Paleomagnetic evidence for dynamo activity driven by inward crystallisation of a metallic asteroid
The direction in which a planetary core solidifies has fundamental implications for the feasibility and nature of dynamo generation. Although Earth's core is outwardly solidifying, the cores of certain smaller planetary bodies have been proposed to inwardly solidify due to their lower central p...
| Autores: | , , , , |
|---|---|
| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2017 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/182255 |
| Acceso en línea: | http://hdl.handle.net/10261/182255 |
| Access Level: | acceso abierto |
| Palabra clave: | Meteorite paleomagnetism Iron meteorite Cloudy zone X-ray photoemission electron microscopy AF demagnetization Core dynamo activity |
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Paleomagnetic evidence for dynamo activity driven by inward crystallisation of a metallic asteroid |
| title |
Paleomagnetic evidence for dynamo activity driven by inward crystallisation of a metallic asteroid |
| spellingShingle |
Paleomagnetic evidence for dynamo activity driven by inward crystallisation of a metallic asteroid Bryson, James F. J. Meteorite paleomagnetism Iron meteorite Cloudy zone X-ray photoemission electron microscopy AF demagnetization Core dynamo activity |
| title_short |
Paleomagnetic evidence for dynamo activity driven by inward crystallisation of a metallic asteroid |
| title_full |
Paleomagnetic evidence for dynamo activity driven by inward crystallisation of a metallic asteroid |
| title_fullStr |
Paleomagnetic evidence for dynamo activity driven by inward crystallisation of a metallic asteroid |
| title_full_unstemmed |
Paleomagnetic evidence for dynamo activity driven by inward crystallisation of a metallic asteroid |
| title_sort |
Paleomagnetic evidence for dynamo activity driven by inward crystallisation of a metallic asteroid |
| dc.creator.none.fl_str_mv |
Bryson, James F. J. Weiss, Benjamin P. Harrison, Richard J. Herrero-Albillos, Julia Kronast, Florian |
| author |
Bryson, James F. J. |
| author_facet |
Bryson, James F. J. Weiss, Benjamin P. Harrison, Richard J. Herrero-Albillos, Julia Kronast, Florian |
| author_role |
author |
| author2 |
Weiss, Benjamin P. Harrison, Richard J. Herrero-Albillos, Julia Kronast, Florian |
| author2_role |
author author author author |
| dc.contributor.none.fl_str_mv |
Helmholtz-Zentrum Berlin for Materials and Energy European Research Council European Commission NASA Natural Environment Research Council (UK) Ministerio de Economía y Competitividad (España) Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72] |
| dc.subject.none.fl_str_mv |
Meteorite paleomagnetism Iron meteorite Cloudy zone X-ray photoemission electron microscopy AF demagnetization Core dynamo activity |
| topic |
Meteorite paleomagnetism Iron meteorite Cloudy zone X-ray photoemission electron microscopy AF demagnetization Core dynamo activity |
| description |
The direction in which a planetary core solidifies has fundamental implications for the feasibility and nature of dynamo generation. Although Earth's core is outwardly solidifying, the cores of certain smaller planetary bodies have been proposed to inwardly solidify due to their lower central pressures. However, there have been no unambiguous observations of inwardly solidified cores or the relationship between this solidification regime and planetary magnetic activity. To address this gap, we present the results of complimentary paleomagnetic techniques applied to the matrix metal and silicate inclusions within the IVA iron meteorites. This family of meteorites has been suggested to originate from a planetary core that had its overlaying silicate mantle removed by collisions during the early solar system. This process is thought to have produced a molten ball of metal that cooled rapidly and has been proposed to have inwardly solidified. Recent thermal evolution models of such a body predict that it should have generated an intense, multipolar and time-varying dynamo field. This field could have been recorded as a remanent magnetisation in the outer, cool layers of a solid crust on the IVA parent core. We find that the different components in the IVA iron meteorites display a range of paleomagnetic fidelities, depending crucially on the cooling rate of the meteorite. In particular, silicate inclusions in the quickly cooled São João Nepomuceno meteorite are poor paleomagnetic recorders. On the other hand, the matrix metal and some silicate subsamples from the relatively slowly cooled Steinbach meteorite are far better paleomagnetic recorders and provide evidence of an intense (≳100 μT) and directionally varying (exhibiting significant changes on a timescale ≲200 kyr) magnetic field. This is the first demonstration that some iron meteorites record ancient planetary magnetic fields. Furthermore, the observed field intensity, temporal variability and dynamo lifetime are consistent with thermal evolution models of the IVA parent core. Because the acquisition of remanent magnetisation by some IVA iron meteorites require that they cooled below their Curie temperature during the period of dynamo activity, the magnetisation carried by Steinbach also provides strong evidence favouring the inward solidification of its parent core. |
| publishDate |
2017 |
| dc.date.none.fl_str_mv |
2017 2019 2019 |
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info:eu-repo/semantics/article http://purl.org/coar/resource_type/c_6501 Publisher's version info:eu-repo/semantics/publishedVersion |
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article |
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publishedVersion |
