The inner core and the geodynamo |
| |
Authors: | Stéphane Labrosse Mélina Macouin |
| |
Affiliation: | Département de géomagnétisme et paléomagnétisme, Institut de physique du Globe, 4, place Jussieu, 75252 Paris cedex 05, France |
| |
Abstract: | Using energy and entropy constraints applicable to the Earth's core, the heat flow at the core–mantle boundary (CMB) needed to sustain a given total dissipation in the core can be computed. Reasonable estimates for the present Joule dissipation in the core gives a present heat flow of 6 to 10 TW at the CMB. Palaeointensity data acquired from rocks younger than 3.5 Ga provide support that the Joule dissipation in the core before inner core crystallization was between today's value and four times lower than today. Prior to inner core crystallization (around 1 Ga), the magnetic field was maintained by thermal convection driven by core cooling, and our calculations of the two extreme cases predict that the heat flow at the CMB at that time was either 14 to 24 TW in the case of constant dissipation, or essentially the same as today in the lower field intensity case. |
| |
Keywords: | Core thermodynamics Thermal evolution Geomagnetism Palaeomagnetism Palaeointensity Earth's magnetic field Thermodynamique du noyau Évolution thermique Géomagnétisme Paléomagnétisme Paléointensité Champ magnétique de la Terre |
本文献已被 ScienceDirect 等数据库收录! |