The early evolution of planetesimals and planets can be constrained using variations in the abundance of neodymium-142 (142Nd), which arise from the initial distribution of 142Nd within the protoplanetary disk and the radioactive decay of the short-lived samarium-146 isotope (146Sm)1,2. The apparent offset in 142Nd abundance found previously between chondritic meteorites and Earth1,2 has been interpreted either as a possible consequence of nucleosynthetic variations within the protoplanetary disk2,3,4 or as a function of the differentiation of Earth very early in its history5. Here we report high-precision Sm and Nd stable and radiogenic isotopic compositions of four calcium–aluminium-rich refractory inclusions (CAIs) from three CV-type carbonaceous chondrites, and of three whole-rock samples of unequilibrated enstatite chondrites. The CAIs, which are the first solids formed by condensation from the nebular gas, provide the best constraints for the isotopic evolution of the early Solar System. Using the mineral isochron method for individual CAIs, we find that CAIs without isotopic anomalies in Nd compared to the terrestrial composition share a 146Sm/144Sm–142Nd/144Nd isotopic evolution with Earth. The average 142Nd/144Nd composition for pristine enstatite chondrites that we calculate coincides with that of the accessible silicate layers of Earth. This relationship between CAIs, enstatite chondrites and Earth can only be a result of Earth having inherited the same initial abundance of 142Nd and chondritic proportions of Sm and Nd. Consequently, 142Nd isotopic heterogeneities found in other CAIs and among chondrite groups may arise from extrasolar grains that were present in the disk and incorporated in different proportions into these planetary objects. Our finding supports a chondritic Sm/Nd ratio for the bulk silicate Earth and, as a consequence, chondritic abundances for other refractory elements. It also removes the need for a hidden reservoir or for collisional erosion scenarios5,6 to explain the 142Nd/144Nd composition of Earth.
This is a preview of subscription content
Subscribe to Journal
Get full journal access for 1 year
only $3.90 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Tax calculation will be finalised during checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
Nyquist, L. E. et al. 146Sm-142Nd formation interval for the lunar mantle material. Geochim. Cosmochim. Acta 59, 2817–2837 (1995)
Boyet, M. & Carlson, R. W. 142Nd evidence for early (>4.53 Ga) global differentiation of the silicate Earth. Science 309, 576–581 (2005)
Carlson, R. W., Boyet, M. & Horan, M. Chondrite barium, neodymium, and samarium isotopic heterogeneity and early Earth differentiation. Science 316, 1175–1178 (2007)
Gannoun, A., Boyet, M., Rizo, H. & El Goresy, A. 146Sm–142Nd systematics measured in enstatite chondrites reveals a heterogeneous distribution of 142Nd in the solar nebula. Proc. Natl Acad. Sci. 108, 7693–7697 (2011)
Jellinek, A. M. & Jackson, M. G. Connections between the bulk composition, geodynamics and habitability of Earth. Nat. Geosci. 8, 587–593 (2015)
O’Neill, H. S. C. & Palme, H. Collisional erosion and the non-chondritic composition of terrestrial planets. Philos. Trans. R. Soc. Lond. A 366, 4205–4238 (2008)
Kinoshita, N. et al. A shorter 146Sm half-life measured and implications for 146Sm-142Nd chronology in the Solar System. Science 335, 1614–1617 (2012)
Boyet, M., Carlson, R. W. & Horan, M. Old Sm-Nd ages for cumulate eucrites and redetermination of the Solar System initial 146Sm/144Sm ratio. Earth Planet. Sci. Lett. 291, 172–181 (2010)
Caro, G., Bourdon, B., Halliday, A. N. & Quitté, G. Super-chondritic Sm/Nd ratios in Mars, the Earth and the Moon. Nature 452, 336–339 (2008)
