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dc.contributor.authorLumiste, Kaarel
dc.contributor.authorLang, Liisa
dc.contributor.authorPaiste, Päärn
dc.contributor.authorLepland, Aivo
dc.contributor.authorKirsimäe, Kalle
dc.date.accessioned2022-01-31T14:20:33Z
dc.date.available2022-01-31T14:20:33Z
dc.date.issued2021-10-27
dc.description.abstractSedimentary phosphorites are important carriers of Rare Earth Elements and Yttrium (REE + Y). Primary biogenic and sedimentary apatite contain very low amounts of REE + Y and enrichment of these elements occurs during diagenesis. Although the influence of post-depositional processes on REE + Y concentrations in sedimentary phosphorites is well established, the processes controlling the degree of enrichment are poorly constrained. In this study, we examine the REE + Y composition of Early Paleozoic shelly phosphorites of the Baltica paleocontinent, using ICP-MS and LA-ICP-MS. Phosphate containing phases in these deposits are (i) phosphatic brachiopod shells, (ii) phosphatic clasts and (iii) phosphatic grain coatings. Measured REE + Y concentrations range from 162.7 to 2415.3 mg/kg. The distribution of REE + Y in phosphatic shells and clasts is heterogeneous, with the highest concentrations found in the outer margins. In the phosphatic shells, remnants of skeletal apatite contain higher REE + Y concentrations than authigenic apatite in baculate laminae. In addition, our results show significant locality-based variability, with up to 14 times differences in REE + Y concentrations from localities situated only a few tens of km apart. Based on (i) the heterogeneous distribution of REE + Y in apatite, (ii) LaN/YbN and LaN/SmN ratios pointing to diagenetic REE + Y uptake from sediment pore-fluids, as well as (iii) variable pyrite content, the geographic variations of REE + Y in sedimentary phosphorites of the Baltica paleocontinent are most parsimoniously explained by differences in local redox conditions during early diagenesis.en_US
dc.identifier.citationLumiste, Lang, Paiste, Lepland, Kirsimäe. Heterogeneous REE + Y distribution in Early Paleozoic shelly phosphorites: Implications for enrichment mechanisms. Chemical Geology. 2021;586:1-15en_US
dc.identifier.cristinIDFRIDAID 1953921
dc.identifier.doi10.1016/j.chemgeo.2021.120590
dc.identifier.issn0009-2541
dc.identifier.issn1872-6836
dc.identifier.urihttps://hdl.handle.net/10037/23854
dc.language.isoengen_US
dc.publisherElsevieren_US
dc.relation.journalChemical Geology
dc.relation.projectIDNorges forskningsråd: 223259en_US
dc.relation.projectIDinfo:eu-repo/grantAgreement/RCN/SFF/223259/Norway/Centre for Arctic Gas Hydrate, Environment and Climate/CAGE/en_US
dc.rights.accessRightsopenAccessen_US
dc.rights.holderCopyright 2021 The Author(s)en_US
dc.titleHeterogeneous REE + Y distribution in Early Paleozoic shelly phosphorites: Implications for enrichment mechanismsen_US
dc.type.versionacceptedVersionen_US
dc.typeJournal articleen_US
dc.typeTidsskriftartikkelen_US
dc.typePeer revieweden_US


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