scholarly journals Tracing metal–silicate segregation and late veneer in the Earth and the ureilite parent body with palladium stable isotopes

2017 ◽  
Vol 216 ◽  
pp. 28-41 ◽  
Author(s):  
J.B. Creech ◽  
F. Moynier ◽  
M. Bizzarro
Keyword(s):  
Stable Isotopes ◽  
Parent Body ◽  
The Earth ◽  
Metal Silicate ◽  
Late Veneer

Isotopes as clues to the origin and earliest differentiation history of the Earth

2008 ◽  
Vol 366 (1883) ◽  
pp. 4129-4162 ◽  
Author(s):  
Stein B Jacobsen ◽  
Michael C Ranen ◽  
Michael I Petaev ◽  
John L Remo ◽  
Richard J O'Connell ◽  
...  
Keyword(s):  
Time Scale ◽  
Magma Ocean ◽  
Crust Formation ◽  
Early Atmosphere ◽  
The Earth ◽  
Metal Silicate ◽  
Deep Earth ◽  
History Of ◽  
Mean Time ◽  
Late Veneer

Measurable variations in 182 W/ 183 W, 142 Nd/ 144 Nd, 129 Xe/ 130 Xe and 136 Xe Pu / 130 Xe in the Earth and meteorites provide a record of accretion and formation of the core, early crust and atmosphere. These variations are due to the decay of the now extinct nuclides 182 Hf, 146 Sm, 129 I and 244 Pu. The l82 Hf– 182 W system is the best accretion and core-formation chronometer, which yields a mean time of Earth's formation of 10 Myr, and a total time scale of 30 Myr. New laser shock data at conditions comparable with those in the Earth's deep mantle subsequent to the giant Moon-forming impact suggest that metal–silicate equilibration was rapid enough for the Hf–W chronometer to reliably record this time scale. The coupled 146 Sm– 147 Sm chronometer is the best system for determining the initial silicate differentiation (magma ocean crystallization and proto-crust formation), which took place at ca 4.47 Ga or perhaps even earlier. The presence of a large 129 Xe excess in the deep Earth is consistent with a very early atmosphere formation (as early as 30 Myr); however, the interpretation is complicated by the fact that most of the atmospheric Xe may be from a volatile-rich late veneer.

Core formation in the shergottite parent body and comparison with the Earth

1987 ◽  
Vol 92 (B4) ◽  
pp. E627-E632 ◽  
Author(s):  
Allan H. Treiman ◽  
John H. Jones ◽  
Michael J. Drake
Keyword(s):  
Parent Body ◽  
Core Formation ◽  
The Earth

scholarly journals Magnesium isotopic composition of olivine from the Earth, Mars, Moon, and pallasite parent body

2006 ◽  
Vol 33 (15) ◽  
Author(s):  
M. D. Norman ◽  
G. M. Yaxley ◽  
V. C. Bennett ◽  
A. D. Brandon
Keyword(s):  
Isotopic Composition ◽  
Parent Body ◽  
The Earth

Effect of H2O on metal–silicate partitioning of Ni, Co, V, Cr, Mn and Fe: Implications for the oxidation state of the Earth and Mars

2016 ◽  
Vol 192 ◽  
pp. 97-121 ◽  
Author(s):  
V. Clesi ◽  
M.A. Bouhifd ◽  
N. Bolfan-Casanova ◽  
G. Manthilake ◽  
A. Fabbrizio ◽  
...  
Keyword(s):  
Oxidation State ◽  
The Earth ◽  
Metal Silicate

scholarly journals Evolution of the Earth’s atmosphere during Late Veneer accretion

2020 ◽  
Vol 499 (4) ◽  
pp. 5334-5362
Author(s):  
Catriona A Sinclair ◽  
Mark C Wyatt ◽  
Alessandro Morbidelli ◽  
David Nesvorný
Keyword(s):  
Terrestrial Planet ◽  
Hydrodynamic Simulations ◽  
Substantial Growth ◽  
Early Atmosphere ◽  
The Earth ◽  
Wide Range ◽  
History Of ◽  
Current Mass ◽  
Low Mass ◽  
Late Veneer

ABSTRACT Recent advances in our understanding of the dynamical history of the Solar system have altered the inferred bombardment history of the Earth during accretion of the Late Veneer, after the Moon-forming impact. We investigate how the bombardment by planetesimals left-over from the terrestrial planet region after terrestrial planet formation, as well as asteroids and comets, affects the evolution of Earth’s early atmosphere. We develop a new statistical code of stochastic bombardment for atmosphere evolution, combining prescriptions for atmosphere loss and volatile delivery derived from hydrodynamic simulations and theory with results from dynamical modelling of realistic populations of impactors. We find that for an initially Earth-like atmosphere, impacts cause moderate atmospheric erosion with stochastic delivery of large asteroids, giving substantial growth (× 10) in a few ${{\ \rm per\ cent}}$ of cases. The exact change in atmosphere mass is inherently stochastic and dependent on the dynamics of the left-over planetesimals. We also consider the dependence on unknowns including the impactor volatile content, finding that the atmosphere is typically completely stripped by especially dry left-over planetesimals ($\lt 0.02 ~ {{\ \rm per\ cent}}$ volatiles). Remarkably, for a wide range of initial atmosphere masses and compositions, the atmosphere converges towards similar final masses and compositions, i.e. initially low-mass atmospheres grow, whereas massive atmospheres deplete. While the final properties are sensitive to the assumed impactor properties, the resulting atmosphere mass is close to that of current Earth. The exception to this is that a large initial atmosphere cannot be eroded to the current mass unless the atmosphere was initially primordial in composition.

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.

scholarly journals Andesitic Magmatism on a Differentiated Asteroid

2021 ◽  
Author(s):  
Robert Nicklas ◽  
James Day ◽  
Kathryn Gardner-Vandy ◽  
Arya Udry
Keyword(s):  
Partial Melting ◽  
Continental Crust ◽  
Parent Body ◽  
Volatile Components ◽  
Highly Siderophile Elements ◽  
The Past ◽  
Metal Silicate ◽  
Oceanic And Continental Crust ◽  
Siderophile Elements ◽  
Melt Composition

Abstract The Earth differs from other terrestrial planets in having a substantial silica-rich continental crust with a bulk andesitic composition1. The compositional dichotomy between oceanic and continental crust is likely related to water-rich subduction processes2. Over the past decade, the discovery of meteorites with andesitic bulk compositions have demonstrated that continental-crust like compositions can be attained through partial melting of chondritic protoliths3,4,5. Here we show that a newly identified achondrite meteorite, Erg Chech (EC) 002, is a high-Mg andesite but that, unlike previous andesitic achondrites has strongly fractionated and low abundances of the highly siderophile elements (HSE), reminiscent of Earth’s upper continental crust6. The major and HSE composition of EC 002 can be explained if its asteroid parent body underwent metal-silicate equilibrium prior to silicate partial melting without losing significant volatile components. The chemistry of pyroxene grains in EC 002 suggests it approximates a parental melt composition, which cannot be produced by partial melting of pre-existing basaltic lithologies, but more likely requires a metal-free chondritic source. Erg Chech 002 likely formed by ~ 15% melting of the mantle of an alkali-undepleted differentiated asteroid. The discovery of EC 002 shows that extensive silicate differentiation after metal-silicate equilibration was already occurring in the first two million years of solar system history7, and that andesitic crustal compositions do not always require water-rich subduction processes to be produced.

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