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Correlation between the measured 111 Cd/ 105 Pd ratio and the Cd interference-corrected e 110 Pd for the IVB iron meteorites. The dashed line on the left represents the calculated e 110 Pd without Cd isobaric correction but including the nucleosynthetic isotope anomaly in e 110 Pd. The Cd corrections have a negligible effect on the measured Pd isotope ratios.
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The origin of ubiquitous nucleosynthetic isotope anomalies in meteorites may represent spatial and/or temporal heterogeneity in the sources that supplied material to the nascent solar nebula, or enhancement by chemical processing. For elements beyond the Fe peak, deficits in s-process isotopes have been reported in some (e.g., Mo, Ru, W) but not al...
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... Ru and Cd interferences on Pd were monitored via signals at mass 101 ( 101 Ru) and 111 ( 111 Cd). Corrections for Cd interferences were negligible (Figures 2, 3). To assess the degree to which isobaric interferences from Ru could be reliably corrected, Ru-doped Pd solutions were analyzed for their Pd isotopic composition which showed that a 101 Ru/ 105 Pd ratio higher than 0.009 resulted in insufficient correction of 102 Ru on 102 Pd and 101 Ru/ 105 Pd ratios higher than 0.02 resulted in insufficient correction of 104 Ru on 104 Pd (Figure 3). Possible molecular interferences from ZrO + , ZnAr + and NiAr + , etc., were monitored prior to MC-ICP-MS analysis using a single collector ICP-MS (Thermo Element2 TM ), and an additional cation-exchange clean-up column was applied to lower these interferences to negligible levels before analyzing the solutions for Pd isotope composition. For three samples with ZrO interferences (affected masses: 106, 107, 108, 110) additional corrections have been applied. Although the ZrO + does not interfere with 104 Pd, the mass bias correction propagates the interference on 108 Pd to all Pd isotope ratios, with the largest effect on e 106 Pd. 106 Pd has s-and r-process contributions intermediate between 108 Pd and 105 Pd and, therefore, will not show pronounced anomalies resulting from nucleosynthetic processes. In addition, cosmogenic effects are small and more pronounced on 105 Pd (negative) and 108 Pd (positive) than on 106 Pd. Therefore, with the instrumental mass bias correction of 108 Pd/ 105 Pd neither cosmogenic nor nucleosynthetic effects can produce significant anomalies for the resulting e 106 Pd. Since neither cosmogenic nor nucleosyn- thetic processes affect e 106 Pd significantly it becomes a sensitive monitor for ZrO + interferences. Measurements of a Zr-doped Pd standard solution were used to define a relation- ship between each Pd isotope ratio and e 106 Pd due to ZrO + interference alone, and the e values for the three irons for which corrections were necessary were corrected assuming e 106 Pd = 0 ( Figure 4). The robustness and accuracy of this correction procedure was assessed by comparison with replicate measurements of the same sample in which no Zr interference correction was necessary (e.g., Warburton Range- 1, ...
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... 108 Pd/ 105 Pd normalized e values, the model also predicts small positive anomalies of e 106 Pd and e 110 Pd with around the same magnitude (for further details, see Leya & Masarik 2013). Figure 6 shows the correlation between e 106 Pd, e 110 Pd results in the intercept of this ratio being 0.46 e u higher than the model prediction (Figures 2, 6), which assumed terrestrial Pd isotopic composition as the starting composition before cosmic-ray induced isotope ...
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The 182Hf-182W chronology of iron meteorites provides crucial information on the timescales of accretion and differentiation of some of the oldest planetesimals of the Solar System. Determining accurate Hf-W model ages of iron meteorites requires correction for cosmic ray expo-sure (CRE) induced modifications of W isotope compositions, which can be...
Citations
... A comparison between meteorites and terrestrial samples reveals isotopic variability in the following elements: Ca, Ti, Cr, Ni, Sr, Zr, Mo, Ru, Pd, Ba, W, Nd, Sm þ HREE þ noble gases (Ne, Ar, Kr, Xe) (e.g., Warren, 2011;Ott, 2014;Mayer et al., 2015;Qin & Carlson, 2016;Bermingham et al., 2016Bermingham et al., , 2018aBermingham et al., , 2018bDauphas & Schauble, 2016;Kruijer et al., 2017;Nanne et al., 2019). These isotope variations are independent of radiogenic decay, massdependent anomalies, cosmic ray exposure effects, and nuclear field shift effects, although some of these effects can overprint nucleosynthetic isotope compositions. ...
