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Each landform has its unique physical shape, size, materials and is a result of the action of certain geomorphic processes and agent(s). Every landform has a beginning. Landforms once formed may change in their shape, size and nature slowly or fast due to continued action of geomorphic processes and agents. Due to changes in climatic conditions and vertical or horizontal movements of landmasses, either the intensity of processes or the processes themselves might change leading to new modifications in the landforms.
Evolution
It implies stages of transformation of either a part of the earth’s surface from one landform into another or transformation of individual landforms after they are once formed. That means, each and every landform has a history of development and changes through time. A landmass passes through stages of development somewhat comparable to the stages of life — youth, mature and old age.
Geomorphic Agents
Changes on the surface of the earth owe mostly to erosion by various geomorphic agents. Running water, ground-water, Glaciers, wind and waves are powerful erosional and depositional agents shaping and changing the surface of the earth aided by weathering and mass wasting processes. These geomorphic agents acting over long periods of time produce systematic changes leading to sequential development of landforms.
Fluvial landforms
The landforms created as a result of degradational action (erosion) or aggradation work (deposition) of running water is called fluvial landforms.
These landforms result from the action of surface flow/run-off or stream flow (water flowing through a channel under the influence of gravity). The creative work of fluvial processes may be divided into three physical phases—erosion, transportation and deposition.
The landforms created by a stream can be studied under erosional and depositional categories.
Erosional category
Valleys, gorge and Canyon
The extended depression on ground through which a stream flows throughout its course is called a river valley. A gorge is a deep valley with very steep to straight sides. A canyon is characterized by steep step-like side slopes and may be as deep as a gorge.
At a young stage, The profile of valley is typically ‘V’ shaped. As the cycle attains maturity, the lateral erosion becomes prominent and the valley floor flattens out. The valley profile now becomes typically ‘U’ shaped with a broad base and a concave slope.
Potholes, Plunge pools
Potholes are more or less circular depressions over the rocky beds of hills streams.Once a small and shallow depression forms, pebbles and boulders get collected in those depressions and get rotated by flowing water. Consequently, the depressions grow in dimensions to form potholes.Plunge pools are nothing but large, deep potholes commonly found at the foot of a waterfall. They are formed because of the sheer impact of water and rotation of boulders.
Incised or Entrenched Meanders
They are very deep wide meanders (loop-like channels) found cut in hard rocks.In the course of time, they deepen and widen to form gorges or canyons in hard rock.The difference between a normal meander and an incised/entrenched meander is that the latter found on hard rocks.
River Terraces
They are surfaces marking old valley floor or flood plains.They are basically the result of vertical erosion by the stream. When the terraces are of the same elevation on either side of the river, they are called as paired terraces.When the terraces are seen only on one side with none on the other or one at quite a different elevation on the other side, they are called as unpaired terraces.
Depositional Features
Alluvial Fans
They are found in the middle course of a river at the foot of slope/ Mountains.When the stream moves from the higher level break into foot slope plain of low gradient, it loses its energy needed to transport much of its load.Thus, they get dumped and spread as a broad low to the high cone-shaped deposits called an alluvial fan.
Deltas
They are found in the mouth of the river, which is the final location of depositional activity of a river. \The coarser material settle out first and the finer materials like silt and clay are carried out into the sea.
Flood Plains, Natural Levees
Natural levees are found along the banks of large rivers. They are low, linear and parallel ridges of coarse deposits along the banks of a river.The levee deposits are coarser than the deposits spread by flood water away from the river.
Meanders and oxbow lakes
- They are formed basically because of three reasons: (i) propensity of water flowing over very gentle gradient to work laterally on the banks; (ii) unconsolidated nature of alluvial deposits making up the bank with many irregularities; (iii) Coriolis force acting on fluid water deflecting it like deflecting the wind.
- The concave bank of a meander is known as cut-off bank and the convex bank is known as a slip-off
- As meanders grow into deep loops, the same may get cut-off due to erosion at the inflection point and are left as oxbow lakes.
Braided Channels
When selective deposition of coarser materials causes the formation of a central bar, it diverts the flow of river towards the banks, which increases lateral erosion. Similarly, when more and more such central bars are formed, braided channels are formed. Riverine Islands are the result of braided channels.
Karst Topography
Any limestone, dolomite or gypsum region showing typical landforms produced by the action of groundwater through the process of solution and deposition is called as Karst Topography (Karst region in the Balkans).
