title: Oxygen isotope constraints on the sulfur cycle over the past 10 million years.
abstract: Oxygen isotopes in marine sulfate (delta18O(SO4)) measured in marine barite show variability over the past 10 million years, including a 5 per mil decrease during the Plio-Pleistocene, with near-constant values during the Miocene that are slightly enriched over the modern ocean. A numerical model suggests that sea level fluctuations during Plio-Pleistocene glacial cycles affected the sulfur cycle by reducing the area of continental shelves and increasing the oxidative weathering of pyrite. The data also require that sulfate concentrations were 10 to 20% lower in the late Miocene than today.
authors.affiliation: Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138 USA. avan@fas.harvard.edu
authors.forename: Alexandra V
authors.initials: AV
authors.lastname: Turchyn
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Schrag
mesh_terms: D001419:Bacteria / Q000378:metabolism; D001466:Barium Sulfate / Q000737:chemistry*; D019015:Geologic Sediments / Q000737:chemistry* / Q000382:microbiology; D007501:Iron / Q000737:chemistry; D008433:Mathematics; D008962:Models, Theoretical; D009792:Oceans and Seas; D010084:Oxidation-Reduction; D010103:Oxygen Isotopes / Q000032:analysis*; D012623:Seawater / Q000737:chemistry* / Q000382:microbiology; D013440:Sulfides / Q000737:chemistry; D013455:Sulfur / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D013995:Time
chemical_list: D010103:Oxygen Isotopes; D013440:Sulfides; C011342:pyrite; D001466:Barium Sulfate; D013455:Sulfur; D007501:Iron