Solar system Nd isotope heterogeneity: Insights into nucleosynthetic components and protoplanetary disk evolution
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Solar system Nd isotope heterogeneity : Insights into nucleosynthetic components and protoplanetary disk evolution. / Saji, Nikitha Susan; Wielandt, Daniel; Holst, Jesper Christian; Bizzarro, Martin.
In: Geochimica et Cosmochimica Acta, Vol. 281, 2020, p. 135-148.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Solar system Nd isotope heterogeneity
T2 - Insights into nucleosynthetic components and protoplanetary disk evolution
AU - Saji, Nikitha Susan
AU - Wielandt, Daniel
AU - Holst, Jesper Christian
AU - Bizzarro, Martin
PY - 2020
Y1 - 2020
N2 - High-precision Nd isotope measurements of a diverse set of solar system materials including bulk chondrites and achondrites reveal that their Nd isotope composition is governed by several distinct nucleosynthetic components. The full spectrum of non-radiogenic, mass-independent Nd isotope compositions of solar system materials is best explained by heterogeneous distribution of at least three nucleosynthetic components - the classical s-process component, pure p-process component and an anomalous, previously unidentified s-/r-process component. The Nd-142/Nd-144 variations in solar system reservoirs specifically fall into three distinct trends - those that result from variations in the s-process component, those resulting from variations in the pure p-process component, and those resulting from coupled s-process and p-process variations. The mu Nd-148 value, a proxy for s-process variations, as well as mu Nd-142 that has been corrected for s-process heterogeneity to reflect p-process variations, broadly show an inverse correlation with epsilon Cr-54. The linearity in mu Nd-148 - epsilon Cr-54 space for inner solar system bodies, CI chondrite and Allende-type CAIs possibly suggests the thermally labile nature of some s-process carrier grains unlike the mainstream refractory s-process SiC grains. The p-process carrier for Nd is inferred to be a refractory phase enriched in inner solar system materials through thermal processing. The bulk meteorite regression lines that specifically correspond to s- and p-process heterogeneity, largely define mu Nd-142 intercepts indistinguishable from terrestrial composition within analytical uncertainty, ruling out resolvable radiogenic mu Nd-142 excess on Earth that cannot otherwise be accounted for by nucleosynthetic heterogeneity. (C) 2020 Elsevier Ltd. All rights reserved.
AB - High-precision Nd isotope measurements of a diverse set of solar system materials including bulk chondrites and achondrites reveal that their Nd isotope composition is governed by several distinct nucleosynthetic components. The full spectrum of non-radiogenic, mass-independent Nd isotope compositions of solar system materials is best explained by heterogeneous distribution of at least three nucleosynthetic components - the classical s-process component, pure p-process component and an anomalous, previously unidentified s-/r-process component. The Nd-142/Nd-144 variations in solar system reservoirs specifically fall into three distinct trends - those that result from variations in the s-process component, those resulting from variations in the pure p-process component, and those resulting from coupled s-process and p-process variations. The mu Nd-148 value, a proxy for s-process variations, as well as mu Nd-142 that has been corrected for s-process heterogeneity to reflect p-process variations, broadly show an inverse correlation with epsilon Cr-54. The linearity in mu Nd-148 - epsilon Cr-54 space for inner solar system bodies, CI chondrite and Allende-type CAIs possibly suggests the thermally labile nature of some s-process carrier grains unlike the mainstream refractory s-process SiC grains. The p-process carrier for Nd is inferred to be a refractory phase enriched in inner solar system materials through thermal processing. The bulk meteorite regression lines that specifically correspond to s- and p-process heterogeneity, largely define mu Nd-142 intercepts indistinguishable from terrestrial composition within analytical uncertainty, ruling out resolvable radiogenic mu Nd-142 excess on Earth that cannot otherwise be accounted for by nucleosynthetic heterogeneity. (C) 2020 Elsevier Ltd. All rights reserved.
KW - Nucleosynthentic anomalies
KW - Neodymium-142
KW - Chondrites
KW - Bulk silicate Earth
KW - Early solar system
KW - GIANT BRANCH STARS
KW - S-PROCESS
KW - EARLY DIFFERENTIATION
KW - NEUTRON-CAPTURE
KW - BUILDING-BLOCKS
KW - CROSS-SECTIONS
KW - ND-142
KW - EARTH
KW - CHONDRITES
KW - ANOMALIES
U2 - 10.1016/j.gca.2020.05.006
DO - 10.1016/j.gca.2020.05.006
M3 - Journal article
VL - 281
SP - 135
EP - 148
JO - Geochimica et Cosmochimica Acta
JF - Geochimica et Cosmochimica Acta
SN - 0016-7037
ER -
ID: 247387626