English
 
User Manual Privacy Policy Disclaimer Contact us
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT

Released

Journal Article

Convective Erosion of a Primordial Stratification Atop Earth's Core

MPS-Authors
/persons/resource/persons221155

Bouffard,  Mathieu
Department Planets and Comets, Max Planck Institute for Solar System Research, Max Planck Society;

External Ressource
No external resources are shared
Fulltext (public)
There are no public fulltexts stored in PuRe
Supplementary Material (public)
There is no public supplementary material available
Citation

Bouffard, M., Landeau, M., & Goument, A. (2020). Convective Erosion of a Primordial Stratification Atop Earth's Core. Geophysical Research Letters, 47(14): 87109. doi:10.1029/2020GL087109.


Cite as: http://hdl.handle.net/21.11116/0000-0007-0AE2-F
Abstract
Seismic and geomagnetic observations suggest the presence of a stratified layer atop Earth's core. Previous laboratory experiments showed that this layer could be primordial, produced by a collision between the primitive Earth and a giant impactor. However, paleomagnetic data require turbulent flow motions in the core for the last 3.4 Ga. Such flows can erode an existing stratification. It is therefore unclear whether a primordial stratification still exists nowadays. Here, we use numerical simulations to investigate the erosion by thermal convection of a chemical layer atop Earth's core. Our scaling law predicts that a primordial layer thicker than 1 km with a density anomaly above 0.01% can survive 4.5 Ga of convective erosion. We conclude that the observed present-day stratification could be a vestige of core formation. We also observe strong double-diffusive flows in the layer. These might reconcile the existence of a stratification with the present-day structure of the geomagnetic field.