The NASA Dawn mission, launched in 2007, aimed to visit two of the most massive protoplanets of the main asteroid belt: Vesta and Ceres. The aim was to further our understanding of the earliest days of the Solar System, and compare the two bodies to better understand their formation and evolution. This book summarises state-of-the-art results from the mission, and discusses the implications for our understanding not only of the asteroid belt but the entire Solar System. It comprises of three parts: Part 1 provides an overview of the main belt asteroids and provides an introduction to the Dawn mission; Part 2 presents key findings from the mission; and Part 3 discusses how these findings provide insights into the formation and evolution of the Solar System. This is a definitive reference for academic researchers and professionals of planetary science, asteroid science and space exploration.
... The NC-CC isotopic dichotomy is now observed in more than 10 isotope systematics (e.g., Ca, Ti, Ni, Zr, Mo, Ru, Ba, Nd, Sm, Hf, W, Os) with various cosmochemical (e.g., refractory, major components) and geochemical (e.g., lithophile, siderophile) behaviors Bermingham et al., 2020 and references therein). On the other hand, less refractory elements (e.g., Zn, Sn, Pd, Cd, Se, Te) show smaller nucleosynthetic isotopic variations among solar system materials (Fehr et al., 2006;Wombacher et al., 2008;Moynier et al., 2009;Mayer et al., 2015;Fehr et al., 2018;Ek et al., 2020). These isotopic dichotomies of meteorites are considered to record heterogeneous distribution of extrasolar materials produced in the slow (s-process) and rapid (r-process) neutron capture processes of stellar nucleosynthesis (Trinquier et al., 2007(Trinquier et al., , 2009Burkhardt et al., 2011;Budde et al., 2016a;Poole et al., 2017;Kruijer et al., 2017a). ...
Comparative studies of terrestrial planets have provided important insights into physico-chemical processes that produced their similarities and differences. Chemical composition of terrestrial planets records planetary accretion, differentiation, impact, and surface processes. In order to place new constraints on the origin and evolution of rocky planets, I investigated chemical compositions of terrestrial planets and meteorites from primitive asteroids (chondrites).
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... To date, meteoritic nucleosynthetic anomalies have been recorded in isotopes of Ne, Kr, Xe, Ca, Ti, Cr, Ni, Sr, Zr, Mo, Ru, Pd, Ba, W, Nd, Sm (e.g., Warren 2011;Ott 2014;Mayer et al. 2015;Bermingham et al. 2016;Dauphas and Schauble 2016;Qin and Carlson 2016;K.R. Bermingham et al. Kruijer et al. 2017;Bermingham et al. 2018aBermingham et al. , 2018b. ...
Understanding the formation of our planetary system requires identification of the materials from which it originated and the accretion processes that produced the planets. The compositional evolution of the solar system can be constrained by synthesizing astronomical datasets and numerical models with elemental and isotopic compositions from objects that directly sampled the disk: meteorites and their constituents (chondrules, refractory inclusions, and matrix). This contribution reviews constraints on early solar system evolution provided by the so-called non-carbonaceous (NC) and carbonaceous chondrite (CC) groups and their relationship to the volatile element characteristics of chondritic meteorites. In previous work, the NC or CC character of a parent body was used to infer its accretion location in the protoplanetary disk. The NC groups purportedly originated in the inner disk, and the CC groups were derived from the outer disk, where the NC and CC regions of the disk may have been separated early on by proto-Jupiter, a pressure maximum, or a dust trap in the disk. The tenet that all CC parent bodies accreted in the outer disk is, in part, based on evidence that a handful of CC meteorites are enriched in volatile species compared to NC meteorites. Here, it is reviewed if and how the volatile element and nucleosynthetic isotope compositions of meteorites can be linked to accretion locations within the disk. The nucleosynthetic isotope compositions of whole rock meteorite samples contrast the trends found for their major volatile element compositions (i.e., C, N, and O). Although there may be an increase in volatile abundances when comparing some stony NC and CC meteorites and their inferred accretion locations within the disk, this is not necessarily a general rule. The difficulties with inferring parent body accretion locations are discussed. It is found that it cannot always be assumed that parent bodies which formed in the CC reservoir are “volatile-rich” relative to those that formed in the NC reservoir which are “volatile-poor”. Consequently, tracing the origin of terrestrial volatiles using the NC-CC isotope dichotomy remains challenging.
