The present paper addresses petrography, geochemistry and Ar‐Ar geochronology of a significant number of mafic dykes from the Paleo‐ to Neoarchean Bundelkhand Craton in central India. The majority of the dykes are NW‐SE oriented (with a few NE‐SW and ENE‐WSW) with tholeiitic, sub‐alkaline and basalt to basaltic andesite composition. The trace element geochemistry of these dykes indicates an island arc setting during emplacement. The Ar‐Ar mineral dating (plagioclase) of three representative dykes reveals an emplacement age between 1.53 and 1.46 Ga. This finding and earlier reports (2.1–1.73 Ga) point to sustained mafic magmatism throughout the Bundelkhand Craton in a preferred structural orientation between 2.1 and 1.46 Ga. Mafic magmatism was episodic and can be linked to the perpetual subduction accretion processes between the central Indian Archean continents during the development of the Columbia supercontinent. The mafic dykes were emplaced at 45° to the maximum compression direction (E‐W), that is, along the line of no finite longitudinal strain. This time equivalent widespread NW‐SE and NE‐SW trending mafic dyke system is also relatable along the adjacent continents (Singhbhum, Bastar) and thus opened up a new paradigm for the dyke's emplacement across the Indian cratons.
This study in part of Veppilaipatti Village, Tamil Nadu, used 2D profiling, Vertical Electrical Sounding (VES), and self-potential methods for groundwater exploration. A predominance of A and H type curves indicated subsurface layers and water-bearing capacity. Self-potential data identified three water-saturated zones. VES at 73m depth was recommended as a high-yielding well bore point. The electrical resistivity study revealed saltwater presence in the middle portion. The 3D subsurface model illustrated the study area's characteristics. Overall, this integrated approach is valuable for informed water resource management decisions in the region
The Palaeo- to Neoarchaean Bundelkhand Craton (BkC) in central India has received attention due to its felsic crust evolution. There are two linear patches of relict greenstone belts in the BkC, and the central greenstone belt has been the focus of extensive research for the past two decades. In contrast, the southern greenstone belt has received inadequate attention. At the southern BkC, the E-W Madawara Greenstone Belt is represented by patches of remnant mantle serpentinites and metasedimentary rocks that are tectonically juxtaposed with Archaean basement TTG gneisses and Proterozoic Bijawar Group of rocks. This study highlights key findings from fields, geological maps, petrography, and a large number of whole rock chemical analyses of serpentinites and spinel chemistry to unravel the tectonic evolution story. We identified two serpentinites with contrasting petrological and geochemical properties: spinel peridotite (SP) and talc-tremolite schist (TTS). SP is primarily dunite to harzburgite with relatively high MgO (33 wt%), enriched Yb, and shows strong re-fertilization. TTS, on the other hand, is lherzolitic and less refractory (MgO = 25 wt%). Chemically, these two serpentinites were mantle wedge and subducted peridotites, respectively. The unaltered cores of the chromium spinels represent a fore-arc setting. These findings, in conjunction with prior research, paint a compelling picture of a Neoarchaean (~2.5 Ga) subduction system once present in the southern Bundelkhand Craton. The serpentinites represent relict ophiolites – from a northerly dipping trench. It also explains a Mesoarchaean rift basin system between the two cratonic nuclei of southern Bundelkhand, which amalgamated during the Kenorland Supercontinent formation.
Groundwater exploration in a section of Siruvadi Village, Tamil Nadu, utilized the VES method with Schlumberger electrode configuration, proving the efficacy of the Electrical Resistivity method in identifying subsurface structures. Interpretation of VES data revealed two, three, and four layers, with A and H type curves dominating, providing insights into layer number, thickness, and water-bearing capacity. Schlumberger-based VES identified water-bearing zones at 50m, 70m, 40m, 60m, 80m, and 73m depths, with the VES at 80m (VES POINT 5) suggested as a high-yielding well bore point. This comprehensive approach enhances our understanding of subsurface characteristics and informs groundwater resource management decisions in the region
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