Significance of Borehole Geophysics and Measurement of Physical Properties of Core Samples in Sawar Belt, Rajasthan

摘要

The Proterozoic Sawar metasedimentary belt in the eastern part of Ajmer district, Rajasthan contains several small moderate-grade lead-zinc deposits Borehole logging earned out in southern part of this belt has identified the mineralised zones intersected by drilling. It has also indicated some additional conductive zones which may indicate the presence of sulphides in close proximity of the boreholes where the body might have been missed by drilling. Electrical logging in corroboration with magnetic susceptibility values from drill cores is more diagnostic of the mineralised zones particularly due to association of pyrrhotite with other economic sulphides. The measurement of physical properties namely chargeability, resistivity and density of drill core samples is very helpful in identifying the mineralized zones in boreholes and its correlation with ground geophysical responses.