Geochemistry of Proterozoic clastic rocks of the Kerur Formation of Kaladgi-Badami Basin, North Karnataka, South India: implications for paleoweathering and provenance

Authors: ARIPUTHIRAN RAMACHANDRAN, JAYAGOPAL MADHAVARAJU, SOORIAMUTHU RAMASAMY, YONG IL LEE, SESHA RAO, DAVID LALHMINGLIANA CHAWNGTHU, KASILINGAM VELMURUGAN

Abstract: Major, trace, and rare earth element (REE) studies have been conducted on the Proterozoic clastic rocks of the Kerur Formation of the Kaladgi-Badami Basin, South India, to determine their paleoweathering conditions and provenance characteristics. Geochemically, these sedimentary rocks are classified as quartz arenite, arkose, litharenite, and sublitharenite. The chemical index of alteration values and the A-CN-K diagram suggest that the clastics rocks in this study underwent moderate to intensive weathering. Chondrite-normalized REE patterns with light REE enrichment, flat heavy REE, and a negative Eu anomaly also attribute felsic source-rock to sedimentary rocks of the Kerur Formation. In addition, Eu/Eu* (~0.77), (La/Lu)_cn (~7.65), La/Sc (~5.39), Th/Sc (~3.49 ), La/Co (~6.79), and Cr/Th (~0.31) ratios support a felsic source for these rock types. Comparing REE patterns and Eu anomalies of the source rocks reveals that the Kerur Formation clastic rocks received a major contribution of sediments from the Dharwar Craton.

Keywords: Geochemistry, Proterozoic, paleoweathering, provenance, Kerur Formation, Kaladgi-Badami Basin

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