A plateau is a large, flat region of land, sometimes surrounded by mountains but typically surrounded by escarpments. Even though they are higher in elevation than the surrounding topography, plateaus differ from mountain ranges because they are incredibly flat. Typically, plateaus are formed when magma rises to the surface from a deep region of the earth but cannot pierce the crust. As a result, the magma eventually lifts a massive, impenetrable rock above it. These plateaus took millions of years to develop.
- Certain plateaus are located distant from mountain ranges, like the Deccan plateau in central India.
- The geologic processes that gave rise to the various plateaus are responsible for their peculiarities.
One of the three types of tectonic processes necessary to build plateaus includes volcanism, crustal shortening (pushing one block or slice of crust over another or folding rock strata), and thermal expansion.
The simplest of them is the lithosphere's thermal expansion or the asthenosphere's replacement of the cold mantle lithosphere.
Types of Plateaus
There are two kinds of plateaus:
- Molten lava creates these kinds of plateaus. The earth's crust erupts molten lava, which spreads onto the surface to create successive sheets of basaltic lava.
- The lava plateau is created when these solidify.
- The Antrim Plateau in Northern Ireland and the North Western Plateau of the Deccan Plateau are two well-known lava plateaus.
- The Columbia-Snake Plateau, which spans an area nearly twice the size of Malaysia, is the most impressive lava-built plateau.
- An angular plateau forms as the Earth's crust rises. The slow collision of tectonic plates causes the uplift.
- The continental process of weathering and erosion by flowing water, ice, and winds progressively wear down high, wide plateaus, causing their surfaces to become uneven. Dissected plateaus are those found in the humid highlands where streams and occasionally glaciers have carved deep, narrow valleys in the plateau.
- In drier climates, plateaus are separated into steep-sided tabular masses known as mesas and butter, carved out by deep canyons, rivers flowing vertically, and wind- and river-induced erosion. This is a characteristic of semi-arid and arid areas.
- An example of a divided plateau is the Scottish Highlands.
Plateaus in India
Ancient crystalline, igneous, and metamorphic elements make up the peninsular plateau of India. It is one of the oldest landmasses, having formed as a result of the disintegration and drift of the Gondwana continent. The plateau contains rounded hills and wide, shallow valleys.
The Central Highlands and the Deccan Plateau are the two divisions of this plateau.
- India's plateaus are rich in mineral resources.
- Massive amounts of iron, coal, and manganese can be found in India's Chota Nagpur plateau.
- There may be more than one waterfall in the plateau areas because the river drops from a great height. Two examples of these waterfalls in India are the Hundru falls on the river Subarnarekha on the Chota Nagpur plateau and the Jog falls in Karnataka.
- A lot of the black soil on the lava plateaus is fertile and suited for cultivation.
- One of the defining features of the Peninsular plateau is the area of black dirt known as the Deccan Trap. Since the rocks are volcanic in nature, they are igneous. Actually, the stones have diminished over time, which is why black soil has formed.
- The Aravalli Hills are on the western and northern margins of the Peninsular Plateau.
- These have deteriorated hills that resemble broken hills. From Gujarat to Delhi, they move in a southwest-northeast direction.
Plateaus of India: Peninsular Plateau
The Peninsular Plateau is one of the Plateaus in India. It is generally triangular in shape, with its apex near Kanyakumari and base at the southernmost point of the broad plain of North India. It has an area of over 16 lakh square kilometres, and the plateau's average height is between 600 and 900 meters above sea level.
- One of Earth's oldest features is the Peninsular Plateau.
- The majority of the rivers on the peninsula run from west to east, indicating its general slope.
- The Narmada-Tapti is an outlier, flowing in a rift from east to west.
- The Peninsular Plateau comprises several smaller plateaus, hill ranges, river basins, and valleys.
- Many of the Archaean gneisses and schists Rock System make up this extremely solid block.
Types of Plateaus in India
There are a total of seven Plateaus in India. The Marwar Plateau, Central Highland, Bundelkhand Upland, Malwa Plateau, Baghelkhand, Chota Nagpur Plateau, Meghalaya Plateau, Deccan Plateau, and Maharashtra Plateau are the names of the seven plateaus.
- Eastern Rajasthan's plateau is known as the Marwar plateau. West of Aravalis is the Marwar plain, while the east is the Marwar plateau.
- The Marwar plateau dips down eastward and has an average elevation of 250–500 m above sea level.
- Sandstone, shales, and limestone from the Vindhayan era make up its composition.
- The Banas River and its tributaries, the Berach River and the Khari River rise in the Aravali Range before joining the Chambal River in the northwest.
- These rivers' erosional activity gives the plateau top the appearance of a rolling plain.
- Central Highland, or the Madhya Bharat Pathar or Madhya Bharat Plateau, is east of the Marwar or Mewar Upland.
- The basin of the Chambal river, which flows in a rift valley, makes up the majority of the plateau.
- Its principal tributaries include the Kali Sindh, which emerges from Rana Pratap Sagar; the Banas, which runs across the Mewar plateau; and the Parwan and Parbati, which emerge from Madhya Pradesh.
