Geochemical evolution of basaltic flows from Dongargarh Supergroup, Bastar Craton, Central India

Abstract

Composition of basalts in magmatic arcs influenced by the subducting lithosphere, mantle wedge, dehydration of oceanic crust, and/or crustal assimilation beneath the arc. In this paper, we compiled earlier published geochemical data of Dongargarh basalts to decipher the genesis of volcanic rocks. SiO2 vs (FeO + MgO) plot of basalt suggests the volcanic rocks are tholeiitic in composition. Primitive mantle and REE normalized plots indicate either the source was enriched mantle or a possible interaction of depleted magmatic source with the Paleoarchean continental crust in the Bastar Craton. The primitive mantle normalized diagram shows a negative anomaly of Nb, Ti, and Ta indicates subduction-related magmatism. In addition to the basalt composition, variation diagrams for tectonic settings represent the continental arc-related magmatism. From the available geochemical data of basalts and earlier studies on Dongargarh volcanic, there was an oceanic ridge that was subducted beneath the continental plate. The source of Pitepani basalts was significantly enriched in HFSE and REE as compared to mid-oceanic basalts. Thus the study finds the volcanic rocks are part of enriched mantle source that formed in the subduction-related magmatism.