Indias Divisions Based on Geological Structure and Geomorphic Processes - Geography Notes

India is home to some of the world's oldest geological structures and features. It has geological and structural conditions that are unique to almost all epochs of the geological time scale. India is home to a diverse range of rock masses, mineral deposits, and mineral fuels, including coal and oil. It ranges from the snow-capped Himalayas in the north to sun-drenched seaside settlements in the south and humid tropical forests on the south-west coast, as well as from the rich Brahmaputra valley in the east to the Thar Desert in the west. This article will explain in detail to you about India's Divisions Based on Geological Structure and Geomorphic Processes which will be helpful in Geography preparation for the UPSC Civil service exam.

Geological Structure of India

• Geologists define geologic divisions as areas with comparable rocks, structures, and geologic history.
• About a century of geological research and exploration of various earth materials has yielded a vast amount of information about India's geology.
• India is geologically divided into the following divisions.

Peninsular Block

• Peninsular Block is an Indian plate that was once a component of the Gondwana land/plate, which split apart throughout geological time and moved in various directions as Indian plate, Australian plate, Antarctica plate, African plate, and so on.
• The Indian Peninsular Plateau is an uneven triangle that rises from a height of 150 metres above the river lowlands to a height of 600-900 metres.
• The Peninsular plateau is defined by the Delhi ridge in the northwest (an extension of the Aravallis), the Rajmahal hills in the east, the Gir range in the west, and the Cardamom hills in the south.
• The Plateau of Peninsular India is another name for the Peninsular Plateau of India.
• It is one of India's most important physiographic features.

*To know more about this, click Peninsular Block

The Extra-peninsular Region

• The Himalayan mountain ranges make up the extra-peninsular region.
• Unlike the stiff and stable Peninsular Block, the Himalayas have a young, fragile, and flexible geological structure.
• As a result, they continue to be subjected to the interaction of exogenic and endogenic pressures, which leads to the formation of faults, folds, and thrust plains.
• These mountains are tectonic in nature, with fast-flowing rivers that are still in their infancy slicing them apart.
• This level is marked by gorges, V-shaped valleys, rapids, waterfalls, and other landforms.
• From west to east, it is divided longitudinally into five parts as follows.

Kashmir or North Western Himalayas

• The Karakoram, Ladakh, Zaskar, and Pir Panjal are some of the ranges that make up this region.
• Between the Greater Himalayas and the Karakoram ranges, the northeastern half of the Kashmir Himalayas is a frigid desert.
• The world-renowned Kashmir valley and the famed Dal Lake are located between the Great Himalayas and the Pir Panjal range.
• This region also has important South Asian glaciers such as the Baltoro and Siachen.
• The Kashmir Himalayas are also known for the Karewa formations, which are used to grow Zafran, a local saffron type.

*To know more about this, click Kashmir or North-Western Himalayas

Himachal and Uttarakhand Himalayas

• The Himachal and Uttarakhand Himalayas span across three states of Jammu and Kashmir, Himachal Pradesh and Uttarakhand.
• This stretch is roughly between the Ravi (a tributary of Ghaghara) in the west and the Kali (a tributary of Ghaghara) in the east.
• It is drained by two of India's largest river systems, the Indus and the Ganga.
• The Ravi, the Beas, and the Satluj are Indus tributaries, while the Yamuna and the Ghaghara are Ganga tributaries that run through this region.
• The Himachal Himalayas' northernmost reaches are an extension of the Ladakh cold desert, which is located in the district Lahul and Spiti subdivision.

*To know more about this, click Himachal and Uttarakhand Himalayas

Darjeeling and Sikkim Himalayas

• They are bordered on the west by the Nepal Himalayas and on the east by the Bhutan Himalayas.
• It is a small part of the Himalayas, yet it is quite important.
• It is a home to high mountain peaks like Kanchenjunga (Kanchengiri) and deep valleys, and is known for fast-flowing rivers like Tista.
• The Lepcha tribes live in the higher elevations of this region, while Nepalis, Bengalis, and Central Indian tribals live in the lower elevations, mainly in the Darjeeling Himalayas.

*To know more about this, click Darjeeling and Sikkim Himalayas

Arunachal Himalayas

• Arunachal Himalayas range from the east of Bhutan Himalayas to the Diphu pass in the east.
• The mountain range runs in a broad southwest-to-northeast direction.
• Kangtu and Namcha Barwa are two of the region's most notable mountain summits.
• Fast-flowing rivers cut through these ranges from north to south, causing deep gorges.
• After crossing Namcha Barwa, the Bhramaputra runs through a deep gorge.

