Overview

Different tectono-thermal processes, like extensional and/or compressional tectonics, plume activities, that shape the crustal architecture beneath the Earth’s surface leave imprints on surface as well as subsurface levels. Such tectonic processes form several geological features like grabens, extensive thrust belts, large sedimentary basins, orogenic belts, high grade metamorphism, magmatic emplacements, exhumation of deep crustal rocks on the surface, large igneous provinces, sporadic geothermal systems, both volcanic and non- volcanic in origin. These signatures, seen at surface and deeper crustal levels, play an important role in reconstructing the several assembly-breakup cycles between the different cratons and supercontinents in the geological past. Rift basins, which have later turned into massive sedimentary sequences, and mobile belts fringing the Archean cratons across the globe, their crustal structure are usually complicated by numerous deformational processes they have undergone during the reorganization of the adjoining cratonic landmasses.

The objective is to construct the crustal configuration below two regions, the Taptapani hot spring area, located in the Eastern Ghats Mobile Belt (EGMB) in Odisha and the region around the southern area of the Bundelkhand craton, the adjoining Vindhyan basin, as well as the outcrops of Deccan traps, along the southern- southwestern edge of the craton. An integrated geophysical approach, using gravity and magnetic methods is being used for understanding the subsurface features for regional scale study as well as for detailed shallow depth mapping of geological features, to delineate the geometry, lateral extent and depths of the source bodies causing these variations. Since these regions are geologically distinct, the two regions are being studied with different perspectives, while the main aim is to understand the crustal evolution and tectonics forming the regions. The presence of the Taptapani hot spring, and others like Atri, Tarabalo, in a collisional orogenic belt of Proterozoic age, the EGMB, is the motivation behind investigating in and around this area to understand the possible correlation between the prevailing crustal structure underneath the area and the geothermal systems occurring within the mobile belt. There are several competing views on whether the Bundelkhand craton forms the basement below the surrounding Vindhyan basin and subducts further south beneath the landmass containing the Dharwar craton or that the southern limit of the craton lies along the margin between the craton and the Vindhyan basin. Thus, the study focuses on understanding the crustal structure and associated subsurface features under this region, bordering the craton, beneath the neighbouring Vindhyan basin as well the Deccan trap exposures observed in some parts along the edges of Bundelkhand.

• Developing 2D and 3D crustal models for the two regions to understand the crustal geometry, thickness, structure of the underlying Moho from gravity and magnetic studies.

• Delineation of shallow subsurface features to understand their relationship with the geothermal system of the Taptapani region of EGMB

  • • • Generating a conceptual crustal model to understand the geothermal systems of the Eastern geothermal province in EGMB in Odisha area.

• Understanding the crustal configuration below the southern region of the Bundelkhand craton, and its contact region with the bordering Vindhyan basin, Deccan traps.

  • • • To establish the relationship between the identified structural features, existing lithology, and tectonic history of the study area.