The tungsten isotopic composition of the Earth’s mantle before the terminal bombardment

  title={The tungsten isotopic composition of the Earth’s mantle before the terminal bombardment},
  author={Matthias Willbold and Tim Elliott and Stephen Erwin Moorbath},
Many precious, ‘iron-loving’ metals, such as gold, are surprisingly abundant in the accessible parts of the Earth, given the efficiency with which core formation should have removed them to the planet’s deep interior. One explanation of their over-abundance is a ‘late veneer’—a flux of meteorites added to the Earth after core formation as a ‘terminal’ bombardment that culminated in the cratering of the Moon. Some 3.8 billion-year-old rocks from Isua, Greenland, are derived from sources that… 
Lunar tungsten isotopic evidence for the late veneer
Data independently show that HSE abundances in the bulk silicate Earth were established after the giant impact and core formation, as predicted by the late veneer hypothesis and constitutes a challenge to current models of lunar origin.
Tungsten Isotopes in Planets.
Tungsten isotopic data for meteorites show that the parent bodies of some differentiated meteorites accreted within 1 million years after Solar System formation, demonstrating that traces of Earth's earliest formative period have been preserved throughout Earth's history.
Preservation of Earth-forming events in the tungsten isotopic composition of modern flood basalts
High-precision tungsten isotopic data from rocks from two large igneous provinces, the North Atlantic Igneous Province and the Ontong Java Plateau, reveal preservation to the Phanerozoic of tung sten isotopic heterogeneities in the mantle, indicating that portions of the mantle that formed during Earth's primary accretionary period have survived to the present.
Geoscience: Earth's patchy late veneer
Matthias Willbold and colleagues present high-precision tungsten isotope analyses of ancient Greenland rocks and show that they have significantly higher 182W/184W ratios than modern terrestrial samples, in good agreement with the expected influence of a meteoritic late heavy bombardment.
Ru isotope vestige of Earth’s pre-late veneer mantle preserved in Archean rocks
Ruthenium isotope compositions of the oldest preserved mantle rocks from Greenland imply that volatile-rich outer Solar System material was not delivered to Earth until very late in the planet’s formation.
Identifying remnants of early Earth
The range of µ182W values in mantle-derived rocks is larger than can be accommodated by late accretion; the implication is that remnants of Earth's earliest mantle have been preserved over the entirety of Earth’s history.
Identification of the giant impactor Theia in lunar rocks
Triple oxygen isotope data reveal a 12 ± 3 parts per million difference in Δ17O between Earth and the Moon, which supports the giant impact hypothesis of Moon formation, and show that enstatite chondrites and Earth have different Δ 17O values, and speculate on an enstatITE chondrite–like composition of Theia.
A colossal impact enriched Mars' mantle with noble metals
Once the terrestrial planets had mostly completed their assembly, bombardment continued by planetesimals left over from accretion. Highly siderophile element (HSE) abundances in Mars' mantle imply


Tungsten isotope evidence that mantle plumes contain no contribution from the Earth's core
None of the samples analysed have a negative tungsten isotope value, which rules out a simple core–mantle mixing scenario and suggests that the radiogenic osmium in ocean-island basalts can better be explained by the source of such basalts containing a component of recycled crust.
Tungsten isotope evidence from ∼3.8-Gyr metamorphosed sediments for early meteorite bombardment of the Earth
The ‘Late Heavy Bombardment’ was a phase in the impact history of the Moon that occurred 3.8–4.0 Gyr ago, when the lunar basins with known dates were formed. But no record of this event has yet been
Composition of the Earth's interior: the importance of early events
  • R. Carlson, M. Boyet
  • Geology
    Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
  • 2008
Calculations of the mass of the enriched reservoir along with seismically determined properties of the D″ layer at the base of the mantle allow the speculation that this enriched reservoir formed by the sinking of dense melts deep in a terrestrial magma ocean may now be confined to a combination of compositionally induced high density and low viscosity, which allow only minimal entrainment into the overlying convecting mantle.
Stochastic Late Accretion to Earth, the Moon, and Mars
It is shown that leftover planetesimal populations dominated by massive projectiles can explain additions to iron-loving elements on Earth, Mars, and the Moon, with the inferred size distribution matching those derived from the inner asteroid belt, ancient martian impact basins, and planetary accretion models.
142Nd Evidence for Early (>4.53 Ga) Global Differentiation of the Silicate Earth
New high-precision samarium-neodymium isotopic data for chondritic meteorites show that their 142Nd/144Nd ratio is 20 parts per million lower than that of most terrestrial rocks. This difference
Progressive mixing of meteoritic veneer into the early Earth’s deep mantle
Komatiites are ancient volcanic rocks, mostly over 2.7 billion years old (from the Archaean era), that formed through high degrees of partial melting of the mantle and therefore provide reliable