skip to main content
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: A nucleosynthetic origin for the Earth’s anomalous 142Nd composition

Abstract

A long-standing paradigm assumes that the chemical and isotopic compositions of many elements in the bulk silicate Earth are the same as in chondrites(1-4). But, the accessible Earth has a greater Nd-142/Nd-144 ratio than do chondrites. Because Nd-142 is the decay product of the now-extinct Sm-146 (which has a half-life of 103 million years(5)), this Nd-142 difference seems to require a higher-than-chondritic Sm/Nd ratio for the accessible Earth. This must have been acquired during global silicate differentiation within the first 30 million years of Solar System formation(6) and implies the formation of a complementary Nd-142-depleted reservoir that either is hidden in the deep Earth(6), or lost to space by impact erosion(3,7). Whether this complementary reservoir existed, and whether or not it has been lost from Earth, is a matter of debate(3,8,9), and has implications for determining the bulk composition of Earth, its heat content and structure, as well as for constraining the modes and timescales of its geodynamical evolution(3,7,9,10). We show that, compared with chondrites, Earth's precursor bodies were enriched in neodymium that was produced by the slow neutron capture process (s-process) of nucleosynthesis. This s-process excess leads to higher Nd-142/Nd-144 ratios; after correction for this effect, the Nd-142/Nd-144 ratiosmore » of chondrites and the accessible Earth are indistinguishable within five parts per million. The Nd-142 offset between the accessible silicate Earth and chondrites therefore reflects a higher proportion of s-process neodymium in the Earth, and not early differentiation processes. Our results obviate the need for hidden-reservoir or super-chondritic Earth models and imply a chondritic Sm/Nd ratio for the bulk Earth. Although chondrites formed at greater heliocentric distances and contain a different mix of presolar components than Earth, they nevertheless are suitable proxies for Earth's bulk chemical composition.« less

Authors:
 [1];  [2];  [3];  [3];  [4];  [5]
  1. Univ. of Chicago, IL (United States). Dept. of Geophysical Sciences and Enrico Fermi Inst.; Munster Univ. (Germany). Inst. for Planetology
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  3. Munster Univ. (Germany). Inst. for Planetology; Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  4. Univ. of Chicago, IL (United States). Dept. of Geophysical Sciences and Enrico Fermi Inst.
  5. Munster Univ. (Germany). Inst. for Planetology
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1395508
Report Number(s):
LLNL-JRNL-689320
Journal ID: ISSN 0028-0836; nature18956
Grant/Contract Number:  
AC52-07NA27344
Resource Type:
Accepted Manuscript
Journal Name:
Nature (London)
Additional Journal Information:
Journal Name: Nature (London); Journal Volume: 537; Journal Issue: 7620; Journal ID: ISSN 0028-0836
Publisher:
Nature Publishing Group
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; 58 GEOSCIENCES; geochemistry; geodynamics; early solar system; SOLAR PROTOPLANETARY DISK; HETEROGENEOUS DISTRIBUTION; ISOTOPIC HETEROGENEITY; ENSTATITE CHONDRITES; BULK COMPOSITION; HALF-LIFE; NEBULA; SYSTEMATICS; ND; DIFFERENTIATION

Citation Formats

Burkhardt, C., Borg, L. E., Brennecka, G. A., Shollenberger, Q. R., Dauphas, N., and Kleine, T. A nucleosynthetic origin for the Earth’s anomalous 142Nd composition. United States: N. p., 2016. Web. doi:10.1038/nature18956.
Burkhardt, C., Borg, L. E., Brennecka, G. A., Shollenberger, Q. R., Dauphas, N., & Kleine, T. A nucleosynthetic origin for the Earth’s anomalous 142Nd composition. United States. doi:10.1038/nature18956.
Burkhardt, C., Borg, L. E., Brennecka, G. A., Shollenberger, Q. R., Dauphas, N., and Kleine, T. Wed . "A nucleosynthetic origin for the Earth’s anomalous 142Nd composition". United States. doi:10.1038/nature18956. https://www.osti.gov/servlets/purl/1395508.
@article{osti_1395508,
title = {A nucleosynthetic origin for the Earth’s anomalous 142Nd composition},
author = {Burkhardt, C. and Borg, L. E. and Brennecka, G. A. and Shollenberger, Q. R. and Dauphas, N. and Kleine, T.},
abstractNote = {A long-standing paradigm assumes that the chemical and isotopic compositions of many elements in the bulk silicate Earth are the same as in chondrites(1-4). But, the accessible Earth has a greater Nd-142/Nd-144 ratio than do chondrites. Because Nd-142 is the decay product of the now-extinct Sm-146 (which has a half-life of 103 million years(5)), this Nd-142 difference seems to require a higher-than-chondritic Sm/Nd ratio for the accessible Earth. This must have been acquired during global silicate differentiation within the first 30 million years of Solar System formation(6) and implies the formation of a complementary Nd-142-depleted reservoir that either is hidden in the deep Earth(6), or lost to space by impact erosion(3,7). Whether this complementary reservoir existed, and whether or not it has been lost from Earth, is a matter of debate(3,8,9), and has implications for determining the bulk composition of Earth, its heat content and structure, as well as for constraining the modes and timescales of its geodynamical evolution(3,7,9,10). We show that, compared with chondrites, Earth's precursor bodies were enriched in neodymium that was produced by the slow neutron capture process (s-process) of nucleosynthesis. This s-process excess leads to higher Nd-142/Nd-144 ratios; after correction for this effect, the Nd-142/Nd-144 ratios of chondrites and the accessible Earth are indistinguishable within five parts per million. The Nd-142 offset between the accessible silicate Earth and chondrites therefore reflects a higher proportion of s-process neodymium in the Earth, and not early differentiation processes. Our results obviate the need for hidden-reservoir or super-chondritic Earth models and imply a chondritic Sm/Nd ratio for the bulk Earth. Although chondrites formed at greater heliocentric distances and contain a different mix of presolar components than Earth, they nevertheless are suitable proxies for Earth's bulk chemical composition.},
doi = {10.1038/nature18956},
journal = {Nature (London)},
number = 7620,
volume = 537,
place = {United States},
year = {2016},
month = {9}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 43 works
Citation information provided by
Web of Science

