• A landform is a feature on the Earth’s surface that is part of the terrain. 
• Endogenic forces and exogenic forces can create a lot of landforms. 
• Mountains, hills, plateaus, and plains are the four major types of landforms. 
• Minor landforms include buttes, canyons, valleys, and basins.

Mountains

• A mountain is a large landform that rises above the surrounding land in a limited area, usually in the form of a peak.
• Mountains are generally steeper than hills.
• Mountains are formed through tectonic forces or volcanism that can locally raise the surface of the earth.
• Mountains erode slowly through the action of rivers, weather conditions, and glaciers.
• Most mountains occur in huge mountain ranges.
• Nearly 27% of the world’s land surface is covered by mountains.
• Up to 80% of the planet’s fresh surface water comes from the mountains.
• About 12% of the world’s population lives in the mountains, but over 50% are directly or indirectly dependent on mountain resources.
• Mountains can be classified as: Fold Mountains, Block Mountains, Volcanic Mountains/ Accumulated Mountains, Residual Mountains/ Relict Mountains

Fold Mountains

• Fold Mountains are formed due to compression of tectonic plates.
• This leads to the formation of large fold-like structures on the earth’s crust.
• Fold Mountains primarily exist as mountain ranges.
• Most of the earth’s well-known mountain ranges are examples of Fold Mountains.
• Characteristics of fold mountains:
  • Fold Mountains are formed through the collision of tectonic plates along a convergent boundary.
  • They have an arcuate shape with length exceeding width.
  • Pressure on rock layers causes metamorphosis in the process of their formation.
  • They are mainly located along the margins of continents near oceans.
  • They feature an arc shape with one slope concave and the other slope convex.
• Formation of fold mountains:
  • Fold mountains are formed when two continental tectonic plates collide at the destructive plate boundary.
  • The pressure exerted by the rocks during the collision distorts the earth’s crust and creates large fold-like structures.
  • The folding effect is more profound in regions with a weak layer in the crust, such as salt.
• Types of fold mountains:
  • Age:
    • Young fold mountains: aged between 10 and 15 million years
    • Old fold mountains: aged 200 million years and above
  • Geography of the mountains:
    • Simple fold mountains: synclines and anticlines are well developed creating a wave-like appearance to the mountains
    • Complex fold mountains: compression forces cause the formation of a very complex structure known as the nappe.
• Examples of fold mountains:
  • Fold Mountains are found worldwide, with many of the world’s tallest peaks being fold mountains.
  • The Himalayas in Asia are an example of fold mountains, rising over 23,000 feet above sea level and including Mount Everest, the world’s tallest mountain.
  • The Himalayas were formed through the collision of the Eurasian and Indian tectonic plates, making them young fold mountains, less than 15 million years old.
  • The Andes Mountains in South America, stretching about 4,300 miles in length and having a maximum width of 430 miles, are also an example of Fold Mountains.
  • The Andes were formed as a result of tectonic forces between the South American, Nazca, and Antarctic tectonic plates.
• 

Block Mountains

• Block Mountains id defined as the result of faulting caused by tensile and compressive forces motored by endogenetic forces coming from within the earth, also known as fault-block mountains.
• Block mountains represent the upstanding parts of the ground between two faults or on either side of a rift valley or a graben.
• Characteristics of block mountains:
  • Block mountains have flat tops or slightly sloping surfaces.
  • They have steep sides and they are associated with rift valleys.
  • It is a block between two fluids.
  • It has fairly steep, straight edges.
  • Block Mountains are usually high. Examples of block Mountains include: Voges Mountain, Black forest of the Rhine land.
• Formation of block mountains:
  • Block mountains are formed by faults in the crust, where rocks have moved past each other.
  • When rocks on one side of a fault rise relative to the other, it can form a mountain, known as a block mountain or horst.
  • The intervening dropped blocks are called graben and can be small or form extensive rift valley systems.
  • This form of landscape can be seen in various areas, including East Africa, the Vosges, the Basin and Range Province of Western North America, and the Rhine valley.
  • Fault blocks are large blocks of rock, created by tectonic and localized stresses in the Earth’s crust, broken up into blocks by faults.
  • Blocks are characterized by relatively uniform lithology.
  • Large crustal blocks broken off from tectonic plates are called terranes and microplates.
  • Vertical movement of blocks produces much more dramatic results and can form high escarpments.
  • Landforms such as mountains, hills, ridges, lakes, valleys, etc. are sometimes formed when the faults have a large vertical displacement.
  • The movement of these blocks is often accompanied by tilting, due to compaction or stretching of the crust at that point.
  • 

