• Gautam Gupta

Articles written in Journal of Earth System Science

• Temporal geoelectric behaviour of dyke aquifers in northern Deccan Volcanic Province, India

Vertical electrical resistivity soundings (VES) were carried out over four major dykes of Nandurbar district in the northern Deccan Volcanic Province (DVP) of Maharashtra to investigate the subsurface geological conditions, with an aim of identifying zones with groundwater resource potential. Dykes can act as pathways or barrier to the groundwater flow depending upon the intensity of fracturing in the dyke rock. Whether the dykes act as water conduits or as barriers depends on their structure, location and orientation with respect to the groundwater flow. The Nandurbar district is known for occurrence of dykes and dyke swarms. A total of 33 dykes were demarcated in the study region and four major dykes (D4, D5, D6, and D7) from these were chosen for detailed VES studies. Data were acquired over these four dykes during pre-monsoon and post-monsoon periods to observe the seasonal variation in groundwater movement. These studies revealed changes in field characters, their attitudes, thickness and structure of the dykes. Longitudinal geoelectrical sections along these dykes demonstrated carrier as well as barrier stretches which identified potential aquifers up to depths of 25–30m below which hard and compact rock exists. These studies also indicated that dykes with sufficient width, length and favourable hydrogeological structure form potential aquifers for the occurrence and movement of groundwater in the study area.

• Geoelectric investigation to delineate groundwater potential and recharge zones in Suki river basin, north Maharashtra

Suki river basin of Raver sub-division is located towards the northeastern part of Jalgaon district in Maharashtra State. The existing land use pattern of the region clearly shows that more than 60% of the area is utilized for agricultural sector. Groundwater is the major source of irrigation and domestic purposes. To assess the overall water resources development of Raver area for better environment in future, investigation was carried out with the help of geophysical indicators. Vertical electrical sounding studies were conducted at 17 stations in the study area using Wenner configuration. The study was aimed at characterizing the aquifer in the area as well as assessing its potential risk to contaminant seepage in terms of protective capacity of the overburden rock materials using Dar-Z arrouk (D-Z) parameters, viz., the transverse resistance (𝑇), longitudinal conductance (𝑆), transverse resistivity ($\rho_{t}$) and longitudinal resistivity ($\rho_{l}$). These were computed to generate the resistivity regime of freshwater-bearing formations and its movement. The central-western part of the study area reflects very good to good protective capacity rating as can be seen from the high longitudinal conductance values. The low value of the protective capacity in the eastern part is making the aquifer system in the area highly vulnerable to surface contamination. This indicates that the ground water quality may have been deteriorated in the area and borehole water samples should be randomly sampled for contaminant loads based on this analysis.

• Structural mapping of Chikotra River basin in the Deccan Volcanic Province of Maharashtra, India from ground magnetic data

Ground magnetic data collected over Chikotra River in the peripheral region of Deccan Volcanic Province (DVP) of Maharashtra located in Kolhapur district was analysed to throw light on the structural pattern and distribution of magnetic sources within the basin. In order to isolate the magnetic anomalies showing varying trend and amplitude, several transformation operations including wavelength filtering, and upward continuation has been carried out on the reduced to pole anomaly map. Qualitative interpretation of these products help identify the distribution of magnetic sources, viz., the Deccan basalts, dolerite intrusives and older greenstone and schist belts in the subsurface. Present study suggests that the Chikotra basin is composed of three structural units; a NE–SW unit superposed on deeper NW–SE unit with randomly distributed trap flows on the surface. One of the major outcome of the present study is the delineation of almost 900-m thick Proterozoic Kaladgi sediments below the Deccan trap flows. The NE–SW magnetic sources may probably represent intrusives into the Kaladgi sediments, while the deeper NW–SE trends are interpreted as the northward extension of the Dharwars, underneath theDeccan lava flows, that forms the basement for the deposition of Kaladgi sediments.

• # Journal of Earth System Science

Volume 129, 2020
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