The oldest crust in the Ukrainian Shield - Eoarchaean U-Pb ages and Hf-Nd constraints from enderbites and metasedimentsVise andre og tillknytning
2014 (engelsk)Inngår i: Continent Formation Through Time / [ed] Roberts, N. M. W., van Kranendonk, M., Parman, S., Shirey, S. and Clift, P. D., London: The Geological Society Publishing House, 2014, Vol. 389Kapittel i bok, del av antologi (Fagfellevurdert)
Abstract [en]
The oldest crust in the Ukrainian Shield occurs in the Podolian and Azov domains which both include Eoarchaeanarchaean components. U-Pb age data for Dniestr-Bug enderbites, Podolian Domain, indicate these are ca. 3.75 Ga old, and Lu-Hf isotope date indicate extraction from chondritic to mildly isotopically depleted sources with εHf up to ca. +2. Nd model ages support their Eoarchaeanarchaean 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 Eoarchaeanarchaean primary crustal sources with chondritic to mildly depleted Hf isotope signatures at 3.75 Ga. A minor portion is derived from Mesoarchaeanarchaean crust with a depleted εHf signature of ca. +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 Neoarchaeanarchaean, ca. 2.8 Ga, and Palaeoproterozoic, ca. 2.0 Ga metamorphism. The spatial distribution indicates that the Podolian and Azov domains have evolved independently of each other before the amalgamation of the Ukrainian Shield.
sted, utgiver, år, opplag, sider
London: The Geological Society Publishing House, 2014. Vol. 389
Emneord [en]
Archean, Crustal evolution, Ukrainian Shield, U-Pb, Hf
HSV kategori
Forskningsprogram
Den föränderliga jorden
Identifikatorer
URN: urn:nbn:se:nrm:diva-1012DOI: 10.1144/SP389.9OAI: oai:DiVA.org:nrm-1012DiVA, id: diva2:770726
Forskningsfinansiär
Swedish Research Council, 621-2011.54352014-12-112014-12-112015-02-02bibliografisk kontrollert