Uranium enrichment in altered metasedimentary rocks of Jahaz uranium deposit, North Delhi fold belt, Rajasthan, India: Inferences from whole-rock geochemical studies

Abstract

Jahaz deposit is one of the promising Na-metasomatic uranium deposits along the “albitite line” and is hosted in the Meso-Proterozoic metamorphic rocks of the North Delhi Fold Belt, Rajasthan, India. This article presents whole-rock geochemical analyses of major, trace, and rare-earth elements of less to moderately altered and albitized rocks, which are used to quantify the exchange of chemical components during fluid-rock interaction. The alteration box plot indicates the intensity of alterations (albitization, chloritization, calcitization, sericitization, pyritization), and it is inferred that Na-Ca-Mg-K metasomatism was responsible for the formation of albite, chlorite, calcite, and sericite in the altered rocks. Isocon diagrams have been constructed using major and selected trace element concentrations of less to moderately altered and albitized garnetiferous quartz biotite schist/amphibolite to determine the net loss and gain of elements during rock-fluid interaction. The correlation coefficients indicated that elements such as Zr, Nb, Hf, and Ti were less mobile during fluid-rock interaction. Isocon analyses show that the albitized garnetiferous quartz biotite schist is significantly enriched in U, Na, Mg, Fe, Ca, Mo, Cu, Rb, and depleted in K, Pb, Ba, Ni, Zn. Albitized amphibolites are enriched in Na, Cu, Mg, Cu, Y, Cr, Se, Ni, K, LOI and depleted in Ba, Co, Pb, Zn, Ca, P, Mn, Fe. The low Th/U ratio of albitized garnetiferous quartz biotite schist indicates that the albitized rocks are significantly enriched in uranium. Hence, uranium enrichment is positively correlated with Na, Mo, Cu, Th, Zr, LOI, and light rare-earth elements of albitized garnetiferous quartz biotite schist/amphibolite in the Jahaz uranium deposit. These results are similar to Kirovograd and Novoukrainka (Ukraine), Lagoa Real (Brazil), Valhalla (Australia), Longshoushan (China), Aricheng (Guyana) and Coles Hill (USA) Na-metasomatic uranium-deposits. © 2025 Elsevier Ltd