Integration of Geological and Geophysical Approaches in Meeting the Challenges of Uranium Exploration in the Cuddapah Basin — a Case Study from Chitrial Area, Nalgonda District, Telangana

Abstract

Abstract Uranium exploration in the Cuddapah Basin is both scientifically and logistically challenging. An integrated multidisciplinary approach is adopted to infer the subsurface geology. Very Low Frequency Electromagnetic (VLF-EM) survey, conducted over parts of Chitrial outlier, Nalgonda district, Telangana, has indicated thirteen subsurface conductors. Two prominent trends, viz. NE-SW and NNE-SSW/N-S, are revealed from the stacked profiles and pseudosections. Six of these conductors (2 NE-SW and 4 NNE-SSW/N-S trending) are found to have appreciable strike extent (>300 m) with steeply dipping (60°–75°) to vertical attitude. These conductors are interpreted to extend ≥75 m into the basement from the overlying sediments. The ballooned-up zones of low apparent resistivity especially in the sediments, associated with one NNE-SSW/N-S and two NESW trending conductors, are interpreted as zones of hydrothermal alteration and, therefore, demarcated as potential targets for subsurface exploration by inclined boreholes. This study indicates that integration of geophysical data with geological features will help in optimizing the exploration input and narrowing down the target zones for uranium exploration even in deeper reaches of the Cuddapah Basin.