Activity No.
2
Geological Work of Wind
Write a handwritten/computerized answer to each item based on the posted Land Pollution Effects on
the Environment video. Describe the following.
1. Describe each of the geological works that wind does.
2. Outline some of the main geological features that result in erosion and deposition on the
Earth’ssurface.
GEOLOGICAL WORK OF WIND
Wind is one of the major agents of the change on the surface of the earth. The changes are mainly
brought due to their movement and during such movement it may causes temporary or permanent
changes.
Wind is effective in following areas like desert, arid and semi-arid and basically it is carried out in
three ways: erosion, transportation, and deposition.
I. Wind Erosion
Wind erosion is a natural process that moves soil from one location to another by wind power. Light
winds can gently push soil along the ground, while strong winds can lift lots of soil into the air, causing
dust storms. Wind erosion occurs in arid and semi-arid regions where vegetation is sparse. Key processes
include:
Deflation - the process of the removal of loose, fine particles such as dust and sand from the ground.
Attrition - is when rocks or small stones hit and rub against each other as they are carried by wind.
Abrasion - the wearing a way of rock surfaces by wind-driven particles, shaping features like
ventifacts and yardangs.
II. Wind Transportation
Wind transports materials through:
Suspension: Fine particles like dust are carried high in the air over long distances. This is called
suspension because the particles once lifted are not allowed to rest on the ground again till the
velocity of wind in those upper layers is checked.
Saltation: Sand-sized particles are lifted briefly and bounce along the surface. The movement
takes place close to the surface and may be dropped and picked up again and again during
transport process. On falling the lifted particles transmit an impact to another stationary particle
resting on the ground there by making that particle to be available for transport. Therefore,
saltation process involves series of jump.
Surface Creep: Larger particles are rolled or pushed along the ground by wind, especially on the
slopes of heaps of loose material.
III. Wind Deposition
When wind picks up soil and particles from the ground, it carries them as far as its strength
allows. If the wind slows down or weakens for any reason, some or all of these particles settle and
are dropped in that spot. Wind deposition results in aeolian deposits, which are formed when wind
loses energy and drops the materials it carries.
MAIN GEOLOGICAL FEATURES RESULTING FROM EROSION AND DEPOSITION
Features from Erosion
Ventifacts: Rocks that have been smoothed, polished, or faceted by wind-blown sand.
Yardangs: Streamlined, ridge-like formations sculpted by strong, consistent wind erosion.
Pedestal Rocks (Mushroom Rocks): Tall, narrow rock formations with a wider top and narrower
base caused by differential abrasion at varying heights.
Desert Pavements: Surfaces covered with closely packed stones and gravel, formed when wind
removes finer particles, leaving coarser materials behind
Features from Deposition
Dunes: Mounds or ridges of sand that form in desert or coastal regions due to wind accumulation.
They are constantly reshaped by the wind and can vary in size and shape, such as:
Types of Dunes:
• Crescentic Dunes – form under winds that blow from one direction, and they also are
known as barchans.
• Linear Dunes – form in areas where wind direction shifts slightly but remains fairly
consistent.
• Star Dunes – form where wind blows from many directions, piling up sand in a single
spot.
• Parabolic Dunes – formed in areas with strong winds, abundant sand, and some
vegetation.
Loess Deposits: Fine, wind-blown silt that accumulates in thick layers, often forming fertile soils.
Loess is highly porous, making it excellent for retaining water and nutrients, which is why it often
leads to fertile soils ideal for farming. These deposits are important for agriculture due to their rich
mineral content and ability to retain water.
