Types of lakes and the reasons for their formation, and the reasons for the formation of lakes

In general, the causes of lakes can be divided into the following types.

Tectonic lake: The development of tectonic lake is related to faults, which are graben structures formed after rock fractures and subsidence, and then accumulate water to form lakes. These lakes generally have steep shores and develop along tectonic lines, and the waters are generally deep. Typical lakes are: Dianchi Lake in Yunnan.

Erhai Lake; Qinghai Lake.

Kanas Lake in Xinjiang, etc.

Crater Lake: A lake formed by a volcanic eruption that leaves a large crater in the part of the volcano, and the crater gradually stores water. Typical are:

The volcanic lake of Oregon in the United States, the Tianchi of Changbai Mountain.

Wait. Rivers form lakes: Some rivers in plain areas are subject to river migration and silting, which can lead to the formation of lakes on their channels.

Causes: The shoreline is tortuous, the bottom of the lake is shallow and flat, and the water depth is shallow.

These lakes are affected by river water inflows: they expand during the wet season and shrink during the dry season. When the water volume is relatively balanced, the lake form of the river is more stable.

Oxbow Lake: In the plain area, the river will be more and more bent due to the erosion and erosion of the river channel by the current, and finally the river will be naturally cut and straightened, and the original curved river channel will be abandoned, forming the so-called oxbow lake.

For example: Wuliangsuhai in Inner Mongolia.

Dammed lakes: Dammed lakes are lakes 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, for example, Jingpo Lake is a typical dammed lake.

Glacial lake. The glacial lake is large.

It is mostly found in high mountains where there are glaciers, and when the glaciers melt, they become lakes due to the craters formed by the glaciers and the water from the melting icebergs.

Artificial lake: It is a reservoir.

Humans have built dams in river valleys to intercept water from the rivers for irrigation and other factors, and reservoirs can store reservoirs and collect more water resources, such as Qiandao Lake in Zhejiang. Wait.

According to the salinity of the lake water, lakes can be divided into 3 types:

1.Fresh water.

Freshwater lakes with a salt content of less than 1 are freshwater lakes. Freshwater lakes discharge water through surface runoff or underground runoff, and the salt content of lake water is similar to that of river water, such as Taihu Lake and Dongting Lake. Freshwater lakes are mostly formed in humid temperate and tropical regions, and are the main type of lake.

2.Saltwater lakes.

The salt content of the lake water is greater than. Saltwater lakes have no outlets, and water is mainly consumed by evaporation. Such as the Jilan Qin Salt Pond in Ningxia and the Chaka Salt Lake in Qinghai.

3.Brackish water lake.

Between the above two categories, the salt content of the lake water is between 1, such as Qinghai 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. In general, the causes of lakes can be divided into several types:

a) Tectonic lake.

In the surface of alpine plateaus, hills and plains, there are fractures and depressions, and the depressions gradually accumulate water to form lakes, such as Sun Moon Lake.

It is Yushan and Alishan.

It is an alpine tectonic lake that has been turned into water accumulation in a mountain basin.

b) Crater Lake.

After a volcanic eruption, a huge crater will be left at the top of the volcano, and the crater gradually stores 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 the plain areas will form lakes on the river due to the migration and swing of the river channel, the silting of the river channel, etc., and such lakes will expand during the wet season and shrink during 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.

iv) Oxbow Lake.

In the plains, the rivers will be more and more curved due to the erosion and erosion of the river channel by the current, and finally the river will naturally bend and straighten, 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 lakes.

A dammed lake is a lake formed by a landslide caused by geological changes, such as volcanic lava flows, ** activity, etc., which causes the blockage of a river valley or riverbed, and then stores 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.

vi) Glacial Lake.

The glacial lake is large. It is mostly distributed in the high mountains and has glaciers.

When the glacier melts, it will become a lake due to the craters dug by the glacier and the water blocked and accumulated by the melting of the icebergs, and the glacial lakes in Taiwan are mostly distributed in high-altitude areas, such as the Snow Mountain Range.

7) Artificial lakes - reservoirs, ponds.

Humans have built dams in river valleys for irrigation and drinking 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.

