Structure of a mushy layer under hypergravity with implications for Earth's inner core

Ludovic Huguet,Michael I Bergman,Germain Lesœur,Renaud Deguen,Stéphane Labrosse,Thierry Alboussière

doi:10.1093/gji/ggv554

Ludovic Huguet, Michael I Bergman + Show 4 more

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https://doi.org/10.1093/gji/ggv554

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Abstract

Structure of a mushy layer under hypergravity with implications for Earth's inner core

Highlights

Due to secular cooling, the Earth’s core crystallizes
Convection has an impact on the solidification processes by altering the transfer of light elements at the inner core boundary (ICB)
Fearn et al (1981) have argued that the solidification conditions at the ICB must lead to the formation of a mushy layer—a two-phase medium where solid dendrites coexist with a light-elements-rich liquid—and that ‘the mushy zone will be very thick, possibly extending to the centre of the Earth’

Summary

Introduction

The Earth’s core crystallizes. As the slope of the Clapeyron profile is steeper than the adiabatic gradient, crystallization starts from the centre of the Earth. Observations of PKJKP waves (Okal & Cansi 1998; Deuss et al 2000; Cao et al 2005) denote the presence of a sharp transition at the ICB to allow the conversion of compressive waves to shear waves (Deuss 2014). These observations suggest that the transition zone at the ICB should be less than 5 km thick

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Discussion

Conclusion