Giant Plagioclase Basalt from the Deccan Volcanic Province (DVP), Sagar District, Madhya Pradesh, India: First Report and Implications

ABSTRACT One giant plagioclase basalt GPB) flow from the northeast corner of the DVP, about 70 km south of Sagar, is reported for the first time. This GPB flow, over 40 m in thickness, is exposed approximately for 15 sq. km area and overlies a fine-grained, non-porphyritic basalt at 40 m depth in a borehole. Plagioclase phenocrysts, 4-5 cm in length, and occasionally larger, range in composition from bytownite-labradorite (An 80-60). Clinopyroxene phenocrysts though present, are rare. Major and trace element chemistry of the GPB and the non-porphyritic basalt below is presented and discussed in comparison to the well-known GPBs from Western Ghats as also those reported later from Jhabua and Jabalpur districts in Madhya Pradesh. Among other differences, MgO content of the Sagar GPB (6.13 %) seems to be the highest of all the GPBs reported from DVP so far.