The oldest crust in the Ukrainian shield - Eoarchaean U-Pb ages and Hf-Nd constraints from enderbites and metasediments

The oldest crust in the Ukrainian Shield occurs in the Podolian and Azov domains, which both include Eoarchaean components. U-Pb age data for Dniestr-Bug enderbites, Podolian Domain, indicate that these are c. 3.75 Ga old, and Lu-Hf isotope data indicate extraction from chondritic to mildly isotopically depleted sources with ε<inf>Hf</inf> up to c. +2. Nd model ages support their Eoarchaean age, while model ages for Dniestr-Bug metasedimentary gneisses indicate that these also include younger crustal material. Most of the Hf-age data for metasedimentary zircon from the Soroki greenstone belt, Azov Domain, reflects Eoarchaean primary crustal sources with chondritic to mildly depleted Hf isotope signatures at 3.75 Ga. A minor portion is derived from Mesoarchaean crust with a depleted ε<inf>Hf</inf> signature of c. +4 at 3.1 Ga. U-Pb zircon ages from Fedorivka greenstone belt metasediments are consistent with the Soroki age data, but also include a 2.7-2.9 Ga component. Nd whole rock model ages provide support for a younger crustal component in the latter. Both domains have been subject to Neoarchaean, c. 2.8 Ga, and Palaeoproterozoic, c. 2.0 Ga, metamorphism. The spatial distribution indicates that the Podolian and Azov domains evolved independently of each other before the amalgamation of the Ukrainian Shield.