Processes of Erosion and Deposition: Geography 202 Essay

This essay explores the geographical processes of erosion and deposition, detailing how materials like sediments, soil, and rocks are removed and transported by wind, water, or ice. It distinguishes between physical and chemical erosion, and examines the influence of factors such as topography, climate, and human activities. The essay then describes the process of deposition, where eroded materials are laid down, influenced by forces within transporting agents. It outlines landforms formed by rivers (e.g., sea stacks and sea caves), glaciers (e.g., horns and U-shaped valleys), and wind (e.g., ripples and sand dunes), and describes the depositional landforms like beaches and spits at coastlines, eskers and moraines from ice deposition, and loess and sand dunes from wind deposition. The essay references various studies to support the explanations of these processes and landforms.

Erosion and deposition
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Erosion and deposition
Erosion is described as the geographical process by which materials like sediments, soil, rocks,
fragments and regolith are removed and transported by wind, water or ice. Erosion is responsible
for removal of materials and sediments from areas that were once covered by ice, carries
sediments downslopes and is also responsible of shaping lakes shorelines and coastal lines
(Welivitiya, Willgoose, & Hancock 2019).Erosion can be physical where the rocks change their
physical properties like shape and texture without changing the chemical composition. Chemical
erosion or weathering occurs when rocks and other geographical structures decay and breaks
down through a chemical process which can be a man- made activity or a natural process when
the water is flowing on the rock surface ( Roth 1999). .Erosion can be caused by water in form of
floods, rain, rivers and ocean when they carry away sediments, soil and sand gradually or ice
movement. Erosion is influenced by topography, climate, vegetation, tectonic activity and human
activities.
Water erosion causes the formation of sea stacks when erosion causes isolated column rocks
detach from mainland. Sea caves are formed when sea waves cuts massive holes in weak
coastline rocks. Ice erosion forms horns which can be described as peaks with a pyramid shape
and v-shaped or u-shaped valleys or depressions which are left behind after ice melts away.
Wind erosion on the other hand forms ripples which are sand waves that are always on the move
and appear and disappear in various locations at different times. Sand dunes forms when wind
leaves behind sand masses in form of a hill especially in desert areas when the sand is obstructed
by a objects like vegetation.

Erosion and deposition
Deposition is the process by which the eroded materials are laid down after transportation by
wind, ice or water. The transportation of these sediments depends largely on the balance of
various forces in the transporting agent. When the sediments are obstructed by hills, vegetation
and rocks, the velocity of the material being transported reduces causing the deposition. The
speed of wind for example can is varied by various spatial heating and cooling which causes
different pressure ascents. Running water always carries sediments especially during the rainy
seasons and they are deposited in different areas. Deposition also occurs at the coast lines when
waves carry materials and deposit them at the beaches when their energy is less. Ice flows which
leads to deposition occurs when the glacier flow reduces and when the precipitation levels
reduces or when the ice melts.
The landforms that occurs from deposition especially at the coast lines includes the beaches
which are formed in areas between low tide levels and high tide levels of the sea waves. Every
beach is different in its own way but mostly they are formed when sand, gravels and grits are
deposited at the sea line( Isla 1993). On rare cases, these beaches can also be made from mud or
silt deposition. The second landform that occurs at the coastal line is the spit. A spit forms from
expansive beach sediments that protrudes out of the sea and is connected to the mainland at one
point. This occurs when the coastline changes its direction or when the power of the waves
decreases and materials being transported are left behind. This is also common where the rivers
and its tributaries join the sea. Spits are formed gradually for over a period of time when
sediments are deposited to form a long edge (Bird 2011).
Ice deposition occurs when the ice melt leaving behind sediments like rocks and sand that were
transported during their drifts. Various landforms occurs from this ice drifts, for example the
Eskers which forms in the ice tunnels that flows under the ice glacier during the transportation

Erosion and deposition
and when the ice melts away, sand and gravel are left behind forming ridges and elevations.
Another feature that forms from the ice deposition is a moraine. These features forms when
unconsolidated rocks and regolith amasses in lands that were previously glaciated. They are
formed from materials of different sizes ranging from large rocks to fine glacial flour (Hobley,
Howard & Moore 2011).
Wind deposition usually forms the loess and the sand dunes. Loess are formed from the
deposition of very fine grained sand which sometimes appear like dust are deposited and
accumulated over a period of time. It is believed that 10 % of the earth surfaces are roofed by
loess or deposits of similar nature. Wind deposition also forms sand dunes which are famous in
the desert areas around the world. They are mounds of sand that forms when the sand is being
transported by wind meet an obstacle and it accumulates forming a mount of sand. Sand dunes
usually have a windward side which is where the wind is blowing and building up the materials
and slip face which is the wind without the wind and it occurs to be smoother than the windward
side (Crouvi, Amit, Enzel & Gillespie 2010).

Erosion and deposition
References
Welivitiya, W. D. P., Willgoose, G. R., & Hancock, G. R. (2019). A coupled soilscape–landform
evolution model: model formulation and initial results. Earth Surface Dynamics, 7(2),
591-607.
Roth, J. (1999). Chemical erosion of carbon based materials in fusion devices. Journal of nuclear
materials, 266, 51-57.
Isla, F. I. (1993). Overpassing and armouring phenomena on gravel beaches. Marine Geology,
110(3-4), 369-376.
Bird, E. C. (2011). Coastal geomorphology: an introduction. John Wiley & Sons.
Hobley, D. E., Howard, A. D., & Moore, J. M. (2014). Fresh shallow valleys in the Martian
midlatitudes as features formed by meltwater flow beneath ice. Journal of Geophysical
Research: Planets, 119(1), 128-153.
Crouvi, O., Amit, R., Enzel, Y., & Gillespie, A. R. (2010). Active sand seas and the formation of
desert loess. Quaternary Science Reviews, 29(17-18), 2087-2098.