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Updated: Jan 9, 2026

Simulation of the Planetary Interior Differentiation Processes in the Laboratory
Published on: November 15, 2013
Depth-dependent anisotropy in the Earth's inner core linked to chemical stratification
Efim Kolesnikov1,2, Xiang Li3,4, Susanne C Müller3,4
1Institute for Mineralogy, University of Münster, Münster, Germany. ekolesni@uni-muenster.de.
None:
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.
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