CHEMICAL AGE OF DETRITAL ZIRCONS FROM THE BASAL QUARTZ-PEBBLE CONGLOMERATE OF DHANJORI GROUP, SINGHBHUM CRATON, EASTERN INDIA

Chemical ages of detrital zircon concentrates from the uranium-bearing basal quartz-pebble conglomerate of Dhanjori Group from six localitie s have been determined based on high precision analysis of U, Th and P b. Three of the zircons gave concordant ages of 3044-3090 Ma, which re present the minimum age of the provenance rock and older age limit of Dhanjori sedimentation, The Singhbhum Granite Complex dating between 3 .3 Ga (Phases I & II) and 3.12 Ga (Phase III) are the likely provenanc e rocks. Chemical ages, coupled with evidences from field relations an d temporal nature of uranium-bearing QPCs suggest that the sedimentary members of Dhanjori Group are likely to be older than the presently a ssigned age of 2300 Ma.