According to the generally accepted scenario, the last giant impact on Earth formed the Moon and initiated the final phase of core formation by melting Earth’s mantle. A key goal of geochemistry is to date this event, but different ages have been proposed. Some1,2,3 argue for an early Moon-forming event, approximately 30 million years (Myr) after the condensation of the first solids in the Solar System, whereas others4,5,6 claim a date later than 50 Myr (and possibly as late as around 100 Myr) after condensation. Here we show that a Moon-forming event at 40 Myr after condensation, or earlier, is ruled out at a 99.9 per cent confidence level. We use a large number of N-body simulations to demonstrate a relationship between the time of the last giant impact on an Earth-like planet and the amount of mass subsequently added during the era known as Late Accretion. As the last giant impact is delayed, the late-accreted mass decreases in a predictable fashion. This relationship exists within both the classical scenario7,8 and the Grand Tack scenario9,10 of terrestrial planet formation, and holds across a wide range of disk conditions. The concentration of highly siderophile elements (HSEs) in Earth’s mantle constrains the mass of chondritic material added to Earth during Late Accretion11,12. Using HSE abundance measurements13,14, we determine a Moon-formation age of 95 ± 32 Myr after condensation. The possibility exists that some late projectiles were differentiated and left an incomplete HSE record in Earth’s mantle. Even in this case, various isotopic constraints strongly suggest that the late-accreted mass did not exceed 1 per cent of Earth’s mass, and so the HSE clock still robustly limits the timing of the Moon-forming event to significantly later than 40 Myr after condensation.
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Yin, Q. et al. A short timescale for terrestrial planet formation from Hf–W chronometry of meteorites. Nature 418, 949–952 (2002)
Jacobsen, S. B. The Hf-W isotopic system and the origin of the Earth and Moon. Annu. Rev. Earth Planet. Sci. 33, 531–570 (2005)
Taylor, D. J., McKeegan, K. D. & Harrison, T. M. Lu-Hf zircon evidence for rapid lunar differentiation. Earth Planet. Sci. Lett. 279, 157–164 (2009)
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)
Allègre, C. J., Manhès, G. & Göpel, C. The major differentiation of the Earth at 4.45 Ga. Earth Planet. Sci. Lett. 267, 386–398 (2008)
Halliday, A. N. A young Moon-forming giant impact at 70–110 million years accompanied by late-stage mixing, core formation and degassing of the Earth. Phil. Trans. R. Soc. A 366, 4163–4181 (2008)
O'Brien, D. P., Morbidelli, A. & Levison, H. F. Terrestrial planet formation with strong dynamical friction. Icarus 184, 39–58 (2006)
Raymond, S. N., O'Brien, D. P., Morbidelli, A. & Kaib, N. A. Building the terrestrial planets: constrained accretion in the inner Solar System. Icarus 203, 644–662 (2009)
Walsh, K. J., Morbidelli, A., Raymond, S. N., O'Brien, D. P. & Mandell, A. M. A low mass for Mars from Jupiter’s early gas-driven migration. Nature 475, 206–209 (2011)
O'Brien, D. P., Walsh, K. J., Morbidelli, A., Raymond, S. N. & Mandell, A. M. Water delivery and giant impacts in the ‘Grand Tack’ scenario. Icarus (submitted)
Chyba, C. F. Terrestrial mantle siderophiles and the lunar impact record. Icarus 92, 217–233 (1991)
Bottke, W. F., Walker, R. J., Day, J. M. D., Nesvorný, D. & Elkins-Tanton, L. Stochastic Late Accretion to Earth, the Moon, and Mars. Science 330, 1527–1530 (2010)
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)
Walker, R. J. Highly siderophile elements in the Earth, Moon and Mars: update and implications for planetary accretion and differentiation. Chemie Erde Geochem. 69, 101–125 (2009)
König, S. et al. The Earth's tungsten budget during mantle melting and crust formation. Geochim. Cosmochim. Acta 75, 2119–2136 (2011)
Wetherill, G. W. Why isn't Mars as big as Earth? Abstr. Lunar Planet. Sci. Conf. 22, 1495 (1991)
Chambers, J. E. & Cassen, P. M. The effects of nebula surface density profile and giant-planet eccentricities on planetary accretion in the inner solar system. Meteorit. Planet. Sci. 37, 1523–1540 (2002)
Hansen, B. M. S. Formation of the terrestrial planets from a narrow annulus. Astrophys. J. 703, 1131–1140 (2009)
