{"@context":{"@vocab":"https://cir.nii.ac.jp/schema/1.0/","rdfs":"http://www.w3.org/2000/01/rdf-schema#","dc":"http://purl.org/dc/elements/1.1/","dcterms":"http://purl.org/dc/terms/","foaf":"http://xmlns.com/foaf/0.1/","prism":"http://prismstandard.org/namespaces/basic/2.0/","cinii":"http://ci.nii.ac.jp/ns/1.0/","datacite":"https://schema.datacite.org/meta/kernel-4/","ndl":"http://ndl.go.jp/dcndl/terms/","jpcoar":"https://github.com/JPCOAR/schema/blob/master/2.0/"},"@id":"https://cir.nii.ac.jp/crid/1361981470446563712.json","@type":"Article","productIdentifier":[{"identifier":{"@type":"DOI","@value":"10.1073/pnas.1207086109"}},{"identifier":{"@type":"URI","@value":"https://pnas.org/doi/pdf/10.1073/pnas.1207086109"}}],"dc:title":[{"@value":"Sound velocities of Fe and Fe-Si alloy in the Earth’s core"}],"description":[{"type":"abstract","notation":[{"@value":"<jats:p>Compressional wave velocity-density (<jats:italic>V</jats:italic><jats:sub><jats:italic>P</jats:italic></jats:sub> - <jats:italic>ρ</jats:italic>) relations of candidate Fe alloys at relevant pressure-temperature conditions of the Earth’s core are critically needed to evaluate the composition, seismic signatures, and geodynamics of the planet’s remotest region. Specifically, comparison between seismic<jats:italic>V</jats:italic><jats:sub><jats:italic>P</jats:italic></jats:sub> - <jats:italic>ρ</jats:italic>profiles of the core and candidate Fe alloys provides first-order information on the amount and type of potential light elements—including H, C, O, Si, and/or S—needed to compensate the density deficit of the core. To address this issue, here we have surveyed and analyzed the literature results in conjunction with newly measured<jats:italic>V</jats:italic><jats:sub><jats:italic>P</jats:italic></jats:sub> - <jats:italic>ρ</jats:italic>results of hexagonal closest-packed (hcp) Fe and hcp-Fe<jats:sub>0.85</jats:sub>Si<jats:sub>0.15</jats:sub>alloy using in situ high-energy resolution inelastic X-ray scattering and X-ray diffraction. The nature of the Fe-Si alloy where Si is readily soluble in Fe represents an ideal solid-solution case to better understand the light-element alloying effects. Our results show that high temperature significantly decreases the<jats:italic>V</jats:italic><jats:sub><jats:italic>P</jats:italic></jats:sub>of hcp-Fe at high pressures, and the Fe-Si alloy exhibits similar high-pressure<jats:italic>V</jats:italic><jats:sub><jats:italic>P</jats:italic></jats:sub> - <jats:italic>ρ</jats:italic>behavior to hcp-Fe via a constant density offset. These<jats:italic>V</jats:italic><jats:sub><jats:italic>P</jats:italic></jats:sub> - <jats:italic>ρ</jats:italic>data at a given temperature can be better described by an empirical power-law function with a concave behavior at higher densities than with a linear approximation. Our new datasets, together with literature results, allow us to build new<jats:italic>V</jats:italic><jats:sub><jats:italic>P</jats:italic></jats:sub> - <jats:italic>ρ</jats:italic>models of Fe alloys in order to determine the chemical composition of the core. Our models show that the<jats:italic>V</jats:italic><jats:sub><jats:italic>P</jats:italic></jats:sub> - <jats:italic>ρ</jats:italic>profile of Fe with 8 wt % Si at 6,000 K matches well with the Preliminary Reference Earth Model of the inner core.</jats:p>"}]}],"creator":[{"@id":"https://cir.nii.ac.jp/crid/1380576196987760769","@type":"Researcher","foaf:name":[{"@value":"Zhu Mao"}],"jpcoar:affiliationName":[{"@value":"Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, TX 78712;"}]},{"@id":"https://cir.nii.ac.jp/crid/1380576196987760897","@type":"Researcher","foaf:name":[{"@value":"Jung-Fu Lin"}],"jpcoar:affiliationName":[{"@value":"Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, TX 78712;"}]},{"@id":"https://cir.nii.ac.jp/crid/1380576196987760770","@type":"Researcher","foaf:name":[{"@value":"Jin Liu"}],"jpcoar:affiliationName":[{"@value":"Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, TX 78712;"}]},{"@id":"https://cir.nii.ac.jp/crid/1380576196987760768","@type":"Researcher","foaf:name":[{"@value":"Ahmet Alatas"}],"jpcoar:affiliationName":[{"@value":"Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439; and"}]},{"@id":"https://cir.nii.ac.jp/crid/1380576196987760896","@type":"Researcher","foaf:name":[{"@value":"Lili Gao"}],"jpcoar:affiliationName":[{"@value":"Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439; and"}]},{"@id":"https://cir.nii.ac.jp/crid/1380576196987760898","@type":"Researcher","foaf:name":[{"@value":"Jiyong Zhao"}],"jpcoar:affiliationName":[{"@value":"Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439; and"}]},{"@id":"https://cir.nii.ac.jp/crid/1380576196987760899","@type":"Researcher","foaf:name":[{"@value":"Ho-Kwang Mao"}],"jpcoar:affiliationName":[{"@value":"High Pressure Collaborative Access Team, Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC 20015"}]}],"publication":{"publicationIdentifier":[{"@type":"PISSN","@value":"00278424"},{"@type":"EISSN","@value":"10916490"}],"prism:publicationName":[{"@value":"Proceedings of the National Academy of Sciences"}],"dc:publisher":[{"@value":"Proceedings of the National Academy of Sciences"}],"prism:publicationDate":"2012-06-11","prism:volume":"109","prism:number":"26","prism:startingPage":"10239","prism:endingPage":"10244"},"reviewed":"false","url":[{"@id":"https://pnas.org/doi/pdf/10.1073/pnas.1207086109"}],"createdAt":"2012-06-12","modifiedAt":"2023-06-23","relatedProduct":[{"@id":"https://cir.nii.ac.jp/crid/1050001202892464768","@type":"Article","resourceType":"学術雑誌論文(journal article)","relationType":["isReferencedBy"],"jpcoar:relatedTitle":[{"@value":"Sound velocity measurements of hcp Fe-Si alloy at high pressure and high temperature by inelastic X-ray 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