Mineralogical Studies of Metasomatized Host Rocks of Jahaz Uranium Prospect, North Delhi Fold Belt, Rajasthan

Uranium mineralization in Jahaz prospect of North Delhi Fold Belt, Rajasthan is closely associated with deformed and metasomatized meta-sediments of Ajabgarh Group. Detailed petrographic and electron microprobe studies of bore-hole samples indicate that the host rocks consist of metamorphic mineral assemblage such as quartz-annite-muscovite-hornblende (magnesiohornblende - ferrohornblende) - anorthite—bytownite with almandine - staurolite-corundum- ilmenite. Brittle-ductile deformation is evident by brecciation, micro-folds and fracture filled micro-veinlets of quartz and calcite. Fluid induced alteration products are pennine-albite-phlogopite-orthoclase-sphene-rutile-actinolite-ferropargasite-sericite-calcite-apatite. Two types of albite are prominent, albite-1 formed by alteration of parent metamorphic plagioclase, whereas albite-2 is feathery and found to be in open spaces and formed by precipitation of sodium rich fluid. Sulfide minerals (pyrrhotite-chalcopyrite) are most common in albitized rocks and commonly associated with calcite. The above studies clearly indicate the geological processes responsible for the formation of metamorphic-metasomatic mineral assemblages in host rocks associated with uranium mineralization.