Tracing metal–silicate segregation and late veneer in the Earth and the ureilite parent body with palladium stable isotopes
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Tracing metal–silicate segregation and late veneer in the Earth and the ureilite parent body with palladium stable isotopes. / Creech, J. B.; Moynier, F.; Bizzarro, Martin.
In: Geochimica et Cosmochimica Acta, Vol. 216, 01.11.2017, p. 28-41.Research output: Contribution to journal › Journal article › Research › peer-review
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T1 - Tracing metal–silicate segregation and late veneer in the Earth and the ureilite parent body with palladium stable isotopes
AU - Creech, J. B.
AU - Moynier, F.
AU - Bizzarro, Martin
PY - 2017/11/1
Y1 - 2017/11/1
N2 - Stable isotope studies of highly siderophile elements (HSE) have the potential to yield valuable insights into a range of geological processes. In particular, the strong partitioning of these elements into metal over silicates may lead to stable isotope fractionation during metal–silicate segregation, making them sensitive tracers of planetary differentiation processes. We present the first techniques for the precise determination of palladium stable isotopes by MC-ICPMS using a 106Pd–110Pd double-spike to correct for instrumental mass fractionation. Results are expressed as the per mil (‰) difference in the 106Pd/105Pd ratio (δ106Pd) relative to an in-house solution standard (Pd_IPGP) in the absence of a certified Pd isotopic standard. Repeated analyses of the Pd isotopic composition of the chondrite Allende demonstrate the external reproducibility of the technique of ±0.032‰ on δ106Pd. Using these techniques, we have analysed Pd stable isotopes from a range of terrestrial and extraterrestrial samples. We find that chondrites define a mean δ106Pdchondrite = −0.19 ± 0.05‰. Ureilites reveal a weak trend towards heavier δ106Pd with decreasing Pd content, similar to recent findings based on Pt stable isotopes (Creech et al., 2017), although fractionation of Pd isotopes is significantly less than for Pt, possibly related to its weaker metal–silicate partitioning behaviour and the limited field shift effect. Terrestrial mantle samples have a mean δ106Pdmantle = −0.182 ± 0.130‰, which is consistent with a late-veneer of chondritic material after core formation.
AB - Stable isotope studies of highly siderophile elements (HSE) have the potential to yield valuable insights into a range of geological processes. In particular, the strong partitioning of these elements into metal over silicates may lead to stable isotope fractionation during metal–silicate segregation, making them sensitive tracers of planetary differentiation processes. We present the first techniques for the precise determination of palladium stable isotopes by MC-ICPMS using a 106Pd–110Pd double-spike to correct for instrumental mass fractionation. Results are expressed as the per mil (‰) difference in the 106Pd/105Pd ratio (δ106Pd) relative to an in-house solution standard (Pd_IPGP) in the absence of a certified Pd isotopic standard. Repeated analyses of the Pd isotopic composition of the chondrite Allende demonstrate the external reproducibility of the technique of ±0.032‰ on δ106Pd. Using these techniques, we have analysed Pd stable isotopes from a range of terrestrial and extraterrestrial samples. We find that chondrites define a mean δ106Pdchondrite = −0.19 ± 0.05‰. Ureilites reveal a weak trend towards heavier δ106Pd with decreasing Pd content, similar to recent findings based on Pt stable isotopes (Creech et al., 2017), although fractionation of Pd isotopes is significantly less than for Pt, possibly related to its weaker metal–silicate partitioning behaviour and the limited field shift effect. Terrestrial mantle samples have a mean δ106Pdmantle = −0.182 ± 0.130‰, which is consistent with a late-veneer of chondritic material after core formation.
KW - Late-veneer
KW - Meteorites
KW - Palladium
KW - Stable isotopes
KW - Terrestrial planet accretion
UR - http://www.scopus.com/inward/record.url?scp=85019879363&partnerID=8YFLogxK
U2 - 10.1016/j.gca.2017.04.040
DO - 10.1016/j.gca.2017.04.040
M3 - Journal article
AN - SCOPUS:85019879363
VL - 216
SP - 28
EP - 41
JO - Geochimica et Cosmochimica Acta
JF - Geochimica et Cosmochimica Acta
SN - 0016-7037
ER -
ID: 185408419