TYPES of geographic DEPRESSIONS

The great surface of our planet Earth is not totally flat, but there are elevations and depressions that shape the geography of our planet along its entire length. In this last point we are going to focus on this article by a PROFESSOR and we are going to see what are the types of geographic depressions with examples that exist on our planet. If you are interested in learning more about the geography of our Earth, keep reading!

Index

1. What is a geographic depression
2. Types of geographic depressions and examples of them
3. Causes of geographic depressions

The geographic depressions are areas of the earth's surface characterized by having a lower height that the regions that surround it or because they are Below sea level. These areas can be completely flooded, dry or even arid.

The size that these regions can reach is very variable and in the world we can find small depressions, such as subsidence of a few meters in diameter, or large, reaching scales even continental.

There are very various causes by which these geographic depressions can form. Occasionally, depressions can be formed by the movement of tectonic plates. Other causes of the descent of the terrain and the subsequent formation of a depression can be climate, human action or soil permeability, Inter alia.

Image: Union CDMX

We differentiate two types of geographic depression. Next, we are going to discover them and give examples of them so that you understand it better.

Relative geographic depressions

On the one hand, we find the relative geographic depressions, in which the terrain is surrounded by an area of ​​higher altitude, but always by above sea level.

In this group we find the Great Basin in the western United States Yet the Tarim Basin in western China, which are two of the most extensive.

Absolute geographic depressions

On the other hand, there are absolute geographic depressions, in which the terrain is lower than the surrounding, but is located below sea level.

There are only 33 countries with this type of depression. One of the clearest examples is the Caspian Sea, which is located 28 meters below sea level and is one of the largest absolute depressions in the world, with 371,000 square kilometers.

The Netherlands is one of the most representative territories, since up to two thirds of its territory is located over 4 meters below sea level. Another example that is up to 86 meters below sea level is the Valley of Death in the United States. One of the largest depressions on earth is in the Dead Sea, with up to 413 meters below sea level and is the so-called Jordan Valley.

Other examples of types of geographic depressions are the Turfan depression in China, the Afar depression in Africa, the Qattara depression in Egypt, or the San Julián depression in Argentina.

As we saw in the previous paragraph, the causes of the formation of geographic depressions are very diverse and they can be absolute or relative. The vast majority of these formations are due to the movement of tectonic plates and another important factor is destabilization of the terrain due to factors such as erosion, weather, human action or activity volcanic. Therefore, it is to be expected that there are regions of the planet with a greater concentration of these geographical depressions.

Generally, these causes can be classified in several groups:

• Geographic depressions due to land collapse
• Geographic depressions due to soil erosion
• Geographical depressions due to soil sediments
• Geographical depressions due to impacts on the ground
• Geographic depressions due to tectonic movements

If the formation of the depression is due to a slow movement of destabilization of the terrain, it is spoken depressions produced by subsidence of the ground, that is, a progressive subsidence of the ground. In this class of depressions we find those that are generated by soil erosion, which are usually more common in ecosystems more arid as in dry soils or dunes, or those generated by erosion in river valleys or on land glaciers.

Other depressions formed by subsidence are the endorheic basins. These are areas in which the water has no fluvial outlet to the ocean and as a consequence salts accumulate that end up destabilizing the terrain and giving rise to geographical depressions.

Other processes that can lead to the formation of geographic depressions are human action and sedimentation. Thus, for example, it is common to find depressions near oil extraction points or mining areas. In other cases, a depression such as consequence of the accumulation of sediment, in the so-called karst areas or by the variation of the groundwater level.

Depressions can also form due to the collision of tectonic plates at the converging edges, due to volcanic activity that destabilizes the ground or due to the impact of meteorites.

If you want to read more articles similar to Types of geographic depressions - with examples, we recommend that you enter our category of geology.

• Holmes, A., Vila, R. C., & de Candel, J. C. (1962). Physical geology. Omega.
• Iriondo, M. (2007). Introduction to Geology. Editorial Bruges.