Dharwar System (Proterozoic Formations): Geological Structure of India

Dharwar System (Proterozoic Formations)

The geologic time extends from 2500 million years ago to 1800 million years ago. These are the first metamorphosed sedimentary rock systems known as the Dharwar System in the Indian Geological Time Scale, as they were studied for the first time in the Dharwar district of Karnataka. 

They are composed largely of igneous debris, schists, and gneisses. 

The Dharwar rocks occur in scattered patches in;

• Dharwar and Bellary districts of Karnataka and extends up to Nilgiris and Madurai districts of Tamil Nadu.

• Central and Eastern parts of the Chotanagpur Plateau, Meghalaya Plateau, and Mikir Hills.

• The Aravallis, Rialo (Delhi series) from Delhi to the South of Alwar and the Himalayan region.

The Dharwar rocks are rich in minerals like iron ore, manganese, lead, zinc, gold, silver, dolomite, mica, copper, tungsten, nickel, precious stones, and building materials.

Some of the important series of the Dharwar System are:

Name of the series of Dharwar System	Distribution in India	Significant Features
Champion Series	1. NE of Mysore city to the east of Bangalore. 2. It stretches in the Kolar and Raichur districts of Karnataka.	1. One of the deepest gold mines in the world. 2. Depth= >3.5 Km. 3. Gold content= 5.5 per tonne of the ore. 4. Headquarters of the National Institute of Miner's Health is located here.
Champaner Series	1. Lies in the outlier of the Aravalli system in the vicinity of Vadodara.	1. Minerals: Quartzites, conglomerates, phyllites, slates, limestones, and marbles. 2. Popular for the green variety of marble.
Chilpi Series	1. Occupies parts of Balaghat, Jabalpur, and Chindwara districts of Madhya Pradesh.	1. Minerals: grit, phyllite, quartzites, green stones, magniferous rocks.
Closepet Series	1. Distributed in Balaghat and Chhindwara districts of Madhya Pradesh.	1. It is the Dharwaian formation. 2. Minerals found: quartzite, copper pyrite, magniferous rocks. 3. Ore supplied to the Malanjhand Copper plant.
Iron Ore Series	1. Distributed in Singhbhum, Bonai, Mayubhanj, Keonjhar in the form of a range.	1. It is about 65 km in length has reserves of about 3000 million tonnes of iron ore. 2. Iron ore is supplied to Jamshedpur, Durgapur, Rourkela, and Bokaro Steel plants.
Khondolite Series	1. Occupies large area in the eastern Ghats from the northern extremity to Krishna valley.	1. Principal rock types: khondlites, kodurites, charnockites, gneisses.
Rialo Series (Delhi Series)	1. Extends from Delhi (Majnu ka Tila) to Alwar (Rajsthan in the northeast to southwest direction).	1. Rich in limestone and Makrana marbles. 2. Makrana and Bhagwanpur are known for their high quality of marbles.
Sakoli Series	1. Stretches over Jabalpur and Rewa districts	1. Series belongs to the Dharwian formation. 2. Rich in mica, dolomite, schist, and marble (Superiormost quality).
Sausar Series	1. Series spreads over Nagpur and Bhandara districts of Maharashtra and Chhindwara district of Madhya Pradesh.	1. It belongs to the Dharwarian group. 2. Minerals found: mica schist, quartzite, marble, and magniferous rocks.

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