scholarly journals Contraction or expansion of the Moon's crust during magma ocean freezing?

2014 ◽  
Vol 372 (2024) ◽  
pp. 20130240 ◽  
Author(s):  
Linda T. Elkins-Tanton ◽  
David Bercovici
Keyword(s):  
Lower Crust ◽  
The Moon ◽  
Magma Ocean ◽  
Lunar Crust ◽  
Initial State ◽  
Early State ◽  
Gravity Measurements ◽  
Viscous Relaxation ◽  
Tectonic Features

The lack of contraction features on the Moon has been used to argue that the Moon underwent limited secular cooling, and thus had a relatively cool initial state. A cool early state in turn limits the depth of the lunar magma ocean. Recent GRAIL gravity measurements, however, suggest that dikes were emplaced in the lower crust, requiring global lunar expansion. Starting from the magma ocean state, we show that solidification of the lunar magma ocean would most likely result in expansion of the young lunar crust, and that viscous relaxation of the crust would prevent early tectonic features of contraction or expansion from being recorded permanently. The most likely process for creating the expansion recorded by the dikes is melting during cumulate overturn of the newly solidified lunar mantle.

scholarly journals A long-lived magma ocean on a young Moon

2020 ◽  
Vol 6 (28) ◽  
pp. eaba8949 ◽  
Author(s):  
M. Maurice ◽  
N. Tosi ◽  
S. Schwinger ◽  
D. Breuer ◽  
T. Kleine
Keyword(s):  
Thermal Conductivity ◽  
Partial Melting ◽  
Time Scale ◽  
Solidification Time ◽  
Heat Extraction ◽  
The Moon ◽  
Magma Ocean ◽  
Lunar Crust ◽  
Lunar Samples ◽  
Remarkable Agreement

A giant impact onto Earth led to the formation of the Moon, resulted in a lunar magma ocean (LMO), and initiated the last event of core segregation on Earth. However, the timing and temporal link of these events remain uncertain. Here, we demonstrate that the low thermal conductivity of the lunar crust combined with heat extraction by partial melting of deep cumulates undergoing convection results in an LMO solidification time scale of 150 to 200 million years. Combining this result with a crystallization model of the LMO and with the ages and isotopic compositions of lunar samples indicates that the Moon formed 4.425 ± 0.025 billion years ago. This age is in remarkable agreement with the U-Pb age of Earth, demonstrating that the U-Pb age dates the final segregation of Earth’s core.

scholarly journals Crystallization of the lunar magma ocean and the primordial mantle-crust differentiation of the Moon

2018 ◽  
Vol 234 ◽  
pp. 50-69 ◽  
Author(s):  
Bernard Charlier ◽  
Timothy L. Grove ◽  
Olivier Namur ◽  
Francois Holtz
Keyword(s):  
The Moon ◽  
Magma Ocean

Structure in the upper lunar crust

1977 ◽  
Vol 285 (1327) ◽  
pp. 469-473 ◽  
Keyword(s):  
Thermal Conductivity ◽  
Elastic Moduli ◽  
Velocity Profiles ◽  
Depth Range ◽  
The Moon ◽  
Rock Layer ◽  
Lunar Crust ◽  
Seismic Profiles ◽  
Lunar Samples

Estimates are made of the degree of lithification and of structure densities which are compatible with lunar in situ seismic profiles in the top 30 km of the Moon. Estimates are based on comparison of results of passive and active lunar seismic experiments with the pressure dependence of elastic moduli for various classes of lunar samples. Competent rock, such as igneous rock or recrystallized breccias with crack porosity of not more than about 0.5 % are required to satisfy velocity profiles in the depth range 1-30 km. Velocity profiles in the upper 1 km are best satisfied by comminuted material to highly fractured lithic units. These estimates constrain those thermal and shock histories which are compatible with lunar seismic results. After crystallization, or recrystallization, rock below 1 km cannot have been exposed to more than moderate shock levels. In the uppermost 1 km, an unannealed and broken rock layer would imply low thermal conductivity resulting in possible temperatures at 1 km depth of several hundred kelvins.