Volcanic Mountains

• As the name suggests, volcanic mountains are formed by volcanoes. Volcanic Mountains are formed when molten rock (magma) deep within the earth, erupts, and piles upon the surface. Magna is called lava when it breaks through the earth’s crust. 
• When the ash and lava cools, it builds a cone of rock. Rock and lava pile up, layer on top of layer.
• Charaterstics of volcanic mountains:
  • Eruption: volcanic mountain ejects lava, ashes, and gases
  • Explosion: volcanic mountain explodes, producing extreme heat and red-hot lava, thick smoke, and debris
  • Expansion: volcanic mountain expands due to molten magma, extreme heat, and debris, creating a solidified land surface
  • Uplift or Inflation: mass of new lava rises to the surface, pushing old rock aside and upward, making a bulge on the surface
  • Emulsification: volcanic mountain releases molten lava that combines with chemical gases and aqueous fluids, forming stable emulsions that can be drilled and exported
  • Craters: bowl-shaped depression formed by volcanic eruption or impact of a meteorite
• Types of volcanic mountains:
  • Cinder cone mountains: made up of material blasted out that falls back down, not usually large.
  • Shield volcanoes: built up by many lava flows of low viscosity lava, can be very wide.
  • Stratovolcanoes or composite volcanoes: made up of many layers of ash, rock, and hardened lava, some of the largest and most impressive volcanoes.
• Formation of volcanic mountains:
  • Small crack in Earth’s crust triggers the formation of volcanic mountains
  • Movement of tectonic plates causes the crack
  • Magma (molten rock) escapes through the crack and reaches the Earth’s surface
  • Volcanic ash and gases are also released during an eruption
  • The volcanic material cools and settles around the vent
  • Over time, solidified lava layers build up and form a mountain
  • Formation of volcanic mountains takes thousands of years
  • Volcanic activity in oceans can also result in island formation.
• Examples of volcanic mountains:
  • Krakatau, Indonesia – The entire island was obliterated by its 1883 eruption, and sunsets around the world changed color for the next two years.
  • Lassen Peak, California, USA – erupted in 1917, beginning a period of nearly 75 eruption-free years in the 48 contiguous states.
  • Llullaillaco, Argentina/Chile – At more than 22,000 ft, the world’s highest active volcano last erupted in 1877.
  • Mauna Loa, Hawaii, USA – This is the world’s largest active volcano. Its most recent eruption was in 1984.
  • Mt. Fuji, Japan – This famous symbol of Japan last erupted in 1707.
  • Mt. Mazama, Oregon, USA – Crater Lake formed 7,000 years ago when its side blew out and top collapsed.
  • Mt. Pelee, Martinique – In 1902 only two of the 30,000 inhabitants of the adjacent town survived its 1902 blast.
  • Mt. St. Helens, Washington, USA – It gave several days warning before erupting in 1980, yet 57 people ignored experts advice to relocate and lost their lives.
  • Mt. Tambora, Indonesia – The ashes from its 1815 eruption blocked the sun through most of 1816, creating a ―year without summer.‖
  • Mt. Vesuvius, Italy – The city of Pompeii was buried under its eruption in the year 79.
  • 

Residual Mountains

• Residual mountains are those mountains that have been eroded by the agents of degradation such as winds, rain, frost, and running water. The hard rocks that are left behind are called residual mountains.
• Formation of residual mountains:
  • Residual mountains are formed from already existing mountains.
  • They are lowered or reduced by agents of denudation such as running water, ice, and wind.
  • Residual mountains are the remains of already existing mountains.
  • Some hard and very resistant parts of the existing mountains remain after the lowering of the upper part.
  • This remaining part is called the Residual Mountains, which are also Mountains of Denudation.
  • The Aravalli Mountain and the Parasnath mountain of Bihar belong to this type.
• Examples of residual mountains:
  • The Nilgiris
  • The Parasnath
  • The Rajmahal
  • The Aravallis

