Equilibration in the aftermath of the lunar-forming giant impact

By K. Pahlevan, D. Stevenson. 2007

362 citations recorded by the source corpus.

Abstract Simulations of the moon-forming impact suggest that most of the lunar material derives from the impactor rather than the Earth. Measurements of lunar samples, however, reveal an oxygen isotope composition that is indistinguishable from terrestrial samples, and clearly distinct from meteorites coming from Mars and Vesta. Here we explore the possibility that the silicate Earth and impactor were compositionally distinct with respect to oxygen isotopes, and that the terrestrial magma ocean and lunar-forming material underwent turbulent mixing and equilibration in the energetic aftermath of the giant impact. This mixing may arise in the molten disk epoch between the impact and lunar accretion, lasting perhaps 10 2 –10 3 yr. The implications of this idea for the geochemistry of the Moon, the origin of water on Earth, and constraints on the giant impact are discussed.

Subfields: Astronomy and Astrophysics, Atmospheric Science

View Paper: https://www.semanticscholar.org/paper/30ed77d91d2440716b66848d34b8edc296501958

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Citations in the corpus

Hydrogen isotope ratios in lunar rocks indicate delivery of cometary water to the Moon (2011, background): “One possibility is that the Earth–Moon system was able to diffusively equilibrate its volatiles shortly after the Moon-forming impac”
Linked magma ocean solidification and atmospheric growth for Earth and Mars (2008, background): “Second, the impactor may be devolatilized upon impact (O'Keefe and Ahrens, 1977; Canup, 2004; Ni and Ahrens, 2005; Pahlevan and Stevenson, 2007).”
COLLISIONS BETWEEN GRAVITY-DOMINATED BODIES. II. THE DIVERSITY OF IMPACT OUTCOMES DURING THE END STAGE OF PLANET FORMATION (2011, background): “They suggest that either that the Earth and Moon equilibrated after the giant impact (Pahlevan & Stevenson 2007) or that the time scales for planet growth are too short in the N - body simulations.”
The timeline of the lunar bombardment: Revisited (2018, background): “ is that, at the time of formation, the Earth and the Moon had identical isotopic compositions for all elements (including W), due to a rapid equilibration between the Earth and the proto-Lunar disk (Pahlevan and Stevenson, 2007; Lock et al., 2016; Lock and Stewart, 2017). In this case, the current ”
A Perspective from Extinct Radionuclides on a Young Stellar Object: The Sun and Its Accretion Disk (2011, result): “This finding has two important implications: (a) the Moon was equilibrated isotopically with the proto-Earth mantle during impact (e.g., Pahlevan & Stevenson 2007), and (b) the Moon formed late, after 182Hf had decayed.”
Calcium-48 isotopic anomalies in bulk chondrites and achondrites: Evidence for a uniform isotopic reservoir in the inner protoplanetary disk (2014, background): “These include isotopic equilibration between Earth’s mantle and the proto-lunar disk (Pahlevan and Stevenson, 2007), impact between two equal-size bodies (Canup, 2012), or impact of a small body onto a fast-spinning proto-Earth (Cuk and Stewart, 2012).”
Melting and mixing states of the Earth’s mantle after the Moon-forming impact (2015, background): “ 1.5 AU( 17O of Mars), and case 2: c 1 and c 2 are chosen such that the Earth and Mars analogues in each simulation have 017O(r ) = 0 ‰ and 0:321 ‰, respectively (this is the same setting as those of Pahlevan and Stevenson 2007). Simulations that do not produce Mars analogues are discarded. Figure 6”
The Origin of the Moon Within a Terrestrial Synestia (2018, background): “First, post-impact mixing between the planet and lunar disk could erase initial isotopic heterogeneities (Pahlevan and Stevenson, 2007), but the extent of mixing required to explain the observations is”
Water in the Moon's interior: Truth and consequences (2015, background): “…atmosphere will be pushed out to large distances from the Earth, ahead of the expanding proto-lunar disk as the molten ejecta from the giant impact expands in an attempt to reach hydrostatic equilibrium (Thompson and Stevenson, 1988; Pahlevan and Stevenson, 2007; Nakajima and Stevenson, 2014a).”
The origin of water in the primitive Moon as revealed by the lunar highlands samples (2014, background): “…melt–vapour model from Visscher and Fegley (2013) may actually negate the dominating effect of hydrodynamic escape as a mechanism to lose H from the proto-lunar disk (e.g., Pahlevan and Stevenson, 2007) given the highly oxidising nature of the silicate material which likely comprised the disc.”