| dc.identifier.none.fl_str_mv |
http://hdl.handle.net/10261/182255 |
| url |
http://hdl.handle.net/10261/182255 |
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Inglés |
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Inglés |
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#PLACEHOLDER_PARENT_METADATA_VALUE# #PLACEHOLDER_PARENT_METADATA_VALUE# #PLACEHOLDER_PARENT_METADATA_VALUE# info:eu-repo/grantAgreement/MINECO/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/MAT2014-53921-R info:eu-repo/grantAgreement/EC/FP7/320750 info:eu-repo/grantAgreement/EC/FP7/312284 https://doi.org/10.1016/j.epsl.2017.05.026 Sí |
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info:eu-repo/semantics/openAccess |
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openAccess |
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Elsevier |
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Elsevier |
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reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC instname:Consejo Superior de Investigaciones Científicas (CSIC) |
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Consejo Superior de Investigaciones Científicas (CSIC) |
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DIGITAL.CSIC. Repositorio Institucional del CSIC |
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DIGITAL.CSIC. Repositorio Institucional del CSIC |
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1869418554686701568 |
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Paleomagnetic evidence for dynamo activity driven by inward crystallisation of a metallic asteroidBryson, James F. J.Weiss, Benjamin P.Harrison, Richard J.Herrero-Albillos, JuliaKronast, FlorianMeteorite paleomagnetismIron meteoriteCloudy zoneX-ray photoemission electron microscopyAF demagnetizationCore dynamo activityThe direction in which a planetary core solidifies has fundamental implications for the feasibility and nature of dynamo generation. Although Earth's core is outwardly solidifying, the cores of certain smaller planetary bodies have been proposed to inwardly solidify due to their lower central pressures. However, there have been no unambiguous observations of inwardly solidified cores or the relationship between this solidification regime and planetary magnetic activity. To address this gap, we present the results of complimentary paleomagnetic techniques applied to the matrix metal and silicate inclusions within the IVA iron meteorites. This family of meteorites has been suggested to originate from a planetary core that had its overlaying silicate mantle removed by collisions during the early solar system. This process is thought to have produced a molten ball of metal that cooled rapidly and has been proposed to have inwardly solidified. Recent thermal evolution models of such a body predict that it should have generated an intense, multipolar and time-varying dynamo field. This field could have been recorded as a remanent magnetisation in the outer, cool layers of a solid crust on the IVA parent core. We find that the different components in the IVA iron meteorites display a range of paleomagnetic fidelities, depending crucially on the cooling rate of the meteorite. In particular, silicate inclusions in the quickly cooled São João Nepomuceno meteorite are poor paleomagnetic recorders. On the other hand, the matrix metal and some silicate subsamples from the relatively slowly cooled Steinbach meteorite are far better paleomagnetic recorders and provide evidence of an intense (≳100 μT) and directionally varying (exhibiting significant changes on a timescale ≲200 kyr) magnetic field. This is the first demonstration that some iron meteorites record ancient planetary magnetic fields. Furthermore, the observed field intensity, temporal variability and dynamo lifetime are consistent with thermal evolution models of the IVA parent core. Because the acquisition of remanent magnetisation by some IVA iron meteorites require that they cooled below their Curie temperature during the period of dynamo activity, the magnetisation carried by Steinbach also provides strong evidence favouring the inward solidification of its parent core.We acknowledge the Helmholtz-Zentrum Berlin for the use of the synchrotron radiation beamtime at beamline UE49 of BESSY II. The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007–2013)/ERC grant agreement numbers 320750 and 312284. BPW and JFJB thank the NASA Solar System Exploration Research Virtual Institute (SSERVI), the NASA Solar System Workings Program (grant # NNX15AL62G) and Thomas F. Peterson for support. JFJB thanks the Natural Environment Research Council for financial support. J.H.-A. thanks the MAT2014-53921-RMINECO project.Peer reviewedElsevierHelmholtz-Zentrum Berlin for Materials and EnergyEuropean Research CouncilEuropean CommissionNASANatural Environment Research Council (UK)Ministerio de Economía y Competitividad (España)Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]201920192017info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501Publisher's versioninfo:eu-repo/semantics/publishedVersionhttp://hdl.handle.net/10261/182255reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Inglés#PLACEHOLDER_PARENT_METADATA_VALUE##PLACEHOLDER_PARENT_METADATA_VALUE##PLACEHOLDER_PARENT_METADATA_VALUE#info:eu-repo/grantAgreement/MINECO/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/MAT2014-53921-Rinfo:eu-repo/grantAgreement/EC/FP7/320750info:eu-repo/grantAgreement/EC/FP7/312284https://doi.org/10.1016/j.epsl.2017.05.026Síinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/1822552026-05-22T06:33:51Z |
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15,812429 |