scholarly journals Thermal evolution of an early magma ocean in interaction with the atmosphere

2013 ◽  
Vol 118 (6) ◽  
pp. 1155-1176 ◽  
Author(s):  
T. Lebrun ◽  
H. Massol ◽  
E. Chassefière ◽  
A. Davaille ◽  
E. Marcq ◽  
...  
Keyword(s):  
Thermal Evolution ◽  
Magma Ocean

Linking the core heat content to Earth's accretion history

2020 ◽  
Author(s):  
Renaud Deguen ◽  
Vincent Clési
Keyword(s):  
Thermal State ◽  
Thermal Evolution ◽  
Heat Content ◽  
Magma Ocean ◽  
The Core ◽  
Current State ◽  
Partitioning Coefficients ◽  
The Mean ◽  
Mantle Diapirism ◽  
Do So

<p>The composition of Earth's mantle, when compared to experimentally determined partitioning coefficients, can be used to constrain the conditions of equilibration - pressure P, temperature T, and oxygen fugacity fO<sub>2</sub> - of the metal and silicates during core-mantle differentiation.<br>This places constraints on the thermal state of the planet during its accretion, and it is tempting to try to use these data to estimate the heat content of the core at the end of accretion. To do so, we develop an analytical model of the thermal evolution of the metal phase during its descent through the solid mantle toward the growing core, taking into account compression heating,   viscous dissipation heating, and heat exchange with the surrounding silicates. For each impact, the model takes as initial condition the pressure and temperature at the base of the magma ocean, and gives the temperature of the metal when it reaches the core. The growth of the planet results in additional pressure increase and compression heating of the core. The thermal model is coupled to a Monte-Carlo inversion of the metal/silicates equilibration conditions (P, T, fO<sub>2</sub>) in the course of accretion from the abundance of Ni, Co, V and Cr in the mantle, and provides an estimate of the core heat content at the end of accretion for each geochemically successful accretion. The core heat content depends on the mean degree of metal-silicates equilibration, on the mode of metal/silicates separation in the mantle (diapirism, percolation, or dyking), but also very significantly on the shape of the equilibration conditions curve (equilibration P and T vs. fraction of Earth accreted). We find that many accretion histories which are successful in reproducing the mantle composition yield a core that is colder than its current state. Imposing that the temperature of the core at the end of accretion is higher than its current values therefore provides strong constraints on the accretion history. In particular, we find that the core heat content depends significantly on the last stages of accretion. </p>

Characteristics of an hybrid atmosphere with disk-captured and degassing contributions over a rocky planet’s magma ocean. A modeling approach.

2020 ◽  
Author(s):  
Athanasia Nikolaou ◽  
Lorenzo Mugnai ◽  
Oliver Herbort ◽  
Enzo Pascale ◽  
Peter Woitke
Keyword(s):  
Thermal Evolution ◽  
Chemical Characterization ◽  
Protoplanetary Disk ◽  
International Institute ◽  
Atmospheric Conditions ◽  
Magma Ocean ◽  
Silicate Mineral ◽  
Chemical Abundances ◽  
Magma Oceans ◽  
The University

