Abstract
According to the most widely accepted theory of lunar origin, a giant impact on the Earth led to the formation of the Moon, and also initiated the final stage of the formation of the Earth’s core1. Core formation should have removed the highly siderophile elements (HSE) from Earth’s primitive mantle (that is, the bulk silicate Earth), yet HSE abundances are higher than expected2. One explanation for this overabundance is that a ‘late veneer’ of primitive material was added to the bulk silicate Earth after the core formed2. To test this hypothesis, tungsten isotopes are useful for two reasons: first, because the late veneer material had a different 182W/184W ratio to that of the bulk silicate Earth, and second, proportionally more material was added to the Earth than to the Moon3. Thus, if a late veneer did occur, the bulk silicate Earth and the Moon must have different 182W/184W ratios. Moreover, the Moon-forming impact would also have created 182W differences because the mantle and core material of the impactor with distinct 182W/184W would have mixed with the proto-Earth during the giant impact. However the 182W/184W of the Moon has not been determined precisely enough to identify signatures of a late veneer or the giant impact. Here, using more-precise measurement techniques, we show that the Moon exhibits a 182W excess of 27 ± 4 parts per million over the present-day bulk silicate Earth. This excess is consistent with the expected 182W difference resulting from a late veneer with a total mass and composition inferred from HSE systematics2. Thus, our 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. But, unexpectedly, we find that before the late veneer, no 182W anomaly existed between the bulk silicate Earth and the Moon, even though one should have arisen through the giant impact. The origin of the homogeneous 182W of the pre-late-veneer bulk silicate Earth and the Moon is enigmatic and constitutes a challenge to current models of lunar origin.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Canup, R. M. & Asphaug, E. Origin of the Moon in a giant impact near the end of the Earth’s formation. Nature 412, 708–712 (2001)
Walker, R. J. Highly siderophile elements in the Earth, Moon and Mars: update and implications for planetary accretion and differentiation. Chem. Erde Geochem. 69, 101–125 (2009)
Day, J. M. D., Pearson, D. G. & Taylor, L. A. Highly siderophile element constraints on accretion and differentiation of the Earth-Moon system. Science 315, 217–219 (2007)
Kleine, T. et al. Hf–W chronology of the accretion and early evolution of asteroids and terrestrial planets. Geochim. Cosmochim. Acta 73, 5150–5188 (2009)
Willbold, M., Elliott, T. & Moorbath, S. The tungsten isotopic composition of the Earth’s mantle before the terminal bombardment. Nature 477, 195–198 (2011)
Touboul, M., Puchtel, I. S. & Walker, R. J. 182W evidence for long-term preservation of early mantle differentiation products. Science 335, 1065–1069 (2012)
Day, J. M. D., Walker, R. J., James, O. B. & Puchtel, I. S. Osmium isotope and highly siderophile element systematics of the lunar crust. Earth Planet. Sci. Lett. 289, 595–605 (2010)
Walker, R. J. Siderophile element constraints on the origin of the Moon. Phil. Trans. R. Soc.. A 372,http://dx.doi.org/10.1098/rsta.2013.0258 (2014)
Leya, I., Wieler, R. & Halliday, A. N. Cosmic-ray production of tungsten isotopes in lunar samples and meteorites and its implications for Hf–W cosmochemistry. Earth Planet. Sci. Lett. 175, 1–12 (2000)
