Crustal reworking during the transition of tectonic regime in the Paleoproterozoic Era: Constraints from geochemistry, Sm-Nd isotope and U-Pb geochronology of granitic gneisses, Dudhi Granitoid Complex, Mahakoshal belt, Central Indian Tectonic Zone (CITZ), India

Abstract

The Paleoproterozoic Dudhi Granitoid Complex is composed of numerous granitoid intrusions and gneissic components that is located in the Mahakoshal belt, which is an important supracrustal belt of the Central Indian Tectonic Zone (CITZ) and played a vital role in the crustal accretion of the Columbia supercontinent. Thus, we present new geochemical data, Sm-Nd isotope analyses, and U-Pb geochronology of the granitic gneisses from the Dudhi Granitoid Complex to understand their origin, evolution and tectonic setting. The LA-ICP-MS zircon U-Pb dating yields ages of 1707.9 ± 7.4 Ma, 1724.3 ± 8.6 Ma, 1736.8 ± 9.9 Ma, 1748.3 ± 7.9 Ma, and 1756.3 ± 10 Ma for studied granitic gneisses. These rocks are strongly metaluminous and show enrichment in high field strength elements (HFSE) and depletion in large ion lithophile elements (LILE). The trace element composition allows classifying these rocks as an A₂-type affinity in an extensional environment. They show negative values of ɛNd(t) (−5.7 to −0.4) and old Nd-model ages (T_DM: 2068–2420) support their crustal origin. Geochemical and Nd isotope data indicate that they were derived by partial melting of older granites and granitic gneisses crust i.e., Archean Bundelkhand crust and Paleoproterozoic (>1.9 Ga) juvenile crustal basement of the Mahakoshal basin. Finally, their magmatism during 1.75–1.70 Ga is linked to the transition period of accretion and dispersal of the Columbia supercontinent, which is incorporated into the lithosphere of the CITZ.