Save / Share:

Works referenced in this record:

Coupled 142Nd–143Nd evidence for a protracted magma ocean in Mars
journal, November 2007

  • Debaille, V.; Brandon, A. D.; Yin, Q. Z.
  • Nature, Vol. 450, Issue 7169
  • DOI: 10.1038/nature06317

Evidence from coupled 147Sm–143Nd and 146Sm–142Nd systematics for very early (4.5-Gyr) differentiation of the Earth's mantle
journal, December 1992

  • Harper, Charles L.; Jacobsen, Stein B.
  • Nature, Vol. 360, Issue 6406
  • DOI: 10.1038/360728a0

Neutron Capture in Low‐Mass Asymptotic Giant Branch Stars: Cross Sections and Abundance Signatures
journal, November 1999

  • Arlandini, Claudio; Kappeler, Franz; Wisshak, Klaus
  • The Astrophysical Journal, Vol. 525, Issue 2
  • DOI: 10.1086/307938

Ru isotope heterogeneity in the solar protoplanetary disk
journal, November 2015

  • Fischer-Gödde, Mario; Burkhardt, Christoph; Kruijer, Thomas S.
  • Geochimica et Cosmochimica Acta, Vol. 168
  • DOI: 10.1016/j.gca.2015.07.032

Composition of the Earth's interior: the importance of early events
journal, September 2008

  • Carlson, Richard W.; Boyet, Maud
  • Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, Vol. 366, Issue 1883
  • DOI: 10.1098/rsta.2008.0166

Zirconium isotope evidence for the heterogeneous distribution of s-process materials in the solar system
journal, September 2015


Calcium-48 isotopic anomalies in bulk chondrites and achondrites: Evidence for a uniform isotopic reservoir in the inner protoplanetary disk
journal, December 2014


Coupled 142Nd-143Nd Isotopic Evidence for Hadean Mantle Dynamics
journal, December 2007


Correlated nucleosynthetic isotopic variability in Cr, Sr, Ba, Sm, Nd and Hf in Murchison and QUE 97008
journal, December 2011

  • Qin, Liping; Carlson, Richard W.; Alexander, Conel M. O’D.
  • Geochimica et Cosmochimica Acta, Vol. 75, Issue 24
  • DOI: 10.1016/j.gca.2011.10.009

Al-rich objects in ordinary chondrites: Related origin of carbonaceous and ordinary chondrites and their constituents
journal, April 1984


Evidence for supernova injection into the solar nebula and the decoupling of r-process nucleosynthesis
journal, October 2013

  • Brennecka, G. A.; Borg, L. E.; Wadhwa, M.
  • Proceedings of the National Academy of Sciences, Vol. 110, Issue 43
  • DOI: 10.1073/pnas.1307759110

Planetary-Scale Strontium Isotopic Heterogeneity and the age of Volatile Depletion of Early Solar System Materials
journal, September 2012

  • Moynier, Frédéric; Day, James M. D.; Okui, Wataru
  • The Astrophysical Journal, Vol. 758, Issue 1
  • DOI: 10.1088/0004-637X/758/1/45

146Sm-142Nd formation interval for the lunar mantle
journal, July 1995


Refractory element fractionation in the Allende meteorite: Implications for solar nebula condensation and the chondritic composition of planetary bodies
journal, May 2012


Super-chondritic Sm/Nd ratios in Mars, the Earth and the Moon
journal, March 2008

  • Caro, Guillaume; Bourdon, Bernard; Halliday, Alex N.
  • Nature, Vol. 452, Issue 7185
  • DOI: 10.1038/nature06760

