The MaCoMaOc project

The MaCoMaOc project is joint between the Laboratoire de géologie de Lyon (ENS de Lyon, Université Claude Bernard-Lyon 1) and the Institute für Geophysik (Department of Earth Sciences, ETH Zürich) and is devoted to the study of mantle convection in planetary mantles interacting with magma oceans above and/or below.

It is funded by the ANR on the French side and the SNF on the Swiss side.

Scientific questions

Convection in the solid mantle of terrestrial planets and in the icy layers of some satellites of Jupiter and Saturn is or was occuring while an ocean of similar composition exists above and/or below. The possibility of melting and freezing at the horizontal boundaries of the solid layer modifies its dynamics: A vertical flow toward the boundary needs not necessarily come to a halt since matter can flow through the boundary by melting. Conversely, matter can enter the domain by freezing in regions of flow away from the boundary. For this to happen, a heat flow in the liquid layer is necessary to redistribute latent heat from regions of freezing to regions of melting. We consider this effect on mantle convection and implied evolution of planets through application of boundary conditions originally developed for the dynamics of Earth’s inner core.

Contributors

In Lyon:

Stéphane Labrosse (PI)
Renaud Deguen
Thierry Alboussière
Adrien Morison (PhD student)
Roberto Agrusta (Post-doc)

In Zürich:

Achievements

Model development

A pseudo-spectral Chebyshev collocation code has been written to solve the linear stability problem of convection with phase change boundary conditions at either or both horizontal boundaries, in cartesian and spherical shell geometry. The weakly non-linear analysis is also implemented for the 2D cartesian geometry. Results for the cartesian geometry are presented in a paper published in the Journal of Fluid Mechanics (Labrosse et al, 2018). A paper has been published in Earth and Planetary Science Letters (Morison et al, 2019) in which we present linear stability calculations for the timescale of the mantle overturn during its crystallisation in a magma ocean. Another publication about the linear stability and non-linear numerical simulation in spherical shells is in preparation (lead author: Adrien Morison). Direct numerical simulations of convection in a plane layer have also been performed and the results have been published in the Geophysical Journal International (Agrusta et al, 2019).
In this project, we use the code StagYY (Tackley 2008) as main tool to model mantle convection. This requires some modifications:
- we implemented the phase change boundary conditions.
- we implemented the variation of composition by fractional crystallisation at regions of ingoing flow and treatment of compositional aspects in the solid using tracers.
- we implemented the moving boundaries owing to the net motion during secular evolution.
Aside from the main frame but still part of this project, we published a paper on the evolution of an initially stably stratified basal magma ocean (Laneuville et al, 2018).
Also part of the projet, the paper in review for Frontiers in Earth Sciences (Bouffard et al, 2019) presents the possible compositional stratification of the outer core by accumulation of light elements released from the inner core. This work uses the code developped by Mathieu Bouffard which also has implications for the dynamics of magma oceans.

Publications

[5]	Agrusta, R., Morison, A., Labrosse, S., Deguen, R., Alboussière, T., Tackley, P. J., and Dubuffet, F. Mantle convection interacting with magma oceans. Geophys. J. Int., 220:1878–1892, 2019. [ DOI ]
[4]	Morison, A., Labrosse, S., Deguen, R., and Alboussière, T. Timescale of overturn in a magma ocean cumulate. Earth Planet. Sci. Lett., 516:25 – 36, 2019. [ DOI \| http ]
[3]	Bouffard, M., Choblet, G., Labrosse, S., and Wicht, J. Chemical convection and stratification in the Earth's outer core. Frontiers in Earth Science, 7:99, 2019. [ DOI \| http ]
[2]	Labrosse, S., Morison, A., Deguen, R., and Alboussière, T. Rayleigh-Bénard convection in a creeping solid with a phase change at either or both horizontal boundaries. J. Fluid Mech., 846:5–36, 2018. [ DOI ]
[1]	Laneuville, M., Hernlund, J., Labrosse, S., and Guttenberg, N. Crystallization of a compositionally stratified basal magma ocean. Phys. Earth Planet. Inter., 276:86–92, 2018. [ DOI \| http ]

This file was generated by bibtex2html 1.98.

