¹Bérengère Mougel, ^1,2Frédéric Moynier, ¹Christa Göpel, ^3,4Christian Koeberl
Earth and Planetary Science Letters 460, 105-111 Link to Article [https://doi.org/10.1016/j.epsl.2016.12.008]
¹Institut de Physique du Globe de Paris, Université Sorbonne Paris Cité, CNRS UMR 7154, Paris, France
²Institut Universitaire de France and Université Paris Diderot, Paris, France
³Department of Lithospheric Research, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria
⁴Natural History Museum, Burgring 7, A-1010 Vienna, Austria
Copyright Elsevier

Non-mass dependent chromium isotopic signatures have been successfully used to determine the presence and identification of extra-terrestrial materials in terrestrial impact rocks. Paleoproterozoic spherule layers from Greenland (Grænsesø) and Russia (Zaonega), as well as some distal ejecta deposits (Lake Superior region) from the Sudbury impact (1849±0.3 Ma) event, have been analyzed for their Cr isotope compositions. Our results suggest that 1) these distal ejecta deposits are all of impact origin, 2) the Grænsesø and Zaonega spherule layers contain a distinct carbonaceous chondrite component, and are possibly related to the same impact event, which could be Vredefort (2023±4 Ma) or another not yet identified large impact event from that of similar age, and 3) the Sudbury ejecta record a complex meteoritic signature, which is different from the Grænsesø and Zaonega spherule layers, and could indicate the impact of a heterogeneous chondritic body.