Determination of REE, Ba, Fe, Mg, Na and K in carbonaceous and ordinary chondrites
journal, May 1974


146Sm-142Nd systematics measured in enstatite chondrites reveals a heterogeneous distribution of 142Nd in the solar nebula
journal, April 2011

  • Gannoun, A.; Boyet, M.; Rizo, H.
  • Proceedings of the National Academy of Sciences, Vol. 108, Issue 19
  • DOI: 10.1073/pnas.1017332108

Connections between the bulk composition, geodynamics and habitability of Earth
journal, July 2015

  • Jellinek, A. M.; Jackson, M. G.
  • Nature Geoscience, Vol. 8, Issue 8
  • DOI: 10.1038/ngeo2488

The Lu–Hf and Sm–Nd isotopic composition of CHUR: Constraints from unequilibrated chondrites and implications for the bulk composition of terrestrial planets
journal, August 2008

  • Bouvier, Audrey; Vervoort, Jeffrey D.; Patchett, P. Jonathan
  • Earth and Planetary Science Letters, Vol. 273, Issue 1-2
  • DOI: 10.1016/j.epsl.2008.06.010

Hf–W mineral isochron for Ca,Al-rich inclusions: Age of the solar system and the timing of core formation in planetesimals
journal, December 2008

  • Burkhardt, Christoph; Kleine, Thorsten; Bourdon, Bernard
  • Geochimica et Cosmochimica Acta, Vol. 72, Issue 24
  • DOI: 10.1016/j.gca.2008.10.023

Evidence against a chondritic Earth
journal, March 2012

  • Campbell, Ian H.; St C. O’Neill, Hugh
  • Nature, Vol. 483, Issue 7391
  • DOI: 10.1038/nature10901

Modal abundances of CAIs: Implications for bulk chondrite element abundances and fractionations
journal, November 2008


Chondrite Barium, Neodymium, and Samarium Isotopic Heterogeneity and Early Earth Differentiation
journal, May 2007


Molybdenum isotope anomalies in meteorites: Constraints on solar nebula evolution and origin of the Earth
journal, December 2011

  • Burkhardt, Christoph; Kleine, Thorsten; Oberli, Felix
  • Earth and Planetary Science Letters, Vol. 312, Issue 3-4
  • DOI: 10.1016/j.epsl.2011.10.010

Solar Nebula Heterogeneity in p-Process Samarium and Neodymium Isotopes
journal, November 2006


Samarium–neodymium chronology and rubidium–strontium systematics of an Allende calcium–aluminum-rich inclusion with implications for 146Sm half-life
journal, November 2014


Sm-Nd isotopic evolution of chondrites
journal, October 1980


Origin of Nucleosynthetic Isotope Heterogeneity in the Solar Protoplanetary Disk
journal, April 2009


Thulium anomalies and rare earth element patterns in meteorites and Earth: Nebular fractionation and the nugget effect
journal, August 2015


147Sm-143Nd systematics of Earth are inconsistent with a superchondritic Sm/Nd ratio
journal, March 2013

  • Huang, S.; Jacobsen, S. B.; Mukhopadhyay, S.
  • Proceedings of the National Academy of Sciences, Vol. 110, Issue 13
  • DOI: 10.1073/pnas.1222252110

Nucleosynthetic Nd isotope anomalies in primitive enstatite chondrites
journal, November 2013


Impact features of enstatite-rich meteorites
journal, March 2015


Isotopic evidence for chondritic Lu/Hf and Sm/Nd of the Moon
journal, October 2013


Re-evaluating 142Nd/144Nd in lunar mare basalts with implications for the early evolution and bulk Sm/Nd of the Moon
journal, October 2009

  • Brandon, Alan D.; Lapen, Thomas J.; Debaille, Vinciane
  • Geochimica et Cosmochimica Acta, Vol. 73, Issue 20
  • DOI: 10.1016/j.gca.2009.07.015

A petrologic, thermodynamic and experimental study of brachinites: Partial melt residues of an R chondrite-like precursor
journal, December 2013

  • Gardner-Vandy, Kathryn G.; Lauretta, Dante S.; McCoy, Timothy J.
  • Geochimica et Cosmochimica Acta, Vol. 122
  • DOI: 10.1016/j.gca.2013.07.035

    Works referencing / citing this record:

    In search of the Earth-forming reservoir: Mineralogical, chemical, and isotopic characterizations of the ungrouped achondrite NWA 5363/NWA 5400 and selected chondrites
    journal, March 2017

    • Burkhardt, Christoph; Dauphas, Nicolas; Tang, Haolan
    • Meteoritics & Planetary Science, Vol. 52, Issue 5
    • DOI: 10.1111/maps.12834

    Redox States of Initial Atmospheres Outgassed on Rocky Planets and Planetesimals
    journal, July 2017