DHARWAR SYSTEM (PROTEROZOIC FORMATIONS)

This 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. In India, these rocks 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 (i) Dharwar and Bellary districts of Karnataka and extend up to the Nilgiris and Madurai districts of Tamil Nadu, (ii) Central and eastern parts of the Chotanagpur Plateau, Meghalaya Plateau and Mikir Hills, and

(iii) the Aravallis, Rialo (Delhi series), from Delhi to the south of Alwar and the Himalayan region (Fig. 1.3).

Fig. 1.2 Archaean Formations (Pre-2500 Million Years)

Fig. 1.3 Dharwar System (2500-1800 million years ago)

The Dharwar rocks are highly metalliferous. They are rich in 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;