three exclusive basins, Vindhyan, Chattisgarh, Cuddapah.formed from the archaen crators of Bundelkhanad, Bastar and Dharwad.

formation : later proterazoic to mesoproterozoic.

proterzoic sedimentary basin in peninsular india aka Purana Basin,

its crescent shaped, easterly N-S direction, extends upto 450m along the eastern margin of Indian Peninsula.

located in the south central part of Andhra Pradesh and Telengana, covers an area of 44,500 sq. km

Consists of Orthoquartzite Carbonate, Basic to acid volcanos and sills, Lower parts- sillicaceous shales. Upper parts, Quartzite.

estimated thickness 6-12 km.

lithography of cuddapah basin is divided into : Cuddapah Supergroup and Kurnool Supergroup.

Cuddapah Supergroup/ predomintantly aricaneous to argillacious with subordinate calacareous to dolomite units.

Upper proterzoic succession of the cuddappah basin is known as Kurnool group.

Kurnool group rest unformable on the top of the rocks of Cuddpah Supergroup, mainly consisitig carbonate sediment to subordinate fine clastics.

The stratigraphic classification of Cuddapah basin is divided into three sub groups namely : Papaghni, Chitravati and Nallamalai.

Each group starts with quartzite and ends with shale, which represents a cycle of quartzite shale sequence that happens in the Cuddapah basin

This cycle is also capable to denote reflective succesive transgression at the basin