title: Ferruginous conditions dominated later neoproterozoic deep-water chemistry.
abstract: Earth's surface chemical environment has evolved from an early anoxic condition to the oxic state we have today. Transitional between an earlier Proterozoic world with widespread deep-water anoxia and a Phanerozoic world with large oxygen-utilizing animals, the Neoproterozoic Era [1000 to 542 million years ago (Ma)] plays a key role in this history. The details of Neoproterozoic Earth surface oxygenation, however, remain unclear. We report that through much of the later Neoproterozoic (<742 +/- 6 Ma), anoxia remained widespread beneath the mixed layer of the oceans; deeper water masses were sometimes sulfidic but were mainly Fe2+-enriched. These ferruginous conditions marked a return to ocean chemistry not seen for more than one billion years of Earth history.
authors.affiliation: Nordic Center for Earth Evolution and Institute of Biology, Campusvej 55, University of Southern Denmark, 5230 Odense, Denmark. dec@biology.sdu.dk
authors.forename: Donald E
authors.initials: DE
authors.lastname: Canfield
authors.forename: Simon W
authors.initials: SW
authors.lastname: Poulton
authors.forename: Andrew H
authors.initials: AH
authors.lastname: Knoll
authors.forename: Guy M
authors.initials: GM
authors.lastname: Narbonne
authors.forename: Gerry
authors.initials: G
authors.lastname: Ross
authors.forename: Tatiana
authors.initials: T
authors.lastname: Goldberg
authors.forename: Harald
authors.initials: H
authors.lastname: Strauss
mesh_terms: D000818:Animals; D001272:Atmosphere; D019015:Geologic Sediments / Q000737:chemistry*; D046448:Ice Cover; D007501:Iron / Q000032:analysis*; D009792:Oceans and Seas; D010084:Oxidation-Reduction; D010100:Oxygen / Q000032:analysis*; D012623:Seawater / Q000737:chemistry*; D013431:Sulfates / Q000032:analysis; D013440:Sulfides / Q000032:analysis; D013995:Time
chemical_list: D013431:Sulfates; D013440:Sulfides; D007501:Iron; D010100:Oxygen