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Article: Deep mantle heat flow and thermal evolution of the Earth's core in thermochemical multiphase models of mantle convection

TitleDeep mantle heat flow and thermal evolution of the Earth's core in thermochemical multiphase models of mantle convection
Authors
KeywordsMulticomponent phase changes
Thermal evolution
Radioactive heating
Core-mantle boundary
Issue Date2005
Citation
Geochemistry, Geophysics, Geosystems, 2005, v. 6, n. 8 How to Cite?
AbstractA coupled model of thermochemical multiphase mantle convection and parameterized heat balance in the Earth's core is used to investigate the need for radioactive potassium in the core, and chemical layering above the core-mantle boundary (CMB), to obtain a successful thermal evolution of the core, i.e. one in which the magnetic field exists over geological time and the final inner core size matches that observed. The mantle convection model includes both the olivine and pyroxene phase change systems linked via the compositional field. The most successful core thermal evolution is obtained when the compositional density difference between subducted MORB and pyrolite in the deep mantle is 1.1% and the core contains 100 ppm radioactive potassium, both of which are consistent with estimates from laboratory experiments. In that scenario, the CMB heat flow at the present time is 8.5 TW, and the time-averaged ohmic dissipation is 2 TW. However, during the modeled magnetic evolution, the ohmic dissipation associated with the geodynamo occasionally becomes zero, which means that the geodynamo stops working, although these large fluctuations could be an artifact of two-dimensional geometry. Various model uncertainties still remain. Copyright 2005 by the American Geophysical Union.
Persistent Identifierhttp://hdl.handle.net/10722/264898
ISSN
2023 Impact Factor: 2.9
2023 SCImago Journal Rankings: 1.457
ISI Accession Number ID

 

DC FieldValueLanguage
dc.contributor.authorNakagawa, Takashi-
dc.contributor.authorTackley, Paul J.-
dc.date.accessioned2018-11-08T01:35:14Z-
dc.date.available2018-11-08T01:35:14Z-
dc.date.issued2005-
dc.identifier.citationGeochemistry, Geophysics, Geosystems, 2005, v. 6, n. 8-
dc.identifier.issn1525-2027-
dc.identifier.urihttp://hdl.handle.net/10722/264898-
dc.description.abstractA coupled model of thermochemical multiphase mantle convection and parameterized heat balance in the Earth's core is used to investigate the need for radioactive potassium in the core, and chemical layering above the core-mantle boundary (CMB), to obtain a successful thermal evolution of the core, i.e. one in which the magnetic field exists over geological time and the final inner core size matches that observed. The mantle convection model includes both the olivine and pyroxene phase change systems linked via the compositional field. The most successful core thermal evolution is obtained when the compositional density difference between subducted MORB and pyrolite in the deep mantle is 1.1% and the core contains 100 ppm radioactive potassium, both of which are consistent with estimates from laboratory experiments. In that scenario, the CMB heat flow at the present time is 8.5 TW, and the time-averaged ohmic dissipation is 2 TW. However, during the modeled magnetic evolution, the ohmic dissipation associated with the geodynamo occasionally becomes zero, which means that the geodynamo stops working, although these large fluctuations could be an artifact of two-dimensional geometry. Various model uncertainties still remain. Copyright 2005 by the American Geophysical Union.-
dc.languageeng-
dc.relation.ispartofGeochemistry, Geophysics, Geosystems-
dc.subjectMulticomponent phase changes-
dc.subjectThermal evolution-
dc.subjectRadioactive heating-
dc.subjectCore-mantle boundary-
dc.titleDeep mantle heat flow and thermal evolution of the Earth's core in thermochemical multiphase models of mantle convection-
dc.typeArticle-
dc.description.naturelink_to_OA_fulltext-
dc.identifier.doi10.1029/2005GC000967-
dc.identifier.scopuseid_2-s2.0-33745862515-
dc.identifier.volume6-
dc.identifier.issue8-
dc.identifier.spagenull-
dc.identifier.epagenull-
dc.identifier.eissn1525-2027-
dc.identifier.isiWOS:000231379800001-
dc.identifier.issnl1525-2027-

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