Mare basalt petrogenesis and the composition of the lunar interior

1977 ◽  
Vol 285 (1327) ◽  
pp. 577-586 ◽  
Keyword(s):  
Experimental Investigation ◽  
Recent Literature ◽  
Bulk Composition ◽  
The Moon ◽  
Compositional Model ◽  
Earth’S Mantle ◽  
Source Regions ◽  
Lunar Interior ◽  
Wide Range ◽  
Mare Basalts

Mare basalts, which are believed to form by partial melting at considerable depths in the lunar interior, are capable of providing a wealth of information concerning the compositions of their source regions. Conversely, any acceptable estimate of the lunar bulk composition must in principle be able to provide source regions capable of yielding mare basalts. A wide range of lunar bulk compositions has been proposed in the recent literature. These differ principally in the proportions of involatile elements, e.g. Ca, A1, to elements of moderate volatility, e.g. Mg, Si, Fe. A detailed experimental investigation has been made of the capacity of the Taylor—Jakes compositional model (8.2 % A12O3) to provide source regions for mare basalts. It is demonstrated that this composition is much too rich in alumina to be acceptable. Other lunar bulk compositions even richer inA12O3 such as those advocated by Ganapathy & Anders, Wanke and co-workers and Anderson can likewise be rejected. In order to produce mare basalts, particularly the least fractionated varieties represented by some Apollo 12 and 15 basalts, lunar bulk compositions containing only about 4 % of A12O3 appear to be required. This is similar to the alumina content of the Earth’s mantle. The relative abundances of many other involatile elements, e.g. Ga, U, Ti, r.e.e., Zr, Ba, Sr, may likewise be similar in the Moon and in the Earth’s mantle. These relationships point towards a common origin for the Moon and for the Earth’s mantle.

The Earth-Moon Connection

1989 ◽  
Vol 44 (10) ◽  
pp. 891-923 ◽  
Author(s):  
A. E. Ringwood
Keyword(s):  
Genetic Relationship ◽  
The Moon ◽  
Core Formation ◽  
Earth’S Mantle ◽  
Terrestrial Atmosphere ◽  
The Earth ◽  
Wide Range ◽  
Siderophile Elements ◽  
The Impact ◽  
Close Genetic Relationship

Abstract The early thermal state of the Earth provides important constraints on hypotheses relating to its origin and its connection with the Moon. The currently popular giant impact hypothesis of lunar origin requires the Earth’s mantle to have been completely melted during the impact. Differentiation of a molten mantle would have produced strong chemical and mineralogical stratification, causing the mantle to become gravitationally stable and resistant to convective rehomogenization. The resulting composition and mineralogy of the upper mantle and primitive crust would have been dramatically different from those which have existed during the past 3.8 b. y. It is concluded that the Earth’s mantle was not extensively melted at the conclusion of accretion of the planet and therefore the hypothesis that the Moon was formed by the impact of a martian-sized planetesimal on the proto-Earth is probably incorrect. Nevertheless, a wide range of geochemical evidence demonstrates the existence of a close genetic relationship between the Moon and the Earth’s mantle. The key evidence relates to the processes of core formation in planetary bodies and resultant abundance patterns of siderophile elements which remain in their silicate mantles. Because of the complexity of the core formation process within a given body and the multiplicity of chemical and physical processes involved, the mantle siderophile signature is expected to be a unique characteristic. Thus, the siderophile signatures of Mars and of the eucrite parent body are quite distinct from that of the Earth’s mantle. Lunar siderophile geochemistry is reviewed in detail. It is demonstrated that a large group of siderophile elements display similar abundances in the terrestrial and lunar mantles. The similarity implies that a major proportion of the material now in the Moon was derived from the Earth’s mantle after core formation. This implication, however, does not require that the bulk compositions of the lunar and terrestrial mantles should be essentially identical, as is often assumed. Factors which may contribute to significant compositional differences between the two bodies within the context of a close genetic relationship are reviewed. The most promising mechanism for removing terrestrial material from the Earth’s mantle arises from the impacts of a number of large (0.001 to 0.01 ME) but not giant (≥ 0.1 ME) planetesimals after core formation and at the terminal stage of the Earth’s accretion. These impacts evaporated several times their own masses of mantle material and shock-melted considerably more. However, they did not lead to complete or extensive (e.g. > 50%) melting of the entire mantle. Impact-generated clouds of shock-melted spray and vapours were accelerated to high velocities in the presence of a primitive terrestrial atmosphere that co-rotated with the Earth. This provided an effective means of transferring angular momentum from the Earth to the ejected material which condensed to form a ring of Earth-orbiting planetesimals and moonlets. The Moon was formed by coagulation from material derived from the outer regions of this ring. Accretion of the Earth in the presence of the gases of the solar nebula and the co-rotating primitive terrestrial atmosphere may also have provided a mechanism for generating the rapid prograde spin of the proto-Earth.

