Tectonics of proterozoic Cuddapah Basin, southern India: A conceptual model

• Published in: Journal of the Geological Society of India 2011-11, Vol.78 (5), p.446-456
• Main Author: Chetty, T. R. K.
• Format: Article
• Language: English
• Subjects: Basins; Earth and Environmental Science; Earth Sciences; Fault lines; Geology; Hydrogeology; Landsat; Plate tectonics; Remote sensing; Sedimentary basins; Tectonics
• ISSN: 0016-7622; 0974-6889
• DOI: 10.1007/s12594-011-0109-1

A tectonic map of Cuddapah Basin (CB) and its adjacent regions has been compiled using LANDSAT TM data and the available literature on the prominent tectonic features which include Archaean greenstone belts, disposition of Proterozoic mobile belts along with the associated mid-crustal shear zones, and the mafic dyke swarms. The field characteristics of the two major fault zones: Gudur-Cuddapah and the Veldurti-Kalva-Gani fault system that cut across the CB have been re-examined and are re-interpreted as typical of transfer faults, which are generated exclusively by extensional tectonics. The earlier concept that these fault systems form a conjugate set of “Anderson type” causing the ‘Cuddapah salient’, needs to be reviewed. The widespread extension in the upper crust is manifest in the form of normal faulting of ‘listric’ type in the Papaghni basin and a ‘domino’ type in the Nallamalai basin. While extensional tectonics have played a major role in shaping the geometry and kinematics of CB, the intermittent phases of compression seem to have been derived from major shearing events related to Proterozoic collisional processes in the region. A hypothetical crustal-cross section across the CB has been constructed considering the available geological and geophysical data and analogies were drawn from well-studied sedimentary basins of other continents. The presence of low-dipping detachment faults and shear zones in the lower crust, and their possible linkage with the extensional faults in the upper crust have been inferred to explain the evolution of the CB. The fault patterns and kinematic history in conjunction with the crustal architecture strongly suggest that the evolution of CB is genetically related to the Proterozoic collisional processes and associated crustal-scale transpressional tectonics in the basement at the eastern margin.