Types of Genesis of Lakes:

1 Volcanoes: Accumulation of water in volcanic craters into lakes, such as Tianchi in Changbai Mountain2 Faults: Lakes developed on fault lines, such as Tanganyika Lake3 Glacial erosion into lakes:

Such as the Great Lakes Ice Death Moraine Lake: such as Tianshan Tianchi; Lake basins and water volume are the elements that make up lakes, so it is necessary to analyze the genesis of Asian lakes from these two aspects. Types of Asian Lake Basin Genesis:

It mainly includes tectonic lakes (such as Lake Baikal, Kusupor, Dead Sea, etc.); sea trace lakes (such as the Caspian Sea, the Aral Sea); glacial lakes (such as most lakes on the Tibetan Plateau); Lakes formed by volcanism (such as Baekdu Mountain Cheonchi, Gyeongpo Lake, etc.).

The terrain is low-lying, which leads to rainwater pooling.

The low-lying land is very large, which can cause it to become a lake.

Lakes are generally formed in low-lying areas, and when there is a lot of rain, lakes will occur.

1. 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, narrow lake, deep and clear water, such as Dianchi Lake on the Yunnan Plateau.

Erhai Lake and Fuxian Lake.

Qinghai Lake, Xinjiang Kanas Lake, etc. Tectonic lakes generally have very distinct morphological characteristics, that is, the shores of the lakes are 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.

2. It is caused by the accumulation of water after the dormancy of the volcanic vent.

Its shape is round or oval, the shore of the lake is steep, and the water of the lake is unfathomable, such as the Tianchi of Changbai Mountain.

With a depth of 373 meters, it is the deepest lake in China.

3. The lava erupted by the volcano, the landslide caused by the ** and the landslide caused by the glacier and debris flow are congested by the riverbed, and the water outlet is cut off, and the upper part of the river is flooded into a lake, such as Wudalianchi and Jingpo Lake.

4. Carbonate strata are formed by long-term dissolution of flowing water to form karst depressions, karst funnels or sinkholes, etc., which are blocked and formed by catchment.

Such as the sea of grass in Weining County, Guizhou Province. There is a sea view building in the suburbs of Weining, climb the tower and look out, only to see the blue waves in the lake, the beauty is charming; On the island in the middle of the lake, the green pavilion is exquisite, the flowers and trees are sparse, and it is known as a water park.

5. Lakes formed by glacial erosion of potholes and moraines blocking the water in glacial troughs.

For example, Xinjiang Fukang Tianchi, also known as Yao Pond, is said to be the place where the Queen Mother bathes. North America: Great Lakes, Finland, Sweden.

of many lakes, etc.

6. A lake formed by the seepage of the surrounding sand dunes in the interhilaly depression lower than the diving surface in the desert.

Such as Dunhuang. The nearby Crescent Lake is surrounded by sand mountains, the water surface resembles a crescent moon, and the lake water is as clear as jade.

7. Due to the swing of the river, its natural embankment blocks the tributaries and becomes a lake. Such as Poyang Lake.

Dongting Lake, Jianghan Lake Group (Yunmengze area), Taihu Lake, etc.

8. Because the river itself is blocked by foreign sediment, the water flow is not smooth, and the water becomes a lake. Such as the South Four Lakes on the border of Sulu.

9. The abandoned section of the river after the bay is straightened to form an oxbow lake. Such as Wuliang Suhai in Inner Mongolia.

10. Due to sediment deposition, part of the bay is separated from the sea, which is usually called a lagoon.

Such as Caspian Lake, Hangzhou West Lake.

Dongqian Lake in Ningbo. About thousands of years ago, West Lake was still a shallow sea bay, and later due to the tide and the Qiantang River.

The sediment was continuously deposited near the mouth of the bay, completely separating the seawater in the bay from the ocean, and the seawater gradually desalination to form today's West Lake.

11. Because the bay is sandbarded.

The lake is enclosed and evolved, so it is generally by the sea. These lakes were originally bays, but later became lakes due to sediment deposits at the mouth of the bay, which formed sandbars at the mouth of the bay, which in turn separated the bay from the sea.

The basis of basin formation is the lake and water zone, lake sediment can form marshland, lake sediment can form lacustrine plain, marshland evolves into land and plain, the shape of marshland is completely similar to the shape of basin, and lake sediment can form lacustrine basin.

Therefore, it can be scientifically concluded that all basins, which come from the sedimentation of lakes and waters, are formed by sedimentation.

1. Tectonic lake: tectonic lake is a lake formed by the accumulation of water in the depression basin caused by the tectonic movement of the earth's crust, and the fault lake formed by tectonic fault is the most common, which is characterized by water depth, steep bank slope, and often long and narrow. Such as Dianchi Lake in Yunnan, China, Tanganyika Lake in the Great Rift Valley of Africa, etc.

