Giant plagioclase basalt from northern part of Jhabua district, Madhya Pradesh, Central India

Abstract

A brief petrological account of six basalt flows from northern part of Jhabua district, Madhya Pradesh, central India is presented. The lowest flow with a thick red bole horizon at the bottom resting over the Precambrian Aravalli Supergroup of rocks is a giant plagioclase basalt (GPB) flow. The second flow is distinctly porphyritic containing augite phenocrysts. The other four flows are also porphyritic with phenocrysts of mainly plagioclase and microphenocryst of augite. Major element chemistry indicates that lowest two flows (Flows-1 and 2) belong to one chemical type (CT-I) while the rest four flows (Flows-3-6) belong to other (CT-II). Flows-1 and 2 appear to be two different flow units of a single compound flow. It is interpreted here that filtration mechanism after a period of magma chamber dormancy might have played which caused the difference in phenocryst mineralogy. © 2011 Springer Science+Business Media B.V.