Mann, U., Frost, D. J., Rubie, D. C., Becker, H. & Audétat, A. Partitioning of Ru, Rh, Pd, Re, Ir and Pt between liquid metal and silicate at high pressures and high temperatures—implications for the origin of highly siderophile element concentrations in the Earth's mantle. Geochim. Cosmochim. Acta 84, 593–613 (2012)
Chou, C. L. Fractionation of siderophile elements in the Earth's upper mantle. Abstr. Lunar Planet. Sci. Conf. 9, 219–230 (1978)
Morbidelli, A., Marchi, S., Bottke, W. F. & Kring, D. A. A sawtooth-like timeline for the first billion years of lunar bombardment. Earth Planet. Sci. Lett. 355, 144–151 (2012)
Albarede, F. et al. Asteroidal impacts and the origin of terrestrial and lunar volatiles. Icarus 222, 44–52 (2013)
Rudge, J. F., Kleine, T. & Bourdon, B. Broad bounds on Earth's accretion and core formation constrained by geochemical models. Nature Geosci. 3, 439–443 (2010)
Wiechert, U. et al. Oxygen isotopes and the Moon-forming giant impact. Science 294, 345–348 (2001)
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)
Leinhardt, Z. M. & Stewart, S. T. Collisions between gravity-dominated bodies. I. Outcome regimes and scaling laws. Astrophys. J. 745, 79 (2012)
Kokubo, E. & Genda, H. Formation of terrestrial planets from protoplanets under a realistic accretion condition. Astrophys. J. 714, L21–L25 (2010)
Chambers, J. E. Late-stage planetary accretion including hit-and-run collisions and fragmentation. Icarus 224, 43–56 (2013)
Asphaug, E., Agnor, C. B. & Williams, Q. Hit-and-run planetary collisions. Nature 439, 155–160 (2006)
Strom, R. G., Malhotra, R., Ito, T., Yoshida, F. & Kring, D. A. The origin of planetary impactors in the inner Solar System. Science 309, 1847–1850 (2005)
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)
Duncan, M. J., Levison, H. F. & Lee, M. H. A multiple time step symplectic algorithm for integrating close encounters. Astron. J. 116, 2067–2077 (1998)
Chambers, J. E. A hybrid symplectic integrator that permits close encounters between massive bodies. Mon. Not. R. Astron. Soc. 304, 793–799 (1999)
Morbidelli, A., Lunine, J. I., O'Brien, D. P., Raymond, S. N. & Walsh, K. J. Building terrestrial planets. Annu. Rev. Earth Planet. Sci. 40, 251–275 (2012)
Haisch, K. E. J., Lada, E. A. & Lada, C. J. Disk frequencies and lifetimes in young clusters. Astrophys. J. 553, L153–L156 (2001)
Chambers, J. E. Making more terrestrial planets. Icarus 152, 205–224 (2001)
Raymond, S. N., Quinn, T. R. & Lunine, J. I. High-resolution simulations of the final assembly of Earth-like planets I. Terrestrial accretion and dynamics. Icarus 183, 265–282 (2006)
Morishima, R., Stadel, J. & Moore, B. From planetesimals to terrestrial planets: N-body simulations including the effects of nebular gas and giant planets. Icarus 207, 517–535 (2010)
Levison, H. F., Morbidelli, A., Tsiganis, K., Nesvorný, D. & Gomes, R. S. Late orbital instabilities in the outer planets induced by interaction with a self-gravitating planetesimal disk. Astron. J. 142, 152 (2011)
Morbidelli, A., Tsiganis, K., Crida, A., Levison, H. F. & Gomes, R. S. Dynamics of the giant planets of the Solar System in the gaseous protoplanetary disk and their relationship to the current orbital architecture. Astron. J. 134, 1790–1798 (2007)
Kokubo, E. & Ida, S. Oligarchic growth of protoplanets. Icarus 131, 171–178 (1998)
Canup, R. M. Lunar-forming collisions with pre-impact rotation. Icarus 196, 518–538 (2008)
Canup, R. M. Forming a Moon with an Earth-like composition via a giant impact. Science 338, 1052–1055 (2012)
Olson, P. & Weeraratne, D. Experiments on metal-silicate plumes and core formation. Phil. Trans. R. Soc. A 366, 4253–4271 (2008)
Dauphas, N. & Marty, B. Inference on the nature and the mass of Earth's late veneer from noble metals and gases. J. Geophys. Res. Planets 107, 5129 (2002)
Maier, W. D. et al. Progressive mixing of meteoritic veneer into the early Earth's deep mantle. Nature 460, 620–623 (2009)
Rubie, D. C., Gessmann, C. K. & Frost, D. J. Partitioning of oxygen during core formation on the Earth and Mars. Nature 429, 58–61 (2004)
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)
Meisel, T., Walker, R. J. & Morgan, J. W. The osmium isotopic composition of the Earth's primitive upper mantle. Nature 383, 517–520 (1996)
