Indian Rocks

The types and qualities of rocks and slopes, the physical and chemical properties of soils, mineral availability, and surface and subsurface water sources can all be determined by knowing a country's geological structure. Here you will learn about the classification of Indian rocks.

Indian Rocks Classifications - Indian Rock System

• The Gondwana structure is an example of the geological structure, which relates to the groups and deposition of rocks in the earth's crust as a result of (or absence of) earth movements. However, it can also refer to the morphological features (morphology) of rocks.

• Chronological dating of diverse geological formations (Geological strata) and life on a geological time scale based on their time and location of genesis, evolution, and extinction. Giovanni Ardunia created the Geological Time Scale in 1760. The Standard Geological Time Scale was created in 1881 in Italy by the International Geological Congress.

(Image Will be Uploaded Soon)

Based on its geographical position and geological history, the country's geological structure and rock systems are examined. To refer to geological formations in India, the following physiographic divisions are used:

Archaean Rock System (Pre-Cambrian Rocks)

• The Archaean period (pre-2.5 billion years; Precambrian Period) was marked by the cooling and solidification of the earth's upper crust, as evidenced by the exposure of gneisses and granites, particularly on the Peninsula.

• The core of the Indian Craton is made up of these (Block of Indian Subcontinent of Gondwanaland).

• The Archaean rocks are divided into two systems.

1. Achaean System: Granites and Gneisses

2. Dharwar System: First Sedimentary Rocks

Gneiss — Mineral composition varies from granite to gabbro.

Schists — mostly crystalline, include mica, talc, hornblende, chlorite, etc.

Archaean Gneisses and Schists

These rocks are:

• These are the oldest rocks (approximately 4 billion years ago) from the pre-Cambrian epoch.

• During a period when the earth's surface was extraordinarily hot, the solidification of liquid lava produced rocks.

• It's known as the 'Basement Complex.' (They're the oldest and serve as the foundation for the layers that follow.)

• Foliated Azoic or unfossiliferous Azoic or unfossiliferous Azoic or unfossiliferous Az (consisting of thin sheets),

• Plutonic intrusions are very crystalline (due to their volcanic origin) (volcanic rocks found deep inside).

Dharwar System - Rocks of Dharwar System

• The age of formation spans from 4 billion to - 1 billion years.

• Sedimentary rock system that has been highly metamorphosed. (produced through the transformation of Archaean gneisses and schists deposits)

• They're the oldest metamorphosed rocks on the planet.

• The Dharwar district of Karnataka has a lot of them.

• The most important rocks in terms of economics since they contain precious minerals such as high-grade iron ore, manganese, copper, lead, gold, and so on.

Purana Rock System

• The Purana rock system is made up of the Cuddapah and Vindhyan rock systems.

• They were produced by the erosion and deposition of Archean and Dharwar rocks between 1400-600 million years ago, and the process is thought to have occurred between 1400-600 million years ago.

• The majority of them are sedimentary in nature.

Cuddapah System

• Due to the extensive development of Cuddapah rock outcrops, it was named after the Cuddapah district of Andhra Pradesh.

• They were produced by the deposition of sedimentary rocks such as sandstone, limestone, and clay in synclinal folds (between two mountain ranges).

• The Cuddapah district of Andhra Pradesh has the best outcrops.

• Iron, manganese, copper, cobalt, nickel, and other ores can be found in these rocks.

Vindhyan System (1300-600 million years)

• The massive Vindhyan mountains give this system its name.

• Ancient sedimentary strata (4000 m thick) are piled on the Archaean basis in this system.

• The Deccan trap covers a considerable portion of this belt and is mostly composed of unfossiliferous rocks.

• Panna and Golconda diamonds have been mined from the Vindhayan system's diamond-bearing zones.

Dravidian Rock System (Palaeozoic)

• Dravidian systems are Paleozoic rock formations that existed in India during the Paleozoic era (600-300 million years ago). Because of the high-quality coal formation throughout the world, it is also known as the Carboniferous rocks System.

• These rocks are generally found in the Himalayan extra-Peninsular regions and the Gangetic plain, with only a few in the Peninsular shield (Umaria in Rewa).

• The Dravidian rocks mainly include shales, sandstones, clays, quartzites, slates, salts, talc, dolomite, marble, etc.

• It is the period when Pangaea was broken and the Tethys Sea came into existence.

• It is the first sign of life on the surface of the world. There were numerous fossils found in the rocks of this time period.

• All geological formations from this time period have them. They also discovered marine conditions in India's Paleozoic rocks.