Touboul, M., Kleine, T., Bourdon, B., Palme, H. & Wieler, R. Late formation and prolonged differentiation of the Moon inferred from W isotopes in lunar metals. Nature 450, 1206–1209 (2007)
Kleine, T., Palme, H., Mezger, K. & Halliday, A. N. Hf-W chronometry of lunar metals and the age and early differentiation of the Moon. Science 310, 1671–1674 (2005)
Kruijer, T. S. et al. Protracted core formation and rapid accretion of protoplanets. Science 344, 1150–1154 (2014)
Sprung, P., Kleine, T. & Scherer, E. E. Isotopic evidence for chondritic Lu/Hf and Sm/Nd of the Moon. Earth Planet. Sci. Lett. 380, 77–87 (2013)
Meyer, C. The Lunar Sample Compendium. Available at http://curator.jsc.nasa.gov/Lunar/lsc/index.cfm (20 May 2013)
Morgan, J. W., Ganapathy, R., Higuchi, H., Krähenbühl, U. & Anders, E. Lunar basins: tentative characterization of projectiles, from meteoritic elements in Apollo 17 boulders. Proc. Lunar Planet. Sci. Conf. 2, 1703–1736 (1974)
Fischer-Gödde, M. & Becker, H. Osmium isotope and highly siderophile element constraints on ages and nature of meteoritic components in ancient lunar impact rocks. Geochim. Cosmochim. Acta 77, 135–156 (2012)
Gaffney, A. M. & Borg, L. E. A young solidification age for the lunar magma ocean. Geochim. Cosmochim. Acta 140, 227–240 (2014)
Carlson, R. W., Borg, L. E., Gaffney, A. M. & Boyet, M. Rb-Sr, Sm-Nd and Lu-Hf isotope systematics of the lunar Mg-suite: the age of the lunar crust and its relation to the time of Moon formation. Phil. Trans. R. Soc.. A 372, http://dx.doi.org/10.1098/rsta.2013.0246 (2014)
Wang, Z. & Becker, H. Ratios of S, Se and Te in the silicate Earth require a volatile-rich late veneer. Nature 499, 328–331 (2013)
Becker, H. et al. Highly siderophile element composition of the Earth’s primitive upper mantle: constraints from new data on peridotite massifs and xenoliths. Geochim. Cosmochim. Acta 70, 4528–4550 (2006)
Borg, L. E., Connelly, J. N., Boyet, M. & Carlson, R. W. Chronological evidence that the Moon is either young or did not have a global magma ocean. Nature 477, 70–72 (2011)
Zhang, J., Dauphas, N., Davis, A. M., Leya, I. & Fedkin, A. The proto-Earth as a significant source of lunar material. Nature Geosci. 5, 251–255 (2012)
Armytage, R. M. G., Georg, R. B., Williams, H. M. & Halliday, A. N. Silicon isotopes in lunar rocks: implications for the Moon’s formation and the early history of the Earth. Geochim. Cosmochim. Acta 77, 504–514 (2012)
Herwartz, D., Pack, A., Friedrichs, B. & Bischoff, A. Identification of the giant impactor Theia in lunar rocks. Science 344, 1146–1150 (2014)
Dauphas, N., Burkhardt, C., Warren, P. & Teng, F.-Z. Geochemical arguments for an Earth-like Moon-forming impactor. Phil. Trans. R. Soc.. Ahttp://dx.doi.org/10.1098/rsta.2013.0244 (2014)
Ćuk, M. & Stewart, S. T. Making the Moon from a fast-spinning Earth: a giant impact followed by resonant despinning. Science 338, 1047–1052 (2012)
Reufer, A., Meier, M. M. M., Benz, W. & Wieler, R. A hit-and-run giant impact scenario. Icarus 221, 296–299 (2012)
Canup, R. M. Forming a Moon with an Earth-like composition via a giant impact. Science 338, 1052–1055 (2012)
Pahlevan, K. & Stevenson, D. J. Equilibration in the aftermath of the lunar-forming giant impact. Earth Planet. Sci. Lett. 262, 438–449 (2007)
Kleine, T., Hans, U., Irving, A. J. & Bourdon, B. Chronology of the angrite parent body and implications for core formation in protoplanets. Geochim. Cosmochim. Acta 84, 186–203 (2012)
