Electrical and density signatures across Narmada-Son lineament zone (Central India) along the Malkapur-Mandhata profile

摘要

Two-dimensional geoelectric section derived along the Malkapur-Mandhata magnetotelluric (MT) profile, cutting across the Narmada-Son lineament (NSL) zone, brought out a conductive (<50 Ohm m) middle and lower crust under the NSL region. This region underlying the resistive (300-3000 Ohm m) Archaean basement shows shallow depth underneath the weak tectonic zones identified in the area. The constrained density modelling of the Bouguer gravity values suggests high density (2.8 g/cm(3)) material corresponding to the conductive middle lower crust zone. As the region has experienced widespread volcanism during the Cretaceous Tertiary period, the crystallized mafic magmas that were poured into the crust during the volcanism and the fluids entrapped (expelled during magma cooling process) could be the possible explanation for the conductive and high-density characteristics beneath the NSL zone.