Tectonics of the Cuddapah Basin

The Cuddapah Basin in Andhra Pradesh is a remarkable tectonic and orogenic belt of the unfossiliferous Precambrian rocks of Peninsular India. The paper reviews the stratigraphy and structure of the rocks of the Cuddapah System and Kurnool Series as originally proposed by King and gives the author's conclusions on the detailed structure and tectonics of the Basin. A north-plunging low-amplitude asymmetrical synclinorium having a gently dipping western limb and intensely folded, overfolded and thrusted eastern limb is the major structural element. This is further complicated by a major domal upwarp across the middle of the basin marked by monocjinal flexures of the Kurnool strata in Gani Kalawa area; culminations and depressions at Jammalamadugu, Giddaluru and Srisailam plateau; Eshwarakupam dome of the lower Cuddapahs in the northern part of the Nallamalai hills; and granite domes of Vinukonda area in the north-east extremity.

The relation of the structural elements to the localization of mineral deposits in the Cuddapah Basin is discussed and the necessity for their precise interpretation for exploring the depth extension of the ore mineralization is stressed. The author recommends further detailed structural mapping, especially in the eastern half of the basin, for solving the unsolved problems in the Cuddapah stratigraphy and structure.