Chemical composition of the Moon's 'primary' crust – a clue at a terrestrial origin

2020 ◽  
Author(s):  
Audrey Vorburger ◽  
Peter Wurz ◽  
Manuel Scherf ◽  
Helmut Lammer ◽  
André Galli ◽  
...  
Keyword(s):  
Lunar Surface ◽  
Major Elements ◽  
The Moon ◽  
Lunar Crust ◽  
Near Surface ◽  
Origin And Evolution ◽  
The Past ◽  
The Earth ◽  
Terrestrial Origin ◽  
In The Beginning

<p>The Moon is one of the best characterized objects in space science, yet its origin still actively researched. Available orbital, geophysical, and geochemical information imposes clear restrictions on the origin and evolution of the Earth-Moon system (e.g., Canup 2008, 2012; Ćuk and Stewart 2012; Young et al. 2016). In regard to geochemical constraints, one of the most puzzling conundrums is posed by the similar isotopic fingerprints of the Earth and the Moon (e.g., Wiechert et al. 2001; Armytage et al. 2012; Zhang et al. 2012; Young et al. 2016; Schiller et al. 2018), together with the apparent lunar depletion in volatile elements (e.g., Ringwood and Kesson 1977; Wanke et al. 1977; Albarède et al. 2015; Taylor 2014). This apparent lunar volatile depletion is most notable in the low K content in comparison to U, a finding based on chemical analyses of samples collected from the lunar surface and lunar meteorites, and on spectroscopic observations of the lunar near-surface, despite both having been heavily processed in the past ~ 4.4 billion years.</p><p>In the past 4.4 billion years, space has been a harsh environment for our Moon, especially in the beginning, when the young Sun was still very active and the young Moon was continuously bombarded by meteorites of varying sizes. Solar wind and micro-meteoritic interactions with the lunar surface led to rapid and intensive processing of the lunar crust. Hence, the K/U depletion trend observable on today's lunar surface does not necessarily reflect a K/U ratio valid for the Moon in its entirety. We model the evolution of the abundances of the major elements over the past 4.3 to 4.4 billion years to derive the composition of the original lunar crust. Accounting for this processing, our model results show that the original crust is much less depleted in volatiles than the surface observable today, exhibiting a K/U ratio compatible with Earth and the other terrestrial planets, which strengthens the theory of a terrestrial origin for the Moon.</p>

scholarly journals Constraints on olivine-rich rock types on the Moon as observed by Diviner and M3 : Implications for the formation of the lunar crust

2016 ◽  
Vol 121 (7) ◽  
pp. 1342-1361 ◽  
Author(s):  
J. A. Arnold ◽  
T. D. Glotch ◽  
P. G. Lucey ◽  
E. Song ◽  
I. R. Thomas ◽  
...  
Keyword(s):  
The Moon ◽  
Lunar Crust ◽  
Rock Types

Features of the crust-mantle structure of Himalayas-Tibet: a comparison with seismic traverses of Alpine, Pyrenean and Variscan orogenic belts

1988 ◽  
Vol 326 (1589) ◽  
pp. 17-32 ◽  
Keyword(s):  
High Resolution ◽  
Crustal Structure ◽  
Upper Mantle ◽  
Seismic Data ◽  
Lower Crust ◽  
Mantle Structure ◽  
Tectonic Features ◽  
Orogenic Belts

Seismic data able to resolve the crustal structure are limited in quantity and quality with respect to the size and complexity of Tibet—Himalayas. They may be interpreted as indicating a strong heterogeneity: lack of continuity of even major interfaces across strike, defining different crustal blocks, but also lack of continuity of surface tectonic features down through the whole lithosphere. A thickening by imbrication of both the upper crustal and the lower crust-upper mantle levels is suggested. Indications from recent high-resolution surveys in other domains of thickened crust are also of a less smooth geometry of structures and depth than intuitively considered.

The vaporization behavior of carbon and hydrogen from the early global magma ocean

2021 ◽  
Author(s):  
Natalia Solomatova ◽  
Razvan Caracas
Keyword(s):  
First Principles ◽  
Atmospheric Pressure ◽  
Considerable Effect ◽  
Early Earth ◽  
The Moon ◽  
Magma Ocean ◽  
Cooling History ◽  
History Of ◽  
Carbon Molecules ◽  
Dense Atmosphere

