Evolution of Planetary Cores and the Earth-Moon System from Nb/Ta Systematics
@article{Mnker2003EvolutionOP, title={Evolution of Planetary Cores and the Earth-Moon System from Nb/Ta Systematics}, author={Carsten M{\"u}nker and J{\"o}rg A. Pf{\"a}nder and Stefan Weyer and Anette B{\"u}chl and Thorsten Kleine and Klaus Mezger}, journal={Science}, year={2003}, volume={301}, pages={84 - 87} }
It has been assumed that Nb and Ta are not fractionated during differentiation processes on terrestrial planets and that both elements are lithophile. High-precision measurements of Nb/Ta and Zr/Hf reveal that Nb is moderately siderophile at high pressures. Nb/Ta values in the bulk silicate Earth (14.0 ± 0.3) and the Moon (17.0 ± 0.8) are below the chondritic ratio of 19.9 ± 0.6, in contrast to Mars and asteroids. The lunar Nb/Ta constrains the mass fraction of impactor material in the Moon to…
351 Citations
The Extent, Nature, and Origin of K and Rb Depletions and Isotopic Fractionations in Earth, the Moon, and Other Planetary Bodies
- Geology, PhysicsThe Planetary Science Journal
- 2022
Moderately volatile elements (MVEs) are depleted and isotopically fractionated in the Moon relative to Earth. To understand how the composition of the Moon was established, we calculate the…
Identification of the giant impactor Theia in lunar rocks
- Geology, PhysicsScience
- 2014
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.
Tungsten isotopic evidence for disproportional late accretion to the Earth and Moon
- GeologyNature
- 2015
Characterization of the hafnium–tungsten systematics of the lunar mantle will enable better constraints on the timescale and processes involved in the currently accepted giant-impact theory for the formation and evolution of the Moon, and for testing the late-accretion hypothesis.
On the enigma of Nb-Ta and Zr-Hf fractionation—A critical review
- Geology
- 2011
Elemental ratios Zr/Hf and Nb/Ta are expected to be constant and of chondritic value (∼36.30 and ∼17.57, respectively) in mantle and mantle-derived rocks. Studies in recent years have shown, however,…
Geochemical arguments for an Earth-like Moon-forming impactor
- Geology, PhysicsPhilosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
- 2014
An inversion method is presented to calculate the Hf/W ratios and ϵ182W values of the proto-Earth and impactor mantles for a given Moon-forming impact scenario.
References
SHOWING 1-10 OF 23 REFERENCES
Rutile-bearing refractory eclogites: missing link between continents and depleted mantle
- GeologyScience
- 2000
Trace element compositions of minerals in xenolithic eclogites derived from cratonic lithospheric mantle show that rutile dominates the budget of Nb and Ta in the eClogites and imparts a superchondritic Nb/Ta, N b/La, and Ti/Zr to the whole rocks.
Fluid- and melt-related enrichment in the subarc mantle: Evidence from Nb/Ta variations in island-arc basalts
- Geology
- 1996
The single most distinctive feature of volcanic rocks from convergent-margin settings is a marked depletion of the high field strength elements (HFSE) Nb, Ta, and Ti relative to large ion lithophile…
The solar-system abundances of Nb, Ta, and Y, and the relative abundances of refractory lithophile elements in differentiated planetary bodies
- Geology, Physics
- 1986
Rapid accretion and early core formation on asteroids and the terrestrial planets from Hf–W chronometry
- Geology, PhysicsNature
- 2002
It is concluded that core formation in the terrestrial planets and the formation of the Moon must have occurred during the first ∼30 million years of the life of the Solar System.
A short timescale for terrestrial planet formation from Hf–W chronometry of meteorites
- Geology, PhysicsNature
- 2002
Measurements of tungsten isotope compositions and hafnium–tungsten ratios of several meteorites indicate that the bulk of metal–silicate separation in the Solar System was completed within <30 Myr, completely consistent with other evidence for rapid planetary formation.
Origin of the Moon in a giant impact near the end of the Earth's formation
- Physics, GeologyNature
- 2001
This work reports a class of impacts that yield an iron-poor Moon, as well as the current masses and angular momentum of the Earth–Moon system, and suggests that the Moon formed near the very end of Earth's accumulation.