Provenance signatures from whole rock Geochemistry of Archaean Metapelites from Eastern Dharwar Craton, Southern India

Abstract

In this paper an attempt has been made to present the major, trace and REE geochemistry, whole rock Sm-Nd and Rb-Sr isotope data of metapelites from different localities (Pavagada, Bidaloti, Bandihalli and Duntur) in the Eastern Dharwar Craton, in order to characterize the nature of provenance, weathering conditions, tectonic settings and crustal evolution. Major elements, trace element contents, Rb/Sr, Th/U, Zr/Y, Th/Sc, Nb/Ta, Zr/Hf, Cr/Ni, Ni/Co, Cr/Y, Eu/Eu* ratios and REE patterns of the studied metapelites indicate their derivation from provenance comprising varying proportions of ultramafic-mafic-intermediate source. Highly variable CIA and CIW values with low contents of Ca and Na indicate variable and locally moderate to intense weathering of the source rocks. On La/Sc Vs Ti/Zr, Co -Th-Zr/10, Sc-Th-Zr/10 and Th-La-Sc discriminating plots, the studied metapelites plot within the oceanic island arc and continental island arc fields, confirming the Arc provenance for the studied metapelites. The studied metapelites defines negative εNd values at 3000 Ma with TDM Nd model ages ranging from 3400 to 3600 Ma implies that their sources were derived from exotic sources localized outside the Dharwar craton (Today exposed terrains in western Australia, southern Africa or Antarctica) as all those fragments were once part of a supercontinent.