Thermal zone identification by gravity data modeling using Euler deconvolution and geochemical analysis of hot springs in Saurashtra and Cambay Basins

Objective: This study is aimed at interpreting geochemical and geophysical data of 4 locations in Gujarat, India to understand the subsurface geothermal hotspot locations. Methods: CG-5 gravimeter was used to collect the gravity data. Data corrections were done to obtain a complete Bouguer anomaly. The depth of the dense bodies was calculated using Euler deconvolution. Also, the geochemical classification of physiochemical properties of geothermal spring waters of the locations was evaluated to assess their possible applications. Findings: In the sample region, the complete Bouguer anomaly analysis ranges between 1.99 mGal-2.23 mGal. The Euler deconvolution produced depth solutions ranging from 100 to 450 meters, which were mostly found near gravity highs, and the presence of deep structures can be deduced. These deep structures are translated as dense intruding bodies trapped by an overlying cap rock. The Geochemical analysis was done of the four samples. Based on the results of various plots such as Ternary, Durov, Piper, Stiff, the waters are graded as cationic with Na+K and anionic with Cl+SO4. The sample waters indicate suitability for drinking and irrigation at some locations. Finding these hotspots and exploiting them is of importance for these areas which are dealing with the acute water crisis. Novelty: Euler deconvolution of gravity data was first time applied for subtle geothermal trap identification in Saurashtra and Cambay basins. It has been established through this study that surface manifestation of these subtle traps are the hot springs. Systematic geochemical characterization of the hot springs progressed the nascent geothermal energy research of India. Keywords: Bouguer anomaly; Heat source; Geothermal energy; Geochemical analysis; Hot spring; water analysis