Geochemical characteristics of amgaon mafic rocks, western bastar craton, central india: emphasis on their palaeotectonic evolution.

The Amgaon mafic rocks occur as restite blocks within Amgaon gneissic complex which are metamorphosed upto amphibolite facies. Low Na₂O+K₂O (<4%), moderate concentration of SiO₂, low differentiation index (DI<30) and solidification index (SI; avg. 32.18) are the characteristics of basic nature of these rocks. Na₂O, MgO and CaO/Al₂O₃ values are similar to MORB (2.68%, 7.6% and 0.74% respectively) values. They show low-K tholeiitic characteristics which have evolved under ocean related tectonic environment close to mid oceanic ridge (MOR) and Fe-rich Archean mantle may be the source of these rocks.