Landforms by Wind, Groundwater & Waves

Landforms by Wind, Groundwater & Waves

Land Forms Created by the Action of Wind

Mushroom Rock

The wind blowing in desert regions erodes the rock near the ground surface to a great extent. At the same time, the upper part of the rock gets eroded to a lesser extent.

• As this is a continuous process, the foot of the rock becomes narrow.

• The top portion of the rock then looks like an umbrella. This landform is called a mushroom rock.

Sand Dunes

Sand gets transported from one place to another along with the wind.

• At a spot where the wind meets an obstruction or where the speed of the wind reduces, dunes are formed out of the sand that gets deposited.

• The side of the dune facing the wind has a gentle slope, nd the opposite side has a steep slope.

• Because of the slow speed of the wind, the sand on the gentle slope gets carried to the top and comes down the steep slope on the other side.

• Dunes gradually move forward in this manner.

Barkhan

• The fine sand particles carried by the wind get deposited when the speed of the wind is reduced, forming crescent-shaped dunes.

• Such hills are called barkhans.

Loess

Loess is a soil finer than sand.

• Loess is a silt transported by the wind from the desert regions and deposited much further away.

• Loess transported from the desert regions of Central Asia has been deposited in layers in China. The plain they form is known as the Loess plain.

Groundwater

Some water from the rainfall received on the Earth's surface seeps through the ground.

• The Rajiv Gandhi National Ground Water Training and Research Institute (RGNGWTRI) is located at Raipur, Chhattisgarh.

• This water trickles down until it reaches an impervious rock.

• Water accumulated under the ground surface in this manner is called groundwater.

• Some rocks on the Earth's surface are porous, and some have cracks or joints. Water seeps in through these pores or joints.

• Groundwater gushes out in the form of springs.

Land Forms Created by the Actions of Groundwater

Sink Holes

Water on the ground surface seeps through the limestone. Some portion of the limestone dissolves in that water.

• If this process takes place continuously, it makes a hole in these rocks.

• As this process continues over a number of years, these holes get enlarged. These holes are called sinkholes.

Caves

In the limestone region, water goes very deep through sinkholes.

• If there is a layer of impervious and hard rock underneath, water flows horizontally on the impervious rock instead of going deeper.

• Hence, soft rocks get eroded and a cave is formed.

Stalactites and Stalagmites

Inside the cave created by groundwater under the ground surface in a limestone region, water is always seeping through the roof.

• This water contains calcium carbonate.

• As the seeping water evaporates, some of the calcium carbonate it contains is deposited on the cave's roof.

• This deposition continues to grow very slowly. Hence, a column is seen growing from the roof towards the floor. It is called a stalactite.

• The water dripping on the floor of the cave also evaporates, leaving behind calcium carbonate, which accumulates over time.

• A column then starts growing from the floor to the roof. This column, which grows upwards, is called a stalagmite.

Stalactites and stalagmites, features of Karst topography, are observed in Parner Taluka of Ahmadnagar district, in Bastar District of Chhattisgarh, and also in the Karst region of former Yugoslavia (now Serbia and Montenegro).

Land Forms Created by the Actions of Sea Waves

Sea Cliff

The base of the rocks on the coast gets eroded because of the impact of the ocean waves, and notches develop in these rocks.

• The crest of the rock overhangs the notch.

• These notches in the rocks gradually extend landwards over time.

• Then the crest falls and a cliff, which has receded away from the sea, is formed.

Sea Cave

Rocks on the coast have many cracks.

• They become wider and wider with the impact of the waves, creating small caves.

• They are called sea caves.

Such sea cliffs and sea caves are observed at Shrivardhan, Ratnagiri, Malvan, Vengurle, etc.

Beach

• The fine sand and other material that flows along with the waves get deposited in a direction parallel to the coastline. This deposition of sand is called a beach.

• There are extensive beaches in the coastal regions of the states of Maharashtra, Goa, Kerala, Tamil Nadu, Odisha, and West Bengal in India, and in other countries like Bangladesh and Canada.

Sand Bar

• A deposition of sand that results in a long, narrow embankment in the sea near the coast is called a sand bar.

Lagoon

• A shallow lake is formed between the sand and the coastline. It is called a lagoon. Such a lake is called a Kayal in Kerala.

Final Thoughts

Landforms shaped by natural agents like wind, water, and sea waves highlight the powerful forces that continuously sculpt our planet’s surface.

From mushroom rocks and dunes in deserts to stalactites, stalagmites, and caves formed by groundwater, each feature tells a story of gradual change over time. Coastal formations like sea cliffs, sea caves, and beaches remind us of the relentless action of waves.

These landforms are not only fascinating to study but also hold great geographical and ecological significance. Understanding them helps us appreciate the dynamic nature of Earth and the role of natural processes in shaping landscapes.