Clayton, R. N., Hinton, R. W. & Davis, A. M. Isotopic variations in the rock-forming elements in meteorites. Philos. Trans. R. Soc. Lond. A 325, 483–501 (1988)
Anders, E. & Zinner, E. K. Interstellar grains in primitive meteorites: diamond, silicon carbide, and graphite. Meteoritics 28, 490–514 (1993)
Trinquier, A. et al. Origin of nucleosynthetic isotope heterogeneity in the solar protoplanetary disk. Science 324, 374–376 (2009)
Moynier, F. et al. Planetary-scale strontium isotopic heterogeneity and the age of volatile depletion of early Solar System materials. Astrophys. J. 758, 45 (2012)
Warren, P. H. Stable-isotopic anomalies and the accretionary assemblage of the Earth and Mars: a subordinate role for carbonaceous chondrites. Earth Planet. Sci. Lett. 311, 93–100 (2011)
Clayton, R. N., Mayeda, T. K. & Rubin, A. E. Oxygen isotopic compositions of enstatite chondrites and aubrites. Lunar Planet. Sci. Conf. Proc. 15, C245–C249 (1984)
Bouvier, A. & Wadhwa, M. The age of the Solar System redefined by the oldest Pb–Pb age of a meteoritic inclusion. Nat. Geosci. 3, 637–641 (2010)
Kita, N. T. et al. 26Al-26Mg isotope systematics of the first solids in the early Solar System. Meteorit. Planet. Sci. 48, 1383–1400 (2013)
Marks, N. E. et al. Samarium–neodymium chronology and rubidium–strontium systematics of an Allende calcium–aluminum-rich inclusion with implications for 146Sm half-life. Earth Planet. Sci. Lett. 405, 15–24 (2014)
Meeker, G. P., Wasserburg, G. J. & Armstrong, J. T. Replacement textures in CAI and implications regarding planetary metamorphism. Geochim. Cosmochim. Acta 47, 707–721 (1983)
Gannoun, A., Boyet, M., El Goresy, A. & Devouard, B. REE and actinide microdistribution in Sahara 97072 and ALHA77295 EH3 chondrites: a combined cosmochemical and petrologic investigation. Geochim. Cosmochim. Acta 75, 3269–3289 (2011)
Andreasen, R. & Sharma, M. Solar nebula heterogeneity in p-process samarium and neodymium isotopes. Science 314, 806–809 (2006)
Arlandini, C. et al. Neutron capture in low-mass asymptotic giant branch stars: cross sections and abundance signatures. Astrophys. J. 525, 886–900 (1999)
Hoppe, P. & Ott, U. Mainstream silicon carbide grains from meteorites. AIP Conf. Proc. 402, 27–58 (1997)
Qin, L., Carlson, R. W. & Alexander, C. M. O. D. Correlated nucleosynthetic isotopic variability in Cr, Sr, Ba, Sm, Nd and Hf in Murchison and QUE 97008. Geochim. Cosmochim. Acta 75, 7806–7828 (2011)
Brennecka, G. A., Borg, L. E. & Wadhwa, M. Evidence for supernova injection into the solar nebula and the decoupling of r-process nucleosynthesis. Proc. Natl Acad. Sci. USA 110, 17241–17246 (2013)
Bisterzo, S. et al. Galactic chemical evolution and solar s-process abundances: dependence on the 13C-pocket structure. Astrophys. J. 787, 10 (2014)
Bouvier, A., Vervoort, J. D. & Patchett, P. J. The Lu-Hf and Sm-Nd isotopic composition of CHUR: constraints from unequilibrated chondrites and implications for the bulk composition of terrestrial planets. Earth Planet. Sci. Lett. 273, 48–57 (2008)
Simon, J. I. et al. A short timescale for changing oxygen fugacity in the solar nebula revealed by high-resolution 26Al–26Mg dating of CAI rims. Earth Planet. Sci. Lett. 238, 272–283 (2005)
Jacquet, E. Transport of solids in protoplanetary disks: comparing meteorites and astrophysical models. C. R. Geosci. 346, 3–12 (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)
Krot, A. N., MacPherson, G. J., Ulyanov, A. A. & Petaev, M. I. Fine-grained, spinel-rich inclusions from the reduced CV chondrites Efremovka and Leoville: I. Mineralogy, petrology, and bulk chemistry. Meteorit. Planet. Sci. 39, 1517–1553 (2004)
Bouvier, A., Brennecka, G. A. & Wadhwa, M. Absolute chronology of the first solids in the solar system. In Formation of the First Solids in the Solar System abstr. 9054 (2011)
