The size and the age of the inner core impose constraints in modeling of the Earth's core evolution. The origin of the solid core corresponds to the change in convection regime in the core and, correspondingly, to the change in the magnetic field behavior. Meanwhile the standard evolutionary models predict quite young inner core that is not supported by the palaeomagnetic observations, which claim existence of geomagnetic field older than 3 Gy. We solve the inverse problem and find parameters of the model with the inner core older than 3 Gy.
Liquid core, thermal and compositional convection, geodynamo
1. Alfé, D., M. J. Gillan, G. D. Price (2007) , Temperature and composition of the Earth's core, Contemp. Phys., 48, no. 2, p. 63-80, https://doi.org/10.1080/00107510701529653
2. Braginsky, S. I., P. G. Roberts (1995) , Equations governing convection in Earth's core and the geodynamo, Geophys. Astrophys. Fluid Dyn., 79, no. 1-4, p. 1-97
3. Buffett, B. A. (2002) , Estimates of heat flow in the deep mantle based on the power requirements for the geodynamo, Geophys. Res. Lett., 29, no. 12, p. 1566-7-1-1566-7-4, https://doi.org/10.1029/2001GL014649
4. Calderwood, A., P. Roberts, C. Jones (2003) , Energy fluxes and ohmic dissipation in the Earth's core, Earth's Core and Lower Mantle. Series: The Fluid Mechanics of Astrophysics and Geophysics. Eds. K. Zhang, A. Soward, C. Jones., 68, p. 100-129, https://doi.org/10.1201/9780203207611.ch5
5. Christensen, U. R., J. Aubert (2006) , Scaling properties of convection-driven dynamos in rotating spherical shells and application to planetary magnetic fields, Geophys. J. Int., 166, p. 97-114
6. Driscoll, P (2016) , Simulating 2 Ga of geodynamo history, Geophys. Res. Lett., 43, no. 11, p. 5680-5687, https://doi.org/10.1002/2016GL068858
7. Dziewonski, A. M., D. L. Anderson (1981) , Preliminary reference Earth model, Phys. Earth Planet. Int., 25, p. 297-356
8. Gubbins, D., T. G. Masters, J. A. Jacobs (1979) , Thermal evolution of the Earth's core, Geophys. J. R. Astron. Soc., 59, no. 1, p. 57-99
9. Gubbins, D., C. J. Thomson, K. A. Whaler (1982) , Stable regions in the Earth's liquid core, Geophys. J. Int., 68, p. 241-251
10. Kutluay, S., A. R. Bahadir, A. Özde (1997) , The numerical solution of one-phase classical Stefan problem, J. Comp. App. Math., 81, p. 135-144
11. Labrosse, S., J. P. Poirier, J.-L. Le Mou{ë}l (1997) , On cooling of the Earth's core, Phys. Earth Planet. Int., 99, p. 1-17
12. Labrosse, S. (2003) , Thermal and magnetic evolution of the Earth's core, Phys. Earth Planet. Int., 140, p. 127-143
13. Labrosse, S. (2015) , Thermal evolution of the core with a high thermal conductivity, Phys. Earth Planet. Int., 247, p. 36-55, https://doi.org/10.1016/j.pepi.2015.02.002
14. Loper, D. E. (1984) , Structure of the Core and Lower Mantle, Adv. Geophys., 26, p. 1-34
15. Nakagawa, T. (2018) , On the thermal-chemical origin of the stratified region at the top of the Earth's core, Phys. Earth Planet. Int., 276, p. 172-181, https://doi.org/10.1016/j.pepi.2017.05.011
16. Nimmo, F. (2007) , Energetics of the Core, Treatise on Geophysics, p. 431-432, https://doi.org/10.1126/science.1243477
17. Olson, P. (2013) , The new core paradox, Science, 342, no. 6157, p. 431-432, https://doi.org/10.1126/science.1243477
18. Pozzo, M., C. Davies, D. Gubbins, D. Alfé (2012) , Thermal and electrical conductivity of iron at Earth's core conditions, Nature, 485, p. 355-358, https://doi.org/10.1038/nature11031
19. Reshetnyak, M. Yu., V. E. Pavlov (2016) , Evolution of the Dipole Geomagnetic Field. Observations and Models, Geomagn. Aeronom., 56, no. 1, p. 110-124, https://doi.org/10.1134/S0016793215060122
20. Reshetnyak, M. Yu. (2015) , Inverse problem in Parker's dynamo, Russ. J. Earth Sci., 15, p. ES4001-1-ES4001-7, https://doi.org/10.2205/2015ES000558
21. Reshetnyak, M. Yu. (2019) , Evolution of the inner core of the Earth: consequences for geodynamo, Magnetohydrodynamics, 55, no. 1-2, p. 175-183, https://doi.org/10.22364/mhd.55.1-2.21
22. Rubie, D. C., D. J. Frost, U. Mann, et al. (2011) , Heterogeneous accretion, composition and core-mantle differentiation of the Earth, Earth Planet. Sci. Lett., 301, p. 31-42, https://doi.org/10.1016/j.epsl.2010.11.030