Economic Significance of Mountains

• Mountains are a storehouse of natural resources, including minerals, timber, lac, and medical herbs.
• Mountains are a source of hydro-electricity, generated from perennial rivers in the mountains.
• Perennial rivers arising in snow-fed or heavily rain-fed mountains are an important source of water for irrigation and other purposes.
• Rivers that originate from high mountain ranges bring silt along with water to the lower valleys, helping in the formation of fertile plains.
• Mountains can act as natural boundaries between countries, protecting them from external threats.
• Mountains serve as a climatic divide between two adjoining regions, causing orogenic rainfalls, diversion, and blocking of cold winds.
• Mountains are popular tourist destinations due to their pleasant climate and beautiful scenery.

Plateaus

• A plateau is a flat-topped table land.
• Plateaus are found in every continent and cover a third of the Earth’s land.
• Plateaus are one of the four major landforms, alongside mountains, plains, and hills.
• Plateaus can be young or old, with the Deccan plateau in India being one of the oldest.
• Valleys can form when rivers cut through plateaus, such as the Columbia River cutting through the Columbia Plateau in the northwestern United States.
• Some plateaus may be eroded and broken up into smaller raised sections called outliers.
• Many outliers are composed of very old, dense rock formations and may contain valuable mineral deposits such as iron ore and coal.
• Plateaus are rich in mineral deposits, making them important areas for mining.
• On the basis of their geographical location and structure of rocks, the plateaus can be classified as:
  • Intermontane Plateaus
  • Piedmont plateaus
  • Continental plateaus
  • Volcanic plateaus
  • Dissected plateaus
• 
• Intermontane Plateaus:
  • Intermontane plateaus are located between or within mountain ranges, usually fold mountains.
  • The word ‘intermontane’ means ‘between mountains’.
  • They are the highest type of plateaus in the world.
  • The rock layers in intermontane plateaus are nearly horizontal and are raised to great heights by vertical movements of the Earth.
  • The Plateau of Tibet is an example of an intermontane plateau, which is surrounded by fold mountains like the Himalayas, the Karakoram, the Kunlun, and the Tien Shah.
• Piedmont Plateaus:
  • Piedmont plateaus are situated at the foot of a mountain and are locked on the other side by a plain or a sea/ocean.
  • The word ‘piedmont’ means ‘foot of a mountain’.
  • They are also called Plateaus of denudation as the areas once were high to the level of mountains but have now been reduced to the foot level of the mountain by various agents of erosion.
  • An example of a piedmont plateau is the Malwa Plateau.
• Continental Plateaus:
  • Continental plateaus are formed by either extensive continental upliftment or the spread of horizontal basic lava sheets.
  • They show an abrupt elevation in contrast to the nearby lowland or sea.
  • Continental plateaus are also known as Plateaus of Accumulation.
  • Plateau of Maharashtra is an example of the continental plateau.
• Volcanic Plateaus:
  • A volcanic plateau is formed by numerous small volcanic eruptions that slowly build up over time, forming a plateau from the resulting lava flows.
  • The Columbia Plateau in the northwestern United States of America and Deccan Traps are two examples of such plateaus.
  • There are two main types: Lava plateaus and Pyroclastic plateaus.
  • Lava plateaus are formed by highly fluid basaltic lava during numerous successive eruptions through numerous vents without violent explosions.
  • Pyroclastic volcanic plateaus are produced by massive pyroclastic flows and they are underlain by pyroclastic rocks.
• Dissected Plateaus:
  • A dissected plateau is a plateau area that has been severely eroded so that the relief is sharp.
  • Such an area may appear as mountainous.
  • Dissected plateaus are distinguishable from orogenic mountain belts by the lack of folding, metamorphism, extensive faulting, or magmatic activity that accompanies orogeny (mountain building).
  • Example: The Catskill Mountains in New York state.
• The economic significance of Plateaus:
  • Plateaus are storehouses of minerals, making extraction relatively easier compared to mountains
  • Major industrial raw materials are obtained from plateaus such as gold, copper, diamond, coal, iron, manganese, and mica
  • Plateaus provide ideal sites for generating hydel power due to the waterfalls at their edges
  • The higher parts of plateaus even in tropical and sub-tropical regions have a cool climate
  • Plateaus have large grassland areas suitable for animal rearing such as sheep, goat, and cattle
  • Lava plateaus are richer in minerals, making them suitable for agriculture due to their fertile soil