*To know more about this, click Arunachal Himalayas

Eastern Hills & Mountains

• Eastern Hills & Mountains are part of the Himalayan mountain chain, with a basic alignment from north to south.
• They are recognised by many local names. They are known as Patkai Bum in the north, Naga hills in the south, and Manipur hills in the north.
• These are low hills populated by a variety of tribes that practise Jhum agriculture.
• The region is geologically unstable, with multiple faults crisscrossing it. Its north–south hill ranges are formed by small parallel valleys that slope westward.

*To know more about this, click Eastern Hills & Mountains

Peninsular Mountains

• Peninsular India reflects the geographical and climatic patterns of South India.
• With the Arabian Sea on one side, the Bay of Bengal on the other, and the Vindhya and Satpura ranges to the north, the Arabian Peninsula is shaped like an inverted triangle.
• The bulk of the hills in the peninsular region are residual mountains. They're the remnants of a slew of million-year-old horsts and hills.
• The Peninsular region's plateaus are separated by several Mountain ranges and diverse river basins.
• The Peninsula is shaped like an inverted triangle, with the Arabian Sea on the west, the Bay of Bengal on the east, and the Vindhya and Satpura ranges on the north.
• The historic border between northern and southern India is formed by the Narmada and Mahanadi rivers.
• On the north by the Aravallis, on the northeast by the Hazaribagh and Rajmahal Hills, on the west by the Western Ghats (Sahyadri Mountains), and on the east by the Eastern Ghats.
• Anamudi, at 2695 metres above sea level, is Peninsular India's highest peak.

*To know more about this, click Peninsular Mountains

Indo-Ganga – Brahmaputra Plain

• The Indo-Gangetic-Brahmaputra plain is sometimes referred to as the Northern lowlands of India or the Great Plain of India.
• It is a transitional zone between the northern Himalayas and Peninsular India. The Indo-Gangetic-Brahmaputra Plain is the world's biggest alluvial tract.
• The Great Plain of North India is located to the south of the Himalayas and to the north of the Peninsula.
• It is an aggradational plain produced by the depositional action of three main river systems, including the Indus, Ganga, and Brahmaputra.

*To know more about this, click Indo-Ganga -Brahmaputra Plain

The Coastal Plains

• India is a country that is surrounded on three sides by the sea.
• The faulting of Gondwanaland during the Cretaceous period resulted in India's straight and regular coastline (Continental Drift).
• As a result, there aren't many good natural harbours along India's coast.
• Following the dissolution of Gondwanaland, the Bay of Bengal and the Arabian Sea were formed during the Cretaceous or early Tertiary periods.
• India's coastal plains, in general, go east and west.
• As said earlier, they cover a total area of 7516.6 km and are divided into two types:
• Eastern Coastal Plains of India
• Western Coastal Plains of India

The Islands (Lakshadweep and Andaman and Nicobar)

• The Andaman and Nicobar Archipelago (a chain of islands with similar origins) in the Bay of Bengal and the Lakshadweep Islands in the Arabian Sea are two of India's major island groups.
• The collision of the Indian Plate and the Burma Minor Plate [part of the Eurasian Plate] formed the Andaman and Nicobar Islands [similar to the formation of the Himalayas].
• The Andaman and Nicobar Islands are a southern extension of Myanmar's Arakan Yoma range [Myanmar][Arakan Yoma is a continuation of the Purvanchal Hills].
• The Lakshadweep Islands are a group of coral islands off the coast of India.
• These islands are part of the Reunion Volcanic Hotspot.
• Apart from these two groups, there are islands in the Indo-Gangetic Delta [more of a part of the delta than islands] and between India and Sri Lanka [remains of Adams Bridge or Rama's Bridge or Rama Setu; formed due to submergence].

Conclusion

Above all, understanding a country's geological structure aids in determining the types and characteristics of rocks and slopes, the physical and chemical properties of soils, mineral availability, and surface and subterranean water supplies. In this context, India is richly blessed with its varied geological features.

FAQs

MCQs

Question: Which of the following is not correct in relation to the Indo-Gangetic-Brahmaputra plain?

(a) They are the northern lowlands of India.

(b) It is a transitional zone between the Eastern Himalayas and Peninsular India.

(c) It is an aggradational plain produced by the depositional action of three main river systems.

(d) It is sometimes referred to as theGreat Plain of India.

Question: Consider the following statements on extra-peninsular regions.

1. The Himalayan mountain ranges make up the extra-peninsular region.
2. They have a young, fragile, and flexible geological structure.

Which of the statement(s) given above is/are correct?

(a) 1 only

(b) 2 only

(c) Both 1 and 2

(d) Neither 1 nor 2