Constitution of terrestrial planets

1981 ◽  
Vol 303 (1477) ◽  
pp. 287-302 ◽  
Keyword(s):  
Bulk Composition ◽  
Parent Body ◽  
The Moon ◽  
Volatile Elements ◽  
Earth’S Mantle ◽  
The Earth ◽  
History Of ◽  
Relationship Of ◽  
Reduced State

Reliable estimates of the bulk composition are so far restricted to the three planetary objects from which we have samples for laboratory investigation, i.e. the Earth, the Moon and the eucrite parent asteroid. The last, the parent body of the eucrite— diogenite family of meteorites, an object that like Earth and Moon underwent magmatic differentiations, seems to have an almost chondritic composition except for a considerable depletion of all moderately volatile (Na, K, Rb, F, etc.) and highly volatile (Cl, Br, Cd, Pb, etc.) elements. The Moon is also depleted in moderately volatile and volatile elements compared to carbonaceous chondrites of type 1 (Cl) and also compared to the Earth. Again normalized to Cl and Si the Earth’s mantle and the Moon are slightly enriched in refractory lithophile elements and in magnesium. It might be that this enrichment is fictitious and only due to the normalization to Si and that both Earth’s mantle and Moon are depleted in Si, which partly entered the Earth’s core in metallic form. The striking depletion of the Earth’s mantle for the elements V, Cr and Mn can also be explained by their partial removal into the core. The similar abundances of V, Cr and Mn in the Moon and in the Earth’s mantle indicate the strong genetic relationship of Earth and Moon. Apart from their contents of metallic iron, all siderophile elements, moderately volatile and volatile elements, Earth and Moon are chemically very similar. It might well be that, with these exceptions and that of a varying degree of oxidation, all the inner planets have a similar chemistry. The chemical composition of the Earth’s mantle, for which reliable and accurate data have recently been obtained from the study of ultramafic nodules, yields important information about the accretion history of the Earth and that of the inner planets. It seems that accretion started with highly reduced material, with all Fe as metal and even Si and Cr, V and Mn partly in reduced state, followed by the accretion of more and more oxidized matter.

Lithium and halogens in lunar samples

1977 ◽  
Vol 285 (1327) ◽  
pp. 49-54 ◽  
Keyword(s):  
Bulk Composition ◽  
Fluorine Content ◽  
The Other ◽  
The Moon ◽  
Rock Samples ◽  
A Value ◽  
Refractory Elements ◽  
Incompatible Elements ◽  
Lunar Samples ◽  
Mare Basalts

Lithium and the halogen elements F, Cl, Br and I have been measured in soils, breccias and rock samples from all Apollo missions. With the exception of the anorthosites, the fluorine content of the lunar samples is in the same range as for C l chondrites. Contrary to fluorine the other halogen concentrations show large variations. The lowest concentrations are found in the mare basalts of Apollo 15 and 17, the highest in some highland breccias. Lithium correlates well with some of the incompatible elements in both mare basalts and 'KREEP’-containing highland soils and breccias. From the observed ratios it is evident that in the bulk composition of the Moon Li is neither enriched nor depleted; it belongs to the group of non-refractory elements. From the correlation of Li with some refractory elements (Be, La, etc.) a value of 50:50 for the refractory to non-refractory portion of the Moon is inferred without any further assumption, thus confirming previous estimates of Wanke et al. (1974a, 1975)

scholarly journals Late-stage magmatic outgassing from a volatile-depleted Moon

2017 ◽  
Vol 114 (36) ◽  
pp. 9547-9551 ◽  
Author(s):  
James M. D. Day ◽  
Frédéric Moynier ◽  
Charles K. Shearer
Keyword(s):  
Lunar Surface ◽  
Upper Mantle ◽  
Vapor Condensation ◽  
Internal Source ◽  
The Moon ◽  
Volatile Elements ◽  
Lunar Interior ◽  
Leaching Experiments ◽  
Mare Basalts

The abundance of volatile elements and compounds, such as zinc, potassium, chlorine, and water, provide key evidence for how Earth and the Moon formed and evolved. Currently, evidence exists for a Moon depleted in volatile elements, as well as reservoirs within the Moon with volatile abundances like Earth’s depleted upper mantle. Volatile depletion is consistent with catastrophic formation, such as a giant impact, whereas a Moon with Earth-like volatile abundances suggests preservation of these volatiles, or addition through late accretion. We show, using the “Rusty Rock” impact melt breccia, 66095, that volatile enrichment on the lunar surface occurred through vapor condensation. Isotopically light Zn (δ66Zn = −13.7‰), heavy Cl (δ37Cl = +15‰), and high U/Pb supports the origin of condensates from a volatile-poor internal source formed during thermomagmatic evolution of the Moon, with long-term depletion in incompatible Cl and Pb, and lesser depletion of more-compatible Zn. Leaching experiments on mare basalt 14053 demonstrate that isotopically light Zn condensates also occur on some mare basalts after their crystallization, confirming a volatile-depleted lunar interior source with homogeneous δ66Zn ≈ +1.4‰. Our results show that much of the lunar interior must be significantly depleted in volatile elements and compounds and that volatile-rich rocks on the lunar surface formed through vapor condensation. Volatiles detected by remote sensing on the surface of the Moon likely have a partially condensate origin from its interior.