... Palladium falls between Cd, Te and the refractory elements Zr, Mo and Ru in volatility, making it ideal for testing the link between volatility and the origin of the nucleosynthetic s-process variations. Earlier isotope data limited to the IVB iron meteorite group indicate that nucleosynthetic Pd offsets are smaller than predicted from Ru and Mo s-process deficits 19 . Iron meteorites are enriched in siderophile elements such as Ru, Pd and Mo and show distinct nucleosynthetic variations for Mo (ref. ...
... b-d, Graphs for ε 102 Pd (b), ε 104 Pd (c) and ε 106 Pd (d) versus ε 110 Pd normalized to 108 Pd/ 105 Pd for the analysed meteorite groups after correction for cosmic ray exposure. Panels c and d also include the Pd data for the IVB group from ref. 19 (IVB*). The primary nucleosynthetic source of each is isotope (p-, s-or r-process) is stated above the mass in a. Long-dashed lines depict an s-process mixing line, whereas short dashed lines reflect r-process mixing lines calculated using ref. ...
... The results favour an s-process deficit in iron meteorites relative to the Earth over an r-process excess, based on ε 102 Pd. Our value for the IVB group overlaps within uncertainty with the value reported in ref. 19 . The origin denotes the composition of the terrestrial isotope standard NIST SRM 3138. ...
Rocky asteroids and planets display nucleosynthetic isotope variations that are attributed to the heterogeneous distribution of stardust from different stellar sources in the solar protoplanetary disk. Here we report new high-precision palladium isotope data for six iron meteorite groups. The palladium data display smaller nucleosynthetic isotope variations than the more refractory neighbouring elements. Based on this observation, we present a model in which thermal destruction of interstellar dust in the inner Solar System results in an enrichment of s-process-dominated stardust in regions closer to the Sun. We propose that stardust is depleted in volatile elements due to incomplete condensation of these elements into dust around asymptotic giant branch stars. This led to the smaller nucleosynthetic variations for Pd reported here and the lack of such variations for more volatile elements. The smaller magnitude variations measured in heavier refractory elements suggest that material from high-metallicity asymptotic giant branch stars is the dominant source of stardust in the Solar System. These stars produce fewer heavy s-process elements (proton number Z ≥ 56) compared with the bulk Solar System composition.
... Palladium falls between Cd, Te and the refractory elements Zr, Mo and Ru in volatility, making it ideal for testing the link between volatility and the origin of the nucleosynthetic s-process variations. Earlier isotope data limited to the IVB iron meteorite group indicate that nucleosynthetic Pd offsets are smaller than predicted from Ru and Mo sprocess deficits 19 . Iron meteorites are enriched in siderophile elements such as Ru, Pd and Mo and show distinct nucleosynthetic variations for Mo 14 and Ru 13,15 . ...
... Noteworthy, the s-process deficits in Pd are smaller than predicted from the s-process depletion of Mo and Ru isotopes in the same meteorite groups (Figure 2), in agreement with a previous study of IVB irons 19 . This implies that the relative abundance of Pd, compared to Zr, Mo and Ru, in stardust is 3-4 times lower than in the bulk s-process composition of the Solar System. ...
... Changes in stellar parameters including initial mass and metallicity do not affect the relative yields of Zr, Mo, Ru, Pd and Cd (Figure 4; Extended Data Figure 5) and can therefore not explain the reduced abundance of Pd and Cd in stardust. Likewise, enhanced rates of the 22 Ne neutron source during AGB nucleosynthesis are unable to reduce the Pd yields relative to the neighbouring elements 19 . Therefore, the Pd depletion in stardust is not a consequence of stellar yields. ...
