[en] A new type of uranium mineralization, associated with late stage pegmatitic activity and quartzo-feldspathic injections has been identified in Rohil West that lies at about 500 m west of main Rohil uranium deposit. The injections have caused extensive deformation and silicifications of host quartz-muscovite-biotite schist. Uranium mineralization is represented by uranitite occurring in association with high temperature phases like allanite, monazite and zircon. Uranitite forms coarse to medium euhedral - subhedral grains showing intergrowth textures with minerals like quartz, feldspar and biotite of quartzo-feldspathic injections. Uraninites contained high ThO₂ 2.67-7.21wt% (av. 4.78%, n=30) and high Re₂O₃ (2.35-4.31 wt.%, n=30). Chemical age of uranitite is calculated as 675-834Ma. In view of inter-growth textures, high ThO₂ content and association with quartzofeldspathic injections uranium mineralization in Rohil West block is interpreted as Pegmatitic Type. The recognition of granite-pegmatite related uranium mineralization in Rohil West has opened up another dimension for the exploration, in addition to the largely Metasomatite Type uranium mineralization at Rohil. The possible extensions of newer type of uranium mineralization in NDFB need to be interpreted from heliborne geophysical data for the search of satellite deposit to Rohil. (author)

[en] The South Khetri sub-basin (KSB) in North Delhi Fold Belt (NDFB) along Narsinghpuri-Khandela-Rohil tract exposes Ajabgarh Group of metasediments of Delhi Supergroup. The Ajabgarh Group comprises impure carbonate sequence with volcanics in the lower part and psammopelitic assemblage with minor lenses of carbonate and siliceous rocks in the middle and upper part. The NNE-SSW trending wide spread zone of albitisation in KSB forms a mega lineament, which can be traced from north of Sior-Siswali to south of Kishangarh, covering approximately 170 km length along strike with 6-10 km width. Integrated exploration approach by AMD has led to the establishment of sizeable uranium deposit at Rohil, Sikar district, Rajasthan; thereby NDFB has now been established as uranium potential province. The study area is mostly soil covered baring N-S to NNE-SSW trending quartzite ridge exposed in the northwestern part of Rohil village