georefid:2010-092859SEDIS Publication Catalogue

ana.macario@awi.de

http://sedis.iodp.org/pub-catalogue/informationpointOfContact2011-07-06T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=10.1073/pnas.08036341052008-01-01publicationgeorefid:2010-092859doi:10.1073/pnas.0803634105Schumann, DirkMcGill University, Department of Earth and Planetary Sciences, Montreal, QC, CanadaauthorRaub, Timothy D.California Institute of Technology, United StatesauthorKopp, Robert E.Princeton University, United StatesauthorGuerquin-Kern, Jean-LucInstitut National de la Sante et de la Recherche Medicale, FranceauthorWu, Ting-DiMichigan Technological University, United StatesauthorRouiller, IsabelleFEI Company, NetherlandsauthorSmirnov, Aleksey V.authorSears, S. KellyauthorLucken, UweauthorTikoo, Sonia M.authorHesse, ReinhardauthorKirschvink, Joseph L.authorVali, HojatollahauthorNational Academy of Sciences, Washington, DC, United StatespublisherdocumentHardcopyProceedings of the National Academy of Sciences of the United States of America105 (46)17648-17653We report the discovery of exceptionally large biogenic magnetite crystals in clay-rich sediments spanning the Paleocene-Eocene Thermal Maximum (PETM) in a borehole at Ancora, NJ. Aside from previously described abundant bacterial magnetofossils, electron microscopy reveals novel spearhead-like and spindle-like magnetite up to 4mu m long and hexaoctahedral prisms up to 1.4 mu m long. Similar to magnetite produced by magnetotactic bacteria, these single-crystal particles exhibit chemical composition, lattice perfection, and oxygen isotopes consistent with an aquatic origin. Electron holography indicates single-domain magnetization despite their large crystal size. We suggest that the development of a thick suboxic zone with high iron bioavailability--a product of dramatic changes in weathering and sedimentation patterns driven by severe global warming--drove diversification of magnetite-forming organisms, likely including eukaryotes.completedIsotope geochemistryStratigraphyEnvironmental geologyAncora New JerseyAtlantic Coastal Plainbacteriabiodiversitybiogenic processesC-13/C-12Camden County New JerseycarbonCenozoiccrystal chemistryelectron microscopy dataeukaryotesglobal changeglobal warmingimage analysisironisotope ratiosisotopesLeg 174AXmagnetic domainsmagnetitemagnetizationmagnetotactic taxametalsNew JerseyO-18/O-16Ocean Drilling ProgramoxidesoxygenPaleocene-Eocene Thermal MaximumPaleogenepaleomagnetismsedimentary rockssedimentationSEM datasingle domainsstable isotopesTEM dataTertiaryUnited StatesweatheringEnglishgeoscientificInformation-74.5056-74.505639.413239.4132Ancora New JerseySupplemental information/data is available in the online version of this article