Large conglomerate lenses occur in a fine-grained siliciclastic succession of the Singhbhum craton, eastern India. They overlie an Archaean orthogneiss, from which they are separated by a palaeosol. Neither the conglomerates nor the directly overlying rocks have been dated, but the conglomerate unit is assumed to have also an Archaean age. The conglomerate lenses occur within a succession of pelitic and mafic schists, and the depositional environment of this conglomerate/schist unit had not been clarified thus far. On the basis of a combination of the vertical and horizontal distribution of the conglomerates, their stratigraphic position and analysis of their sedimentological characteristics and the sedimentological context, it is concluded that the succession must have developed in a fluvial lowland environment where volcanic input contributed significantly to the sediment accumulation.

High-precision SHRIMP U–Pb zircon dating yields a late Palaeoarchaean age (3290 ± 8.6 Ma) for a large, unmetamorphosed, weakly peraluminous TTG body (the Keonjhargarh–Bhaunra pluton) in the Singhbhum craton of eastern India. One inherited subhedral zircon grain gave a concordant age of 3495.9 ± 5.3 Ma and Nd isotope characteristics show a juvenile trend with εNdt ~ 0 and TDM 3395–3453 Ma. The data support a model of typical Archaean crustal evolution until late Palaeoarchaean times for the Singhbhum craton, which is in contrast to the more southerly Bastar craton where Palaeoarchaean non-TTG granites have been identified. These data demonstrate the diachronous development of continental crustal blocks now forming the basement of the eastern and central peninsular of India.