Kleine, T., Mezger, K., Münker, C., Palme, H. & Bischoff, A. 182Hf-182W isotope systematics of chondrites, eucrites, and martian meteorites: chronology of core formation and early mantle differentiation in Vesta and Mars. Geochim. Cosmochim. Acta 68, 2935–2946 (2004)
Kruijer, T. S. et al. Hf–W chronometry of core formation in planetesimals inferred from weakly irradiated iron meteorites. Geochim. Cosmochim. Acta 99, 287–304 (2012)
Kruijer, T. S., Kleine, T., Fischer-Gödde, M., Burkhardt, C. & Wieler, R. Nucleosynthetic W isotope anomalies and the Hf-W chronometry of Ca-Al-rich inclusions. Earth Planet. Sci. Lett. 403, 317–327 (2014)
Kruijer, T. S. et al. Neutron capture on Pt isotopes in iron meteorites and the Hf–W chronology of core formation in planetesimals. Earth Planet. Sci. Lett. 361, 162–172 (2013)
Fischer-Gödde, M., Becker, H. & Wombacher, F. Rhodium, gold and other highly siderophile elements in orogenic peridotites and peridotite xenoliths. Chem. Geol. 280, 365–383 (2011)
Fischer-Gödde, M., Becker, H. & Wombacher, F. Rhodium, gold and other highly siderophile element abundances in chondritic meteorites. Geochim. Cosmochim. Acta 74, 356–379 (2010)
Cohen, A. S. & Waters, F. G. Separation of osmium from geological materials by solvent extraction for analysis by thermal ionisation mass spectrometry. Anal. Chim. Acta 332, 269–275 (1996)
Wood, J. A., Dickey, J. S., Marvin, U. B. & Powell, B. N. Lunar anorthosites and a geophysical model of the Moon. Proc. Apollo 11 Lunar Sci. Conf. 1, 965–988 (1970)
Taylor, S. R. & Jakeš, P. The geochemical evolution of the Moon. Proc. Fifth Lunar Conf. 2, 1287–1305 (1974)
Warren, P. H. & Wasson, J. T. The origin of KREEP. Rev. Geophys. 17, 73–88 (1979)
Righter, K. & Shearer, C. K. Magmatic fractionation of Hf and W: constraints on the timing of core formation and differentiation in the Moon and Mars. Geochim. Cosmochim. Acta 67, 2497–2507 (2003)
Münker, C. A high field strength element perspective on early lunar differentiation. Geochim. Cosmochim. Acta 74, 7340–7361 (2010)
Morgan, J. W., Walker, R. J., Brandon, A. D. & Horan, M. F. Siderophile elements in Earth’s upper mantle and lunar breccias: data synthesis suggests manifestations of the same late influx. Meteorit. Planet. Sci. 36, 1257–1275 (2001)
Korotev, R. L. The meteorite component of Apollo 16 noritic impact melt breccias. J. Geophys. Res. 92, E491 (1987)
Puchtel, I. S., Walker, R. J., James, O. B. & Kring, D. A. Osmium isotope and highly siderophile element systematics of lunar impact melt breccias: implications for the late accretion history of the Moon and Earth. Geochim. Cosmochim. Acta 72, 3022–3042 (2008)
Norman, M. D., Bennett, V. C. & Ryder, G. Targeting the impactors?: siderophile element signatures of lunar impact melts from Serenitatis. Geochim. Cosmochim. Acta 202, 217–228 (2002)
Fischer-Gödde, M. & Becker, H. Osmium isotope and highly siderophile element constraints on ages and nature of meteoritic components in ancient lunar impact rocks. Geochim. Cosmochim. Acta 77, 135–156 (2012)
McCoy, T. J. et al. Group IVA irons: new constraints on the crystallization and cooling history of an asteroidal core with a complex history. Geochim. Cosmochim. Acta 75, 6821–6843 (2011)
Pattou, L., Lorand, J. P. & Gros, M. Non-chondritic platinum-group element ratios in the Earth’s mantle. Nature 379, 712–715 (1996)