Boyet, M. & Carlson, R. W. A highly depleted moon or a non-magma ocean origin for the lunar crust? Earth Planet. Sci. Lett. 262, 505–516 (2007)
Marti, T. & Graf, T. Cosmic-ray exposure history of ordinary chondrites. Annu. Rev. Earth Planet. Sci. 20, 221–243 (1992)
Rankenburg, K., Brandon, A. D. & Neal, C. R. Neodymium isotope evidence for a chondritic composition of the Moon. Science 312, 1369–1372 (2006)
Rauscher, T. et al. Constraining the astrophysical origin of the p-nuclei through nuclear physics and meteoritic data. Rep. Prog. Phys. 76, 066201 (2013)
Anders, E. & Grevesse, N. Abundances of the elements: meteoritic and solar. Geochim. Cosmochim. Acta 53, 197–214 (1989)
Begemann, F. et al. Call for an improved set of decay constants for geochronological use. Geochim. Cosmochim. Acta 65, 111–121 (2001)
Meissner, F., Schmidt-Ott, W. D. & Ziegeler, L. Half-life and α-ray energy of 146Sm. Z. Phys. A 327, 171–174 (1987)
Hezel, D. C., Russell, S. S., Ross, A. J. & Kearsley, A. T. Modal abundances of CAIs: implications for bulk chondrite element abundances and fractionations. Meteorit. Planet. Sci. 43, 1879–1894 (2008)
McCulloch, M. T. & Wasserburg, G. J. Barium and neodymium isotopic anomalies in the Allende meteorite. Astrophys. J. 220, L15–L19 (1978)
McCulloch, M. T. & Wasserburg, G. J. More anomalies from the Allende meteorite: samarium. Geophys. Res. Lett. 5, 599–602 (1978)
Amelin, Y. & Rotenberg, E. Sm-Nd systematics of chondrites. Earth Planet. Sci. Lett. 223, 267–282 (2004)
Barrat, J. A. et al. Geochemistry of CI chondrites: major and trace elements, and Cu and Zn Isotopes. Geochim. Cosmochim. Acta 83, 79–92 (2012)
Meteorite samples were provided by L. Garvie (Arizona State University), D. Ebel (American Museum of Natural History) and the US Antarctic Search for Meteorites (ANSMET) programme, which has been funded by NSF and NASA, and were characterized and curated by the Department of Mineral Sciences of the Smithsonian Institution and Astromaterials Curation Office at NASA Johnson Space Center. We thank P. J. Patchett for the Sm–Nd calibrated enriched spike used in this study, D. Auclair and A. Gannoun for mass spectrometer support, and T. Withers for comments on this Letter. This research was supported by the National Science Foundation NSF/EAR 1119135, France-Canada Research Fund, NSERC Canada Research Chair and Discovery Grant awards to A.B. and the French Government ANR-10-LABX-0006, the Région Auvergne, the European Regional Development Fund and the INSU Programme National de Planétologie to M.B. We thank the Laboratory of Excellence ClerVolc.
The authors declare no competing financial interests.
Extended data figures and tables
Extended Data Figure 2 146Nd/147Sm versus μ144Sm from Allende 322 and 323, NWA 2364 and NWA 6991 bulk CAIs.
The deviations are given in parts per million of 144Sm/152Sm ratios measured for samples compared to the average of measured Sm isotopic standards. Error bars represent internal errors (2 s.e.) for individual measurements. There is no correlation between the abundance of Nd within the Sm cuts with μ144Sm compositions in individual CAIs. See Supplementary Tables 1–3 for isotopic data.
Data for CV3 chondrites is from ref. 3. WR, whole rocks. Error bars indicate internal errors (2 s.e.) on individual measurements and black lines are best-fit lines.
Extended Data Figure 4 Deviation of 142Nd/144Nd ratios relative to the JNdi-1 standard measured in dynamic and static modes.
Deviations are given in parts per million. For static mode, the Faraday cup for line 1 was centred at an atomic mass of 145. Error bars indicate internal errors (2 s.e.) on individual measurements and the black line indicates a slope of one.
