title: Secular variation in carbon isotope ratios from Upper Proterozoic successions of Svalbard and East Greenland.
abstract: Analyses of stratigraphically continuous suites of samples from Upper Proterozoic sedimentary successions of East Greenland, Spitsbergen and Nordaustlandet (Svalbard) provide an approximation to the secular variation in carbon isotope ratios during a geologically and biologically important period of change from around 900 million years ago to the beginning of the Cambrian period.  Late Riphean carbonates and organic material show a stratigraphically useful pattern of enrichment in 13C relative to Phanerozoic or earlier Proterozoic samples.  Isotopic compositions of isolated samples from other localities are consistent with a worldwide extended interval of enhanced organic burial and consequent net survival of oxidized material, probably O2, just before the initial radiation of metazoans.
authors.affiliation: Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
authors.forename: A H
authors.initials: AH
authors.lastname: Knoll
authors.forename: J M
authors.initials: JM
authors.lastname: Hayes
authors.forename: A J
authors.initials: AJ
authors.lastname: Kaufman
authors.forename: K
authors.initials: K
authors.lastname: Swett
authors.forename: I B
authors.initials: IB
authors.lastname: Lambert
mesh_terms: D000818:Animals; D001272:Atmosphere / Q000737:chemistry; D002244:Carbon / Q000032:analysis / Q000737:chemistry*; D002247:Carbon Isotopes; D002254:Carbonates / Q000032:analysis*; D019419:Evolution, Planetary; D005580:Fossils; D019015:Geologic Sediments / Q000032:analysis* / Q000737:chemistry; D006116:Greenland; D010100:Oxygen / Q000032:analysis* / Q000737:chemistry; D010163:Paleontology; D013538:Svalbard
chemical_list: D002247:Carbon Isotopes; D002254:Carbonates; D002244:Carbon; D010100:Oxygen