Late veneer and the origins of volatiles of Earth

2022 ◽  
Author(s):  
Chun-Hui Li
Keyword(s):  
Late Veneer

scholarly journals Late veneer and late accretion to the terrestrial planets

2016 ◽  
Vol 455 ◽  
pp. 85-93 ◽  
Author(s):  
R. Brasser ◽  
S.J. Mojzsis ◽  
S.C. Werner ◽  
S. Matsumura ◽  
S. Ida
Keyword(s):  
Terrestrial Planets ◽  
Late Veneer

scholarly journals Late Accretion and the Late Veneer

2015 ◽  
pp. 71-82 ◽  
Author(s):  
Alessandro Morbidelli ◽  
Bernard J. Wood
Keyword(s):  
Late Veneer

Late Veneer

2015 ◽  
pp. 1369-1371
Author(s):  
Francis Albarède
Keyword(s):  
Late Veneer

scholarly journals Ruthenium isotope vestige of Earth’s pre-late-veneer mantle preserved in Archaean rocks

Nature ◽  
2020 ◽  
Vol 579 (7798) ◽  
pp. 240-244 ◽  
Author(s):  
Mario Fischer-Gödde ◽  
Bo-Magnus Elfers ◽  
Carsten Münker ◽  
Kristoffer Szilas ◽  
Wolfgang D. Maier ◽  
...  
Keyword(s):  
Late Veneer

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.

scholarly journals Highly siderophile element and 182 W evidence for a partial late veneer in the source of 3.8 Ga rocks from Isua, Greenland

2017 ◽  
Vol 458 ◽  
pp. 394-404 ◽  
Author(s):  
Christopher W. Dale ◽  
Thomas S. Kruijer ◽  
Kevin W. Burton
Keyword(s):  
Late Veneer

scholarly journals THE LAST STAGES OF TERRESTRIAL PLANET FORMATION: DYNAMICAL FRICTION AND THE LATE VENEER

2012 ◽  
Vol 752 (1) ◽  
pp. 8 ◽  
Author(s):  
Hilke E. Schlichting ◽  
Paul H. Warren ◽  
Qing-Zhu Yin
Keyword(s):  
Planet Formation ◽  
Terrestrial Planet ◽  
Dynamical Friction ◽  
Late Veneer

scholarly journals Stable Isotopes of Platinum: Measurement and Application to Constraining the Formation and Differentiation of Earth

2021 ◽  
Author(s):  
◽  
John Creech
Keyword(s):  
Stable Isotope ◽  
Inductively Coupled Plasma ◽  
Chemical Separation ◽  
Isotope Ratios ◽  
Stable Isotope Ratios ◽  
Core Formation ◽  
Inductively Coupled ◽  
Earth’S Mantle ◽  
Isotope System ◽  
Late Veneer

