màj 16 octobre 2024 – légendes à traduire
Version TES
Sur cette question, la thèse développée par TES me semble la mieux étayée. Elle est exposée dans son article Alternative explicative… .
D’après cette thèse, la chaleur provient d’une transition de phase dans la structure des cristaux de fer à l’interface entre le noyau interne et le noyeau externe. Ces cristaux passeraient d’une structure HCP (hexagonale) à FCC (cubique à face centrée) et cette transition de phase serait exothermique.
À traduire et compléter avec références.
+ explications complémentaires (en quoi le processus du point 1. serait-il discontinu et causerait des phases de « surchauffe » ?)
1. The Earth’s core undergoes extreme exothermic change – sloughing high-latent-energy hexagonal closepack (HCP) iron from its H-layer and into the outer core where it converts to liquid* face centered cubic (FCC/BCC) iron plus kinetic energy (latent heat of phase transition). Core magnetic permeability weakens and its geomagnetic dipole wanders. Earth’s rotation speeds up on a decadal basis from the loss in magnetic coupling from outer core to mantle. Earth’s rotational axial inclination also changes.
* [liquide ?! comment la structure peut-elle être à la fois liquide et FCC ?]
2. The exothermic heat content from this eventually reaches Earth’s asthenosphere. Deep crude acyclic alkane pockets are heated and accelerate fractional and volatile organic compound release into atmosphere. Methane ppms far outpace model predictions. Carbon-12-rich oceans and now-warmer tundra each spring solar warming, both release proportionally more carbon.
3. Abyssal ocean conveyance belts pull novel heat content from small-footprint yet now much hotter contribution points exposed to the asthenosphere – and convey (not conduct, convect, nor radiate) this novel heat content through oceanic advection and upwelling systems to the surface of the ocean. Abyssal ocean currents (and consequently surface ones as well) speed up from the discrete addition of kinetic energy. Arctic and Antarctic polar ice sheets melt rapidly in winter from the bottom up. Land desiccates more quickly and wildfires erupt earlier and out-of-season, especially near heat plumes.
4. Ocean heats atmosphere (or fails to cool it as well as it once did) much more readily than atmosphere heats ocean. This exothermic core-to-mantle equilibrium is cyclic, and can and will eventually reverse.
Présentation des travaux de Nathanaël Schaeffer et de son équipe de l’Institut de Physique du Globe (Paris) concernant les flux de chaleur dans le manteau.
Version CS
D’après CS, un déplacement du noyau aurait été mis en évidence vers 1998 (CS-CR p52 à 54).
Figure 62 : Displacement of the Core in 1997-1998 and Thermal Waves in Magma Caused by the Core Shift. (Barkin, Yu. V.)
The map depicts the displacement vector of the inner core from West Antarctica to Western Siberia, towards the Taimyr Peninsula.
The scheme is overlaid on a map of atmospheric thermal anomalies.
Source: Geophysical implications of relative displacements and oscillations of the Earth’s core and mantle. Presentation by Yu.V.
Barkin, Moscow, IFZ, OMTS. September 16, 2014.
Figure 63 :
Figure 65 :
Figure 66 : In 1998, according to the data obtained by the laser rangefinder system Doppler Orbitography and Radiopositioning Integrated
by Satellite (DORIS), France, a sharp change in the Earth’s shape was observed: it expanded in volume.
Source: Cox, C., & Chao, B. F. (2002). Detection of a large-scale mass redistribution in the terrestrial system since 1998. Science,
297(5582), 831–833. https://doi.org/10.1126/science.1072188