Chondrite data (black circles, carbonaceous chondrites; purple circles, ordinary chondrites; green circles, enstatite chondrites) are from this study and refs 3 and 4. CAIs, FUN inclusions (EK1-4-1 and C1; refs 41, 42) and chondrite 142Nd/144Nd ratios are corrected for radiogenic decay of 142Nd over the age of the Solar System. Gray boxes show 2σ external reproducibility obtained on the standard. Solid and dotted lines correspond to p-process contributions for 142Nd of 4% and 1%, respectively. The complementary part is formed by s-processes. Our data show that there is no correlation between μ144Sm and μ142Nd, in contrast to previous suggestions4.Error bars indicate internal errors (2 s.e.) on individual measurements when larger than symbols and available.
Black dots show isotopes formed by p-processes only; coloured dots show isotopes formed partly by p-process and partly by s-processes (orange, 76Se; purple, 80Kr; green, 152Gd; blue, 164Er). Model abundances of 142Nd are represented by the squares coloured in dark grey for a 20% p-process contribution, light grey for 4% and white for 1%. The black line is the best-fit line.
a, 147Sm–143Nd internal isochron. By combining all the CAI fractions together and fitting the data to a straight line, we determine the 147Sm–143Nd age to be 4,526 ± 150 Myr (MSWD = 1.2, initial 143Nd/144Nd = 0.50673 ± 0.00021). R, residue after leaching; fas, fassaite; mel, melilite. b, The black line represents the 146Sm–142Nd internal isochron of CAIs from Allende 322 and 323, NWA 2364 and NWA 6991; red lines indicate the 95% confidence interval. 146Sm–142Nd systematics of Allende bulk and mineral separates (Al3S4)18 and Allende bulk CAIs25 are shown for comparison (error bars are not shown because individual analytical errors were not provided). The blue rectangle represents the composition of modern Earth’s mantle, as represented by our long-term measurements of the JNdi-1 standard (142Nd/144Nd = 1.141838 ± 0.000006; by definition, μ142Nd = 0) with 147Sm/144Nd = 0.1960, which is within the error of the regression for CAIs from this study. The other rectangles represent the averages for μ142Nd with 2 s.d. given below with values of −7 ± 6 p.p.m. for enstatite chondrites (EC; black, value from this study, n = 3), −6 ± 18 p.p.m. for enstatite chondrites (green, n = 14), −18 ± 6 p.p.m. for ordinary chondrites (OC; purple, n = 5) and −34 ± 18 p.p.m. for carbonaceous chondrites (CC; red, n = 8), all normalized at 147Sm/144Nd = 0.1960 (the widths of the rectangles for 147Sm/144Nd are exaggerated for clarity).
Left, 146Sm/144Sm ratio as a function of age using the two proposed decay constants for the short-lived 146Sm radionuclide. The two curves intersect at 146Sm/144Sm = 0.0073 and 4,546 Ma—the values defined from eucrite internal isochron of Binda in ref. 8. For objects formed after 4,546 Ma ago, ages are younger using the 103-Ma half-life value. Right, time difference ΔT obtained using the two decay constants proposed for 146Sm. Ma, millions of years.
Extended Data Figure 9 Mixing model (black line) between CV3 CAIs (144Sm abundance measured in this study) and matrix (enstatite chondrite (EC) and ordinary chondrite (OC) whole-rock meteorites without a 144Sm anomaly) (open squares).
144Sm anomalies measured in CV3 chondrites (blue symbols) correspond to 1%–3% CAI volume abundances in the mixing model3,20. The numbers on the line indicate the proportion of matrix-component end-member relative to CAI end-member. Error bars (2 s.e.) are for individual measurements of whole-rock CV3 chondrite meteorites.
About this article
Cite this article
Bouvier, A., Boyet, M. Primitive Solar System materials and Earth share a common initial 142Nd abundance. Nature 537, 399–402 (2016). https://doi.org/10.1038/nature19351
Space Science Reviews (2020)
Space Science Reviews (2020)
Loss and Fractionation of Noble Gas Isotopes and Moderately Volatile Elements from Planetary Embryos and Early Venus, Earth and Mars
Space Science Reviews (2020)
Space Science Reviews (2018)