Extraterrestrial Mineralogy: Two major igneous events in the evolution of the Moon

1977 ◽  
Vol 286 (1336) ◽  
pp. 439-451 ◽  
Keyword(s):  
Large Scale ◽  
Bulk Composition ◽  
Large Body ◽  
Uranium Content ◽  
The Moon ◽  
Lunar Crust ◽  
Crust And Upper Mantle ◽  
Lunar Basalts ◽  
Initial Melting ◽  
Mare Basalts

An understanding of the origin of the Moon is strongly dependent upon a knowledge of its bulk composition and thermal history. Both aspects require a detailed consideration of the composition and origin of the lunar crust and of the mantle-derived lunar basalts. The evidence for two major igneous events is discussed, the first being a large-scale melting and fractionation into crust and mantle at —4.6 to —4.5 Ga, and the second a partial melting of the uppermost mantle at —3.8 to — 3.2 Ga. The distribution of uranium is used to place constraints on the minimum extent of initial melting and on the depth at which the mare basalts were generated, using recent lunar heatflow data for a bulk-Moon uranium content of 30 parts/10 9 . The model favours melting of at least 90 % by volume, and a concentration of the high U-contents of the crust and upper mantle by formation of a thick lower mantle of mafic adcumulates ‘barren’ in heat-producing elements. The ‘fertile’ mafic orthocumulates from which the mare basalts were generated are restricted by the model to depths of less than 200 km. A downward revision of the bulk U-content of the Moon results in down-scaling of the other refractory lithophile elements by analogy with the solar-nebula condensation models. This means that the bulk Moon is fairly close in composition to that of the Earth’s mantle, including its iron content but excluding the volatile elements which are strongly depleted in the Moon. Low contents of siderophile and chalcophile elements, and high contents of lithophile refractory elements in the lunar basalts are attributable to the large-scale fractionation into a core, mantle and crust. The hypothesis of an origin for the Moon by fission from a proto-Earth is revived. Earth layering by a heterogeneous accretion sequence would account for non-equilibrium between core and mantle (e.g. nickel distribution) and an outer veneer of volatile-rich condensate that would contribute to subsequent generation of a granitic crust. Early collision with a large body may have caused fission and formation of a proto-Moon from the Earth’s iron-poor, proto-mantle, with loss of volatiles. Early melting of most of the proto-Moon led to strong fractionation such that the crust and mantle-derived basalts appear to have more extreme compositions, relative to Earth basalts, than is indicated by the likely bulk composition of the Moon.

scholarly journals What If the ‘Anthropocene’ Is Not Formalized as a New Geological Series/Epoch?

Quaternary ◽  
2018 ◽  
Vol 1 (3) ◽  
pp. 24 ◽  
Author(s):  
Valentí Rull
Keyword(s):  
Present State ◽  
Executive Committee ◽  
Working Group ◽  
Recent Literature ◽  
Special Issue ◽  
Environmental Sciences ◽  
International Union ◽  
Quaternary Stratigraphy ◽  
Wide Range ◽  
Geological Sciences

In the coming years, the Anthropocene Working Group (AWG) will submit its proposal on the ‘Anthropocene’ to the Subcommission of Quaternary Stratigraphy (SQS) and the International Commission on Stratigraphy (ICS) for approval. If approved, the proposal will be sent to the Executive Committee of the International Union of Geological Sciences (IUGS) for ratification. If the proposal is approved and ratified, then the ‘Anthropocene’ will be formalized. Currently, the ‘Anthropocene’ is a broadly used term and concept in a wide range of scientific and non-scientific situations, and, for many, the official acceptance of this term is only a matter of time. However, the AWG proposal, in its present state, seems to not fully meet the requirements for a new chronostratigraphic unit. This essay asks what could happen if the current ‘Anthropocene’ proposal is not formalized by the ICS/IUGS. The possible stratigraphic alternatives are evaluated on the basis of the more recent literature and the personal opinions of distinguished AWG, SQS, and ICS members. The eventual impact on environmental sciences and on non-scientific sectors, where the ‘Anthropocene’ seems already firmly rooted and de facto accepted as a new geological epoch, are also discussed. This essay is intended as the editorial introduction to a Quaternary special issue on the topic.

