VLF – EM, MAGNETIC AND RADIOMETRIC INVESTIGATIONS IN PARTS OF PEDDAVURA GREENSTONE BELT AND RAMADUGU AREA, NALGONDA DISTRICT, TELANGANA STATE, INDIA

The Archaean –Proterozoic Cuddapah basin, in parts of Eastern Dharwar craton of south India peninsular shield comprising supra crustal (Schist belts, mafic dyke swarms, and younger granites) within the gneissic basement is significant in terms of geological, geophysical and economic interest. The schist belts and the gneissic terrain of Peninsular India are important in determine the structural configuration of the regions as the geological nature and the interrelationship of the volcano-sedimentary supra-crustal rocks help in understanding the tectonic sedimentary environments of deposition. Accordingly, the Peddavura schist belt, the only gold bearing schist belt and Ramadugu Lamproite field occurring in Nalgonda District, Telangana State were identified for integrated geophysical investigations include VLF-EM, magnetic and radiometric methods carried out along six detailed traverses. The VLF filtered real and imaginary component anomalies identify major geological interfaces suspected to be faults/fractured zones, which may reflect that VLF anomalies are due to shear zones or alteration zones located along the contact between different rock types. The VLF– EM results of the Fraser model filtered data plots, as well as Karous-Hjelt filter 2-D inversion current density (Pseudo sections) plots for traverse (PS, V-I,V-II, R-I, R-II and SG ), are presented in Figures (2 to 7). The data analysis revealed the presence of positive and negative amplitude of filtered real and imaginary for possible identification of conductive and resistive formations. The interpreted results of VLF-EM agree with magnetic and radiometric anomalies qualitatively. In particular, the disposition and extent of the Peddavura schist belt and mafic dykes swarms in Ramadugu Lamproites field are discontinuous at places was traced and its relation with the other geological members of the region examined in terms of Lamproite locations