How are basins formed? What are the characteristics of the basin?

The basin is high on all sides and low in the middle, and the whole terrain resembles a large basin. The basin is generally surrounded by plateaus or mountains, and the central part is plains or hills. There are two main types of basins:

One is the basin formed by the tectonic movement of the earth's crust, which is called the tectonic basin, such as the Turpan Basin and the Jianghan Plain Basin in Xinjiang, China; The other is the basin formed by the erosion of glaciers, flowing water, wind and karst, which is called erosion basin, such as the Jinghong Basin in Xishuangbanna, Yunnan Province, China, which is mainly formed by the erosion and expansion of the Lancang River and its tributaries. The basin area varies in size, and China's Sichuan, Tarim, Junggar and Qaidam basins are all more than 100,000 square kilometers. The small basin is only a few kilometers in circumference, and is called "dam" in Guizhou.

The natural conditions in these basins are superior and abundant in resources, which are called "cornucopias".

The basin is basically in the form of a basin with low middle and high at the periphery.

The long-term sedimentation of the lake will form a lacustrine plain, and the formed lacustrine plain does contain a lacustrine basin. [covers face].

Basins are mainly formed due to crustal movements. Under the action of crustal movement, the underground rock layer is squeezed or stretched, and becomes bent or fractured, which causes some parts of the rock to uplift and some parts to fall, such as the descending part is surrounded by those parts of the uplift, and the rudiments of the basin are formed.

Many basins have been flooded by seawater or lakes since they were formed, such as the Sichuan Basin, the Tarim Basin, and the Junggar Basin. Later, as the earth's crust continued to rise and sediment accumulated, the sea and lakes in the basin slowly retreated and dried up, leaving only some rivers or streams. However, in those seas, lakes and rivers that once existed, a large number of organisms that once lived were buried in the silt after death, which will become the material basis for the formation of oil and coal, which is an important reason why scientists pay great attention to basin research.

Most of the rock deposits in the basin are relatively intact and continue to be marketed, and the animals and plants living there are also relatively easy to preserve into fossils after death, so the basin is also a good place for paleontologists to find fossils.

There are also some basins, which are mainly formed by the destruction of external forces on the surface, such as wind and rain. Rivers erode and cut down along the rocky deficit areas of the earth's surface, forming valley basins of various sizes. In the vast arid areas of northwest China, the wind is particularly strong, and after blowing away the sand and gravel on the surface, a saucer-shaped wind erosion basin is formed.

Some basins in regions such as Gansu, Inner Mongolia and Xinjiang were formed in this way.

In addition, in some areas where limestone is developed underground, the perennial flow of groundwater will cause the rocks there to dissolve, causing the surface rocks to collapse, and also forming basins, which geologists call karst basins. There are many basins of this type in southwest China, such as the Yunnan-Guizhou Plateau and Guangxi.

Under the strong extrusion or stretching action, the basement of some large basins with pants will be fractured, forming some "fault basins", which are more common in areas with severe crustal activity such as the Bohai Bay in North China and the Hengduan Mountains in Southwest China.

Sedimentary basins are often affected by tectonic activities in the crust during their development, and this activity can be recorded by the sediments that the basin has received continuously, and through the geological and geochemical study of these sediments, one can describe and reversely describe and reversely the historical processes of the Earth's evolution in these regions, such as climate change, sea level changes, the exchange of greenhouse gases that have a significant impact on the climate and the atmosphere, and topographic changes determined by tectonic activities.

Regardless of the type of basin, it is done by sedimentation. That is to say, basins are formed by the sedimentary material transported by rivers to settle in lakes, and then form marshes, wetlands, sedimentary plains, and sedimentary basins.

Further explanation, lake sediment, can form alluvial plains.

The sedimentary plain, and the sedimentary plain, it covers all the sedimentary areas, but because of the different sizes of the area, it is divided into sedimentary plains, sedimentary basins, sedimentary marshes, sedimentary wetlands, sedimentary areas, and according to the size of the sedimentary area, as well as the geomorphological structure around the sedimentary sedimentary area, there is a sedimentary plain, if the area of this sedimentary plain is relatively small, and the surrounding area is high, then, this is the sedimentary basin. From this point of view, we can see the true origin of the basin thoroughly. Rangliang --- no matter what kind of basin, it is the product of sedimentation.

This is a problem that the whole geology of the world does not recognize, and the relationship between lakes and basins is a huge gap.

The largest basin on Earth, the Congo Basin, covers about 1 3 of Canada's. The basin is surrounded by abundant mineral resources. There are five well-known basins in China, namely Sichuan, Tarim, Turpan, Zhunzhaoer, Qaidam and other basins, covering an area of more than 100,000 square kilometers.

Due to the wind-resistant effect of the basins, many basins are relatively dry and unsuitable for human cultivation, such as the Qaidam Basin. Some basins are relatively low in altitude or have air currents rushing in, and the whole terrain is like a large basin. Reasons for the formation of basins:

The basin is high around and low in the middle, and the climate is relatively humid. The basin is generally surrounded by plateaus or mountains, and the central part is plains or hills. There are two main types of basins:

The first is the basin formed by the tectonic movement of the earth's crust, which is called a tectonic basin, such as the Turpan Basin and the Jianghan Plain Basin in Xinjiang, China; The second is the basin formed by the erosion of glaciers, flowing water, wind and karst, called erosion basins, which are mainly formed by the erosion and expansion of the Lancang River and its tributaries. For example, the Jinghong Basin in Xishuangbanna, Yunnan Province, is mainly occupied by the Lancang River and its tributaries. The basin area varies in size.

China's Sichuan, Tarim, Zhunzhanger, Qaidam and other basins cover an area of more than 100,000 square kilometers. The small basin is several kilometers in circumference, and is called "dam" in Guizhou. Some basins are rich in natural conditions and resources, and are known as "cornucopias".

One of the top five most famous terrain in the world is the Alps, which are widely distributed across the globe. The Congo River Basin is the largest river basin in the world. Due to the basin's blocking effect on air flow, many basins are relatively arid and not suitable for human cultivation, such as the Qaidam Basin, because the climatic conditions of these basins are relatively harsh and the possibility of climate change is relatively high.

Some basins also have a wetter climate because of their relatively low altitude or because of the flow of air. The basin is high on all sides and low in the middle, and the whole terrain resembles a large basin, forming a huge basin. In general, the basin is surrounded by plateaus or mountains, with plains or hills in the middle.

There are two main types of basins: one is the basin formed by the tectonic movement of the earth's crust, such as the Turpan Basin in Xinjiang and the Jianghan Plain Basin; The second type is formed by glacial, flowing water, wind and karst erosion, such as the Jinghong Basin in Xishuangbanna City, Yunnan Province. Sichuan, Tarim, Junggar and Qaidam basins cover an area of more than 100,000 square meters, among which the largest basin in Sichuan Province is located in Yunnan Province, covering an area of more than 100,000 square kilometers.

The small basin with a length of only a few kilometers is called in Guizhou"Dams"。Some of the basins with superior natural conditions are called internally"Cornucopia"is abundant in resources.

1. The basins are mostly distributed on the mountainous surface.

2. There are basins with different structures in hills, mountains and plateaus.

3. The basin is basically in the form of a basin with low middle and high periphery.

4. The terrain inside the basin is relatively gentle compared to the outside of the basin, with many plains and hills, which is suitable for living and production.

5. The outside of the basin is mostly high mountains, which is suitable for the development of mountain agriculture.