Paleoproterozoic rift-related volcanism and associated ore mineralization in the Alwar Basin, India

Abstract

Alwar Basin, located within the North Delhi Fold Belt (NDFB) of India, is a key area to study the processes of Precambrian geological history and related mineralization. In this study, we document two discrete pulses of volcanic activity in the Alwar Basin, dated at 1.865 ± 0.021 Ga and 1.635 ± 0.017 Ga, recorded by weighted‐mean zircon U–Pb ages. These episodic eruptions generated a compositional spectrum from basalt through rhyolite, emplacing volcanic sequences in a shallow‐marine, within‐plate rift environment. Subsequent percolation of metal‐rich hydrothermal fluids – driven by sustained heat flux and extensional fracturing – focused along stratigraphic contacts and pre‐existing weak planes, precipitating Cu–Pb–Zn sulfide mineralization within quartz–carbonate veins. Geochemical signatures, including peraluminous major‐ and trace‐element patterns and characteristic REE anomalies, further attest to syn-rift magma evolution and crustal assimilation. This pulsatory volcanism and linked hydrothermal activity were pivotal in concentrating base metals, revealing the interplay between Precambrian rifting and ore genesis in the North Delhi Fold Belt