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Geological Structure of India

The history of Earth’s geological structure can be divided into five eras- Azoic (Non-living era), Paleozoic, Mesozoic, Cenozoic and Neozoic era. The Azoic era is the era of the origin of the continental shelf. At that time the origin of the continental shelf (Pangaea) was formed by the silica rich granite rocks of less density. The oldest rocks of the Archaean period are found in the peninsular India which is a part of the oldest landmass Pangaea on one hand, while there is an abundance of the latest sedimentary rocks of the Quaternary epoch in its plains.
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The history of Earth’s geological structure can be divided into five eras- Azoic (Non-living era), Paleozoic, Mesozoic, Cenozoic and Neozoic era. The Azoic era is the era of the origin of the continental shelf. At that time the origin of the continental shelf (Pangaea) was formed by the silica rich granite rocks of less density. The divided geological era can be easily understood through the given chart.

Era

Epoch

Period

Time of beginning of the era

Azoic

------

  1. Pre-Cambrian or, Alogonican
  2. Archaean

-------

Palaeozoic

Primary

  1. Cambrian
  2. Ordovician
  3. Silurian
  4. Devonian
  5. Carboniferous
  6. Permian

600 million years ago

Mesozoic

Secondary

  1. Triassic
  2. Jurassic
  3. Cretaceous

 

Cenozoic

Tertiary

  1. Eocene
  2. Oligocene
  3. Miocene
  4. Pliocene

70 million years ago

Neozoic

Quaternary

Pleistocene

Holocene (Modern Age)

One million years ago

• Pangaea was formed in the Azoic era. There is no evidence of the origin of organisms in this era.

• The Silurian period is known as the period of vertebrates. Molluscs, corals and sharks originated in this period.  The breaking up of Pangaea began in the Carboniferous period.

• It was divided into two parts because of the forces of gravity and buoyancy. The northern part was called Laurasia and the southern part, Gondwanaland. The middle part between these two changed into the Tethys Sea.

• In the Jurassic period, Gondwanaland was broken up into the peninsular India, Madagascar, and Australia, Antarctica etc.

The knowledge of the form and nature of rocks found in different parts of a country can be had by studying the geological structure of that country. Sedimentary rocks are found in the land formed by deposition of sediments from which fertile soil is made e.g., the Gangetic plain. Inversely, the soil made of old crystalline rocks is infertile; however, these rocks are important because of the presence of metallic minerals (iron, gold, manganese etc). There is the possibility of petroleum deposits in these areas because of the continuous deposition of the animal remains between the deposited sedimentary rocks in the oceans, e.g., the Gulf of Khambhat, the Bombay High etc.

Both the oldest and the latest rocks are found in the geological structure of India. The oldest rocks of the Archaean period are found in the peninsular India which is a part of the oldest landmass Pangaea on one hand, while there is an abundance of the latest sedimentary rocks of the Quaternary epoch in its plains on the other.