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dc.contributor.authorChurch, Nathan Stewart
dc.contributor.authorFabian, Karl
dc.contributor.authorMcEnroe, Suzanne
dc.date.accessioned2022-08-31T08:22:47Z
dc.date.available2022-08-31T08:22:47Z
dc.date.issued2016-10-27
dc.description.abstractNatural remanent magnetization carriers in rocks can contain mixtures of magnetic minerals that interact in complex ways and are challenging to characterize by current measurement techniques. Here a nonlinear mapping scheme is described that efficiently enhances sensitivity and the resolution power of remanent Preisach maps. Using this scheme a large dynamic range of magnetic moments and coercivities can be reliably resolved. The method is applied to synthetic and natural standard samples containing magnetite and hematite, as well as to natural samples from remanent magnetic anomalies where complex microstructures are observed. It is shown that certain offset high-coercivity patterns in remanent Preisach maps may serve as fingerprints for exsolution structures of ilmenite in hematite or hematite in ilmenite and that in some magnetite-bearing remanent anomalies the magnetite coercivity is increased beyond its intrinsic coercivity range. Experimental results and theoretical considerations indicate a minimal coercivity of about 10 mT for single-domain (SD) magnetite, such that observation of lower coercivities implies pseudo-SD (PSD) or multidomain grain sizes. A diagnostic hematite pattern with a peak downward offset of 17 ± 2% of the intrinsic coercivity is found that is stable over a large range of intrinsic coercivities and may be related to shielding of internal defect or lamellar moments by a spin canting response to the internal field.en_US
dc.identifier.citationChurch NS, Fabian K, McEnroe S. Nonlinear Preisach maps: Detecting and characterizing separate remanent magnetic fractions in complex natural samples. Journal of Geophysical Research (JGR): Solid Earth. 2016;121(12):8373-8395en_US
dc.identifier.cristinIDFRIDAID 1394120
dc.identifier.doi10.1002/2016JB013465
dc.identifier.issn2169-9313
dc.identifier.issn2169-9356
dc.identifier.urihttps://hdl.handle.net/10037/26499
dc.language.isoengen_US
dc.publisherAmerican Geophysical Union (AGU)en_US
dc.relation.journalJournal of Geophysical Research (JGR): Solid Earth
dc.relation.projectIDNorges forskningsråd: 223259en_US
dc.relation.projectIDNorges forskningsråd: 222666en_US
dc.rights.accessRightsopenAccessen_US
dc.rights.holderCopyright 2016 AGUen_US
dc.titleNonlinear Preisach maps: Detecting and characterizing separate remanent magnetic fractions in complex natural samplesen_US
dc.type.versionpublishedVersionen_US
dc.typeJournal articleen_US
dc.typeTidsskriftartikkelen_US
dc.typePeer revieweden_US


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