Search NASA⌕ Search

SEARCH · Search NASA

Results for “Magma ocean”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

Superheat in magma oceans

The existence of 'totally molten' planets implies the existence of a superheat (excess of heat) in the magma reservoirs since the heat buffer (i.e., presence of crystals having high latent heat of fusion) does not exist in a large, completely molten reservoir. Any addition of impacting material results in increase of the temperature of the melt and under favorable circumstances heat is stored. The behavior of superheat melts is little understood; therefore, we experimentally examined properties and behavior of excess heat melts at atmospheric pressures and inert gas atmosphere. Highly siliceous melts (70 percent SiO2) were chosen for the experiments because of the possibility of quenching such melts into glasses, the slow rate of reaction in highly siliceous composition, and the fact that such melts are present in terrestrial impact craters and impact-generated glasses. Results from the investigation are presented.

Jakes, Petr↗
NASA NTRS1983

A partially molten magma ocean model

Under the assumption that the outer 300-400 km of the moon was at first only partially, rather than fully molten, an explanation of the properties of the lunar crust and upper mantle is obtained according to which nuclei of anorthositic crust formed over localized bodies of magma segregated from the partial melt, and then grew peripherally until fully covering the moon. Over most of its growth period, the anorthosite crust floated on a layer of magma whose thickness was regulated by the opposing forces of (1) loss of material by fractional crystallization, and (2) addition of magma from the partial melt below. The clustering of Eu, Sr and Mg values found among pristine ferroan anorthosites are predicted by this model.

Shirley, D. N.↗
NASA NTRS1975

Lunar petrogenesis in a well-stirred magma ocean

The principal group of low-KREEP highlands rocks as indicated by quartz-olivine-anorthite pseudoternary phase diagrams shows chemical trends which violate the Bowen reaction principle, in that the greater the concentration of magnesian and mafic minerals, the more sodic the coexisting plagioclase tends to be. It is suggested that this trend was established during the primary differentiation of the lunar crust and is a result of crystallization in a vigorously convecting (well-stirred) system. Under these conditions all plagioclase crystals, all pyroxene crystals, and all of the residual liquid remain fairly uniform in composition until advanced crystallization immobilizes the system. The rock suite then established would vary continuously from anorthositic types at the top to ultramafic types at the bottom.

Wood, J. A.↗
NASA NTRS1981

Workshop on Magmatic Processes of Early Planetary Crusts: Magma Oceans and Stratiform Layered Intrusions

The significance of the lunar highland pristine cumulate samples were reevaluated with the aid of the additional insights provided by geologically constrained terrestrial investigations. This exercise involved a review of the state of knowledge about terrestrial and lunar cumulate rocks as well as an enumeration and reevaluation of the processes hypothesized to have been responsible for their formation, both classically and at present.

Walker, D.↗
NASA NTRS1983

The magma ocean from the Fra Mauro shoreline - An overview of the Apollo 14 crust

Petrographic and mineralogical studies of coarse grained, polymineralic, texturally monominct igneous clasts from the Apollo 14 breccias show troctolite and troctolitic anorthosite to be the most abundant rock types. The second most abundant group consists of plagioclase cumulates with more evolved mineral compositions than the Mg-rich trend anorthosite cumulates. Coarse grained ilmenite gabbros and mineralogically evolved monzonoritic and granitic clasts are widespread in occurrence, but not abundant. The present data provide further support for widespread regional heterogeneities within the early lunar crust.

Hunter, R. H.↗
NASA NTRS1989

Metasomatic products of the lunar magma ocean - The role of KREEP dissemination

The 'urKREEP' hypothesis of Warren and Wasson (1979) is extended by defining KREEP in terms of specific (i.e., constrained) lunar components. It is shown that, the presilicate liquid immiscibility (pre-SLI) composition can be obtained by recombining experimental data on KREEP basalt components, or by calculating from liquid-liquid Kd's. Both calculated urKREEP compositions were lower in MgO and Al2O3 and higher in FeO and P2O5 than reported low- and high-K KREEP compositions. The calculated REE abundances were higher and the REE profiles were slightly more LREE-enriched than the previously reported KREEP compositions.

Neal, Clive R.↗
NASA NTRS1992

Forsterite/melt partitioning of argon and iodine: Implications for atmosphere formation by outgassing of an early Martian magma ocean

Argon and Xe in the Martian atmosphere are radiogenic relative to the Martian mantle if the SNC meteorites are from Mars. Decay of the short lived isotope I-129 to Xe-129 (t sub 1/2 = 16 m.y.) is the most plausible source of the radiogenic Xe. This short half life constrains any process responsible for the elevated Xe-129/Xe-132 ratio of the Martian atmosphere to occur very early in solar system history. Musselwhite et al. proposed that the differential solubility of I and Xe in liquid water played a key role in producing the radiogenic signature in the Martian atmosphere. Here we explore an alternative hypothesis involving purely igneous processes, and motivated in part by new experimental results on the partitioning of I and Xe between minerals and melt.