A sinkhole is an opening more or less circular at the top and funnel-shaped towards the bottom.When as sinkhole is formed solely through the process of solution, it is called as a solution sink.When several sink holes join together to form valley of sinks, they are called as blind valleys.
Caves
In the areas where there are alternative beds of rocks (non-soluble) with limestone or dolomite in between or in areas where limestone are dense, massive and occurring as thick beds, cave formation is prominent. Caves normally have an opening through which cave streams are discharged Caves having an opening at both the ends are called tunnels.
Stalactites and stalagmites
They are formed when the calcium carbonates dissolved in groundwater get deposited once the water evaporates.These structures are commonly found in limestone caves.Stalactites are calcium carbonate deposits hanging as icicles while Stalagmites are calcium carbonate deposits which rise up from the floor.When a stalactite and stalagmite happened to join together, it gives rise to pillars or columns of different diameters.
GLACIERS
Masses of ice moving as sheets over the land (continental glacier or piedmont glacier if a vast sheet of ice is spread over the plains at the foot of mountains) or as linear flows down the slopes of mountains in broad trough-like valleys (mountain and valley glaciers) are called glaciers.
Cirque
Cirques are the most common of landforms in glaciated mountains. They are deep, long and wide troughs or basins with very steep concave to vertically dropping high walls at its head as well as sides. A lake of water can be seen quite often within the cirques after the glacier disappears. Such lakes are called cirque or tarn lakes.
Horns and Serrated Ridges
Horns form through head ward erosion of the cirque walls. If three or more radiating glaciers cut headward until their cirques meet, high, sharp pointed and steep sided peaks called horns form.
Glacial Valleys/Troughs
Glaciated valleys are trough-like and U-shaped with broad floors and relatively smooth, and steep sides. There may be lakes gouged out of rocky floor or formed by debris within the valleys. There can be hanging valleys at an elevation on one or both sides of the main glacial valley. Very deep glacial troughs filled with sea water and making up shorelines (in high latitudes) are called fjords/fiords.
Depositional landforms
Moraines
They are long ridges of deposits of glacial till. Terminal moraines are long ridges of debris deposited at the end (toe) of the glaciers. Lateral moraines form along the sides parallel to the glacial valleys. The lateral moraines may join a terminal moraine forming a horse-shoe shaped ridge. deposits varying greatly in thickness and in surface topography are called ground moraines.
Eskers
When glaciers melt in summer, the water flows on the surface of the ice or seeps down along the margins or even moves through holes in the ice. These waters accumulate beneath the glacier and flow like streams in a channel beneath the ice. Such streams flow over the ground (not in a valley cut in the ground) with ice forming its banks. Very coarse materials like boulders and blocks along with some minor FRACTIONS of rock debris carried into this stream settle in the valley of ice beneath the glacier and after the ice melts can be found as a sinuous ridge called esker.
Outwash Plains
The plains at the foot of the glacial mountains or beyond the limits of continental ice sheets are covered with glacio-fluvial deposits in the form of broad flat alluvial fans which may join to form outwash plains of gravel, silt, sand and clay.
Drumlins
Drumlins are smooth oval shaped ridge-like features composed mainly of glacial till with some masses of gravel and sand. The long axes of drumlins are parallel to the direction of ice movement. They may measure up to 1 km in length and 30 m or so in height.
Arid Landforms
Wind is one of the dominant agents in hot deserts. The wind action creates a number of interesting erosional and depositional features in the deserts.
EROSIONAL LANDFORMS
Pediments and Pediplains
. Gently inclined rocky floors close to the mountains at their foot with or without a thin cover of debris, are called pediments. through parallel retreat of slopes, the pediments extend backwards at the expense of mountain front, and gradually, the mountain gets reduced leaving an inselberg which is a remnant of the mountain. That’s how the high relief in desert areas is reduced to low featureless plains called pediplains.
Plains are by far the most prominent landforms in the deserts. In times of sufficient water, this plain is covered up by a shallow water body. Such types of shallow lakes are called as playas where water is retained only for short duration due to Evaporation and quite often the playas contain good deposition of salts.
. Deflation Hollows and Caves
Weathered mantle from over the rocks or bare Soil, gets blown out by persistent movement of wind currents in one direction. This process may create shallow depressions called deflation hollows. Deflation also creates numerous small pits or cavities over rock surfaces. The rock faces suffer impact and abrasion of wind-borne sand and first shallow depressions called blow outs are created, and some of the blow outs become deeper and wider fit to be called caves.
