THE 18 MOST OUTSTANDING GEOLOGICAL PHENOMENA - GEOGRAPHY - 2025

The geological phenomena are natural processes resulting from interactions between the core, mantle and crust. Through these the energy accumulated in the center of the Earth is released.

The theory of plate tectonics is one that is responsible for studying external and internal geological phenomena, which is divided into two. On the one hand, in the investigation of continental drift developed by Alfred Wegener at the beginning of the 20th century and, on the other, in the theory of the expansion of the ocean floor developed in the 1960s by Harry Hess.

Alfred Wegener in his work The Origin of Continents and Oceans explained the movement and separation of tectonic plates to show how all the continents were united from the beginning by means of a single one, which he called Urkontinent. In this sense, there are two types of geological processes: internal and external.

Depending on whether they are external geological processes or exogenous processes, the following can be found:

External geological processes

1- erosion

It is the wear of the soil and the rocks that produce movements on the Earth's surface. These movements can cause the transport of the material, the alteration and disintegration of the rocks. And it can also cause other exogenous processes such as weathering.

Among the causes of erosion are the circulation of water or ice, strong winds or changes in temperature. Erosion changes the relief of the ecosystem and can be caused by humans.

In turn, intensive agriculture can cause erosion, which can accelerate the desertification of territories. A current example would be the increase in the Sahara desert due to the acceleration of the desertification process in its surroundings.

Different organizations such as FAO measure soil erosion annually. In fact, in 2015 the International Year of Soils was celebrated and thanks to a study it was determined that erosion caused by human activity affects from 25 to 40 billion tons of the arable layer of the earth each year. In this sense, erosion is one of the causes that damages agricultural production.

2- Sedimentation

It refers to the activity by which materials are altered or worn due to erosion are sediments.

The most common type of sedimentation is linked to the storage of materials in sedimentary basins, that is, when the solid remains are transported by water and are deposited in the course of a river, a reservoir, artificial channel or in an artificial space built to store The matter. In addition, this phenomenon has benefits for water purification.

3- Transportation

Referring to the geological process that takes place between erosion and sedimentation and which is responsible for transporting materials through water, snow, etc.

4- Weathering

Understood as the decomposition of rocks and minerals when they contact the earth's surface. In this sense, there are several types of weathering: physical, chemical and biological.

Biological weathering is the decomposition of materials thanks to the influence of living beings. Chemistry is an alteration that is due to atmospheric influence and physics to the change of physical level that does not affect the chemical or mineralogical components.

Broadly speaking, the weathering process is necessary for the formation of new rocks and for the enrichment of the earth with the minerals that the rocks give off.

5- Compaction

It is the process of reducing the materials that were transported, when they were deposited on a surface. Its structure is packed, filling empty spaces and reducing the volume of materials.

6- Cementation

It refers to the hardening of the materials that will later be compacted. This phenomenon is due to the rocks coming into contact with chemically active fluids.

7- The lithification

It is a geological process, a consequence of compaction and cementing. It refers to the transformation of materials, such as cement or sand, into sedimentary rocks.

Internal geological processes

8- earthquakes

They are sudden and short-lived movements of the earth's crust. They are produced by seismic waves which are temporary disturbances that propagate elastically.

The hypocenter is the point of origin below the earth of the earthquake and the epicenter is the point above the hypocenter on the earth's surface. The Ritcher scale system and other systems have been developed to measure the intensity of telluric movements.

Among the causes of the earthquake are the movement of tectonic plates, although human activity such as fracking, explosions and the construction of large reservoirs can also cause them.

Since 2010 to date there have been many earthquakes around the earth, but no one has explained why this active season is due. Some of the most important to date are: 2010 in Quinghai, China; in February 2011 in New Zealand; in April 2012 in Indonesia; in December 2014 in Pakistan; in April 2016 in Ecuador and others.

9- Metasomatism

It is the subtraction or addition of chemicals to a rock. There are two types of methsomaticism: infiltration and diffusion. The first occurs when water penetrates the rock and diffusional metasomaticism occurs when the fluids remain stagnant within the rock. In both cases the rock is chemically altered.

10- Hydrothermalism

This phenomenon occurs when rocks are affected by the circulation of liquids with high temperatures, which affect the chemical composition of the rock.

Hydrothermalism affects the mineral composition of the rock and accelerates certain chemical reactions. It can be noted that liquids have a relatively low temperature compared to other magmatic processes.

11- volcanic eruptions

They are violent emissions of materials from the interior of the volcano. The matter they expel mostly comes from the volcano, except for geysers, which expel hot water and mud volcanoes.

Most of the eruptions are caused by the increase in temperature of the magma. This causes the volcano to expel the boiling lava. Eruptions can melt ice and glaciers, cause landslides and landslides.

On the other hand, the expulsion of volcanic ash into the atmosphere can affect the climate and cause cold years, since it blocks the sun's rays. A historical example of climate change caused by the eruption of volcanoes was the eruption of Mount Tambora in 1815, which caused "the year without a summer" in Europe in 1816.

12- orogenesis

Or mountain building takes place when the earth's crust shortens or folds due to a push from another tectonic plate. Orogenies also cause thrust and folding formation.

This process gives rise to the mountain ranges to form continents. The process of creating mountains is linked to other internal processes of the earth.

This complex and long process of formation of the mountain ranges is studied by scientists who in turn develop theories. For example, the Andean orogenesis or the Pyrenean orogenesis.

13- continental drift

It is defined as the slow but systematic displacement of the continents. This theory explains how the crust of the earth changed from having a single continent to the current situation. However, this internal process of the earth takes thousands of years.

14- The expansion of the oceanic crust

Explain how the oceans move by helping the continents move. This phenomenon complements the process of continental drift.

15- The collapse of surfaces or subsidence

It is the process of sinking a surface due to the movement of tectonic plates that can be convergent or divergent.

On a smaller scale, it can be caused by the process of erosion or sedimentation of the rock, or after volcanic activity. Subsidence causes a rise in sea level and it is considered that this process at the local level may be caused by human activity.

16- The uprising

Understood as the opposite phenomenon of subsidence, it causes an increase in the altitude of a solid surface and a decrease in sea level.

17- The subduction of plates

It happens at the limits between two tectonic plates, when one sinks due to the pressure of the other below its edge. The opposite would be the superposition of one plate on another.

18- Tidal waves or tsunamis

They are caused in 90% of cases by the energy deployed by an earthquake. In turn, they are considered internal geological processes since they are a consequence of internal movements of the earth.

Its correct name is tectonic tidal waves, since other types of tidal waves have causes related to other phenomena, mostly atmospheric. An example of a tectonic tsunami is the Nias Tsunami, caused by an earthquake in December 2004 in Indonesia that left thousands of victims.