Landform Created by Action of Wind:
Here are some land-forms:
- Dune sands are usually very uniform in size and shape.
- For sand dunes to form there must be an abundant supply of sand and steady winds.
- At a spot where winds meet with an obstacle, the speed of wind gets slows down, and dunes formed due to the deposition of sand carried by the wind.
- The side of the dunes facing the wind has a gentle slope and the opposite side has a steep side.
- 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 and in this manner sand dunes gradually move forward.
- Loess is another major deposit created by wind.
- Loess is a soil finer than sand and important for humans because it creates very fertile soils.
- Because of its small size, it can be held in suspension and carried great distances by wind.
- Loess transported from the desert regions of Central Asia has been deposited in layers in China.
Barchan or Barkhan:
- Crescent-shaped dune whose long axis is transverse to the dominant wind direction
- Barchans usually form where there is a limited supply of sand, reasonably flat ground, and a fairly even flow of wind from one direction.
Land-form Created by the action of Groundwater:
Some water from the rainfall received on the earth’s surface seeps through the ground. Water accumulates under the ground surface in this manner is called groundwater. Here are some landforms created by groundwater:
- Water on the ground surface seeps through limestone and some portion of limestone gets dissolved in that water.
- If this process continues over many years, these holes get enlarged and these holes are known as sinkholes.
- Sinkholes formed due to the erosion caused by the water.
- Working slowly over many years, groundwater travels along small cracks.
- The water dissolves and carries away the solid rock and gradually enlarging the cracks, eventually, a cave may form.
Stalactites and Stalagmites:
- Groundwater carries dissolved minerals in the solution.
- These minerals are then deposited in the form of stalactites and stalagmites.
- These formations are formed inside the cave.
- As the seeping water evaporates, calcium carbonate is deposited on the ceiling or roof of the cave, this deposition continues to grow slowly and a structure from ceiling to roof from which is called Stalactites.
- The water drops on the floor of the cave also evaporate leaving behind calcium carbonate which accumulates over a period of time.
- This deposition from the ground to the roof is known as a stalagmite.
- When stalagmites and stalactites meet, it is known as a column.
- Stalactites and stalagmites are observed in the Partner Taluk of Ahmadnagar District, in Bastar district in Chhatisgarh, and also in the Karst region of the former Yugoslavia now Serbia, and Montenegro.
Landforms created by the action of Sea Waves:
- The most widespread landforms of erosional coasts are sea cliffs.
- The base of the rocks on the coast gets eroded because of the impact of the sea waves and notches develop in these rocks.
- The crest of the rock overhangs the notch.
- These notches in the rocks gradually extend landwards over a period of time, then the crest falls and a steep cliff that has receded away from the sea is formed.
- Rocks on the coast have many cracks.
- These cracks become wider and wider with the impact of the waves, creating small caves.
- These types of caves are common in coastal areas.
- The fine sand and other material that flows along with the sea waves get deposited in a direction parallel to the sea coast.
- The deposition of sand and other material is called the beach.
- A deposition of sand that results in a long, narrow embankment in the sea near the coast is called a sand bar.
- A shallow lake is formed between the sand and the sea coast.
- It is called a lagoon.
- Such types of Lagoons lake are called Kayal in Kerala.
|Serial No.||Book Name||Author Name|
CTET Success Master Social Science/Studies Paper-2 for Class 6 to 8 2020
|2.||12 YEAR-WISE CTET Paper 2 (Social Science/ Studies) Solved Papers (2011 - 2019) - 2nd English Edition|
CTET Social Science and Its Pedagogy
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