<p>A wide range of novel, non-traditional, stable isotope systems have been developed over the last decade, largely as a result of the advent of multiple-collector inductively coupled plasma mass spectrometry (MC-ICPMS), and continue to provide valuable new insights in the earth, environmental and planetary sciences. The platinum (Pt) stable isotope system represents a potentially powerful but, as yet, unexplored addition to this suite of stable isotope tracers. Pt has six naturally occurring isotopes, and can exist in a range of oxidation states. The geochemical behaviour of Pt coupled with the relatively large mass difference (ca. 2%) between the abundant heavy and light isotopes and its variable oxidation states leads to potential applications in tracing a range of natural processes. In particular, the strong elemental partitioning of Pt between metals and silicates makes the Pt stable isotope system uniquely suited to tracing processes of Earth’s accretion and differentiation. This study aims to develop new techniques for measurement of Pt stable isotopes in geological samples, and to apply these to terrestrial and meteorite samples to attempt to resolve outstanding questions relating to Earth’s early evolution.  A technique was developed for measurement of Pt stable isotope ratios using multiple collector inductively coupled plasma mass spectrometry (MCICPMS), employing a ¹⁹⁶Pt–¹⁹⁸Pt double-spike to correct for instrumental mass fractionation. Results are reported in terms of δ¹⁹⁸Pt, which represents the per mil difference in the ¹⁹⁸Pt/¹⁹⁴Pt ratio from the IRMM-010 Pt isotope standard. A range of analytical tests were conducted and show that this approach has a reproducibility of ca. ±0.04 %∘ on δ¹⁹⁸Pt (i.e., ±0.01%∘ amu⁻¹) for Pt solution standards, and is insensitive to minor amounts of matrix that may be retained after chemical purification of Pt. Measurements of Pt solution standards conducted using two different MC-ICPMS instruments showed resolvable variations, which suggest that natural fractionations exist that exceed the reproducibility of the technique.  Techniques were also developed for dissolution of natural samples and chemical separation of Pt. Geological standards were digested using a nickel sulphide fire assay technique, which pre-concentrates the highly siderophile elements in a NiS bead that is readily dissolved in acid. This was followed by chemical separation of Pt from digested samples using anion exchange chemical techniques. Elution curves were constructed for a range of synthetic rock matrices. These tests show that Pt separation is achieved with >90% Pt yield and ca. 95% purity. Analytical tests show that this level of Pt separation is sufficient for accurate determination of Pt stable isotope ratios by double-spike MC-ICPMS. These techniques were then applied to 11 international geological standard reference materials representing mantle peridotites, igneous samples, and Pt ore materials. The reproducibility in natural samples was determined by processing multiple replicate digestions of a standard reference material, and was shown to be ca. ±0.08%∘ (2 sd). Pt stable isotope data for the full set of reference materials have a range of δ¹⁹⁸Pt values with offsets of up to 0.40%∘ from the IRMM-010 standard, which are readily resolved with this technique. Mantle samples yielded the lightest (most negative) isotopic compositions of the terrestrial standards, with igneous and Pt ore samples defining a continuous trend towards zero, which is consistent with the IRMM-010 standard being derived from a Pt ore. These results demonstrate the potential of the Pt isotope system as a tracer in geochemical systems.  The techniques developed above were then applied to investigate an outstanding problem relating to Earth’s accretion and differentiation. Highly siderophile elements (HSE) are strongly partitioned into the cores of terrestrial planets during core formation, and the abundances of HSE in Earth’s mantle compared with primitive meteorites have provided key constraints on models of Earth’s early evolution. Two leading models to explain the HSE abundances in the silicate Earth involve either a late-veneer of chondritic material that was added after core formation or core formation in a deep magma ocean. The platinum (Pt) stable isotope system represents a novel tool for investigating these processes. Using the techniques developed above, Pt stable isotope ratios were measured in a range of meteorite samples, including enstatite, ordinary and carbonaceous chondrites, primitive achondrites, achondrites and iron meteorites, as well as additional terrestrial mantle xenolith samples. Our data set reveals that the Pt stable isotopic composition of Earth’s mantle overlaps with all of the chondrite groups. Primitive achondrite and ureilite samples revealed the heaviest compositions of all meteorite groups. These data suggest that metal–silicate differentiation produces an isotopic fractionation for Pt, with heavy isotopes being preferentially retained in the silicate phase. Thus, Earth’s mantle is expected to have been significantly enriched in the heavy isotopes of Pt during core formation, even if metal–silicate differentiation took place in a magma ocean. The absence of a large fractionation between chondrites, representing the composition of the undifferentiated Earth, and the mantle suggests that the signature of core formation in the mantle has been subsequently overprinted. Considering the overlap between the Pt stable isotopic compositions of the mantle and chondrites, the most likely means for overprinting the composition of the mantle is by addition of a chondritic late-veneer. Mixing calculations show that addition of 0.5% of Earth’s mass by a late-veneer of chondritic material would be sufficient to overprint highly fractionated Pt stable isotope signatures resulting from core-formation.</p>

Sign in / Sign up

Export Citation Format

Share Document