Plains

• Plains are relatively level areas of the Earth’s surface with gentle slopes and small relief.
• They vary in size from a few hectares to hundreds of thousands of square kilometers.
• Plains occupy slightly more than one-third of the terrestrial surface and are found on all continents except Antarctica.
• Most plains have been formed by deposition of sediments brought down by rivers, wind, moving ice, and tectonic activities.
• They occur north of the Arctic circle, in the tropics, and in the middle latitudes.
• The vegetation of plains varies widely, some are tree-covered, grassy, support scrub brush and bunch grass, while others are nearly waterless deserts.

Types of Plains

• Outwash Plain/Sandur:
  • Formed by glaciers
  • Glacier deposits sediments at its terminus
  • Erodes bedrock and carries eroded sediments downstream
  • Sediments are deposited by the meltwater of the glacier at the snout
  • Common landform in Iceland
  • Skeiðarársandur in Iceland is the world’s largest outwash plain with an area of 1,300 square km
• Till Plain:
  • Formed by glacial action
  • Deposited by glacial till (unsorted glacial sediment)
  • Created when a sheet of glacial ice gets detached from the main glacier and melts in place
  • Seen in northern Ohio where they were created by the Wisconsin glaciation
• Lava Field/Plain:
  • Accumulation of layers of lava
  • Stretch for miles and easily visible from the air or in satellite images
  • Darker in color than the surrounding landscape
• Lacustrine Plain:
  • Formed in areas previously occupied by lakes
  • Sediments remain on the lakebed to form a plain when a lake drains out completely due to factors like evaporation, natural drainage, etc.
  • May be highly fertile and support agriculture or might form a wetland or even a desert depending on the composition of the sediments
  • Common in Southern Indiana of the US and the Kashmir Valley of India
• Scroll Plain:
  • Formed in areas where a river meanders across a low gradient
  • Deposition of sediments at such locations results in the formation of a plain
  • Oxbow lakes are common occurrences in such areas
  • Taieri River forms a spectacular scroll plain near Paerau in New Zealand
• Flood Plain:
  • Stretches from the banks of a river or stream to the enclosing valley walls
  • Usually subjected to flooding when the adjacent water body overflows
  • Often fertile and made of deposits of silts, sands, levees, etc., deposited by floodwaters
  • Support a rich ecosystem
  • Many densely populated cities are located on these plains
  • Many of the most devastating floods in history have taken place in floodplains
  • Yellow River’s floodplains are one such area that is frequently subjected to deadly floods
• Alluvial Plain:
  • Vast, sweeping stretches of plain land
  • Formed by the deposition of sediments called alluvium
  • Includes floodplains as part of its area but extends beyond such plains
  • Represents the pattern of floodplain shift over geological time
  • Elevation of the floodplain increases while the width of the river channel decreases
  • Floodplains continue growing and adding up to form massive stretches of alluvial plains
  • Indo-Gangetic Plain in India and the Po Valley in Italy are examples of alluvial plains
• Abyssal Plain:
  • Plain located at great depths on the floor of the ocean
  • Found at depths ranging between 9,800 ft and 20,000 ft
  • Comprise about 50% of the surface of our planet
  • Least explored areas and the flattest and smoothest ones
  • Massive in size
  • Sohm Plain of the North Atlantic Ocean covers an area of about 900,000 square km
  • Most common in the Atlantic Ocean but quite rare in the Pacific Ocean
  • Formed by the deposition of sediments, derived from land, in the abyssal depressions
  • Deposition occurs in many layers till the underlying irregular features are smoothen

The economic significance of Plains:

• Plains have deep and fertile soil, making them the “food baskets of the world”
• Rich agricultural resources in alluvial plains have helped the growth of agro-based industries
• Plenty of labor is available for agriculture and industries due to thick population in plains
• Flat surface of plains facilitates building of roads, airports, and laying down railway lines
• Plains are centers of many civilizations
• Easy transportation and growth of agriculture and industries have resulted in the setting up and expansion of cities and towns
• Most developed trade centers and ports of the world are found in the plains, where 80% of the world’s population lives