In comparison to the greenstone belt volcano-sedimentary successions, mature arenite dominated sedimentary deposits are very rarely preserved in Paleo-Mesoarchean rock record. Such arenitic deposits may be important for the recognition of extensive development of continental freeboard and onset of Phanerozoic style plate tectonics. The Keonjhar siliciclastics are ~715-m thick mature arenite-dominated Mesoarchean succession that unconformably overlies Paleo-Mesoarchean granite-greenstone core of the Singhbhum craton. The succession is mapped on 1:50,000 scale, and is designated as the Keonjhar Quartzite. It is subdivided into conglomerate dominated lower unit as the Asurkhol Member and mature arenite dominated upper unit as the Kamalpur Member. A lensoid body of iron ore clast bearing conglomerate unconformably overlies the Keonjhar Quartzite, and is designated here as the Chamakpur Conglomerate. The succession is repeated by three westerly dipping reverse faults that have upthrown the deeper parts of the basinal transects against shallower parts. The Asurkhol Member represents subaerial part of a coastal alluvial fan. The Kamalpur Member represents shallow-shelf depositional setting. Detailed mapping and recognition of the fault slices led to the reconstruction of the paleogeographic setting. The present study also highlights the importance for the stratigraphic correlation of the Keonjhar Quartzite with underlying metabasics of Malangtaoli- Jagannathpur lava and the overlying western IOG succession. The internal stratigraphic classification proposed here is also significant from economic point of view with regard to the occurrences of uraniferous QPCs in the Asurkhol Member and detrital iron ore deposits in the Chamakpur Conglomerate.

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