GEOGRAPHICAL FACT: TYPES AND THEIR CHARACTERISTICS - GEOGRAPHY - 2025

The geographical facts are all forms observed in the Earth 's surface, characterized by their durability, their reluctance to changes and formed through complex long - term processes.

Geographical facts can be of two types, according to the agent that produces them: exogenous or endogenous. Exogens are produced by agents found above the earth's crust and within the atmosphere. The exogenous are produced by terrestrial geological processes.

Exogenous agents (which means that they come from abroad) are classified into three groups:

1-Atmospheric, such as winds, temperature, humidity and meteorites.

2-Hydrological, such as the waters coming from the rains, the rivers, the seas and the glaciers.

3-Biological, which includes all living beings: plants and animals (including human beings).

For their part, endogenous agents (which come from within) are also classified into three groups:

1-Volcanic, such as magmatism: volcanism and plutonism.

2-Seismic, like earthquakes.

3-Tectonic, such as epirogenic movements (subsidence and upheavals) and orogenic movements (faults, folds, mountain formation).

Likewise, geographical facts can be considered natural or artificial. The only artificial geographic facts are those that originate due to the intervention of human beings, who modify the environment to satisfy their needs.

Next, some geographical facts are presented, taking into account the previously presented classification.

Geographical facts by action of external agents

By the action of atmospheric agents

1-Deflation basins. They are depressions that originate from the action of the wind, specifically thanks to a process called wind deflation that removes the particles attached to the earth's surface.

2-Ventifacts and gliptoliths. Wind abrasion polishes boulders generating these curious formations.

3-Hammadas. These are lustrous surfaces produced from wind abrasion.

4-Dunes and loess. They are deposits of sediments carried by the wind.

Dunes

5-Yardangs and corrosion fungi. Both are caused by wind corrosion, which sculpts rocks into curved and rounded shapes.

6-Craters. They are holes in the earth's surface, produced by meteorites.

By the action of hydrological agents

1-Formations of residual origin. They are produced when the rainwater dissolves the rocks, forming deposits of various residues.

2-Underground currents and aquifers. The waters that infiltrate into the subsoil are originating from aquifers (water pockets) and underground currents.

3-Caverns in the subsoil. Underground currents shape the subsoil, giving rise to cave formations.

4-Valleys, deltas, alluvial terraces, meanders, waterfalls, alluvial plains, flooded plains and full plains. All these geographical facts are produced by the action of rivers.

Deltas

Flooded plains

Meanders are the curves that occur in the course of a river

Alluvial terraces

5-Moraines. They are glacial deposits of rock fragments and other sediments that are washed away by glaciers when they move. Moraines can be central, basal, frontal, or lateral.

Moraines

6-Erratic blocks. They are large rocky structures, deposited by glaciers on the slopes of the mountains.

7-Fjords. Valleys formed by the action of glaciers.

8-Farallones, arches, cliffs, caverns, terraces, bridges, coastal bars, concordant and discordant coastlines, bays, inlets, promontories, stony beaches, sandy beaches, tombstones and literal cords. All these geographical facts are formed by the action of the sea.

Coastal bar

Beaches

Jarring shoreline

Concordant coastline

Formation of bays due to the action of marine erosion

Cliffs

Tómbolo, sand bar that connects an island with the mainland

By the action of biological agents

1-Forests, jungles, grasslands, scrub with xerophytic vegetation, flooded savannas and mangroves. All of these are geographical facts produced by the action of vegetation.

2-Marine sediments. Formed from the organic remains of various aquatic animals, added to terrigenous remains.

3-Coral formations, such as coral reefs. Created by the union of thousands and thousands of corals.

4-Guano Islands. They are islands covered in bird droppings.

5-The cities and all the constructions created by the human being are human geographical facts.

6. The destruction of Hiroshima and Nagasaki in 1945 is also a human geographical fact.

Geographical events that occur due to the action of internal agents

By the action of volcanic agents

1-Volcanism. They are volcanic eruptions, that is, lavas that have managed to reach the earth's surface, giving rise to effusive or volcanic formations.

When eruptions occur under the sea or under the ocean, volcanic islands are produced. When a volcano collapses, calderas form.

2-Plutonism. They are acts that occur within the earth's crust, when magma (hot rock in a liquid state) is not able to ascend and leave the earth's surface. Unable to get out, the magma solidifies, giving rise to plutonite bodies, igneous rocks, batholiths, lacoliths, dikes and mantles.

By the action of seismic agents

Seismic agents produce various geographical events, mainly in the circum-Pacific and Mediterranean areas. They generate dislocations and cracks in the landscape.

By the action of tectonic agents

1-Mountains, deformations and horizontal folds. They are formed by orogenic movements.

2-Failures. They are fractures that occur in the earth's surface due to orogenic movements. They can be of four types: normal and inverse (if the fracture is inclined), vertical or horizontal.

a) Normal. b) Inverse. c) Horizontal

3-Anticline, synclinal, normal, inclined and lying folds. Geographical facts originated by orogenic movements.

Slanted fold

4- Transgressions. They occur when the waters of the sea advance over the earth's surface. They are due to epirogenic movements.

5-Regressions. They occur when the waters of the sea withdraw from the earth's surface. They are also caused by epirogenic movements.

References

1. Dictionary of geographical terms. Retrieved on July 5, 2017, from resources.collins.co.uk
2. Geographical features. Retrieved on July 5, 2017, from en.wikipedia.org
3. Geological formation. Retrieved on July 5, 2017, from en.wikipedia.org
4. Geographic formations. Retrieved on July 5, 2017, from credoreference.libguides.com
5. Habitats. Retrieved on July 5, 2017, from nationalgeographic.com
6. Landforms. Retrieved on July 5, 2017, from enchantedlearning.com
7. Formation and characteristics. Retrieved on July 5, 2017, from bbc.co.uk.