georefid:2011-071274SEDIS Publication Catalogueana.macario@awi.dehttp://sedis.iodp.org/pub-catalogue/informationpointOfContact2013-07-08T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=10.1029/2010GL043390<gco:CharacterString>Self-reversal of magnetization in oceanic submarine basalts studied with XMCD</gco:CharacterString>2010-01-01publicationgeorefid:2011-071274doi:10.1029/2010GL043390Carvallo, C.Universite Pierre et Marie Curie, Institute de Mineralogie et de Physique des Milieux Condenses, Paris, FranceauthorSainctavit, P.University of Minnesota-Twin Cities, United StatesauthorArrio, M. A.European Synchrotron Radiation Facility, FranceauthorGuyodo, Y.authorPenn, R. L.authorForsberg, B.authorRogalev, A.authorWilhelm, F.authorSmekhova, A.authorAmerican Geophysical Union, Washington, DC, United StatespublisherdocumentDigitalGeophysical Research Letters37 (11)In oceanic basalts, self-reversal of magnetization can be produced during extreme low-temperature oxidation of titanomagnetite by ionic reordering, which leads to Neel N-type magnetism. Titanomaghemites showing N-type reversal below room temperature were found in submarine basalts recovered during Ocean Drilling Program (ODP) Leg 197. In order to better understand the mechanism of self-reversal, we carried out X-ray magnetic circular dichroism (XMCD) at Fe K-edge at room temperature and low-temperature on such a titanomaghemite sample as well as on pure magnetite and maghemite samples. We found that the XMCD spectrum of the N-type titanomaghemite at 20 K is a mirror image of the XMCD spectrum at 300 K, which shows that the octahedral and tetrahedral subnetworks reverse in this process. Ligand-field multiplet calculations of XMCD at Fe K-edge help identify the contributions of the different elements in the measured XMCD spectra. This mechanism could also cause self-reversal above room temperature, which has important consequences for the reliability of paleomagnetic measurements.completedSolid-earth geophysicsMineralogy of non-silicatesbasaltscrystal chemistryEmperor Seamountsferric ironferrous ironigneous rocksironLeg 197metalsmid-ocean ridge basaltsNorth PacificNorthwest PacificOcean Drilling ProgramODP Site 1206oxidesPacific Oceanpaleomagnetismreversalsself-reversal of magnetizationspectratitanomaghemitevolcanic rocksWest PacificX-ray magnetic circular dichroismX-ray spectraXANES spectraXMCD spectraurn:org.iodp:exp:197urnlargerWorkCitationcampaignurn:org.iodp:exp:197:site:1206urnlargerWorkCitationstudyurn:org.iodp:exp:197urnlargerWorkCitationcampaignEnglishgeoscientificInformation172.0900172.090034.560034.5600application/pdfunknownSEDIS Publication Catalogueana.macario@awi.dehttp://sedis.iodp.org/pub-catalogue/informationpointOfContacthttp://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1944-8007/homepage/2013Special_Section_Proposal-form.pdfdownload