On Some Aspects of the Stratigraphy, Depositional Environment and its Bearing on Uranium Mineralisation in Parts of the Singhbhum Shear Zone, Bihar

Abstract A review of the geology and controls of uranium mineralisation in the Singhbhum Shear Zone between Narwapahar (Lat. 22°44'N; Long. 86°15'E) in the west, to Ghatsila (Lat. 22°25'N; Long. 86°20'E) in the southeast and up to Dalmas in the north is presented in the light of new data based on facies analysis and palaeo-current studies of the conglomerate and associated meta-sediments in the area. Synthesis and integration of geologic data have led to the following.conclusions: a) The facies variation and its distribution pattern in the area demonstrate fluviatile conditions of deposition with upwatd fining and thinning sequences. b) The sedimentary sequence shows progressive younging towards north without any obvious break, or juxta-position of the older over the younger. c) The nature of Jaduguda sedimentary facies assemblage is indicative of a fluvial fan with conglomerate gray-wacke-arenite assemblage representing proximal fan facies. On the basis of facies model, the area north of Subarnarekha river represents a meandering fluvial pattern. d) Uranium mineralisation is distinctly stratabound with characteristic facies association.