Concordant 3,676 Myr U-Pb formation age for the Kodaikanal iron meteorite

The authors report the results of U-Pb isotope analyses on a silicate inclusion from the Kodaikanal iron meteorite. Leaching experiments on the two major phases, clinopyroxene (CPX) and alkali-rich glass, indicate a contamination by terrestrial Pb attributable to previous curatorial cutting of this iron meteorite. The leached minerals define concordant U-Pb ages that validate the precise Pb-Pb age of 3,676+-3 Myr. These data are consistent with Rb-Sr age determinations. The absence of initial Pb indicates a fast cooling of the silicate material. This has already been established for the metal phase, and a collisional origin for Kodaikanal is favoured. (author)