Polymodal Volcanism in Parts of the South Delhi Fold Belt, Rajasthan

The Proterozoic South Delhi Fold Belt (SDFB) is known to have a dominant volcanic component along the western flank of the Aravalli Range. Earlier studies have indicated both bimodal and unimodal characters of these volcanics in different parts of the SDFB. The Shyopura-Narpura area in north-central part of the Aravalli Range has, on the other hand, volcanics of intermediate and ultrabasic composition, interlayered with basic and felsic volcanics. This polymodal suite of secondary greenstone character is interpreted to have erupted in a rifted back-arc setting.