, and the other is the water body accumulated in the lake basin.

Therefore, in geography, the genesis of lake basins is usually used as the main basis for lake classification. In recent years, the dominant factor in the classification of lakes has taken into account the accumulation of water in the lake basin, because only the depression where water accumulates is called a lake.

There are many reasons for the formation of lakes, such as the movement of the earth's crust, natural erosion, accumulation and man-made forces, which can cause the surface to form a depression and become a lake. Generally speaking, the causes of lakes can be divided into several types: (1) tectonic lakes are fractured and depressions occur on the surface of alpine plateaus, hills and plains, and the depressions gradually store water to form lakes, such as Sun Moon Lake is Yushan Mountain, Alishan is an alpine tectonic lake turned into a mountain tectonic lake due to water accumulation in the intermountain fault basin.

2) Crater Lake After a volcano erupts, a huge crater will be left on the top of the volcano, and the crater will gradually store water to form a lake, for example, there is also a volcano and a crater lake on the island of Guishan outside the Yilan Plain. (3) Rivers become lakes Some rivers located in plain areas will form lakes on the river due to the migration and swing of the river and the silting of the river, and such lakes will expand in the wet season and shrink in the dry season due to the influence of river water injection; When the water volume is relatively balanced, the river lake morphology is more stable, but when the water volume changes greatly, the change of river lake morphology also increases. (4) Oxbow Lake The rivers in the plain area will be more and more curved due to the erosion and erosion of the river channel by the water flow, and finally lead to the natural bending and straightening of the river, and the original curved river channel will be abandoned, forming the so-called oxbow lake.

For example, near Erren Creek, there is a oxbow lake formed by the action of the river. (5) Dammed lake A dammed lake is a lake formed by landslides caused by geological changes, such as volcanic lava flows, ** activities, etc., resulting in the blockage of river valleys or river beds, and then storing water. If a dammed lake is formed due to volcanic lava blockage, it is called a lava dammed lake, such as Bamboo Lake and Caoling Lake are typical dammed lakes.

6) Glacier lakes Glacier lakes are mostly distributed in high mountains and glaciers, when the glaciers melt, they will become lakes because of the craters carved by the glaciers and the water blocked and accumulated by the melting of the icebergs. (7) Artificial lakes - reservoirs, ponds For the purpose of irrigation and drinking and other factors, human beings have built dams in river valleys to intercept the water in the rivers to form lakes, which can store reservoirs and collect more water resources, such as Shimen Reservoir, Mingde Reservoir and Baoshan Reservoir.

Lakes are formed by water accumulation in land depressions, and they are relatively wide and have slow flow changes. Under the geological actions such as crustal tectonic movements, glaciation, and river scouring and silting, many depressions are formed on the surface of the earth, and water accumulates into lakes. Unlike rivers, lakes have unusually slow flow and different from seas in that they do not have direct contact with the ocean.

Under the influence of the natural geographical conditions of the river basin. The lake's basin, lake water and water matter interact with each other and constrain each other, causing the lake to evolve. For example, according to the discharge conditions of the lake, it is divided into outflow lakes and inland lakes.

According to the origin of the lake basin, lakes can be divided into tectonic lakes, crater lakes, glacial lakes, dammed lakes, etc. According to the thermal conditions of the lake, it is divided into tropical lake, temperate lake and cold lake. According to the nutrients in the lake water, it is divided into eutrophic lakes, mesotrophic lakes and poor nutrient lakes.

According to the salinity of the lake water, freshwater lakes are divided into freshwater lakes, and the salinity is below; Brackish water lake with salinity. Between; Saltwater lake with a salinity of 244% to 3

Between 5% of the salt water lake, the salinity is greater than.

The primary condition for the development of lakes is the lake basin, that is, the basin where water is collected and stored, and the second is that there is water. There are many reasons for the formation of lake basins. Tectonic lake basins are commonly found in fault zones or rift zones on the earth's surface, such as lake basins developed along the East African rift, the Caspian Sea, Lake Baikal in Russia, etc.

