Geochronological study of metasediments and carbon isotopes in associated graphites from the Sargur area, Dharwar craton: Constraints on the age and nature of the protoliths

207 Pb/ 206 Pb ages of detrital zircons from the graphite bearing metasediments of the Sargur area are determined using ion microprobe to constrain the probable depositional age. Zircon ages of the samples range from 2.3 to 2.8 Ga which are close to the reported metamorphic ages in the vicinity. Absence of older age (Mesoarchaean >3.0 Ga) in these samples suggest that detrital zircons from the Sargur supracrustal unit has been reset by younger post-depositional metamorphic processes and probably reflect a craton-wide Paleoproterozoic event. The graphites from these samples vary in concentration of carbon as well as in 13 C/ 12 C isotopic ratio. The range of δ 13 C values of graphites indicates organic origin suggesting the existence of bio-organisms in the Sargur area during the Paleoproterozoic period.