Petrogenesis of Flood Basalts of the Narsingpur–Harrai–Amarwara–Lakhnadon Section of Eastern Deccan Province, India

Abstract

The present area of investigation falls in the Eastern Deccan segment where available field and geochemical data are rather limited. In the present study, five distinctive structural zones namely Lower Vesicular zone, Lower Colonnade Zone, Entablature Zone, Upper Colonnade Zone and Upper Vesicular Zone have been identified in different lava flows which are helpful for the purpose of stratigraphic correlation. All the lavas under investigation can be classified into three distinct geochemical groups (viz. Group I, Group 2 and Group 3) on the basis of their Mg′ number and TiO2 wt%. The Group 1 lavas are marked by low Mg′ No (0.39–0.45) and high TiO2 (2.9–3.6 wt%) while Group 2 lavas are characterized by moderate Mg′ No (0.45–0.50) and moderate TiO2 (2.4–2.9 wt%). On the other hand, high Mg′ No (0.49–0.54) and low TiO2 (1.91–2.31 wt%) characterize the Group 3 basalts. Interestingly, the basaltic flows corresponding to three distinct groups are intermixed with each other; in other words, lava flows belonging to several groups are juxtaposed with one another with increasing height.