<p>Motivation:<br />   Early during their formation the planets capture an amount of atmosphere from the protoplanetary disk (Ikoma et al. 2018, Odert et al. 2018, Lammer et al. 2020, Kimura and Ikoma 2020). An additional proportion of their atmosphere is provided during the magma ocean stage by interior degassing. The latter mechanism is assumed to be the main provider of the final atmospheric mass. Its composition is compromised by the source silicate mineral and its chemical characterization (Gaillard and Scaillet 2014, Herbort et al. 2020).<br />   Numerous studies support the degassing of the oxidized gas species H<sub>2</sub>O and CO<sub>2</sub> as main contributions from the magma ocean phase (Abe and Matsui 1988, Abe 1993, Elkins-Tanton 2008, Schaefer et al. 2012, Lebrun et al. 2013, Lupu et al. 2014, Gaillard and Scaillet 2014, Salvador et al. 2017, Nikolaou et al. 2019). Previous work has also shown that H<sub>2</sub>O, in particular, plays a crucial role (Hamano et al. 2013, Katyal et al. 2019, Turbet et al. 2019) in thermal blanketing. H<sub>2</sub>O possibly leads to “long-term” (Hamano et al 2013) or “conditionally continuous” (Nikolaou et al. 2019) magma oceans that effectively cease to cool. Water also ties directly to the availability of hydrogen that drives hydrodynamic escape (Airapetian et al. 2017, Lammer et al. 2018). CO<sub>2 </sub>factors into both above processes, as well (Wordsworth and Pierrehumbert 2013, Odert et al. 2018). Constraining the H<sub>2</sub>O and CO<sub>2</sub> abundances early after formation is indispensible to the planet’s thermal evolution and extensive modeling effort has been devoted to it. Their constraint would in particular help revisit which magma ocean types among transient-conditionally continuous-permanent (Nikolaou et al. 2019) are detectable in future exoplanetary missions (ARIEL, Tinetti et al. 2018; PLATO, Rauer et al. 2014).<br /> </p> <p>Method:<br />   In this work we focus on the combination of degassed and disk-captured atmosphere under the assumption of chemical equilibrium. Using simulations from the 1D Convective Ocean of Magma Radiative Atmosphere and Degassing model (Nikolaou et al. 2019) we obtain the thermal evolution and degassing tracks of a rocky planet. In order to evaluate the chemical abundances under equilibrium conditions we employ the thermodynamical model GGchem (Woitke et al. 2018).<br />   We explore the atmospheric conditions during the lifetime of a magma ocean under varying mineral compositions and protoplanetary disk contributions. We discuss the results in the context of the likely magma ocean types.<br /> <br />A.N. and P.W. wish to thank the Erwin Schrödinger International Institute for Mathematics and Physics (ESI) of the University of Vienna, Thematic Programme on “Astrophysical Origins: Pathways from Star Formation to Habitable Planets” 2019, which enabled this collaboration.</p>

Towards 3D modelling of convection in planetesimals and meteorite parent bodies

2019 ◽  
Vol 490 (1) ◽  
pp. L47-L51 ◽  
Author(s):  
Wladimir Neumann
Keyword(s):  
Solid State ◽  
Thermal Evolution ◽  
Asteroid Belt ◽  
Magma Ocean ◽  
Early Solar System ◽  
Conduction Model ◽  
Time Requirements ◽  
Convection Model ◽  
Magma Oceans ◽  
Free Material

ABSTRACT Observations of asteroid belt members, investigations of meteorites and thermal evolution models converge on the paradigm of the ubiquity of melting processes in the planetesimals of the early Solar system. At least partial melting of planetesimals that fulfilled size and accretion time requirements to surpass the solidus temperatures of metal and silicates led to the weakening of the rock due to the interstitial melt. A decrease of the viscosity relative to melt-free material facilitates solid-state convection on partially molten bodies. Additional melting can produce liquid-like layers with suspended particles, i.e. magma oceans. Thermal evolution models indicate that partially molten layers can occur in the interior of undifferentiated bodies and in silicate mantles of differentiated ones. They can exist before a magma ocean forms or after it solidifies and above a whole-mantle magma ocean or below a shallow magma ocean. Thus, convection is likely. Attempts to model and to quantify the effects of convection in planetesimals remain rare. This study discusses the possibility of solid-state convection in partially molten planetesimals, presents a first-order comparison of a 3D mantle convection model with a conduction model taking a Vesta-sized body as an example and illustrates the importance of convection for meteorite parent bodies.

scholarly journals A mushy Earth's mantle for more than 500 Myr after the magma ocean solidification

2020 ◽  
Vol 221 (2) ◽  
pp. 1165-1181
Author(s):  
J Monteux ◽  
D Andrault ◽  
M Guitreau ◽  
H Samuel ◽  
S Demouchy
Keyword(s):  
Thermal Evolution ◽  
Numerical Models ◽  
Spherical Geometry ◽  
Magma Ocean ◽  
Mantle Dynamics ◽  
Mineral Physics ◽  
The Earth ◽  
Complete Melting ◽  
Metal Silicate ◽  
Impact Heating