- It is a gently rolling plateau with sandstone-based rounded hills.
- The Chambal River's ravines or badlands are to the north. Here, dense forests are present.
- The Bundelkhand Upland is bordered to the north by the Yamuna River, the west by the Madhya Bharat Pathar, the east and south by the Vindhyan Scarplands, and the south by the Malwa Plateau.
- The Plateau, which slopes down from the Vindhyan Scarp toward the Yamuna River, is an ancient dissected upland of the Bundelkhand gneiss, composed of granite and gneiss.
- Five districts in Uttar Pradesh and four in Madhya Pradesh make up the Bundelkhand Upland.
- A series of granite and sandstone hillocks serves as the area's identifying feature.
- It has an undulating (wave-like surface) due to the erosive work of the rivers that run here, making it unsuitable for farming.
- Several streams, including Betwa, Dhasan, and Ken, traverse the plateau.
- The Aravali Range in the west, Madhya Bharat Pathar to the north, and Bundelkhand to the east encircle the Malwa Plateau, which is essentially shaped like a triangle based on the Vindhyan Hills.
- This plateau contains two drainage systems: one that empties into the Arabian Sea (where the Narmada, Tapi, and Mahi rivers flow), while the other empties into the Bay of Bengal (Chambal and Betwa, joining the Yamuna).
- The Chambal and many of its right bank tributaries, including the Kali, the Sindh, and the Parbati, drain it in the north. It also comprises the Ken, Betwa, and upper courses of the Sindh.
- It is made up of a sizable lava flow and has black soil all over it.
- Rivers cut through this plateau's rolling terrain. The Chambal ravines in the plateau's north are its defining feature.
- The Baghelkhand plateau lies to the north of the Maikal Range. On the west, it is constructed of limestone and sandstone; on the east, it is made of granite.
- The Son river forms the northern border of Baghelkhand.
- The Son drainage system in the north and the Mahanadi river system in the south are separated by water in the middle of the plateau.
- The trough axis is not far from the locations of the Bhanrer and Kaimur.
- The general horizontality of the strata demonstrates that there haven't been any significant disturbances in this region.
Chota Nagpur Plateau
- Gondwana rocks make up most of the Chotanagpur plateau, which is the Indian Peninsula's northeastern projection.
- Jharkhand, the northern portion of Chhattisgarh, and the Purulia district of West Bengal are included in the region.
- North-west of the plateau, the Son river feeds into the Ganga.
- The plateau has a radial drainage pattern because it is drained by various rivers and streams that flow in different directions.
- Large drainage basins have been created by rivers, including the Damodar, Subarnarekha, North Koel, South Koel, and Barkar.
- In a rift valley running from west to east across the centre of this area is the Damodar river. Here are the Gondwana coal fields, which are India's main source of coal.
- The Chotanagpur Plateau's Rajmahal Hills, which are largely built of basalt and are covered in lava flows, is located on its northeastern side.
- Beyond the Rajmahal hills, to the east, the peninsular plateau stretches to Meghalaya or the Shillong plateau.
- The plateau's highest peak is Shillong (1,961 m).
- This plateau is separated from the main block by the Garo-Rajmahal Gap.
- Down-faulting caused this gap to appear. Later, sediments left behind by the Ganga and the Brahmaputra filled it.
- The Meghalaya plateau slopes southward toward the Surma and Meghna rivers and northward toward the Brahmaputra valley.
- Its western border roughly corresponds with the border with Bangladesh.
- The Khasi-Jaintia Hills (1,500 m), the Mikir Hills (900 m), and the Garo Hills (900 m) are the names of the western, middle, and eastern portions of the plateau, respectively (700 m).
- About five lakh square kilometres are covered by the Deccan Plateau.
- The Satpura and Vindhya in the northwest, the Mahadev and Maikal in the north, the Western Ghats in the west, and the Eastern Ghats in the east define its triangle shape.
- The Deccan Plateau is 600 metres above sea level on average. The elevation varies from 500 m in the north to 1000 m in the south.
- The flow of its principal rivers serves as a good indicator of its general slope, which runs from west to east.
- The northern portion of the Deccan Plateau is made up of the Maharashtra Plateau, which is located in Maharashtra.
- Basaltic rocks formed by lava underlie a large portion of the area.
- Weathering has given the land the appearance of a rolling plain.
- The Deccan Trap topography, or step-like formation, is a result of the horizontal lava sheets.
- Flat-topped, steep-sided hills and ridges border Godavari, Bhima, and Krishna's wide and shallow valleys.
- Regur, a black cotton soil, blankets the entire area.
Plateaus is covered under the Geography section of the UPSC Syllabus. It is one of the four major landforms. The Plateaus in India are mainly of seven types. To learn more about the topic, one can refer to the Geography Books for UPSC.
Practising UPSC Prelims Previous Year Questions helps a lot in understanding the pattern.
Question: Which is the largest physiographic division of India?
- The Northern Mountains
- The Great Plains
- The Peninsular Plateau
- The Islands
Answer: Option C
Question: Which river bounds Bundelkhand Uplands in the north?
Answer: Option B