Pd-Ag chronometry of IVA iron meteorites and the crystallization and cooling of a protoplanetary core
Abstract
To constrain the timescales and processes involved in the crystallization and cooling of protoplanetary cores, we examined the Pd-Ag isotope systematics of the IVA iron meteorites Muonionalusta and Gibeon. A Pd-Ag isochron for Muonionalusta provides an initial 107Pd/108Pd = (2.57 ± 0.07) × 10-5. The three metal samples analyzed from Gibeon plot below the Muonionalusta isochron, but these samples also show significant effects of cosmic ray-induced neutron capture reactions, as is evident from 196Pt excesses in the Gibeon samples. After correction for neutron capture effects on Ag isotopes, the Gibeon samples plot on the Muonionalusta isochron, indicating that these two IVA irons have indistinguishable initial 107Pd/108Pd. Collectively, the Pd-Ag data indicate cooling of the IVA core below Pd-Ag closure between 2.9 ± 0.4 Ma and 8.9 ± 0.6 Ma after CAI formation, where this age range reflects uncertainties in the initial 107Pd/108Pd ratios of the solar system, which in turn result from uncertainties in the Pb-Pb age of Muonionalusta. The Ag isotopic data indicate that the IVA core initially evolved with a modestly elevated Pd/Ag, but the low Ag concentrations measured for some metal samples indicate derivation from a source with much lower Ag contents and, hence, higher Pd/Ag. Thesemore »
- Authors:
-
- Univ. of Munster, Munster (Germany). Inst. fur Planetologie
- Publication Date:
- Research Org.:
- Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
- Sponsoring Org.:
- USDOE; German Research Foundation (DFG)
- OSTI Identifier:
- 1430987
- Report Number(s):
- LLNL-JRNL-734230
Journal ID: ISSN 0016-7037
- Grant/Contract Number:
- AC52-07NA27344
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Geochimica et Cosmochimica Acta
- Additional Journal Information:
- Journal Volume: 220; Journal Issue: C; Journal ID: ISSN 0016-7037
- Publisher:
- The Geochemical Society; The Meteoritical Society
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 79 ASTRONOMY AND ASTROPHYSICS; 58 GEOSCIENCES; Pd/Ag; IVA iron meteorites; Early solar system; Core formation; Volatile depletion; Chronology
Citation Formats
Matthes, M., Fischer-Godde, M., Kruijer, T. S., and Kleine, T. Pd-Ag chronometry of IVA iron meteorites and the crystallization and cooling of a protoplanetary core. United States: N. p., 2017.
Web. doi:10.1016/j.gca.2017.09.009.
Matthes, M., Fischer-Godde, M., Kruijer, T. S., & Kleine, T. Pd-Ag chronometry of IVA iron meteorites and the crystallization and cooling of a protoplanetary core. United States. https://doi.org/10.1016/j.gca.2017.09.009
Matthes, M., Fischer-Godde, M., Kruijer, T. S., and Kleine, T. Thu .
"Pd-Ag chronometry of IVA iron meteorites and the crystallization and cooling of a protoplanetary core". United States. https://doi.org/10.1016/j.gca.2017.09.009. https://www.osti.gov/servlets/purl/1430987.