SUMMARY In its early evolution, the Earth mantle likely experienced several episodes of complete melting enhanced by giant impact heating, short-lived radionuclides heating and viscous dissipation during the metal/silicate separation. After a first stage of rapid and significant crystallization (Magma Ocean stage), the mantle cooling is slowed down due to the rheological transition, which occurs at a critical melt fraction of 40–50%. This transition first occurs in the lowermost mantle, before the mushy zone migrates toward the Earth's surface with further mantle cooling. Thick thermal boundary layers form above and below this reservoir. We have developed numerical models to monitor the thermal evolution of a cooling and crystallizing deep mushy mantle. For this purpose, we use a 1-D approach in spherical geometry accounting for turbulent convective heat transfer and integrating recent and solid experimental constraints from mineral physics. Our results show that the last stages of the mushy mantle solidification occur in two separate mantle layers. The lifetime and depth of each layer are strongly dependent on the considered viscosity model and in particular on the viscosity contrast between the solid upper and lower mantle. In any case, the full solidification should occur at the Hadean–Eoarchean boundary 500–800 Myr after Earth's formation. The persistence of molten reservoirs during the Hadean may favor the absence of early reliefs at that time and maintain isolation of the early crust from the underlying mantle dynamics.

scholarly journals Low-spin ferric iron in primordial bridgmanite crystallized from a deep magma ocean

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yoshiyuki Okuda ◽  
Kenji Ohta ◽  
Yu Nishihara ◽  
Naohisa Hirao ◽  
Tatsuya Wakamatsu ◽  
...  
Keyword(s):  
Lower Mantle ◽  
Ferric Iron ◽  
Thermal Evolution ◽  
Spin Transition ◽  
Mantle Heterogeneity ◽  
Magma Ocean ◽  
Electronic Spin ◽  
Energy Domain ◽  
History Of ◽  
Open Question

AbstractThe crystallization of the magma ocean resulted in the present layered structure of the Earth’s mantle. An open question is the electronic spin state of iron in bridgmanite (the most abundant mineral on Earth) crystallized from a deep magma ocean, which has been neglected in the crystallization history of the entire magma ocean. Here, we performed energy-domain synchrotron Mössbauer spectroscopy measurements on two bridgmanite samples synthesized at different pressures using the same starting material (Mg0.78Fe0.13Al0.11Si0.94O3). The obtained Mössbauer spectra showed no evidence of low-spin ferric iron (Fe3+) from the bridgmanite sample synthesized at relatively low pressure of 25 gigapascals, while that directly synthesized at a higher pressure of 80 gigapascals contained a relatively large amount. This difference ought to derive from the large kinetic barrier of Fe3+ rearranging from pseudo-dodecahedral to octahedral sites with the high-spin to low-spin transition in experiments. Our results indicate a certain amount of low-spin Fe3+ in the lower mantle bridgmanite crystallized from an ancient magma ocean. We therefore conclude that primordial bridgmanite with low-spin Fe3+ dominated the deeper part of an ancient lower mantle, which would contribute to lower mantle heterogeneity preservation and call for modification of the terrestrial mantle thermal evolution scenarios.

Effects of a long lived global magma ocean on mantle dynamics of the early Moon

2021 ◽  
Author(s):  
Adrien Morison ◽  
Stephane Labrosse ◽  
Daniela Bolrao ◽  
Antoine Rozel ◽  
Maxim Ballmer ◽  
...  
Keyword(s):  
Boundary Condition ◽  
Boundary Conditions ◽  
Fractional Crystallization ◽  
Thermal Evolution ◽  
Classical Case ◽  
Magma Ocean ◽  
Viscous Forces ◽  
Solid Part ◽  
Convection Patterns ◽  
Magma Oceans

<p>The light plagioclase-enriched crust as well as the KREEP layer at the surface of the Moon are believed to be remnants of the bottom-up crystallization of a global Lunar Magma Ocean.  In such a setup, the primitive Lunar solid mantle is coated by a liquid magma ocean of similar composition. We propose here to study the dynamic and evolution of the primitive Lunar solid mantle, accounting for the presence of the Lunar Magma Ocean.</p><p>We solve numerically the equations of solid-state convection in the solid part of the mantle.  This model is coupled to 1D models of crystallization of the magma oceans to self-consistently compute the thickening of the solid part as heat is evacuated from the mantle.  We take into account fractional crystallization at the freezing front.</p><p>Moreover, the boundaries between the solid and the magma oceans are phase-change interfaces.  Convecting matter in the solid arriving near the boundary or getting away from it forms a topography which can be erased by melting or freezing.  Hence, provided the melting and freezing occurs rapidly compared to the time needed to build the topographies by viscous forces, dynamical exchange of matter can occur between the solid mantle and the magma oceans.  We take this effect into account in our model with a boundary condition applied to the solid.</p><p>We find that the boundary condition allowing matter to cross the interfaces between the solid and the magma oceans greatly affects the convection patterns in the solid as well as its heat flux.  Larger-scale convection patterns are selected compared to the classical case with non-penetrative boundary conditions; and the heat transfert in the solid is more efficient with these boundary conditions.  This affects the long term thermal evolution of the mantle as well as the shape of chemical heterogeneities that can be built by fractional crystallization of magma oceans.</p>

