Year: 2025
Type: article
Abstract: Seismic anisotropy in the Earth's inner core (IC), including the heterogeneous, depth-dependent anisotropy structure, is a well-documented yet poorly understood feature plausibly related to the alignment of iron alloy crystals. Here, we report the effect of silicon and carbon on the plastic deformation of hexagonal close-packed (hcp) iron using radial X-ray diffraction at pressures up to 128 GPa and temperatures up to 1100 K. Our results reveal a low compressional wave anisotropy (~2 %) in the Fe-Si-C alloy, consistent with the seismic anisotropy observed in the outer regions of the IC. These findings, together with the higher anisotropy exhibited by pure hcp-Fe, suggest that the depth-dependent elastic anisotropy of the IC may originate from chemical stratification, i.e., radial gradients in silicon and carbon concentrations, during crystallization.
Source: Nature Communications
Authors: Efim Kolesnikov, Xiang Li, Susanne C. Müller, Arno Rohrbach, Stephan Klemme, Jasper Berndt, Hanns-Peter Liermann, Carmen Sanchez-Valle, Ilya Kupenko
Institutions: Centre National de la Recherche Scientifique, University of Münster, Université de Lille, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, Unité Matériaux et Transformations, Centrale Lille Institut, European Synchrotron Radiation Facility, Deutsches Elektronen-Synchrotron DESY
Language: English
Subfield: Geophysics
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $6,990
OpenAlex ID: W4417116071