scholarly journals Thiazole Ring—A Biologically Active Scaffold

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3166
Author(s):  
Anthi Petrou ◽  
Maria Fesatidou ◽  
Athina Geronikaki
Keyword(s):  
Recent Literature ◽  
Biological Activities ◽  
Literature Survey ◽  
Biologically Active ◽  
Thiazole Ring ◽  
Peer Reviews ◽  
Experimental Drugs ◽  
Wide Range ◽  
Approved Drugs ◽  
Fda Approved Drugs

Background: Thiazole is a good pharmacophore nucleus due to its various pharmaceutical applications. Its derivatives have a wide range of biological activities such as antioxidant, analgesic, and antimicrobial including antibacterial, antifungal, antimalarial, anticancer, antiallergic, antihypertensive, anti-inflammatory, and antipsychotic. Indeed, the thiazole scaffold is contained in more than 18 FDA-approved drugs as well as in numerous experimental drugs. Objective: To summarize recent literature on the biological activities of thiazole ring-containing compounds Methods: A literature survey regarding the topics from the year 2015 up to now was carried out. Older publications were not included, since they were previously analyzed in available peer reviews. Results: Nearly 124 research articles were found, critically analyzed, and arranged regarding the synthesis and biological activities of thiazoles derivatives in the last 5 years.

scholarly journals Bayesian constraints on the origin and geology of exo-planetary material using a population of externally polluted white dwarfs

2021 ◽  
Author(s):  
John H D Harrison ◽  
Amy Bonsor ◽  
Mihkel Kama ◽  
Andrew M Buchan ◽  
Simon Blouin ◽  
...  
Keyword(s):  
Solar System ◽  
White Dwarf ◽  
Bayesian Model ◽  
Total Mass ◽  
White Dwarfs ◽  
Bulk Composition ◽  
Planetary Systems ◽  
The Moon ◽  
Planetary Bodies ◽  
Nearby Stars

Abstract White dwarfs that have accreted planetary bodies are a powerful probe of the bulk composition of exoplanetary material. In this paper, we present a Bayesian model to explain the abundances observed in the atmospheres of 202 DZ white dwarfs by considering the heating, geochemical differentiation, and collisional processes experienced by the planetary bodies accreted, as well as gravitational sinking. The majority (>60%) of systems are consistent with the accretion of primitive material. We attribute the small spread in refractory abundances observed to a similar spread in the initial planet-forming material, as seen in the compositions of nearby stars. A range in Na abundances in the pollutant material is attributed to a range in formation temperatures from below 1,000 K to higher than 1,400 K, suggesting that pollutant material arrives in white dwarf atmospheres from a variety of radial locations. We also find that Solar System-like differentiation is common place in exo-planetary systems. Extreme siderophile (Fe, Ni or Cr) abundances in 8 systems require the accretion of a core-rich fragment of a larger differentiated body to at least a 3σ significance, whilst one system shows evidence that it accreted a crust-rich fragment. In systems where the abundances suggest that accretion has finished (13/202), the total mass accreted can be calculated. The 13 systems are estimated to have accreted masses ranging from the mass of the Moon to half that of Vesta. Our analysis suggests that accretion continues for 11Myrs on average.

Stochastic Late Accretion to Earth, the Moon, and Mars

Science ◽  
2010 ◽  
Vol 330 (6010) ◽  
pp. 1527-1530 ◽  
Author(s):  
William F. Bottke ◽  
Richard J. Walker ◽  
James M. D. Day ◽  
David Nesvorny ◽  
Linda Elkins-Tanton
Keyword(s):  
Size Distribution ◽  
Asteroid Belt ◽  
The Moon ◽  
Core Formation ◽  
Highly Siderophile Elements ◽  
Earth’S Mantle ◽  
Distribution Matching ◽  
Siderophile Elements ◽  
Impact Basins

Core formation should have stripped the terrestrial, lunar, and martian mantles of highly siderophile elements (HSEs). Instead, each world has disparate, yet elevated HSE abundances. Late accretion may offer a solution, provided that ≥0.5% Earth masses of broadly chondritic planetesimals reach Earth’s mantle and that ~10 and ~1200 times less mass goes to Mars and the Moon, respectively. We show that leftover planetesimal populations dominated by massive projectiles can explain these additions, with our inferred size distribution matching those derived from the inner asteroid belt, ancient martian impact basins, and planetary accretion models. The largest late terrestrial impactors, at 2500 to 3000 kilometers in diameter, potentially modified Earth’s obliquity by ~10°, whereas those for the Moon, at ~250 to 300 kilometers, may have delivered water to its mantle.

Sign in / Sign up

Export Citation Format

Share Document