Mushroom, Table and Pedestal Rocks
Many rock-outcrops in the deserts easily susceptible to wind deflation and abrasion are worn out quickly leaving some remnants of resistant rocks polished beautifully in the shape of mushroom with a slender stalk and a broad and rounded pear shaped cap above. Sometimes, the top surface is broad like a table top and quite often, the remnants stand out like pedestals.
Depositional Landforms
When the wind slows or begins to die down, depending upon sizes of grains and their critical velocities, the grains will begin to settle.
Sand Dunes
Dry hot deserts are good places for sand dune formation. Obstacles to initiate dune formation are equally important. There can be a great variety of dune forms Crescent shaped dunes called barchans with the points or wings directed away from wind .Parabolic dunes form when sandy surfaces are partially covered with vegetation. That means parabolic dunes are reversed barchans with wind direction being the same.
Seif is similar to barchan with a small difference. Seif has only one wing or point. Longitudinal dunes form when supply of sand is poor and wind direction is constant. They appear as long ridges of considerable length but low in height. Transverse dunes are aligned perpendicular to wind direction. These dunes form when the wind direction is constant and the source of sand is an elongated feature at right angles to the wind direction.,
A landform is any natural feature of the Earth’s surface that has a significant elevation relative to the surrounding area. Landforms can be classified into two main types: physical and cultural. Physical landforms are those that are formed by the natural processes of the Earth, such as erosion, deposition, and Plate tectonics. Cultural landforms are those that are created by human activity, such as roads, buildings, and Dams.
There are many different types of landforms, each with its own unique characteristics. Some of the most common landforms include mountains, valleys, plateaus, plains, and deserts. Mountains are high, elevated areas of land that are typically characterized by steep slopes and rugged terrain. Valleys are low-lying areas of land that are typically surrounded by mountains or hills. Plateaus are large, flat areas of land that are typically elevated above the surrounding area. Plains are large, flat areas of land that are typically at or near sea level. Deserts are dry, arid areas of land that typically receive very little rainfall.
Landforms play an important role in the Earth’s Climate and Environment. Mountains, for example, help to regulate the Earth’s temperature by trapping heat and moisture. Valleys are often home to rivers and streams, which provide water for drinking, Irrigation, and recreation. Plateaus are often used for agriculture and grazing. Plains are often used for farming and ranching. Deserts are home to a variety of Plants and animals that have adapted to the dry conditions.
Landforms are also important for human activity. Mountains provide a source of Minerals and other Resources. Valleys are often used for transportation and agriculture. Plateaus are often used for agriculture and grazing. Plains are often used for farming and ranching. Deserts are often used for mining and oil and gas exploration.
Landforms are a vital part of the Earth’s landscape. They provide us with resources, shelter, and beauty. We should all take the time to appreciate the landforms that surround us.
Here are some additional details about some of the landforms mentioned above:
- Mountains are formed when tectonic plates collide and one plate is forced under the other. The material that is forced down into the Earth’s mantle melts and rises back up to the surface, creating Volcanoes-2/”>Volcanoes. Over time, the volcanoes erode away, leaving behind the mountains.
- Valleys are formed when rivers flow through the land. The river’s water erodes the land, creating a V-shaped valley. Valleys are often used for transportation and agriculture.
- Plateaus are formed when the Earth’s crust is pushed up, creating a large, flat area of land. Plateaus are often used for agriculture and grazing.
- Plains are formed when the Earth’s crust is slowly lowered, creating a large, flat area of land. Plains are often used for farming and ranching.
- Deserts are formed when there is very little rainfall. The lack of rainfall causes the land to become dry and arid. Deserts are often home to a variety of plants and animals that have adapted to the dry conditions.
Here are some frequently asked questions and short answers about the following topics:
- Weather
What is weather?
Weather is the state of the Atmosphere at a particular place and time, with respect to variables such as temperature, moisture, wind speed and direction, and barometric pressure.
What are the different types of weather?
There are many different types of weather, but some of the most common include:
- Sunny: Sunny weather is characterized by clear skies and bright sunshine.
- Cloudy: Cloudy weather is characterized by the presence of clouds, which can be either thin or thick.
- Rainy: Rainy weather is characterized by the presence of rain, which can be either Light or heavy.
- Snowy: Snowy weather is characterized by the presence of snow, which can be either light or heavy.
- Windy: Windy weather is characterized by the presence of wind, which can be either light or strong.
What causes weather?
Weather is caused by the interaction of the sun’s energy with the Earth’s atmosphere. The sun’s energy heats the Earth’s surface, which in turn heats the air above it. This heated air rises, and as it rises, it cools. As it cools, it condenses, forming clouds. The clouds release the water they contain as rain or snow.
