CH-2 | Geological Formations of India

1	Archean	First formed oldest rocks of the earth’s crust. No marks of fossils, i.e., they are azoic or unfossiliferous.	Gneiss, granite	Tamil Nadu, AP, Karnataka, Orissa, MP, Chattisgarh, Rajasthan, Jharkhand Also found in some parts of Himalayas.
2	Dharwar	Earliest formed sedimentary rocks that are found in metamorphic forms at present. Do not contain fossils. Highly metalliferous and the rocks carry iron-ore, gold, manganese, lead, zinc, building material etc.	Schist, slate, quartzite, conglomerates	Karnataka, MP, Jharkhand, Meghalaya, Rajasthan Also found in northern and central Himalayas.
3	Cuddapah	Rich in iron-ore, manganese ore	Slate, marble	Rajasthan, Tamil Nadu, AP, MP, Chattisgarh
4	Vindhyan	Generally stand over the cuddapah rocks.	Limestone, sandstone, shale, slate which are used as building materials	MP, Chattisgarh, UP, Rajasthan
5	Dravidian	Absent from the peninsular plateau as it was above the sea level at that time. Found in continuous sequence with the Himalayas.
6	Gondwana	Formed when the Indian peninsula experienced crustal movements during the Upper Carboniferous period, which led to the formation of basin-shaped depressions having countless terrestrial plants and animals that were buried to form coal deposits in India. Marks of climatic changes.		Damodar, Mahanadi, Godavari valley in peninsular India
7	Palaeozoic	Northern part of the central Himalayan axis extending from Kashmir to Sikkim		Gujarat, Rajasthan, Tamil Nadu, northern India
8	Mesozoic	Deccan traps were formed when vast areas of the peninsula were flooded with lava due to intense volcanic activity at the end of the Mesozoic era. Contain thin fossiliferous sedimentary layers between the lava flows which indicate that the lava flow was not continuous. The volcanic activity led to two great events – 1)       Breaking of Gondwana landmass 2)       Uplifting of the Himalayas out of Tethys Sea.
9	Tertiary	Comparatively recent origin.	Brown coal, rock salt, gypsum, limestone	Coastal areas of Gujarat, Kerala, Tamil Nadu.
10	Quaternary	Most recent Important formations are – 1)       Ice Age deposits in Kashmir 2)       Formation of alluvial plains 3)       Creation of Rajasthan desert & Rann of Kutch 4)       Laterite formation of peninsula 5)       Formation of regur soils.