STUDY OF DIAGNOSTIC CHARACTERS OF GEOELECTRICAL SOUNDING CURVE OVER LIGNITE-BEARING VIS-A-VIS BARREN FORMATIONS, PALANA AREA, BIKANEE DISTRICT, RAJASTHAN

摘要

Paiana area in Bikaner district of Rajasthan is known for the Tertiary lignite deposit under the desert tract of Thar. In view of low-resistivity property of lignite, electrical soundings were carried out. The sounding curves over the lignite-bearing area are characterised by asymptotic rise of 45 and exhibit the infinite resistivity to the bedrock (Nagaur sandstone). Further, the lignite-bearing horizon overlying the bedrock possesses lower order of resistivity value (3 to 5 ohm-m) in comparison to the barren area having about 10 to 20 ohm-m. In barren area, the asymptotic segment indicating the bedrock (Nagaurs) possesses finite resistivity value and rise of segment is less than 45". The depth to the bedrock is observed to be larger in the lignite-bearing area than that of the barren area, which suggests favourable basinal/sub-basinal environment for lignite deposition over the bedrock.