Petrology, Geochemistry and Stable Isotope Studies of Carbonate-Rich Dyke-Like Bodies, Chhaktalao Area, Madhya Pradesh

Carbonate-rich rocks occur as E-W trending dyke-like bodies in the Deccan 'basalts at Chhaktalao area in the lower Narmada valley and show a structurally controlled mode of emplacement. Modal composition shows calcite as the dominent mineral (∼90%). Ankerite, apatite, altered olivine, augite and opaques account for the remaining percentage. Geochemically, these rocks show high CaO (>50%) with low SiO₂, TiO₂, FeO* and K₂O. Trace element concentrations are low compared to average carbonatites. Stable isotope studies show that δ¹³C(-1.74‰ to -2.8‰) and δ¹⁸O(+12.75‰ to +13.35‰) values do not compare with those of "primary igneous carbonatites" eventhough they fall within the wide range of "igneous carbonatites". These rocks can be considered only as carbonate-rich rocks and not as true carbonatites.