Musselwhite, Donald S.↗
NASA NTRS1992

Evidences for the terrestrial magma ocean from high-pressure melting experiments

In order to study the early evolutionary history of our planet, the author has carried out a series of melting experiments on primitive mantle peridotites. Using a new multi-anvil apparatus (SPI-1000), the author revisited the melting study on mantle peridotites and also started a melting study for representative chondrite compositions in the pressure range of 25 Gpa. The updated phase diagram for the peridotite is shown as is the preliminary melting phase diagram for Allende C3 chondrite. The liquidus and solidus of the Allende chondrite are extrapolated based on experimental results at 24 to 26 GPa on the same rock.

Takahashi, Eiichi↗
NASA NTRS1992

Inheritance of magma ocean differentiation during lunar origin by giant impact

The giant impact model for the Moon has won widespread support. It seems to satisfactorily explain the high angular momentum of the Earth-Moon system, and the strong depletion of FeNi in the Moon. This model is usually assumed to entail no significant fractionation of nonvolatile lithophile elements relative to a simple binary mixture of impactor silicates plus protoearth silicates. Although the Earth may have been hot enough before the impact to be completely molten, analysis of the likely number and timing of major impacts in the prehistory of the impactor indicates that a fully molten, undifferentiated condition for that relatively small body is unlikely. Given selective sampling by the giant impact, any significant vertical differentiation within the noncore portion of the impactor would have been largely inherited by the Moon.

Warren, Paul H.↗
NASA NTRS2017

Core Formation on Asteroid 4 Vesta: Iron Rain in a Silicate Magma Ocean

Geochemical observations of the eucrite and diogenite meteorites, together with observations made by NASA's Dawn spacecraft, suggest that Vesta resembles H chondrites in bulk chemical composition, possibly with about 25% of a CM-chondrite like composition added in. For this model, the core is 15% by mass (or 8 volume %) of the asteroid. The abundances of moderately siderophile elements (Ni, Co, Mo, W, and P) in eucrites require that essentially all of the metallic phase in Vesta segregated to form a core prior to eucrite solidification. Melting in the Fe-Ni-S system begins at a cotectic temperature of ~940 deg. C. Only about 40% of the total metal phase, or 3-4 volume % of Vesta, melts prior to the onset of silicate melting. Liquid iron in solid silicate initially forms isolated pockets of melt; connected melt channels, which are necessary if the metal is to segregate from the silicate, are only possible when the metal phase exceeds about 5 volume %. Thus, metal segregation to form a core does not occur prior to the onset of silicate melting.

Kiefer, Walter S.↗
NASA NTRS2018

Asymmetric Post-Magma Ocean Crust-Building on the Lunar Nearside

Mg-suite is a series of ancient plutonic rocks from the lunar crust with ages and com-positions indicating that they represent the first post-differentiation crust-building magmatism [1, 2]. Sam-ples of Mg-suite materials were found at every Apollo landing site except 11 and all exhibit geochemical characteristics indicating the involvement of KREEP in their petrogenesis [3-5]. This has led to the sugges-tion that the KREEP reservoir under the nearside was responsible for Mg-suite magmatism [e.g., 5, 6]. The lack of readily identifiable Mg-suite rocks in meteoritic regolith breccias sourced from outside the Procellarum KREEP Terrane (PKT) seemingly supports this interpretation.

Elardo, S. M.↗
NASA NTRS2023

4.46 Ga Zircons Anchor Chronology of Lunar Magma Ocean

The crystallisation ages of lunar samples provide critical constraints on the minimum formation age of the Moon and its early evolution. Zircon crystals from Apollo 17 lunar impact melt breccia 72255 preserve ancient domains with a concordant average uranium-lead radiometric date of 4460 ± 31 Ma (Zhang et al., 2021), the oldest lunar zircon yet reported. To assess the possible mobility of radiogenic lead in zircon, which may lead to redistribution and clustering of Pb atoms that may cause a U-Pb age bias (Valley et al., 2014), we investigated a zircon grain from Zhang et al. (2021) by atom probe tomography (APT). The atomic spatial resolution analysis of individual mineral grains demonstrates the absence of nanoscale clustering of lead, which supports a 4.46 Ga ancient formation age for lunar zircon in sample 72255. This age pushes back the age of the first preserved lunar crust by ∼40 Myr and provides a minimum formation age for the Moon within 110 Myr after the formation of the solar system.

atom probe tomography↗