Electrical conductance map for Saurashtra region, Gujarat, India

Abstract

In the present study, we have deployed 35 fluxgate magnetometers and 20 long-period magnetotelluric sites to derive the electrical conductivity distribution of Saurashtra region, Gujarat, India. Geomagnetic field variations (X-north–south, Y-east–west and Zvertically downward components) recorded at the above sites are investigated to obtain single-station vertical field transfer functions. Maps of induction arrows suggest that the offshore basins are more conducting than inland basins of the region. Thin sheet modelling of the induction features suggests that the anomalous behaviour is strongly influenced by the offshore and shelf edge sedimentary basins that contain thick depo centres of Mesozoic sediments. Jamnagar, Ulva and Mesozoic sedimentary basins on land are also reflected as high conductivity anomalies that could be related to the presence of carbonate/shale sediments. Release of carbon (in the form of thin films) due to thermal activity of Reunion hotspot on carbonate rich sediments may give rise to high conductivity anomalies.