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Magnetic properties of sedimentary greigite (Fe3S4): An update

Roberts, Andrew; Chang, Liao; Rowan, Christopher J; Horng, Chorng‐Shern; Florindo, Fabio

Description

Greigite (Fe3S4) is an authigenic ferrimagnetic mineral that grows as a precursor to pyrite during early diagenetic sedimentary sulfate reduction. It can also grow at any time when dissolved iron and sulfide are available during diagenesis. Greigite is important in paleomagnetic, environmental, biological, biogeochemical, tectonic, and industrial processes. Much recent progress has been made in understanding its magnetic properties. Greigite is an inverse spinel and a collinear ferrimagnet with...[Show more]

dc.contributor.authorRoberts, Andrew
dc.contributor.authorChang, Liao
dc.contributor.authorRowan, Christopher J
dc.contributor.authorHorng, Chorng‐Shern
dc.contributor.authorFlorindo, Fabio
dc.date.accessioned2015-12-10T23:24:24Z
dc.identifier.issn8755-1209
dc.identifier.urihttp://hdl.handle.net/1885/67168
dc.description.abstractGreigite (Fe3S4) is an authigenic ferrimagnetic mineral that grows as a precursor to pyrite during early diagenetic sedimentary sulfate reduction. It can also grow at any time when dissolved iron and sulfide are available during diagenesis. Greigite is important in paleomagnetic, environmental, biological, biogeochemical, tectonic, and industrial processes. Much recent progress has been made in understanding its magnetic properties. Greigite is an inverse spinel and a collinear ferrimagnet with antiferromagnetic coupling between iron in octahedral and tetrahedral sites. The crystallographic c axis is the easy axis of magnetization, with magnetic properties dominated by magnetocrystalline anisotropy. Robust empirical estimates of the saturation magnetization, anisotropy constant, and exchange constant for greigite have been obtained recently for the first time, and the first robust estimate of the low-field magnetic susceptibility is reported here. The Curie temperature of greigite remains unknown but must exceed 350C. Greigite lacks a low-temperature magnetic transition. On the basis of preliminary micromagnetic modeling, the size range for stable single domain behavior is 17-200 nm for cubic crystals and 17-500 nm for octahedral crystals. Gradual variation in magnetic properties is observed through the pseudo-single-domain size range. We systematically document the known magnetic properties of greigite (at high, ambient, and low temperatures and with alternating and direct fields) and illustrate how grain size variations affect magnetic properties. Recognition of this range of magnetic properties will aid identification and constrain interpretation of magnetic signals carried by greigite, which is increasingly proving to be environmentally important and responsible for complex paleomagnetic records, including widespread remagnetizations.
dc.publisherAmerican Geophysical Union
dc.rightsAuthor/s retain copyright
dc.sourceReviews of Geophysics
dc.subjectKeywords: Anisotropy constants; Antiferromagnetic coupling; Authigenic; Cubic crystal; Diagenetics; Dissolved iron; Easy axis of magnetization; Empirical estimate; Exchange constants; Ferrimagnetic minerals; Ferrimagnets; Grain size variation; Greigites; Industrial
dc.titleMagnetic properties of sedimentary greigite (Fe3S4): An update
dc.typeJournal article
local.description.notesImported from ARIES
local.identifier.citationvolume49
dc.date.issued2011
local.identifier.absfor040406 - Magnetism and Palaeomagnetism
local.identifier.ariespublicationf2965xPUB1410
local.type.statusPublished Version
local.contributor.affiliationRoberts, Andrew, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationChang, Liao, University of Southampton
local.contributor.affiliationRowan, Christopher J, University of Southampton
local.contributor.affiliationHorng, Chorng‐Shern, Institute of Earth Sciences
local.contributor.affiliationFlorindo, Fabio, Instituto Nazionale di Geofisica e Vulcanologia
local.bibliographicCitation.issue1
local.bibliographicCitation.startpage46
local.identifier.doi10.1029/2010RG000336
local.identifier.absseo970104 - Expanding Knowledge in the Earth Sciences
dc.date.updated2016-02-24T08:13:38Z
local.identifier.scopusID2-s2.0-79551595505
local.identifier.thomsonID000286770000001
dcterms.accessRightsOpen Access
CollectionsANU Research Publications

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