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Constraints from material properties on the dynamics and evolution of Earth's core

Davies, C; Pozzo, M; Gubbins, D; Alfe, D; (2015) Constraints from material properties on the dynamics and evolution of Earth's core. Nature Geoscience , 8 (9) 678-+. 10.1038/NGEO2492. Green open access

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Abstract

The Earth’s magnetic field is powered by energy supplied by the slow cooling and freezing of the liquid iron core. Efforts to determine the thermal and chemical history of the core have been hindered by poor knowledge of the properties of liquid iron alloys at the extreme pressures and temperatures that exist in the core. This obstacle is now being overcome by high-pressure experiments and advanced mineral physics computations. Using these approaches, updated transport properties for Fe–Si–O mixtures have been determined at core conditions, including electrical and thermal conductivities that are higher than previous estimates by a factor of two to three. Models of core evolution with these high conductivities suggest that the core is cooling much faster than previously thought. This implies that the solid inner core formed relatively recently (around half a billion years ago), and that early core temperatures were high enough to cause partial melting of the lowermost mantle. Estimates of core–mantle boundary heat flow suggest that the uppermost core is thermally stratified at the present day.

Type: Article
Title: Constraints from material properties on the dynamics and evolution of Earth's core
Open access status: An open access version is available from UCL Discovery
DOI: 10.1038/NGEO2492
Publisher version: http://dx.doi.org/10.1038/NGEO2492
Language: English
Additional information: © 2015 Macmillan Publishers Limited. All Rights Reserved.
Keywords: Core processe;s Geomagnetism; Mineralogy
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Earth Sciences
URI: https://discovery.ucl.ac.uk/id/eprint/1473844
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