@article{osti_1430987,
title = {Pd-Ag chronometry of IVA iron meteorites and the crystallization and cooling of a protoplanetary core},
author = {Matthes, M. and Fischer-Godde, M. and Kruijer, T. S. and Kleine, T.},
abstractNote = {To constrain the timescales and processes involved in the crystallization and cooling of protoplanetary cores, we examined the Pd-Ag isotope systematics of the IVA iron meteorites Muonionalusta and Gibeon. A Pd-Ag isochron for Muonionalusta provides an initial 107Pd/108Pd = (2.57 ± 0.07) × 10-5. The three metal samples analyzed from Gibeon plot below the Muonionalusta isochron, but these samples also show significant effects of cosmic ray-induced neutron capture reactions, as is evident from 196Pt excesses in the Gibeon samples. After correction for neutron capture effects on Ag isotopes, the Gibeon samples plot on the Muonionalusta isochron, indicating that these two IVA irons have indistinguishable initial 107Pd/108Pd. Collectively, the Pd-Ag data indicate cooling of the IVA core below Pd-Ag closure between 2.9 ± 0.4 Ma and 8.9 ± 0.6 Ma after CAI formation, where this age range reflects uncertainties in the initial 107Pd/108Pd ratios of the solar system, which in turn result from uncertainties in the Pb-Pb age of Muonionalusta. The Ag isotopic data indicate that the IVA core initially evolved with a modestly elevated Pd/Ag, but the low Ag concentrations measured for some metal samples indicate derivation from a source with much lower Ag contents and, hence, higher Pd/Ag. These contrasting observations can be reconciled if the IVA irons crystallized from an initially more Ag-rich core, followed by extraction of Fe-S melts during compaction of the nearly solidified core. Owing to its strong tendency to partition into Fe-S melts, Ag was removed from the IVA core during compaction, leading to the very low Ag concentration observed in metal samples of IVA irons. Alternatively, Ag was lost by evaporation from a still molten metallic body just prior to the onset of crystallization. The Pd-Ag isotopic data indicate that Muonionalusta cooled at >500 K/Ma through the Pd-Ag closure temperature of ~900 K, consistent with the rapid cooling inferred from metallographic cooling rates for IVA irons. Finally, combined, these observations are consistent with cooling of IVA irons in a metallic body with little or no silicate mantle.},
doi = {10.1016/j.gca.2017.09.009},
journal = {Geochimica et Cosmochimica Acta},
number = C,
volume = 220,
place = {United States},
year = {Thu Sep 07 00:00:00 EDT 2017},
month = {Thu Sep 07 00:00:00 EDT 2017}
}
Web of Science
Works referenced in this record:
Siderophile elements in IVA irons and the compaction of their parent asteroidal core
journal, January 2013
- Albarède, Francis; Bouchet, Romain A.; Blichert-Toft, Janne
- Earth and Planetary Science Letters, Vol. 362
The early formation of the IVA iron meteorite parent body
journal, August 2010
- Blichert-Toft, Janne; Moynier, Frédéric; Lee, Cin-Ty A.
- Earth and Planetary Science Letters, Vol. 296, Issue 3-4
The Cu isotopic composition of iron meteorites: Cu isotopes in iron meteorites
journal, January 2012
- Bishop, Matthew Cole; Moynier, Frederic; Weinstein, Charlotte
- Meteoritics & Planetary Science, Vol. 47, Issue 2
Natural variations in uranium isotope ratios of uranium ore concentrates: Understanding the 238U/235U fractionation mechanism
journal, March 2010
- Brennecka, Gregory A.; Borg, Lars E.; Hutcheon, Ian D.
- Earth and Planetary Science Letters, Vol. 291, Issue 1-4
Extending the 107Pd-107Ag chronometer to low Pd/Ag meteorites with multicollector plasma-ionization mass spectrometry
journal, June 2001
- Carlson, Richard W.; Hauri, Erik H.
- Geochimica et Cosmochimica Acta, Vol. 65, Issue 11
The parameterization of solid metal-liquid metal partitioning of siderophile elements
journal, October 2003
- Chabot, Nancy L.; Jones, John H.
- Meteoritics & Planetary Science, Vol. 38, Issue 10
Sulfur contents of the parental metallic cores of magmatic iron meteorites
journal, September 2004
- Chabot, Nancy L.
- Geochimica et Cosmochimica Acta, Vol. 68, Issue 17
Effect of silicon on trace element partitioning in iron-bearing metallic melts: Effect of silicon on trace element partitioning
journal, August 2010
- Chabot, Nancy L.; Safko, Trevor M.; McDONOUGH, William F.
- Meteoritics & Planetary Science, Vol. 45, Issue 8
The isotopic composition of Ag in meteorites and the presence of 107Pd in protoplanets
journal, June 1990
- Chen, J. H.; Wasserburg, G. J.
- Geochimica et Cosmochimica Acta, Vol. 54, Issue 6
The Absolute Chronology and Thermal Processing of Solids in the Solar Protoplanetary Disk
journal, November 2012
- Connelly, J. N.; Bizzarro, M.; Krot, A. N.
