Mineralogical, Geochemical and Nd Isotopic Study of the Meta-Clastic Rocks of the Paleoproterozoic Mahakoshal Basin, Central Indian Tectonic Zone: Implications for Provenance Characterization, Paleoweathering Conditions and Tectonic Setting

Abstract

The present study focuses on the petrographic studies, XRD patterns, whole-rock geochemical data and Nd isotopic data of the clastic rocks of the Paleoproterozoic Mahakoshal Basin which includes meta-argillites, meta-greywackes and quartzites to characterize their provenance, tectonic setting, weathering intensity, and paleoclimate condition. Geochemically, the rock samples of meta-argillite and meta-greywacke in the bivariate plot Log Na₂O/K₂O vs. Log SiO₂/Al₂O₃ are classified as litharenite and greywacke. The samples of quartzite fall in the fields from the sublitharenite to quartzarenite. The weathering indices such as CIA, \(\alpha _{{{\text{Ca}}}}^{{{\text{Al}}}}\), \(\alpha _{{{\text{Na}}}}^{{{\text{Al}}}}\), \(\alpha _{{\text{K}}}^{{{\text{Al}}}}\), \(\alpha _{{{\text{Sr}}}}^{{{\text{Al}}}}\), \(\alpha _{{{\text{Ba}}}}^{{{\text{Al}}}}\) and Th/U suggest that the clastic rocks have undergone moderate to intense chemical weathering and show K-metasomatism. Chondrite normalized REE patterns, discriminant diagrams of La–Th–Sc and Ni–V–10*Th and various transition elements ratio such as Cr/Th, Th/Co, Th/Sc, and La/Sc support the mixing of the mafic, intermediate and felsic sources. The Eu anomaly is highly variable and ranges from 0.29 to 1.08 and supports that the sediments have been derived from the heterogeneous source. T_CHUR model ages are consistent with 1.98–2.92 Ga possible provenance. εNd(t) and f(Sm/Nd) values overlap with the arc and the Archean crust signatures indicating that the sediments are derived from a Paleoproterozoic arc and older Archean crust (TTG gneisses and Archean granite). The opening of the Mahakoshal Basin is characterized by the retreating accretionary orogen and the closure of the basin is due to switching retreating accretionary orogen into advancing accretionary orogen which is contemporaneous to the assembly of the Columbia Supercontinent (∼1.8 Ga).