• The commencement of coal formation (high-quality Carboniferous coal) occurred during the Dravidian period, however, these deposits were not common in the Dravidian period.

• The Dravidian system of geological formations includes the rocks of the following geological ages:

• The Cambrian System;

• The Ordovician Systems;

• The Silurian System;

• The Devonian System (fossils & corals) &

• The Carboniferous Systems (Lower & Middle Carboniferous system).

Carboniferous rocks (350 million years)

• Limestone, shale, and quartzite dominate the Carboniferous rocks (350 million years).

• Upper Carboniferous limestones make up Mount Everest.

• Coal was first formed during the Carboniferous period.

• In geology, carboniferous refers to coal-bearing rocks. (The majority of coal discovered in India is not from the Carboniferous period; high-quality coal from the Great Lakes Region of the United States and the United Kingdom and Ruhr region is Carboniferous coal).

Aryan Rock System

• The Aryan Group, which began the Upper Carboniferous period and now extends from the Upper Carboniferous to the Holocene period, has arrived at the end of the final, longest, and most eventful age.

• The Aryan Group of Rock Formations is divided into three groups:

• Upper Paleozoic Era - Upper Primary, Epoch Upper Carboniferous & Permian Period formation

• Mesozoic Era Secondary Epoch - Triassic, Jurassic & Cretaceous period Formation(Gondwana Rock system, Deccan trap, Jurassic system)

• Cenozoic Era -Tertiary Epoch-Paleocene, Eocene, Oligocene-Miocene & Pliocene Period

• Neozoic Era - Quaternary Epoch-Pleistocene & Holocene/recent Period.

Gondwana System

• The Gondwana System (gets its name from the Gonds, Telangana's and Andhra Pradesh's most primitive people)

• They are deposits that have been set down in synclinal troughs on the surface of an ancient plateau.

• The loaded troughs sank as the sediments piled.

• Terrestrial plants and animals flourished as fresh water and sediments gathered in these troughs.

• This has been going on since the Permian period (250 million years ago).

Deccan Trap

• Deccan Traps were formed by volcanic eruptions that occurred over a large area of Peninsular India from the end of the Cretaceous to the beginning of the Eocene.

• Basaltic lava spilled from fissures over a ten-thousand-square-kilometer area.

• Because these volcanic deposits have a flat top and steep sides, they are referred to as a 'trap,' which in Swedish means a 'stair' or a 'step.'

• Weathering and erosion (denudation) have reduced the Deccan Trap to nearly half its original size over millions of years.

• The current Deccan Trap comprises around 5 lakh square kilometers, mostly in Kuchchh, Saurashtra, Maharashtra, the Malwa plateau, and northern Karnataka.

• The Deccan Traps are 3,000 meters thick in the west, but only 600-800 meters thick in the south, 800 meters thick in Kuchchh, and just 150 meters thick in the east.

• Long-term weathering of these rocks has resulted in the formation of black cotton soil known as 'regur.'

Tertiary System

• About 60 to 7 million years ago, the Eocene to Pliocene transitioned. The final breaking up of old Gondwana land and the upliftment of Tethys geosynclines or Himalayas characterize this period.

• The tertiary is the most important age in India's geological history since it is at this time that the Himalayas were formed and India took on its current form.

• The Bengal and Ganges deltas, the East coast, and the Andaman Islands are all covered by the Tertiary Succession. They can also be found in the Salt Range, Potwar Plateau, Jammu and Punjab's outer Himalayan regions, Assam, Sind, and Baluchistan. The Karewas of Kashmir, Bhangra, and Khadar of the Gangetic plains, among others, are important rock systems.

Geology of India

India's geology has a distinct and diversified character. Rocks from various geologic ages can be found in different parts of India. The Indian Craton was originally a part of the Pangaea supercontinent. The Himalayan mountain range was formed once the Gondwanaland plate broke (225 million years ago) and fell towards the Eurasian craton (65 my ago).

The Indo- Ganga- Brahmaputra plain region emerged after a succession of Outer Himalayas wide spared alluvial plain formation in the upper Pliocene and Pleistocene periods. The Archean System, Dharwar rock System, Cudappah System, Vindhyan System, Dravidian System, and Aryan System are some of the divisions of India's stratigraphy (Gondwana, Jurassic, Deccan Trap, Tertiary and Quaternary rocks).

India is defined by its geological strata, which range from the earliest rocks to the most recent alluvial forms. Peninsular India is home to the Archaean period's earliest rocks. Land created by the deposition of sediments from the Indo-Gangetic plains contains sedimentary rocks. The Great folded mountainous region contains a variety of sedimentary and metamorphic rocks.