Aero-Electromagnetic Signatures over a Zinc-Nickel Prospect in Umarvaniyan Block, Udaipur District, Rajasthan.

摘要

Aero-geophysical surveys have been carried out in the study area by BRGM-CGG of France during 1971-72 using INPUT system comprising electromagnetic, magnetic and radiometric methods. Several anomalous zones for sulphide mineralization have been identified in Sanjela-Manpur-Lohagarh metallogenic belt of Udaipur District, Rajasthan. The study area, Umarvaniyan block forms the part of Manpura-Lohagarh zone of Sanjela-Manpur-Dugocha belt, Udaipur district, Rajasthan. Six channel aero electromagnetic intercepts have been recorded over the study area. Decay curve has been prepared to assess qualitatively the type of six channel intercepts from the mineralization point of view. Result are presented in this paper and correlated with the mineralization Decay curve plots of the six channel aero-em intercepts falling over the Umarvaniyan area are showing slow decay with strong curvature indicative of poor conductor with depth persistence. Poor conductivity is attributable to zinc mineralization. Systematic litho geochemical surveys in Umarvaniyan brought out an anomalous zone in phyllitic dolomite over a strike length of 400m. Anomalous zinc values between 820ppm and 2400ppm with corroborative nickel values between 100ppm and 410ppm have been recorded. Exploration by drilling in Umarvaniyan block has brought out low grade zinc(± nickel) mineralization for a strike length of about 500 m, which is broadly in agreement with the aero em signatures.