A Petrological and Geochemical Account of Subsurface Noritic Intrusion in the Western Part of Bundelkhand Massif, Shivpuri District, M.P.

Abstract

Subsurface exploration for uranium in the northwestern part of Bundelkhand massif, near Khor area, Shivpuri dist., M.P., resulted in intercepting a substantial thickness of mafic rock within Bundelkhand granitoid. Intercepts of this mafic rock at various levels in the boreholes, indicate that the rock mainly occurs as dyke-like intrusion and fracture-fills within Bundelkhand granite. It is essentially composed of hypersthene and plagioclase, with or without olivine, leading to the characterisation as hypersthene microdolerite, noritic dolerite and norite (±olivine), depending on the grainsize and variation from intergranular to ophitic texture. Chemically, the rock is characterised by av. 49.09% SiO2, 2.46%TiO2, 2.33 Fe2O3, 9.45% FeO, 5.75% MgO, 8.37% CaO and 0.96% K2O. The normative composition ranges from 3.53% quartz, 46.86% plagioclase, 12.58% diopside, 19.24% hypersthene. The olivine normative samples show av. 5.65% olivine. Geochemical plots indicate an intra-plate affinity along with oceanic signature, while presence of mineralogical and normative olivine, together with the REE pattern, point towards a lower crustal or mantle source. The mineralogical and normative presence of either quartz or olivine in these mafic rocks implies that it has an intermediate character between the tholeiitic dolerite dykes and the komatiite-type ultramafics reported from Bundelkhand craton. The complex geochemical signature of the rocks also reveals that both intra-continental as well as a mixture of oceanic-to upper mantle signatures are evident. The present study is a first time report of the occurrence of this hitherto unknown noritic body at depth within the Bundelkhand granite, which has no visible surface expression. The findings may strengthen the existing concept of a continuum between Rajasthan craton in the west and Bundelkhand craton in the east, as a single proto-continent.

Estimation of Geotechnical Parameters for Coal Exploration from Quasi-3D Electrical Resistivity Measurements

“…The Panchet/Pachmari formation mainly comprises thick beds of coarse felspathic and micaceous sandstones, generally white or greenish white, with minor spots of red clay. Granite intrusions influence the Chotanagpur plateau from the east to the west [38].…”

Evolution of Bundelkhand Craton

“…BuC 2015;Kaur et al, 2016;Saha et al, 2016;Joshi et al, 2017;Pati et al, 2017;Singh et al, 2019;Nasipuri et al, 2019;Alfimova et al, 2019). The lithology mainly comprises tonalite-trondhjemitegranodioritic (TTG) gneisses, metasupracrustals (amphibolites, banded iron formation, komatiitic basalts (~modern boninite), metaperidotite, calc-silicate rocks, corundum-bearing phengite schist, quartzsericite schists, fuchsite quartzite and quartzite), granitic rocks (plutonic, hypabyssal and volcanic variants), giant quartz veins, mafic dykes and some noritic intrusions in the western part of BuC (Basu, 1986;Sarkar et al, 1996;Sharma and Rahman, 2000;Mondal et al, 2002;Malviya et al, 2006;Saha et al, 2011Saha et al, , 2016Kaur et al, 2016;Verma et al, 2016;Joshi et al, 2017;Singh et al, 2018;Roy et al, 2018;Nasipuri et al, 2019;Alfimova et al, 2019).…”