Walker, R. J., Horan, M. F., Shearer, C. K. & Papike, J. J. Low abundances of highly siderophile elements in the lunar mantle: evidence for prolonged late accretion. Earth Planet. Sci. Lett. 224, 399–413 (2004)
Frost, D. J. et al. Experimental evidence for the existence of iron-rich metal in the Earth's lower mantle. Nature 428, 409–412 (2004)
Frost, D. J. & McCammon, C. A. The redox state of Earth's mantle. Annu. Rev. Earth Planet. Sci. 36, 389–420 (2008)
Sharp, Z. D., McCubbin, F. M. & Shearer, C. K. A hydrogen-based oxidation mechanism relevant to planetary formation. Earth Planet. Sci. Lett. 380, 88–97 (2013)
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)
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 (2007)
Day, J. M. D. & Walker, R. J. The highly siderophile element composition of the lunar mantle. Abstr. Lunar Planet. Sci. Conf. 42, 1288 (2011)
Raymond, S. N., Schlichting, H. E., Hersant, F. & Selsis, F. Dynamical and collisional constraints on a stochastic late veneer on the terrestrial planets. Icarus 226, 671–681 (2013)
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 (2012)
Rubie, D. C., Melosh, H. J., Reid, J. E., Liebske, C. & Righter, K. Mechanisms of metal silicate equilibration in the terrestrial magma ocean. Earth Planet. Sci. Lett. 205, 239–255 (2003)
Deguen, R., Olson, P. & Cardin, P. Experiments on turbulent metal-silicate mixing in a magma ocean. Earth Planet. Sci. Lett. 310, 303–313 (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)
Samuel, H. A re-evaluation of metal diapir breakup and equilibration in terrestrial magma oceans. Earth Planet. Sci. Lett. 313, 105–114 (2012)
Rubie, D. C. et al. Heterogeneous accretion, composition and core-mantle differentiation of the Earth. Earth Planet. Sci. Lett. 301, 31–42 (2011)
Wade, J. & Wood, B. J. Core formation and the oxidation state of the Earth. Earth Planet. Sci. Lett. 236, 78–95 (2005)
Spicuzza, M. J., Day, J. M. D., Taylor, L. A. & Valley, J. W. Oxygen isotope constraints on the origin and differentiation of the Moon. Earth Planet. Sci. Lett. 253, 254–265 (2007)
Clayton, R. N. & Mayeda, T. K. Oxygen isotope studies of carbonaceous chondrites. Geochim. Cosmochim. Acta 63, 2089–2104 (1999)
Dauphas, N., Davis, A. M., Marty, B. & Reisberg, L. The cosmic molybdenum-ruthenium isotope correlation. Earth Planet. Sci. Lett. 226, 465–475 (2004)
Fitoussi, C. & Bourdon, B. Silicon isotope evidence against an enstatite chondrite Earth. Science 335, 1477 (2012)
Lugmair, G. W. & Shukolyukov, A. Early solar system timescales according to 53Mn-53Cr systematics. Geochim. Cosmochim. Acta 62, 2863–2886 (1998)
Trinquier, A., Birck, J. L., Allègre, C. J., Göpel, C. & Ulfbeck, D. 53Mn–53Cr systematics of the early Solar System revisited. Geochim. Cosmochim. Acta 72, 5146–5163 (2008)
Leya, I., Schönbächler, M., Wiechert, U., Krähenbühl, U. & Halliday, A. N. Titanium isotopes and the radial heterogeneity of the solar system. Earth Planet. Sci. Lett. 266, 233–244 (2008)
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)
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)
Laskar, J. Large scale chaos and the spacing of the inner planets. Astron. Astrophys. 317, L75–L78 (1997)
Brasser, R., Walsh, K. J. & Nesvorný, D. Constraining the primordial orbits of the terrestrial planets. Mon. Not. R. Astron. Soc. 433, 3417–3427 (2013)
Petitat, M., Kleine, T., Touboul, M., Bourdon, B. & Wieler, R. Hf-W chronometry of aubrites and the evolution of planetary bodies. Abstr. Lunar Planet. Sci. Conf. 39, 2164 (2008)
Connelly, J. N. et al. The absolute chronology and thermal processing of solids in the solar protoplanetary disk. Science 338, 651–655 (2012)
Herwartz, D. Differences in the Δ17O between Earth, Moon and enstatite chondrites. Royal Society/Kavli Institute Meeting on “The Origin of the Moon—Challenges and Prospects” (25–26 September, Chicheley Hall, Buckinghamshire, UK, 2013)
S.A.J., A.M., D.P.O’B. and D.C.R were supported by the European Research Council Advanced Grant ‘ACCRETE’ (contract number 290568). D.P.O’B. was also supported by grant NNX09AE36G from NASA’s Planetary Geology and Geophysics research programme. S.N.R. acknowledges support from the NASA Astrobiology Institute’s Virtual Planetary Laboratory lead team, supported by NASA under cooperative agreement NNH05ZDA001C.