<p>Estimating the fluxes and speciation of volatiles during the existence of a global magma ocean is fundamental for understanding the cooling history of the early Earth and for quantifying the volatile budget of the present day. Using first-principles molecular dynamics, we predict the vaporization rate of carbon and hydrogen at the interface between the magma ocean and the hot dense atmosphere, just after the Moon-forming impact. The concentration of carbon and the oxidation state of the melts affect the speciation of the vaporized carbon molecules (e.g., the ratio of carbon dioxide to carbon monoxide), but do not appear to affect the overall volatility of carbon. We find that carbon is rapidly devolatilized even under pressure, while hydrogen remains mostly dissolved in the melt during the devolatilization process of carbon. Thus, in the early stages of the global magma ocean, significantly more carbon than hydrogen would have been released into the atmosphere, and it is only after the atmospheric pressure decreased, that much of the hydrogen devolatilized from the melt. At temperatures of 5000 K (and above), we predict that bubbles in the magma ocean contained a significant fraction of silicate vapor, increasing with decreasing depths with the growth of the bubbles, affecting the transport and rheological properties of the magma ocean. As the temperature cooled, the silicate species condensed back into the magma ocean, leaving highly volatile atmophile species, such as CO<sub>2</sub> and H<sub>2</sub>O, as the dominant species in the atmosphere. Due to the greenhouse nature of CO<sub>2</sub>, its concentration in the atmosphere would have had a considerable effect on the cooling rate of the early Earth.</p>

Newton novel magnetic instrument. Potential application to unveil key questions as the origin of the Moon

2020 ◽  
Author(s):  
José Luis Mesa Uña ◽  
Marina Díaz Michelena ◽  
Francisco Javier de Frutos Hernánsanz ◽  
Claudio Aroca Hernández-Ros ◽  
Marina Pérez Jiménez ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Temporal Variations ◽  
Magnetic Characteristics ◽  
Potential Contribution ◽  
The European Union ◽  
The Moon ◽  
Lunar Crust ◽  
Sensors And Actuators ◽  
Earth Planet

<p>The main objective of this contribution is to present the evolution of NEWTON novel magnetic susceptometer for planetary exploration, a state of the art sensor for the measurement of the complex magnetic susceptibility developed in the frame of an EU H2020 funded project [1].</p><p>The magnetic susceptibility is a complex parameter dependent on the external magnetic field amplitude, direction and frequency. NEWTON susceptometer has been developed to determine the magnetic susceptibility of rocks and soils, with the capability to determine not only the real part but also the imaginary part of the susceptibility.</p><p>The calibration and validation process for the susceptometer prototype casted very good results in comparison with other commercial and high resolution laboratory devices, reaching a resolution in the order of χ = 10<sup>−4</sup> (I.S. Vol. Susceptibility), representative of Earth, Moon and Mars rocks. The critical parts of the prototype have been subjected to different tests, i.e. vibration and TVT, to verify the capability to withstand the hard environmental conditions of interplanetary missions.</p><p>In this work we discuss the potential contribution of NEWTON instrument on the technical and scientific objectives achievement in future investigations on the Moon, either as payload during in-situ exploration with rovers or in sample return missions, providing a useful tool for fast in place sample analysis.</p><p>There are still open questions regarding Moon’s magnetic field and geological characteristics of the satellite. Most hypotheses to explain the magnetic characteristics and anomalies on the lunar surface invoke a thermally driven core dynamo during its Pre-Nectarian and Nectarian history [2]. However, this theory is problematical given the small size of the core and the required strong magnetic field strength of an ancient dynamo. Further investigations on the lunar samples from missions [3] indicate ancient magnetic fields with intensities of <1 to 120 μT for the period between 4.2 to 4.0 Ga. This huge range of intensities may indicate that the Moon’s magnetic field experienced extreme high temporal variations [2]. Even if considering large uncertainties, dynamo models should consider paleointensities of at least ~35 μT for this high-field period.</p><p>The use of scientific instruments like NEWTON susceptometer in rover exploration missions could shed some light on the ancient dynamo magnetic field, the magnetic and mineral composition of the lunar crust and other unanswered questions from the Moon.</p><p>Acknowledgements:</p><p>This project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 730041 and the Spanish Programme of Research, Development and Innovation oriented to the challenges of the society under grant ESP2017-88930-R.</p><p> </p><p><strong>References:</strong></p><p>[1] M.Diaz Michelena, J.L Mesa Uña, M. Perez Jimenez, M. Maicas Ramos, P. Cobos Arribas, C. Aroca Hernandez-Ros, Sensors and Actuators, A: Physical, volume 263, pages 471-479 (2017)</p><p>[2] Tikoo, S.M., Weiss, B.P., Cassata, W.S., Shuser, D.L., Gattacceca, J., Lima, E.A., Suavet, C., Nimmo, F. & Fuller, M.D. Earth Planet. Sci. Lett., 404: 89-97 (2014)</p><p>[3] Tsunakawa, H., Takahashi, F., Shimizu, H., Shibuya, H., & Matsushima, M. Icarus 228: 35-53 (2014).</p><p>[3] Fuller, M. (1974). Reviews of Geophysics, 12 – 1, 101-103 (1974)</p>

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