Provenance and Tectonic Setting of the Proterozoic Clastic Rocks of the Kerur Formation, Badami Group, Mohare Area, Karnataka, India

Abstract

The clastic rocks of the Kerur Formation Group were analyzed for major, trace and rare earth elements to infer the tectonic settings and provenance signatures. The lithology of the Kerur Formation includes basal arenite (BA), lower conglomerate (LC), quartz arenite (QA) and upper conglomerate (UC). The CIA and PIA values and A–CN–K diagram indicate a moderate to intense chemical weathering for the clastic rocks of the Kerur Formation. The bivariate plot and multidimensional diagram based on major-trace elements suggesting the clastic rocks were derived mainly from the passive margin setting. A silicic source for clastic rocks of the Kerur Formation is indicated by higher ratios of SiO2/Al2O3, ΣLREE/ΣHREE, elemental ratios, bivariate and ternary plots. REE patterns and Eu anomalies support that TTG (Tonalite-Trondhjemite gneiss), granodiorite, granitic rocks of the Dharwar Craton and the basement rock (schist) of the Kaladgi-Badami Basin could be the source rocks for the Kerur Formation. REE modeling suggests that the average composition of the Kerur Formation represents a mixture of sediments derived from a provenance consisting of 40% TTG, 30% granite, 20% granodiorite and 10% schist.