A Proterozoic Intracratonic Basin, Dyke Swarms and Thermal Evolution in South India

The spatial and temporal relationships between mid-Proterozoic, intracratonic sedimentation in the Cuddapah Basin and earlier Proterozoic basic dyke swarms are analyzed in the context of thermal and mechanical models for crustal doming, erosion and subsidence. The dyke orientations imply that the Archaean crust of South India was thermally warped into an elliptical dome with a roughly E-W axis, under varying regional tectonic conditions. Thermal relaxation of this dome, after erosion and crustal thinning, laid the basis for sedimentation in the Cuddapah Basin, whose deepest part lay to the SW of its present outcrop. Late-Proterozoic sedimentation of the Kurnool rocks must have been initiated by a later, separate thermal event.