Integrated remote sensing and geophysical techniques for shallow base metal deposits (Zn, Pb, Cu) below the gossan zone at Kalabar, Western Aravalli Belt, India

Abstract

Occurrences of small base metal deposits are reported along the western margin of Aravalli Belt in India. Surface manifestation of one such deposit is found to occur as gossan zone within the host rock of amphibolite in Kalabar area of Rajasthan State. Assessment of this occurrence through drilling technology is a time-consuming exercise, more expensive and requires huge manpower. In the present study, an attempt has been made to rediscover the mineral deposit in Kalabar area using remote sensing and High-resolution Electrical Resistivity Tomography (HERT) techniques. Spectral data analysis with Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor shows the characteristic mineral constituents of the gossan zone. 2D electrical resistivity tomograms helped in identifying a narrow vertical zone with low resistivity but high chargeability value up to a depth of 127.9 m. Geospatial analysis of the resistivity data provides the size of the sub-surface deposits. Several exploratory drillings confirm the existence of such deposit up to a depth of 180 m due to presence of highly conductive metallic ore body (Zn, Pb, Cu). Thus, a unique approach is adopted in mineral exploration technology through integrated analysis of surface to sub-surface information. HERT technique is found to be a cost-effective geophysical survey for identifying the geometry and type of shallow base metal deposits.