Decoding Provenance, Paleoweathering Conditions and Tectonic Setting of the Mangalwar Complex, Central Rajasthan, <scp>NW</scp> India: Evidence From Elemental and Sr‐Nd Isotopic Studies of the Amphibolites and Metasedimentary Rocks

ABSTRACT The Paleoproterozoic Mangalwar Complex (MC) comprises various lithologies, including granitoids, amphibolites, metasediments and basement gneisses. Limited geochemical data have made the provenance, paleoweathering conditions and tectonic setting of the MC ambiguous. Addressing these issues, we present the first comprehensive geochemical and Sr‐Nd isotopic study of metasediments, along with the geochemistry of amphibolites. Field observations reveal that amphibolites occur as isolated bodies, as intrusive dykes, and as intercalated with studied metasediments. Petrographic studies indicate that both lithologies underwent metamorphism to amphibolite facies. The amphibolites are tholeiites, which are derived from high‐degree partial melting of a depleted mantle at shallow depths. Geochemistry and detailed field observations suggest that the amphibolites were emplaced in a continental rift setting, and the studied metasediments were deposited in this rift basin. The geographically nearby situated provenance suggests rapid and short‐distance deposition, consistent with low chemical weathering despite globally warm, humid conditions during the Paleoproterozoic. Elemental and isotopic ratios, including Na 2 O/K 2 O, SiO 2 /Al 2 O 3 , Al 2 O 3 /TiO 2 , La/Sc, Cr/Th, Th/Co, Th/Sc, Zr/Sc, 87 Sr/ 86 Sr and 143 Nd/ 144 Nd, and the REE patterns coupled with field observations, indicate that the sediments were derived dominantly from a felsic igneous source with insignificant mafic contribution. The negative ε Nd (1.7 Ga) (−15.1 to −4.9) values and T CHUR ages (2.10 to 3.18 Ga) suggest that the provenance of the studied metasediments was a felsic crust. Earlier studies suggested a subduction‐related arc setting and an Archean provenance; however, our findings contrast with earlier studies and indicate that the metasedimentary rocks were deposited in a continental rift setting, and the Paleoproterozoic granitoids and ortho‐gneisses belonging to the MC served as the provenance.