georefid:2007-087728georefid:2007-087719SEDIS Publication Catalogue

ana.macario@awi.de

http://sedis.iodp.org/pub-catalogue/informationpointOfContact2011-06-23T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=10.2973/odp.proc.sr.207.109.20062007-01-01publicationgeorefid:2007-087728doi:10.2973/odp.proc.sr.207.109.2006Boettcher, Michael E.Max Planck Institute for Marine Microbiology, Department of Biogeochemistry, Bremen, Federal Republic of GermanyauthorHetzel, AlmutBundesanstalt fuer Geowissenschaften und Rohstoffe, Federal Republic of GermanyauthorBrumsack, Hans-JuergenOcean Drilling Program, United StatesauthorSchipper, AndreaWoods Hole Oceanographic Institution, United StatesauthorTexas A&M University, Ocean Drilling Program, College Station, TX, United StatespublisherdocumentHardcopyIn: Mosher, David C., Erbacher, Jochen, Malone, Mitchell J., Berti, Debora, Bice, Karen L., Bostock, Helen, Brumsack, Hans-Juergen, Danelian, Taniel, Forster, Astrid, Glatz, Christine, Heidersdorf, Felix, Henderiks, Jorijntje, Janecek, Thomas R., Junium, Christopher, Le Callonnec, Laurence, MacLeod, Kenneth G., Meyers, Philip A., Mutterlose, H. Joerg, Nishi, Hiroshi, Norris, Richard D., Ogg, James G., O'Regan, A. Matthew, Rea, Brice, Sexton, Philip, Sturt, Helen, Suganuma, Yusuke, Thurow, Juergen W., Wilson, Paul A., Wise, Sherwood W., Jr., Proceedings of the Ocean Drilling Program; scientific results; Demerara Rise; equatorial Cretaceous and Paleogene paleoceanographic transect, western Atlantic; covering Leg 207 of the cruises of the Drilling Vessel JOIDES Resolution; Bridgetown, Barbados, to Rio de Janeiro, Brazil; sites 1257-1261; 11 January-6 March 2003207The geochemical composition of sediments (squeeze cake samples) from five drill sites (Ocean Drilling Program Sites 1257-1261) on the Demerara Rise in the tropical Atlantic was determined, with special regard to a sequence of Cretaceous black shales. Sediments were analyzed for different iron (total, pyrite, Na dithionite, and HCl leachable) and sulfur (total, pyrite, acid volatile, and organic bound) fractions, in addition to total organic carbon (TOC) and total inorganic carbon. The relative abundance of highly reactive iron (Fe (sub HR) /Fe (sub T) ) in the investigated black shale samples indicates that pyrite was formed both in the water column and the sediment. This corresponds to euxinic paleoenvironmental conditions, a situation similar to the modern deep Black Sea. This geochemical approach is independent of a possible minor contribution from ongoing sulfate reduction which is triggered by anaerobic methane oxidation above the black shale sequence. Pyrite sulfur in black shales makes up between 30% and 100% of total sulfur. In addition to fixation of sulfide with iron, organic matter (OM) acted as an important sulfur trap during early diagenesis, with organic sulfur composing between 5 and 10 atom% of TOC. The relative importance of OM sulfurization is increasing with its content.completedGeochemistry of rocks, soils, and sedimentsaliphatic hydrocarbonsalkanesanaerobic environmentAtlantic Oceanblack shaleboreholescarbonchemostratigraphyclastic rocksconcentrationcontinental margincoresCretaceousDemerara Risedepositional environmentEquatorial AtlanticFrench GuianageochemistryhydrocarbonsironLeg 207marine sedimentsMesozoicmetalsmethaneNorth AtlanticNorthwest AtlanticOcean Drilling ProgramODP Site 1257ODP Site 1258ODP Site 1259ODP Site 1260ODP Site 1261organic compoundsoxidationpaleo-oceanographypaleoenvironmentpore waterpyritereductionsedimentary rockssedimentsSEM dataSouth AmericasulfatessulfidessulfurSurinamtotal organic carbonwestern Equatorial Atlanticurn:org.iodp:exp:207urnlargerWorkCitationcampaignurn:org.iodp:exp:207:site:1257urnlargerWorkCitationstudyurn:org.iodp:exp:207urnlargerWorkCitationcampaignurn:org.iodp:exp:207:site:1258urnlargerWorkCitationstudyurn:org.iodp:exp:207urnlargerWorkCitationcampaignurn:org.iodp:exp:207:site:1259urnlargerWorkCitationstudyurn:org.iodp:exp:207urnlargerWorkCitationcampaignurn:org.iodp:exp:207:site:1260urnlargerWorkCitationstudyurn:org.iodp:exp:207urnlargerWorkCitationcampaignurn:org.iodp:exp:207:site:1261urnlargerWorkCitationstudyurn:org.iodp:exp:207urnlargerWorkCitationcampaignEnglishgeoscientificInformation-54.4400-54.11009.02009.2800