Rocky asteroids and planets display nucleosynthetic isotope variations that are attributed to the heterogeneous distribution of stardust from different stellar sources in the solar protoplanetary disk. Here we report new high precision palladium isotope data for six iron meteorite groups, which display smaller nucleosynthetic isotope variations than the more refractory neighbouring elements. Based on this observation we present a new model in which thermal destruction of interstellar medium dust results in an enrichment of s-process dominated stardust in regions closer to the Sun. We propose that stardust is depleted in volatile elements due to incomplete condensation of these elements into dust around asymptotic giant branch (AGB) stars. This led to the smaller nucleosynthetic variations for Pd reported here and the lack of such variations for more volatile elements. The smaller magnitude variations measured in heavier refractory elements suggest that material from high-metallicity AGB stars dominated stardust in the Solar System. These stars produce less heavy s-process elements compared to the bulk Solar System composition.
... Small palladium nucleosynthetic anomalies in isotopic composition (related to s-process variability) were identified in type IVB iron meteorites [340]. These nucleosynthetic isotope anomalies may represent spatial and/or temporal heterogeneity in the early solar nebula or may be due to chemical processing within the solar nebula [327,341]. ...
The IUPAC (International Union of Pure and Applied Chemistry) Periodic Table of the Elements and Isotopes (IPTEI) was created to familiarize students, teachers, and non-professionals with the existence and importance of isotopes of the chemical elements. The IPTEI is modeled on the familiar Periodic Table of the Chemical Elements. The IPTEI is intended to hang on the walls of chemistry laboratories and classrooms. Each cell of the IPTEI provides the chemical name, symbol, atomic number, and standard atomic weight of an element. Color-coded pie charts in each element cell display the stable isotopes and the relatively long-lived radioactive isotopes having characteristic terrestrial isotopic compositions that determine the standard atomic weight of each element. The background color scheme of cells categorizes the 118 elements into four groups: (1) white indicates the element has no standard atomic weight, (2) blue indicates the element has only one isotope that is used to determine its standard atomic weight, which is given as a single value with an uncertainty, (3) yellow indicates the element has two or more isotopes that are used to determine its standard atomic weight, which is given as a single value with an uncertainty, and (4) pink indicates the element has a well-documented variation in its atomic weight, and the standard atomic weight is expressed as an interval. An element-by-element review accompanies the IPTEI and includes a chart of all known stable and radioactive isotopes for each element. Practical applications of isotopic measurements and technologies are included for the following fields: forensic science, geochronology, Earth-system sciences, environmental science, and human health sciences, including medical diagnosis and treatment.
... Isotopic variability unambiguously related to nucleosynthetic causes at the scale of meteorite parent bodies has now been seen in a wide range of elements including Ca (Chen et al. 2011;Dauphas et al. 2014b;Simon et al. 2009), Ti (Leya et al. 2008;Trinquier et al. 2009;Zhang et al. 2012), Cr (Qin et al. 2010;Trinquier et al. 2007), Ni (Regelous et al. 2008;Steele et al. 2011), Mo (Budde et al. 2016a;Burkhardt et al. 2011;Dauphas et al. 2002a;Poole et al. 2017;Render et al. 2017;Yin et al. 2002b), Ru (Chen et al. 2010;Fischer-Gödde et al. 2013, 2015, Zr (Akram et al. 2015;Schönbächler et al. 2003), Pd (Mayer et al. 2015), Ba, Nd, and Sm (Andreasen and Sharma 2006;Burkhardt et al. 2016;Carlson et al. 2007;Gannoun et al. 2011;Hidaka et al. 2003), and W (Kruijer et al. 2013(Kruijer et al. , 2017Qin et al. 2008;Wittig et al. 2013). A recent review of these anomalies and their likely cause is given in Qin and Carlson (2016). ...
The processes of planet formation in our Solar System resulted in a final product of a small number of discreet planets and planetesimals characterized by clear compositional distinctions. A key advance on this subject was provided when nucleosynthetic isotopic variability was discovered between different meteorite groups and the terrestrial planets. This information has now been coupled with theoretical models of planetesimal growth and giant planet migration to better understand the nature of the materials accumulated into the terrestrial planets. First order conclusions include that carbonaceous chondrites appear to contribute a much smaller mass fraction to the terrestrial planets than previously suspected, that gas-driven giant planet migration could have pushed volatile-rich material into the inner Solar System, and that planetesimal formation was occurring on a sufficiently rapid time scale that global melting of asteroid-sized objects was instigated by radioactive decay of ²⁶Al. The isotopic evidence highlights the important role of enstatite chondrites, or something with their mix of nucleosynthetic components, as feedstock for the terrestrial planets. A common degree of depletion of moderately volatile elements in the terrestrial planets points to a mechanism that can effectively separate volatile and refractory elements over a spatial scale the size of the whole inner Solar System. The large variability in iron to silicon ratios between both different meteorite groups and between the terrestrial planets suggests that mechanisms that can segregate iron metal from silicate should be given greater importance in future investigations. Such processes likely include both density separation of small grains in the nebula, but also preferential impact erosion of either the mantle or core from differentiated planets/planetesimals. The latter highlights the important role for giant impacts and collisional erosion during the late stages of planet formation.