Presentations in conferences and workshops

[17]	Bolrão, D., Rozel, A., Ballmer, M., Morison, A., Labrosse, S., and Tackley, P. J. Thermo-compositional evolution of solid mantle bounded by magma oceans: insights from numerical simulations using a phase change boundary condition. In AGU Fall meeting, Washington D.C., 10–14 December 2018. AGU. DI11B-0019.
[16]	Bolrão, D., Rozel, A., Ballmer, M., Morison, A., Labrosse, S., and Tackley, P. J. From magma oceans to solid mantle: insights from numerical simulations (invited). In AGU Fall meeting, Washington D.C., 10–14 December 2018. AGU. U11B-15.
[15]	Morison, A., Labrosse, S., Bolrão, D., Rozel, A., Ballmer, M., Agrusta, R., Deguen, R., Alboussière, T., and Tackley, P. J. Dynamics and evolution of the primitive mantle with magma oceans. In AGU Fall meeting, Washington D.C., 10–14 December 2018. AGU. DI11B-0015.
[14]	Agrusta, R., Morison, A., Labrosse, S., Alboussière, T., Deguen, R., and Tackley, P. J. Mantle convection during magma ocean crystallization. In AGU Fall meeting, Washington D.C., 10–14 December 2018. AGU. DI11B-0009.
[13]	Agrusta, R., Morison, A., Labrosse, S., Deguen, R., and Alboussière, T. How to solve numerically solid convection at high rayleigh numbers with solid/liquid boundaries during magma ocean crystallization. In EGU General Assembly Conference Abstracts, volume 20 of EGU General Assembly Conference Abstracts, page 9072, Vienna, 8–13 April 2018.
[12]	Morison, A., Labrosse, S., Deguen, R., and Alboussière, T. Rapid destabilization of a magma ocean cumulate due to permeable melting/freezing boundary. In EGU General Assembly Conference Abstracts, volume 20 of EGU General Assembly Conference Abstracts, page 7745, Vienna, 8–13 April 2018.
[11]	Bolrão, D., Rozel, A., Ballmer, M., Morison, A., Labrosse, S., and Tackley, P. J. Numerical simulations of the thermo-compositional evolution of the solid mantle bounded by magma oceans. In EGU General Assembly Conference Abstracts, volume 20 of EGU General Assembly Conference Abstracts, page 11023, Vienna, 8–13 April 2018.
[10]	Labrosse, S., Morison, A., Deguen, R., Alboussière, T., and Tackley, P. J. Thermal convection in the earth mantle interacting with magma oceans above and/or below. In Morbidelli, A., Pinto, R., and Rubie, D., editors, Accretion and Early Differentiation of the Earth and Terrestrial Planets, Nice, 29 May–3 June 2017.
[9]	Morison, A., Labrosse, S., Deguen, R., Alboussière, T., and Tackley, P. J. Thermal convection in a spherical shell with phase change boundary conditions. In Morbidelli, A., Pinto, R., and Rubie, D., editors, Accretion and Early Differentiation of the Earth and Terrestrial Planets, Nice, 29 May–3 June 2017.
[8]	Morison, A., Labrosse, S., Deguen, R., Alboussière, T., and Tackley, P. J. Thermal convection in a spherical shell with phase change boundary conditions. In Compresssible Convection Conference, Lyon, 18–22 September 2017.
[7]	Labrosse, S., Morison, A., Deguen, R., Alboussière, T., Tackley, P. J., and Agrusta, R. Thermal convection in a creeping solid with melting/freezing interfaces at either or both boundaries. In Compresssible Convection Conference, Lyon, 18–22 September 2017.
[6]	Bolrão, D. P., Rozel, A., Morison, A., Labrosse, S., and Tackley, P. J. Numerical simulations of melting-crystallization processes at the boundaries between magma oceans and solid mantle. In Compresssible Convection Conference, Lyon, 18–22 September 2017.
[5]	Bolrão, D. P., Rozel, A., Morison, A., Labrosse, S., and Tackley, P. J. Numerical simulations of melting-crystallisation processes at the boundaries between magma oceans and solid mantle. In AGU Fall meeting, New Orleans, 11–15 December 2017. AGU. P51A2574.
[4]	Bolrão, D., Tackley, P. J., Labrosse, S., and Morison, A. Solid-liquid phase changes at the boundaries between magma oceans and solid mantle: implications for mantle dynamics. In EGU General Assembly Conference Abstracts, volume 19 of EGU General Assembly Conference Abstracts, page 15290, Vienna, 23–28 April 2017.
[3]	Labrosse, S., Morison, A., Deguen, R., Alboussière, T., Tackley, P. J., and Agrusta, R. Thermal convection in a creeping solid with melting/freezing interfaces at either or both boundaries. In AGU Fall meeting, New Orleans, 11–15 December 2017. AGU. NG12A06.
[2]	Morison, A., Labrosse, S., Deguen, R., and Alboussière, T. Timescale of destabilization of a magma ocean cumulate. In AGU Fall meeting, New Orleans, 11–15 December 2017. AGU. P54A02.
[1]	Bolrão, D. P., Rozel, A., Morison, A., Labrosse, S., and Tackley, P. J. Numerical simulations of melting-crystallization processes at the boundaries between magma oceans and solid mantle. In NetherMod, Putten, the Netherland, 27–31 August 2017.