Geomorphic Processes

The creation and deformation of landforms on Earth’s surface is a continual process caused by the constant interaction of external and internal factors. These internal and external factors are called geomorphic processes that cause stresses and chemical activities on Earth’s elements, bringing about changes in the shape of Earth’s surface.

Geomorphic agents and processes cause changes in the configuration of Earth’s surface as a result of physical pressures and chemical reactions on different components of Earth. Endogenic and exogenic forces are responsible for the physical and chemical activities.

Most geomorphic agents and processes move slowly but, occasionally, a significant catastrophe, such as a landslide or flood, can drastically alter the environment, endangering humanity in the process. 

Geomorphologists are interested in geological hazards such as volcanic eruptions, earthquakes, tsunamis, and landslides. These experts have benefitted immensely from advances in remote sensing from satellites and GIS mapping during the last few decades, allowing them to grasp worldwide distributions.

Endogenic processes (internal forces)

Endogenic forces can be divided into two types: Slow movements (diastrophic) and sudden movements. Endogenic processes generate subtle changes that may not be noticeable over the average human lifetime.

Slow movements (diastrophic forces)

Diastrophic forces are caused by the movement of the solid substances in Earth’s crust. Diastrophism includes all processes that shift, raise, or create sections in Earth’s crust. These endogenic processes encompass:

• Orogenic processes, including mountain formation by extreme folding by influencing long and narrow strips of Earth’s crust

• Epeirogenic processes, including the lifting or bending of vast portions of Earth’s crust

• Earthquakes with very small motions on a local scale

• Horizontal movement of crustal plates, known as plate tectonics

Slow movements are further subdivided into vertical and horizontal movements.

Vertical movements (epeirogenic movements)

• Vertical movements are mostly linked with continent and plateau building. Epeirogenic movements are another name for them

• Cratons are the wide, central sections of continents that are prone to epeirogeny

• They have little effect on the horizontal rock layers

• While they produce continent elevation, they may also cause continent subsidence

• These motions originate from Earth’s core

Horizontal movements (orogenic movements)

• Orogenic processes are caused by horizontal forces acting on Earth’s crust from side to side

• They are often referred to as orogenic motions (mountain building)

• They cause many disturbances in the horizontal layer or strata, resulting in significant structural deformation of Earth’s crust

Epeirogenic movements

• Radial motions are epeirogenic or continent-forming movements, which act along the radius of Earth

• The movement might be either towards (subsidence) or away (uplift) from the centre

• They generate land upheavals or depressions with long-wavelength undulations (wavy surface) and little folding

• The wide, central sections of continents are known as cratons, and they are prone to epeirogeny, therefore the name continent-forming motions

Orogenic Processes 

• Orogenic movement, in contrast to epeirogenic movement, is a more complex deformation of the Earth’s crust linked with crustal thickening (due to the convergence of tectonic plates)

• Orogenic belts are formed by plate convergence and are characterised by “the folding and faulting of layers of rock, the intrusion of magma, and volcanism”

• As in plate tectonics, orogenic or mountain-forming processes act tangentially to the earth’s surface

• Tension causes fissures (since this form of force applies in two directions away from a point), whereas compression causes folds (because this type of force acts towards a point from two or more directions)

Sudden movements

Sudden geomorphic motions are particularly common near lithospheric plate boundaries (tectonic plate margins). Because of the pressure caused by the pushing and tugging of magma in the mantle, the plate boundaries are extremely unstable (convection currents). These motions generate significant deformation in a short amount of time.

Endogenic factors cause abrupt movements at times and gradual motions at other times. Earthquakes and volcanoes, for example, create widespread devastation on the planet’s surface. A volcano is a hole in Earth’s crust by which a molten substance erupts abruptly. 

Exogenic processes (external forces)

Exogenic forces or external forces are forces that derive their power from Earth’s exterior or originate within Earth’s atmosphere.

Exogenic forces cause wear and tear, which is why they are classified as land wearing forces. All exogenic processes are grouped together under the umbrella word denudation, which means “to peel off” or “to uncover.”

Exogenic processes or exogenic geomorphic processes are those that occur on Earth’s surface as a result of the effect of exogenic factors. The principal exogenic processes include weathering, mass wasting, erosion, and deposition.

Geomorphic agents are natural elements capable of performing these exogenic processes (or exogenic geomorphic agents). For example, the wind, water, and waves are geomorphic agents that precipitate geomorphic processes.

Exogenic forces acquire their energy from the atmosphere, which is governed by the Sun’s ultimate energy as well as the gradient formed by tectonic processes. Slopes on Earth’s surface are mostly caused by tectonic elements or earth movements triggered by endogenic forces, as we have learned in previous sections.

Stress is defined as the force exerted per unit area. Pushing or tugging causes stress in a solid. The gravitational pull acts on all Earth elements with a sloping surface and tends to cause matter to travel down-slope. This causes tension and distortion of the particles.

Weathering

Weathering is the impact of weather and climatic components on Earth’s elements. It is described as the mechanical disintegration and chemical degradation of rocks caused by the operations of numerous weather and climatic variables.

When rocks go through weathering, certain minerals are eliminated by groundwater through chemical/physical leaching, increasing the concentration of remaining (valuable) minerals.

Mass Movements

Under the direct impact of gravity, these processes transport the bulk of rock debris down the slope. Mass motions are far more vigorous on weathered slopes than on unweathered slopes.

Normal geographic agents, such as moving water, glaciers, wind, and waves, have a little part in mass motions, while gravity is the primary driving factor. Slow movements and fast movements are the two types of mass movements.

Erosion and Deposition

Erosion is the natural process through which weathered rock and soil shift from one location to another. Erosion is caused by gravity, moving water, glaciers, waves, and wind. Sediment is the material transported by erosion.

Conclusion

Geomorphology is the study of the Earth’s landforms as a result of largely physical processes, such as physical or chemical changes, as well as changes impacted by biological activities, such as land usage. Physical geographers use geomorphological principles to analyse how landforms have evolved in the past, but such principles are becoming increasingly essential for modern applications. Geomorphology, as an important component of physical geography, is required to comprehend natural landform changes and possible threats to communities. Geomorphology is vital for physical geographers not only for understanding Earth’s physical changes, but also for planning for calamities.