Horan, M. Highly siderophile elements in chondrites. Chem. Geol. 196, 27–42 (2003)
Meisel, T., Walker, R. J., Irving, A. J. & Lorand, J.-P. Osmium isotopic compositions of mantle xenoliths: a global perspective. Geochim. Cosmochim. Acta 65, 1311–1323 (2001)
Arevalo, R. & McDonough, W. F. Tungsten geochemistry and implications for understanding the Earth’s interior. Earth Planet. Sci. Lett. 272, 656–665 (2008)
McDonough, W. F. & Sun, S.-s. The composition of the Earth. Chem. Geol. 120, 223–253 (1995)
Lyubetskaya, T. & Korenaga, J. Chemical composition of Earth’s primitive mantle and its variance: 1. Method and results. J. Geophys. Res. 112, B03211 (2007)
Palme, H. & O’Neill, H. S. C. Cosmochemical Estimates of Mantle Composition. Treatise on Geochemistry (2nd edn) 3, 1–39 (Elsevier, 2014)
König, S. et al. The Earth’s tungsten budget during mantle melting and crust formation. Geochim. Cosmochim. Acta 75, 2119–2136 (2011)
Dahl, T. W. & Stevenson, D. J. Turbulent mixing of metal and silicate during planet accretion — And interpretation of the Hf–W chronometer. Earth Planet. Sci. Lett. 295, 177–186 (2010)
Khan, A., Maclennan, J., Taylor, S. R. & Connolly, J. A. D. Are the Earth and the Moon compositionally alike? Inferences on lunar composition and implications for lunar origin and evolution from geophysical modeling. J. Geophys. Res. 111, E05005 (2006)
Weber, R. C., Lin, P.-Y., Garnero, E. J., Williams, Q. & Lognonné, P. Seismic detection of the lunar core. Science 331, 309–312 (2011)
Palme, H. Lodders, K. & Jones, A. Solar System Abundances of the Elements. Treatise on Geochemistry (2nd edn) 2, 15–36 (Elsevier, 2014)
Cottrell, E., Walter, M. J. & Walker, D. Metal–silicate partitioning of tungsten at high pressure and temperature: Implications for equilibrium core formation in Earth. Earth Planet. Sci. Lett. 281, 275–287 (2009)
Acknowledgements
We thank CAPTEM, NASA and R. Zeigler for providing the Apollo lunar samples for this study. We thank G. Brügmann for providing an HSE spike. C. Brennecka is acknowledged for comments on the paper, and we also thank A. Brandon for comments.
Author information
Authors and Affiliations
Contributions
T.S.K. prepared the lunar samples for W isotope analyses and performed the measurements. All authors contributed to the interpretation of the data and preparation of the manuscript.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing financial interests.
Extended data figures and tables
Extended Data Figure 1 Compilation of ε182W results obtained for three terrestrial rock standards, BCR-2, AGV-2 and BHVO-2.
Each of these standards was analysed together with the lunar samples. ε182W (6/4) indicates that the data have been normalized to 186W/184W = 0.92767 (denoted ‘6/4’); see Methods for details. Error bars indicate internal uncertainties (2 s.e.) for a single measurement of 200 cycles. The external uncertainty (2 s.d.), as inferred from replicate standard analyses, is shown as a grey-hatched area, and the corresponding 95% confidence interval of 2 p.p.m. as a solid grey area.
Extended Data Figure 2 CI-chondrite-normalized and Ir-normalized HSE concentrations of lunar samples 14321, 68115, and 68815.
HSE concentrations are first normalized to chondritic abundances, then to the chondrite normalized Ir concentration. Corresponding HSE concentrations are given in Extended Data Table 3.
Extended Data Figure 3 Change of ε182W of the proto-Earth’s mantle through addition of impactor material.