China's Yunnan Province has developed two basin groups near Kunming and Dali, among which Dianchi Lake and Erhai Lake are tectonic lake basins. The river basin is a lake basin caused by the bending and diversion of the river and the silting up of both ends of the waste channel.

Volcanism creates crater lake basins, which are of two broad categories. One is the crater lake, that is, after the volcanic eruption stops, the crater accumulates water into a lake, such as the Tianchi of Baitou Mountain, the main peak of Changbai Mountain in Jilin; Second, volcanic eruptions dam river valleys into lakes, such as Jingpo Lake in Heilongjiang Province. Glacial lake basins are formed by the erosion of glaciers.

In the mountain glacial area, the original cirque depression area can accumulate water into a small cirque lake; The continental glacial zone forms a long, narrow basin of different depths arranged in the direction of the ice flow. Rivers can also be blocked by glaciers or ice breaks, such as Tianchi in the Tianshan Mountains in Xinjiang. The Haicheng Lake Basin is formed by the rise of the crust of the adjacent area and the isolation of the sea itself, such as the Black Sea in Europe, which was once a bay in the Mediterranean.

Hangzhou's West Lake was originally a part of Hangzhou Bay, which belongs to Haicheng Lake, and now the lake water is ** rainwater, so it is a freshwater lake. The wind into the lake basin is related to the wind, the wind can blow the wind and sand at the same time, can not only dig into the lake, but also pile up sand into a lake. The basin of the lake is round or oval in shape and extends downwindward.

Most of the lakes in the northwest and Inner Mongolia belong to this, such as Juyanhai, Luobu Nuoer in the Turpan Basin. There is also a kind of lake basin caused by a meteorite, that is, an extraterrestrial object strikes to form a nearly circular crater, and the water in the pit is a lake.

It can be divided into the following types. One is due to the movement of the earth's crust, which causes local fractures or subsidence, and the water accumulates into lakes. This type of lake is called a tectonic lake, and it is characterized by its deep water and wide surface.

China's Dianchi Lake and Qinghai Lake, and Africa's Tanganyika Lake all belong to this category. The second type is the crater after the eruption, which accumulates water into a lake for a long time. Such a lake is called crater lake.

The crater lake is mostly circular, with steep shores and deep waters. For example, Tianchi in Changbai Mountain is such a crater lake. The third is the formation of lakes due to lava flows blocking river valleys.

This type of lake is called a dammed lake. For example, China's Jingpo Lake and the Five Great Lotus Ponds belong to this type. The fourth is due to the sedimentation of rivers or shallow seas, resulting in local low-lying terrain and water accumulation into lakes.

These lakes are called sedimentary lakes and are mostly found in river deltas and coastal zones. For example, Taihu Lake and West Lake in China are lakes formed by the gradual siltation of the bay and the isolation from the sea. The fifth type is a lake formed by the wind erosion depression or low terrain between the sand dunes formed by the action of the wind, which is called the aeolian lake.

This type of lake is generally small in area, shallow in water, and moves with the change of water source, so it is also called a migratory lake. There are such lakes in Xinjiang and Inner Mongolia in China. Sixth, in areas of soluble rocks (limestone, dolomite, etc.), dissolution lakes formed by the dissolution of groundwater are funnel-shaped, small, scattered and scattered.

The seventh type is a glacial lake formed by glacial abrasion and the accumulation of moraines (detrital material that is carried and accumulated with the movement of glaciers), and is characterized by a variety of shapes and twisting shores. There are such glacial lakes on the Qinghai-Tibet Plateau in China. In addition, there is a special type of lake, which is the artificial reservoir.

Under geological actions such as crustal tectonic movements, glaciation, and river scouring and silting, many depressions are formed on the surface of the earth, and water accumulates into lakes. Water accumulation in open-pit mining sites and barrages form reservoirs, which also contribute to the formation of lakes.

Rivers and rainwater pass through depressions and accumulate faster than they evaporate, creating lakes naturally. Give it to me, thank you!

There's a depression in the area that has accumulated over the years of rain.