How does weather affect our lives?
Weather can have a significant impact on our lives. For example, it can affect our ability to travel, our ability to work, and our ability to enjoy outdoor activities. Weather can also cause damage to property and Infrastructure-2/”>INFRASTRUCTURE.
- Climate
What is climate?
Climate is the Average weather conditions in a particular place over a long period of time. Climate is determined by factors such as latitude, altitude, and proximity to water bodies.
What are the different Types of Climate?
There are many different types of climate, but some of the most common include:
- Tropical: Tropical climates are characterized by warm temperatures and high humidity.
- Temperate: Temperate climates are characterized by moderate temperatures and moderate humidity.
- Continental: Continental climates are characterized by hot summers and cold winters.
- Polar: Polar climates are characterized by cold temperatures and low humidity.
What causes Climate Change?
Climate change is caused by the emission of greenhouse gases into the atmosphere. Greenhouse gases trap heat from the sun, which causes the Earth’s temperature to rise. The rise in Earth’s temperature is causing a number of changes to the climate, including more extreme weather events, rising sea levels, and changes in plant and animal life.
How does climate change affect our lives?
Climate change is having a significant impact on our lives. For example, it is causing more extreme weather events, such as hurricanes, floods, and droughts. Climate change is also causing sea levels to rise, which is threatening coastal communities.
What is an earthquake?
An earthquake is a sudden shaking of the Earth’s surface caused by the movement of tectonic plates.
What causes earthquakes?
Earthquakes are caused by the movement of tectonic plates. Tectonic plates are large pieces of the Earth’s crust that float on the Earth’s mantle. The Earth’s mantle is a layer of molten rock that is constantly moving. As the tectonic plates move, they can grind against each other, or one plate can slide under another plate. This movement can cause the Earth’s crust to break, which releases energy in the form of seismic waves.
How do earthquakes affect our lives?
Earthquakes can have a significant impact on our lives. For example, they can cause buildings to collapse, roads to buckle, and bridges to fall. Earthquakes can also cause landslides and Tsunamis.
- Volcanoes
What is a volcano?
A volcano is a vent in the Earth’s crust through which magma, ash, and gases erupt.
What causes volcanoes?
Volcanoes are caused by the movement of tectonic plates. Tectonic plates are large pieces of the Earth’s crust that float on the Earth’s mantle. The Earth’s mantle is a layer of molten rock that is constantly moving. As the tectonic plates move, they can grind against each other, or one plate can slide under another plate. This movement can cause the Earth’s crust to break, which allows magma to rise to the surface.
How do volcanoes affect our lives?
Volcanoes can have a significant impact on our lives. For example, they can cause eruptions that release ash and gases into the atmosphere, which can cause respiratory problems and damage crops. Volcanoes can also cause earthquakes, landslides, and tsunamis.
Sure, here are some multiple choice questions without mentioning the topic Landform:
Which of the following is not a type of landform?
(A) Mountain
(B) River
(C) Forest
(D) OceanWhich of the following is the largest landform on Earth?
(A) The Pacific Ocean
(B) The Sahara Desert
(C) The Amazon Rainforest
(D) The Arctic TundraWhich of the following is the highest mountain in the world?
(A) Mount Everest
(B) K2
(C) Mount Kilimanjaro
(D) Mount McKinleyWhich of the following is the longest river in the world?
(A) The Nile River
(B) The Amazon River
(C) The Yangtze River
(D) The Mississippi RiverWhich of the following is the largest desert in the world?
(A) The Sahara Desert
(B) The Arabian Desert
(C) The Gobi Desert
(D) The Atacama DesertWhich of the following is the largest rainforest in the world?
(A) The Amazon Rainforest
(B) The Congo Rainforest
(C) The Indonesian Rainforest
(D) The Amazon RainforestWhich of the following is the coldest landform on Earth?
(A) The Arctic Tundra
(B) The Antarctic Ice Sheet
(C) The Greenland Ice Sheet
(D) The HimalayasWhich of the following is the hottest landform on Earth?
(A) The Sahara Desert
(B) The Arabian Desert
(C) The Gobi Desert
(D) The Atacama DesertWhich of the following is the most populated landform on Earth?
(A) Asia
(B) Africa
(C) Europe
(D) North AmericaWhich of the following is the least populated landform on Earth?
(A) Antarctica
(B) Greenland
(C) Australia
(D) South America
I hope this helps!