- Science, Vol. 338, Issue 6107
Pt-Re-Os systematics of group IIAB and IIIAB iron meteorites 1 1Associate editor: G. Herzog
journal, March 2004
- Cook, D. L.; Walker, R. J.; Horan, M. F.
- Geochimica et Cosmochimica Acta, Vol. 68, Issue 6
Half-Life of
journal, September 1969
- Flynn, K. F.; Glendenin, L. E.
- Physical Review, Vol. 185, Issue 4
The uranium isotopic composition of the Earth and the Solar System
journal, January 2015
- Goldmann, Alexander; Brennecka, Gregory; Noordmann, Janine
- Geochimica et Cosmochimica Acta, Vol. 148
Rb–Sr chronology of volatile depletion in differentiated protoplanets: BABI, ADOR and ALL revisited
journal, July 2013
- Hans, Ulrik; Kleine, Thorsten; Bourdon, Bernard
- Earth and Planetary Science Letters, Vol. 374
Trace element partitioning in the Fe–S–C system and its implications for planetary differentiation and the thermal history of ureilites
journal, November 2011
- Hayden, Leslie A.; Van Orman, James A.; McDonough, William F.
- Geochimica et Cosmochimica Acta, Vol. 75, Issue 21
Pd–Ag chronology of volatile depletion, crystallization and shock in the Muonionalusta IVA iron meteorite and implications for its parent body
journal, October 2012
- Horan, M. F.; Carlson, R. W.; Blichert-Toft, J.
- Earth and Planetary Science Letters, Vol. 351-352
Experimental partitioning studies near the Fe-FeS eutectic, with an emphasis on elements important to iron meteorite chronologies (Pb, Ag, Pd, and Tl)
journal, January 1993
- Jones, J. H.; Hart, S. R.; Benjamin, T. M.
- Geochimica et Cosmochimica Acta, Vol. 57, Issue 2
Evidence for the existence of 107 Pd in the early solar system
journal, December 1978
- Kelly, William R.; Wasserburg, G. J.
- Geophysical Research Letters, Vol. 5, Issue 12
Neutron capture on Pt isotopes in iron meteorites and the Hf–W chronology of core formation in planetesimals
journal, January 2013
- Kruijer, Thomas S.; Fischer-Gödde, Mario; Kleine, Thorsten
- Earth and Planetary Science Letters, Vol. 361
Hf–W chronometry of core formation in planetesimals inferred from weakly irradiated iron meteorites
journal, December 2012
- Kruijer, Thomas S.; Sprung, Peter; Kleine, Thorsten
- Geochimica et Cosmochimica Acta, Vol. 99
Protracted core formation and rapid accretion of protoplanets
journal, June 2014
- Kruijer, T. S.; Touboul, M.; Fischer-Godde, M.
- Science, Vol. 344, Issue 6188
Thermal neutron capture effects in radioactive and stable nuclide systems
journal, March 2013
- Leya, Ingo; Masarik, Jozef
- Meteoritics & Planetary Science, Vol. 48, Issue 4
Solar System Abundances and Condensation Temperatures of the Elements
journal, July 2003
- Lodders, Katharina
- The Astrophysical Journal, Vol. 591, Issue 2
Pd–Ag chronometry of iron meteorites: Correction of neutron capture-effects and application to the cooling history of differentiated protoplanets
journal, November 2015
- Matthes, Maximilian; Fischer-Gödde, Mario; Kruijer, Thomas S.
- Geochimica et Cosmochimica Acta, Vol. 169
Group IVA irons: New constraints on the crystallization and cooling history of an asteroidal core with a complex history
journal, November 2011
- McCoy, T. J.; Walker, R. J.; Goldstein, J. I.
- Geochimica et Cosmochimica Acta, Vol. 75, Issue 22
The Generation and Compaction of Partially Molten Rock
journal, August 1984
- McKENZIE, D.