scholarly journals Thermal evolution of an early magma ocean in interaction with the atmosphere: conditions for the condensation of a water ocean

2014 ◽  
Vol 2 ◽  
pp. 01006 ◽  
Author(s):  
T. Lebrun ◽  
H. Massol ◽  
E. Chassefière ◽  
A. Davaille ◽  
E. Marcq ◽  
...  
Keyword(s):  
Thermal Evolution ◽  
Magma Ocean

Numerical modeling of the thermal state of Earth after the Moon-forming impact event

2021 ◽  
Author(s):  
Laetitia Allibert ◽  
Nicole Güldemeister ◽  
Lukas Manske ◽  
Miki Nakajima ◽  
Kai Wünnemann
Keyword(s):  
Thermal State ◽  
Initial Conditions ◽  
Thermal Evolution ◽  
Three Dimensional ◽  
Impact Angle ◽  
Impact Event ◽  
The Moon ◽  
Magma Ocean ◽  
Self Gravity ◽  
The Impact

<p align="justify">Planetary collisions play an important role in the compositional and thermal evolution of planetary systems and such collisions are caracteristics of the final stage of planetary formation. The Moon-forming impact event is thought to (re)set the conditions for the subsequent thermochemical evolution of Earth and Moon. Large parts of proto-Earth are thought to melt as a consequence of the impact [e.g.1] and the extent of melting affects the evolution of the Earth’s interior and atmosphere. It is then critical to address the initial conditions of the proto-Earth and the volume and shape of a possible magma ocean after the impact. Previously, the Moon-forming giant impact was modeled with mesh-free so-called smoothed particle hydrodynamics (SPH [1, 2, 3]). In this study, we, in contrast, carried out numerical simulations of the Moon-forming impact event considering different impact scenarios with the three-dimensional (3D) iSALE code [4, 5], that tends to be more accurate in the description of thermodynamics and shock waves than SPH simulations. We also compare simulation results from our iSALE code with SPH models for benchmarking ([1]) because SPH uses self-gravity, whereas iSALE uses central gravity. We vary the impact angle (15° to 90°) and impact velocities (12 to 20 km/s). In order to quantify the volume of impact-induced melt, we use the so-called peak-shock pressure approach (‘Tracer method’) that has been used in several modeling studies [6,7] and is described in more detail by [8].</p> <p align="justify">The benchmark study shows a good agreement of the two different numerical approaches with respect to pressure evolution. However the production of a magma ocean show some differences that need to be further explored, with notably the effects of considering central gravity instead of self-gravity into iSALE 3D simulations.</p> <p align="justify"> </p> <p align="justify"><strong>Acknowledgments</strong>: We gratefully thank the iSALE developers, including Gareth Collins, Kai Wünnemann, Dirk Elbeshausen, Boris Ivanov and Jay Melosh and Thomas Davison for the development of the pysaleplot tool. We also thank the Deutsche Forschungsgemeinschaft (SFB-TRR 170, subproject C2 and C4) for funding.</p> <p align="justify"> </p> <p align="justify"><strong>References</strong>:[1] Nakajima M. and Stevenson D. J. (2015) EPSL, 427, 286-295. [2] Canup R. M. et al. (2013) ICARUS 222, 200-219. [3] Canup R, M. (2004) Science 338, 1052-1054. [4] Collins G. S. et al. (2004) Meteoritics & Planet. Sci., 39, 217-231. [5] Wünnemann K. (2006) ICARUS 180, 514-527. [6] Wünnemann K. et al. (2008) EPSL 269, 529-538. [7] Pierazzo et al. (1997) ICARUS 127, 408-423. [8] Manske L. et al. (2018) 49th LPSC, abstract# 2269.[11] Pierazzo and Melosh (1999) EPSL 165, 163-176</p>

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