The varying amounts of impactor material are given as Mimp/M⊕ where Mimp and M⊕ are respectively the mass of impactor material and the Earth’s mass. Hatched area (red) shows the maximum possible difference between the (eventual) ε182W of the pre-late-veneer BSE and the Moon, as inferred from the difference between the lunar pre-exposure ε182W value (+0.27 ± 0.04) and that calculated for the BSE before addition of the late veneer (). Shown are the effects of different degrees of equilibration of the impactor core with the proto-Earth’s mantle, from full (k = 1) to no equilibration (k = 0) and for two different impactor compositions: a, volatile-element-enriched ‘Mars-like’ and b, volatile-element-depleted ‘Vesta-like’. In both cases the impactor was assumed to have core and mantle fractions of 32% and 68%, identical to the Earth. For the (proto-)Earth’s mantle we used a W concentration of 13 ± 5 p.p.b. (2σ) (see Methods); its ε182W is set to zero. For the Mars-like impactor, CI-chondritic Hf (107 p.p.b.) and W (93 p.p.b.) concentrations60 were assumed. As core formation in this impactor would have occurred under more oxidizing conditions, we chose a relatively low metal–silicate partition coefficient61 for W of DW = 6, which yields a relatively high W concentration of [W]IM = 41 p.p.b. in the impactor mantle (and a low Hf/W of 4.4), and a correspondingly low W concentration of [W]IC = 205 p.p.b. in the core. The metal–silicate differentiation age was set to 9 Myr after CAI formation, resulting in a ε182W of −2.7 in the metal core, and a ε182W of +0.32 in the silicate mantle (calculated using a Solar System initial 182Hf/180Hfi of (1.018 ± 0.043) × 10−4; ref. 33). For the Vesta-like impactor we assumed CV-chondritic Hf (200 p.p.b.) and W (175 p.p.b.) concentrations31. Core formation in this impactor would have occurred under more reduced conditions, so the metal–silicate partition coefficient for W was set to a relatively high value (DW = 42)61. This yields a low W concentration in the silicate mantle ([W]IM = 12 p.p.b.), a high Hf/W of 25 in the silicate mantle, and a relatively high W concentration in the metal core ([W]IC = 522 p.p.b.) The metal–silicate differentiation age was set to 2 Myr after CAI formation, resulting in a ε182WIC of −3.3 in the metal core, and a ε182WIM of +27 in the silicate mantle.
Extended Data Figure 4 Effect of mixing impactor core into the lunar accretion disk on the ε182W of the Moon.
Shown are the effects on ε182W for two different impactor compositions (green and blue lines). Hatched area (red) shows the maximum possible difference between the (eventual) ε182W of Earth and Moon as inferred from the difference between the lunar pre-exposure ε182W value (+0.27 ± 0.04) and that calculated for the BSE before addition of late veneer (). In the mass balance we considered the same two impactor compositions as used in the mass balance shown in Extended Data Fig. 3, including (1) an (oxidized) volatile-element-rich impactor (green line), and (2) a (reduced) volatile-element-poor impactor (blue line). We used the same Hf and W concentrations, partition coefficients, core and mantle fractions, and differentiation ages, so the resulting Hf/W and ε182W values of impactor mantle and core are identical to those above. The amount of impactor core material currently present in the Moon is assumed to be equivalent to the lunar core fraction, that is, 2.5% of its mass. For this reason the mixing lines intersect the ordinate (Δε182W = 0) at 2.5%. For simplicity we assume the proportion of impactor material present in the Moon to be 80%, that is, consistent with most ‘canonical’ giant-impact models1.
Rights and permissions
About this article
Cite this article
Kruijer, T., Kleine, T., Fischer-Gödde, M. et al. Lunar tungsten isotopic evidence for the late veneer. Nature 520, 534–537 (2015). https://doi.org/10.1038/nature14360
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/nature14360
This article is cited by
-
H2-H2O immiscibility in Earth’s upper mantle
Contributions to Mineralogy and Petrology (2023)
-
Measurement of the \( ^{181} \)Ta(\(n,\gamma \)) cross sections up to stellar s-process temperatures at the CSNS Back-n
Scientific Reports (2023)
-
The accretion of planet Earth
Nature Reviews Earth & Environment (2022)
-
The Exosphere as a Boundary: Origin and Evolution of Airless Bodies in the Inner Solar System and Beyond Including Planets with Silicate Atmospheres
Space Science Reviews (2022)
-
No 182W evidence for early Moon formation
Nature Geoscience (2021)
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.