- Journal of Petrology, Vol. 25, Issue 3
Size of the group IVA iron meteorite core: Constraints from the age and composition of Muonionalusta
journal, August 2011
- Moskovitz, Nicholas A.; Walker, Richard J.
- Earth and Planetary Science Letters, Vol. 308, Issue 3-4
Comparative stable isotope geochemistry of Ni, Cu, Zn, and Fe in chondrites and iron meteorites
journal, September 2007
- Moynier, Frédéric; Blichert-Toft, Janne; Telouk, Philippe
- Geochimica et Cosmochimica Acta, Vol. 71, Issue 17
Core solidification and dynamo evolution in a mantle-stripped planetesimal: PLANETESIMAL THERMOCHEMICAL DYNAMO
journal, January 2016
- Scheinberg, A.; Elkins-Tanton, L. T.; Schubert, G.
- Journal of Geophysical Research: Planets, Vol. 121, Issue 1
Silver isotope variations in chondrites: Volatile depletion and the initial 107Pd abundance of the solar system
journal, November 2008
- Schönbächler, M.; Carlson, R. W.; Horan, M. F.
- Geochimica et Cosmochimica Acta, Vol. 72, Issue 21
Core crystallization and silicate-metal mixing in the parent body of the IVA iron and stony-iron meteorites
journal, May 1996
- Scott, Edward R. D.; Haack, Henning; McCoy, Timothy J.
- Geochimica et Cosmochimica Acta, Vol. 60, Issue 9
Precise ReOs determinations and systematics of iron meteorites
journal, August 1996
- Shen, J. J.; Papanastassiou, D. A.; Wasserburg, G. J.
- Geochimica et Cosmochimica Acta, Vol. 60, Issue 15
Re-Os Ages of Group IIA, IIIA, IVA, and IVB Iron Meteorites
journal, February 1996
- Smoliar, Michael I.; Walker, Richard J.; Morgan, John W.
- Science, Vol. 271, Issue 5252
Mn-Cr chronology of five IIIAB iron meteorites
journal, January 2003
- Sugiura, N.; Hoshino, H.
- Meteoritics & Planetary Science, Vol. 38, Issue 1
LOW 60 FE ABUNDANCE IN SEMARKONA AND SAHARA 99555
journal, March 2015
- Tang, Haolan; Dauphas, Nicolas
- The Astrophysical Journal, Vol. 802, Issue 1
Modeling fractional crystallization of group IVB iron meteorites
journal, April 2008
- Walker, Richard J.; McDonough, William F.; Honesto, Jenise
- Geochimica et Cosmochimica Acta, Vol. 72, Issue 8
Fractionation trends among IVA iron meteorites: contrasts with IIIAB trends
journal, March 2001
- Wasson, J. T.; Richardson, J. W.
- Geochimica et Cosmochimica Acta, Vol. 65, Issue 6
Silica and pyroxene in IVA irons; possible formation of the IVA magma by impact melting and reduction of L-LL-chondrite materials followed by crystallization and cooling
journal, June 2006
- Wasson, John T.; Matsunami, Yoshiyuki; Rubin, Alan E.
- Geochimica et Cosmochimica Acta, Vol. 70, Issue 12
Accurate measurement of silver isotopic compositions in geological materials including low Pd/Ag meteorites
journal, April 2005
- Woodland, S. J.; Rehkämper, M.; Halliday, A. N.
- Geochimica et Cosmochimica Acta, Vol. 69, Issue 8
Iron meteorite evidence for early formation and catastrophic disruption of protoplanets
journal, April 2007
- Yang, Jijin; Goldstein, Joseph I.; Scott, Edward R. D.
- Nature, Vol. 446, Issue 7138
Metallographic cooling rates and origin of IVA iron meteorites
journal, June 2008
- Yang, Jijin; Goldstein, Joseph I.; Scott, Edward R. D.
- Geochimica et Cosmochimica Acta, Vol. 72, Issue 12
Thermal history and origin of the IVB iron meteorites and their parent body
journal, August 2010
- Yang, Jijin; Goldstein, Joseph I.; Michael, Joseph R.
- Geochimica et Cosmochimica Acta, Vol. 74, Issue 15