Uranium Mineralisation in the Mesoproterozoic Quartzites of Cuddapah Basin in Gandi area, Cuddapah District, Andhra Pradesh: A New Exploration Target for Uranium

Significant uranium occurrences are discovered recently for the first time in the Gulcheru Quartzite of Papaghni Group of Cuddapah Supergroup near Gandi, east of Papaghni river, Cuddapah District, A.P. Mineralisation is associated with an E-W fault. Friable whitish to light pink quartzite is the main host rock of uranium. Mineralisation occurs in the form of lensoidal bodies having dimensions of 20 - 200 m x 2 - 10 m in an E-W fault scarp section, over 2 km in length. Dip section is also mineralised. Samples have revealed anomalous concentrations of uranium, up to 1.441% U₃O₈ with negligible thorium. Concentration of Ni (<25 to 1033 ppm), Mo (<25 to 643 ppm), Pb (33 to 1515 ppm) and Cu (<25 to 170 ppm) points to the economic potentiality of the area. Petrological studies have identified uranium minerals such as pitchblende, uraninite and coffinite as fracture fillings and disseminations in the chlorite-sericite matrix of quartzite. The associated ore minerals are chalcopyrite, arsenopyrite, pyrite and limonite. These findings have important implications in the selection of new exploration targets for uranium in the basal beds of Cuddapah Supergroup unconformably overlying the fertile granitoid basement in the Eastern Dharwar Craton occurring in the southwestern part of Cuddapah basin.