2. Crater Lake: The crater lake was originally an ancient volcanic cone covered by glaciers, Mazama Volcano, and later the volcano erupted, the top of the mountain collapsed, forming a caldera, under the action of weathering and water erosion, the crater gradually expanded, and the water became a lake. Since then, there have been several small eruptions, forming several volcanic cones, some of which have outcropped out of the lake and become small islands, the largest of which is Wizad Island, which rises 213 meters above the water and has a crater at the top.

3. Glacier lake: Glacier lake is a type of lake formed by craters and moraines dug by glaciers. As glaciers flow, they erode and cut the terrain through them in various ways, and the glacier moved forward on its own track, leaving lakes around it.

4. Dammed lake: The dammed lake is a lake formed by a landslide and landslide caused by volcanic lava flows, moraines or mountain rocks that collapse down due to ** activities. Lakes formed by the interception of volcanic lava flows are also known as lava dam lakes.

5. Karst lake: formed by the catchment of karst depressions, karst funnels or sinkholes formed after the formation of karst landforms. The formation of karst lakes is closely related to the formation of karst landforms.

6. River into lake: The formation of river into lake is often closely related to the development of rivers and river changes, and is mainly distributed in plain areas. Due to the influence of undulating terrain and abundant and dry water, rivers often migrate, resulting in the formation of various types of rivers and lakes.

7. Fengcheng Lake: Fengcheng Lake is formed by the depression between the sand dunes in the desert being lower than the diving surface, and the surrounding sand dunes converge on the depression. Due to its unpredictable nature, the lake is often referred to as a haunting lake.

For example, in the eastern highlands of the Cosapeca Desert in Morocco, there is a "ghost lake" in Africa, which is unpredictable. At night, it is a large lake with a depth of several hundred meters, but once it is dawn, not only does the lake disappear, but it also turns into a large sand dune with a height of 100 meters.

8. Haicheng Lake: Haicheng Lake was originally a bay, and the mouth of the back bay separated the bay from the ocean due to sediment deposition, and became a lake, about thousands of years ago, the West Lake of Hangzhou was still a shallow sea bay connected with the Qiantang River, and later due to the sediment carried by the tide and the river continued to be deposited near the mouth of the bay, so that the bay and the ocean were completely separated, and the sea water gradually became fresh water before forming today's West Lake.

9. Artificial lake: Artificial lake is generally a kind of lake excavated by people in a planned and purposeful way, which is produced in an unnatural environment, including landscape lakes and large reservoirs, such as Hongze Lake.

Generally, it is a kind of lake that people have planned and purposefully excavated, and it is produced in an unnatural environment, that is, a reservoir that is often mentioned in daily life. Reservoirs are used for flood storage and water flow regulation, and can be used for irrigation, power generation and fish farming.

Tectonic lake. Crater Lake.

The river becomes a lake. Oxbow Lake.

Barrier lake. Glacial lake.

Karst lakes. Haicheng Lake Lagoon.

Wind into a lake. Artificial lakes - reservoirs.

Classification of lakes According to the lake basin genesis, lakes can be divided into: tectonic lakes, glacial lakes, crater lakes and dammed lakes.

According to the discharge conditions of the lake, the lake water is discharged into the ocean through the river and the inland lake cannot flow into the ocean.

According to the thermal status of the lake, the average temperature of the lake is above 4C throughout the year, and it is a tropical lake with positive stratification except for the same temperature in autumn and winter. The average temperature of the lake is sometimes above 4C, sometimes below 4C, it is stratified in summer, reverse stratified in winter, and it is a temperate lake with the same temperature in spring and autumn, and the average temperature is below 4C throughout the year, except for the cold zone lake with the same temperature in spring and summer.

According to the phenomenon of circulation in the water and under the lake: the lake surface is frozen all year round, and the lake water is stable and has no circulation period; The water temperature is below 4C, and there is only a single cycle of cold single-cycle lakes in summer; The water temperature is above 4C, and there is only a warm single-cycle lake with a cycle period in winter; a double-circulation lake that experiences two cycles in spring and autumn; Oligocirculation lakes with water temperature above 4C, stable stratification, and occasional circulation; The water temperature changes little from year to year, the stratification is weak, and the heat is sufficiently heated during the day and the heat is dissipated at night.

According to the salinity of the lake: freshwater lakes with salinity of 1 gram liter; a saltwater lake with a salinity of 1 35 g liters; Mineralization 35 grams liter of salt lake.

According to the nutrients in the lake water, it is divided into eutrophic lakes, mesotrophic lakes and oligotrophic lakes.

There are also a number of different types of lakes according to other criteria.