Table of Contents (click to expand)
Geographers group landforms by the agent that shaped them. The main types are fluvial (rivers — waterfalls, V-shaped valleys, deltas), glacial (ice — cirques, fjords, moraines, outwash plains), aeolian (wind — sand dunes, mushroom rocks, loess plains), karst (dissolving limestone — caves, sinkholes, pillars), marine/coastal (waves and tides — cliffs, beaches, sea arches), and tectonic/volcanic (Earth's internal forces — mountains, rift valleys, calderas).
From the far-flung sea at a beach to the highest rise of peaks in a mountain range, landforms strike us with awe every time we begin to notice them!
A landform is a reflection of geological structure, sculpting processes, and time. Geologically speaking, it is the resultant impact of differences between endogenetic and exogenetic forces.
Endogenetic forces develop inside the earth, whereas exogenetic forces are the factors that affect the formation of a particular landform externally.
Mainly, there are three types of landforms, namely glacial, fluvial, and aeolian landforms.
What Are Fluvial Landforms?
Landforms developed by a river are called fluvial landforms. You may not be surprised, therefore, to learn that waterfalls are also a type of fluvial landform. This is because when a fast-moving river flows over a cliff, it gives rise to a waterfall.
Moreover, if there is a series of waterfalls stationed one after the other, it results in the formation of a cascade. A cascade also belongs to this category of landforms!
Not only that, but V-shaped valleys and gorges are also classic examples of fluvial landforms. A V-shaped valley forms when a river cuts downward faster than its sides can weather away — the river chisels a deep channel, and gravity and frost gradually slough the walls back into a "V" cross-section. Another widespread type of fluvial landform is the delta: when a river meets a slower body of water (a sea, a lake) and dumps its sediment load at the mouth, the sediment piles up into a fan- or arrowhead-shaped landmass — think of the Mississippi delta or the Nile delta.
What Are Glacial Landforms?
Landforms developed by glaciers are referred to as glacial landforms. Glaciers are nothing but moving rivers of ice. An excellent example of a glacial landform is the cirque (also called a corrie in Scotland or a cwm in Wales). Cirques are bowl-shaped hollows carved out of a mountain at the head of a glacier, where ice plucks and grinds away rock over thousands of years. When three or more cirques eat into the same mountain from different sides, the rock between them is whittled down into a sharp pyramidal peak — Switzerland's Matterhorn is the most famous example.
When we discuss glacial landforms, we certainly can’t forget about the majestic Fjords. Fjords are formed as a result of the submersion of V-shaped valleys in coastal regions. They play an essential role in the development of natural ports. The most common example of Fjords exists along the coast of Norway.
Moreover, outwash plains also fall in this category. Outwash plains are flat or gently sloping landscapes built from sand, gravel, and silt carried out from the snout of a retreating glacier by meltwater streams. Large portions of the upper Midwest in the United States (Wisconsin, Michigan, Minnesota, and the Long Island moraine in New York) sit on outwash deposits left behind by Pleistocene ice sheets, and the well-drained, mineral-rich soils that result are good farmland.
What Are Aeolian Landforms?
Did you ever consider that wind is also capable of giving rise to a landform? Perhaps not, but deserts, playas, and mushroom rocks are a few types of aeolian landforms. They are formed by the action of wind blowing with very high intensity.
Some excellent examples of such topographic wonders are the crescent-shaped sand dunes found in deserts, which are more formally known as barchans.
Pedestal rocks are also classified as aeolian forms. These rocks have a large upper part, although their base is very narrow, thereby resembling a mushroom. These rocks are also found in the regions which face very high intensity of wind. Such a high speed wind carves out the bottom part of these rocks by its abrasive action.
You have likely heard of Loess, which is regarded as the best agricultural soil in the world. It is nothing but an accumulation of windblown silt that gets piled up into a wondrous collection of rich soil!
What Are Some Other Popular Landforms?
Apart from the landform forces mentioned above, there is another type that forms in limestone- and chalk-rich regions. This is known as karst. They give rise to pillars that are usually observed in caves. Moreover, cliffs, caves, sea stacks, sea arches, and lagoons constitute marine or coastal landforms, since they form due to erosion and deposition by sea waves and tides. Beaches are also included in this category.
Another famous, yet vulnerable, landform is the coral reef. Reefs are unique in that the landform itself is built by living animals: corals are tiny cnidarian polyps (close relatives of sea anemones and jellyfish) that secrete calcium-carbonate skeletons and live in colonies in tropical seas. They have a symbiotic relationship with photosynthetic dinoflagellates called Zooxanthellae (genus Symbiodinium) that supply most of their energy. Reefs need sediment-free, sunlit water and temperatures generally above 18 °C (64 °F) — and they're increasingly vulnerable, with the 2023-24 fourth global coral-bleaching event the most extensive on record.
By knowing the causative agents behind the changes taking place, we can actively classify the different landforms on our planet, as explicated above. Having a geological perspective on Earth’s topography makes it all even more beautiful!