The authors declare no competing financial interests.
Extended data figures and tables
Extended Data Figure 1 Four panels comparing the classical (triangles) and Grand Tack (circles) scenarios.
a, The mass of each planet in every simulated Solar System as a function of the semi-major axis. Planets within the grey zone are considered to be Earth-like. Planets at the distance of Mars from the Sun are too massive in classical simulations but are correct in Grand Tack simulations. b, c and d show the relative Late Accretion mass as a function of different parameters and the chondritic mass and its uncertainty MC = 4.8 ± 1.6 × 10−3 as a dashed line and grey region. b is the same as Fig. 1 of the main text, but with a broader timescale. c and d show the relative Late Accretion mass and two orbital structure statistics: concentration37 Sc and angular momentum deficit37,76 Sd. The Solar System has Sc = 89.9 and is marked with a vertical dashed line in c. Grand Tack simulations are as, or more, concentrated than classical simulations. The Solar System has Sd = 0.0018 and this is marked by a vertical dashed line in d. A late giant planet instability (about 500 Myr after the condensation of the first solids in the Solar System) probably excites the inner Solar System; given that these simulations end before the instability, they should possess an angular momentum deficit that is only a fraction of the current value77. Grand Tack simulations are either as dynamically excited or colder than classical simulations, although they are in some cases hotter than the current terrestrial planets.
Extended Data Figure 2 Figure 1 of the main text is reproduced in each panel for each scenario within the classical category.
For reference, the horizontal dashed line and enclosing darkened region are the best estimate and the 1σ uncertainty of the Late Veneer mass MC = 4.8 ± 1.6 × 10−3. Each panel shows the Earth-like planet’s relative late-accreted mass as a function of last giant impact time for different initial ratios of the total mass in embryos to planetesimals, as follows. 1:1 in a, 2:1 in b, 4:1 in c, and 8:1 in d. The mean time of the last giant impact increases and the relative Late Accretion mass decreases as the initial ratio of total embryo mass to planetesimal mass increases.
Extended Data Figure 3 The late-accreted mass MLA shown as greyscale contours of the two parameters X and Y.
The blue dashed contours indicate the location of a few specific late-accreted masses and are labelled in the framed boxes. For this figure, we assumed that Earth receives 52 times as much mass in small projectiles than the Moon (σ = 52). The red region is inaccessible, given that the measured chondritic mass in the lunar mantle requires a minimum flux of small planetesimals onto Earth's mantle.
The constraint X ≥ 0.53, deduced by a reanalysis of Rudge et al.23 with the Hf/W ratio updated from Konig et al.15, is shown in light red in each panel. In b–d, the solid green contours indicate the set of X, Y parameters that reproduce the nominal difference in W-isotope composition between the Moon and Earth (0.09 in units; see Touboul et al.4). The difference among these panels is in the assumed Hf/W and W-isotope composition for the mantle of the differentiated projectiles: b assumes values typical of eucrites; c is for aubrites and d is for Mars. The green dashed contours are the 1σ uncertainties on X, Y related to the uncertainty on the difference between the W-isotope composition between the Moon and Earth: ±0.1 in units. The areas exterior to these 1 − σ uncertainties have been coloured red.
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Jacobson, S., Morbidelli, A., Raymond, S. et al. Highly siderophile elements in Earth’s mantle as a clock for the Moon-forming impact. Nature 508, 84–87 (2014). https://doi.org/10.1038/nature13172
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