Introduction
A land form is a natural feature of the solid surface of the Earth or other planetary body. Land forms together make up a given terrain, and their arrangement in the landscape is known as topography. 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. The article Land forms - Wind and Water Action will help the aspirants to get the basic knowledge related to Land forms and wind and water actions on these wind forms.
Land forms
Land forms - Wind and Water Action - Action of Wind:
Land form is created depending upon the action of wind i.e. land-form may be due to deposition or due
to erosion cause by wind.
The following list is about some Land forms created by wind:
Land forms - Wind and Water Action - Sand Dunes:
- 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 slow down, and dunes formed due to 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.
- Land forms - Wind and Water Action - Loess is another major deposit created by the 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.
- 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 at ground, and a fairly even ow of wind from one direction.
Land forms - Wind and Water Action - Action of Ground Water:
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 land forms created by groundwater:
Land forms - Wind and Water Action - Sink Holes:
- 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.
- Groundwater carries dissolved minerals in solution.
- These minerals are then deposited in the form of the stalactites and stalagmites.
- These formations are formed inside the cave.
- As the seeping water evaporates, calcium carbonate 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 dropping on the floor of the cave also evaporates leaving behind calcium carbonate which accumulates over a period of time.
- This deposition from the ground to roof is known as stalagmite.
- When stalagmites and stalactites meets, it is known as column.
- Stalactites and stalagmites are observed in the Parner Taluk of Ahmadnagar District,in Bastar
- District in Chhatisgarh and also in the Karst region of the former Yugoslavia now Serbia and Montenegro.
- The most widespread land forms 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 which has receded away from the sea is formed.
- Rocks on the cost have many cracks.
- These cracks become wider and wider with the impact of the waves, creating small caves.
- These types of caves are common on coastal area.
- The fine sand and other material that flows along with the sea waves get deposited in a direction parallel to the sea cost.
- The deposition of sand and other material is called as the beach.
- A deposition of sand which results in a long, narrow embankment in the sea near the cost 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.
Quiz
1. In which district, all types of sand dunes are present?
- A. Jaisalmer
B. Barmer
C. Bikaner
D. Jodhpur
- A. Cliffs
B. Cirques
C. Dunes
D. Hamadas
- A. Loess
B. Delta
C. Moraines
D. Mushroom rocks
- A. Silty Soil
B. Loamy Soil
C. Sandy Soil
D. Loess Soil
- A. glacial topography
B. volc and topography
C. karst topography
D. fluvial topography
- A. silica
B. magnesium carbonate
C. calcium carbonate
D. sodium carbonate
- A. Sea Cave
B. Sea cliff
C. Sea beach
D. Sea arches
- A. Dal Lake
B. Chilka Lake
C. Pulicat Lake
D. Mansarover
- A. Bay
B. Isthmus
C. Lagoon
D. Strait
- A. Strait
B. Peninsula
C. Archipelago
D. Lagoon