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The application of hydro geochemical exploration for sub-surface uranium mineralization is becoming significant due to the geochemical properties of uranium. The oxygen in natural water enhances the mobility of uranium by the complexing action of carbonates and bicarbonates with oxidized uranyl ions. The uranium and its decay products (i.e., radium group) can be used as good tracers for pinpointing uranium mineralization. The basement complex in the south of Cuddapah basin comprises granite, gneiss-migmatites and patches of greenstone belts. There are different generation of fractures and mafic dykes trending E–W, N S, NW-SE and NE–SW directions. The NNE–SSW to NE–SW trending fractures are youngest and often show higher uranium values in water along the same trend indicating possible mineralization. The fractures are often intruded by younger basic intrusive rocks and quartz reefs which often show high uranium content. Several NE–SW to NNE–SSW trending fracture zones with uranium mineralization are observed in the areas around Shivaramapuram-Nutankalva, Kamaguttapalle and T. Sundupalle villages. These sympathetic fracture zones are important for further sub-surface exploration. The present focus is given on a NE-SW fracture zone along Sivaramapuram–Nutanakalva tract extends over a strike length of ~15 km with a plan width of ~1 to 1.5 km. The tract is mostly soil covered and rock outcrops are scanty. Radioactive anomalies are located at small outcrops in fractured basic dyke, fractured and altered granite, deformed quartz vein, sludge samples collected from private village drilling sites, Pincha river channel sands and soils (U 3 O 8 values up to 0.19% (β/γ); n = 44;). Hydrogeochemical exploration along this fracture zone has indicated anomalous concentration of uranium in water samples ranging from 100 to 19,434 ppb U (n = 110). Selective borewells have been monitored for 8 months to check the seasonal variation. The data remain persistent and indicated encouraging outcome. This NE–SW fracture zone has affected the Nagari quartzite of Cuddapah Supergroup, thus indicate Post Nallamalai Mesoproterozoic Grenville orogeny, which is metallogenically favourable epoch for fracture controlled uranium mineralization. The surface anomalies vis-a-vis the hydro uranium anomalies and suitable geochemical condition along the NE-SW trending fracture make this zone a potential target for further sub-surface exploration. • The application of hydro geochemical exploration for sub-surface uranium mineralization is the topic of the paper. • the study area is mainly a granitoid province where a soil covered concealed fracture controlled uranium mineralization is being reported. • NE-SW trending fracture zone showed upto 19434 ppb uranium content in water. • Radioactive anomalies are located at small outcrops exposed near Sivarampuram in fractured basic dyke [0.13 and 0.19% U 3 O 8 (β/γ; n =2)] and Katramuduku in fractured granite [0.014 to 0.135% U 3 O 8 (β/γ); n =3]. • These surface anomalies vis-a-vis the hydro uranium anomalies and suitable geochemical condition along the NE-SW trending fracture make this zone a potential target for further sub-surface exploration. [ABSTRACT FROM AUTHOR]

In the eastern part of India, South Purulia Shear zone (SPSZ) forms an elementary feature of Tamar-Porapahar lineament that trends in approximately E -W direction. In terms of Uranium mineralization prospects, SPSZ contributes a significant fraction when it comes to exploration. For a detailed investigation of subsurface characteristics, a quasi 3D resistivity survey using multi-electrode Schlumberger array configuration was performed near Kutni village in South Purulia Shear Zone (SPSZ). For this approach, we carried out measurements at various parallel profiles perpendicular to the strike in the area, to achieve the spatial resistivity distribution beneath the subsurface. Interpretation of the electrical resistivity tomography (ERT) results shows the presence of a conducting body at a depth of approximately 25-30 m that dips in the north direction and has a continuous extent in the E -W direction. Such low resistivity regions in 2D resistivity sections, when compared with gravity results, the outcome was in concurrence with low-density zones. These low resistivity and low gravity anomaly zones may correspond to the hydrous Uranium altered regions. Two more multi-electrode Schlumberger profiles were taken parallel to the strike direction near the exposed outcrop that showed the presence of anomalous zones. The integrated approach of geophysical methods used in this paper improves the likelihood of target location and helps in successfully deciphering the dimension of the geological features present beneath the surface. • ERT survey was performed in SPSZ to delineate U-deposits and correlated with gravity findings. • Results show hydrothermal U-deposits associated with apatite-magnetite-quartzite. • Correlation of resistivity and density sections show a northerly dipping conductor trending E -W. [ABSTRACT FROM AUTHOR]