... They have since been recognized for over 10 elements in all kinds of chondrites, with enstatite chondrites being the closest to the terrestrial composition and carbonaceous chondrites showing the largest anomalies (Burkhardt et al. 2011;Dauphas & Schauble 2016). Differentiated meteorites also show isotopic anomalies at the ε level, e.g., Ni, Mo, Pd, and W in iron meteorites (Dauphas et al. 2002;Burkhardt et al. 2011;Steele et al. 2011;Mayer et al. 2015;Budde et al. 2016a;Kruijer et al. 2017) and Cr and Ti in achondrites (Trinquier et al. 2007(Trinquier et al. , 2009. Iron meteorites show notably diverse nucleosynthetic isotopic compositions ranging from those in main group IAB irons, which have Earth-like Mo and Ru compositions, for example, to those in group IVB, which have large isotopic anomalies matching those in carbonaceous chondrites (Burkhardt et al. 2011;Steele et al. 2012;Fischer-Gödde et al. 2015;Worsham et al. 2017). ...
... However, correlations in bulk chondrites between isotopic anomalies for nuclides that were generated by different processes suggest that the anomalies do not reflect the addition of material from a single stellar source such as a supernova. Instead the isotopic variability in meteorites was probably produced by mechanical or thermal processing of solids in the disk (Trinquier et al. 2009;Burkhardt et al. 2012;Burkhardt & Schönbachler 2015;Mayer et al. 2015). Isotopic anomalies in CAIs were originally attributed to reflect late injection of supernova ejecta into the cloud or the disk (e.g., McCulloch & Wasserburg 1978;Brennecka et al. 2013). ...
Whole rock Δ¹⁷O and nucleosynthetic isotopic variations for chromium, titanium, nickel, and molybdenum in meteorites define two isotopically distinct populations: carbonaceous chondrites (CCs) and some achondrites, pallasites, and irons in one and all other chondrites and differentiated meteorites in the other. Since differentiated bodies accreted 1-3 Myr before the chondrites, the isotopic dichotomy cannot be attributed to temporal variations in the disk. Instead, the two populations were most likely separated in space, plausibly by proto-Jupiter. Formation of CCs outside Jupiter could account for their characteristic chemical and isotopic composition. The abundance of refractory inclusions in CCs can be explained if they were ejected by disk winds from near the Sun to the disk periphery where they spiraled inward due to gas drag. Once proto-Jupiter reached 10-20 M ⊕, its external pressure bump could have prevented millimeter- and centimeter-sized particles from reaching the inner disk. This scenario would account for the enrichment in CCs of refractory inclusions, refractory elements, and water. Chondrules in CCs show wide ranges in Δ¹⁷O as they formed in the presence of abundant ¹⁶O-rich refractory grains and ¹⁶O-poor ice particles. Chondrules in other chondrites (ordinary, E, R, and K groups) show relatively uniform, near-zero Δ¹⁷O values as refractory inclusions and ice were much less abundant in the inner solar system. The two populations were plausibly mixed together by the Grand Tack when Jupiter and Saturn migrated inward emptying and then repopulating the asteroid belt with roughly equal masses of planetesimals from inside and outside Jupiter's orbit (S- and C-type asteroids). © 2018. The American Astronomical Society. All rights reserved.
... Firstly, variations could reflect the heterogeneous distribution of isotopes formed in specific stellar environments (nucleosynthetic variations) and secondly, isotope ratios can be altered due to exposure to GCR. Nucleosynthetic isotope variations are reported in iron meteorites for elements including Mo (Burkhardt et al., 2011;Dauphas et al., 2002;Worsham et al., 2017), Ru (Chen et al., 2010;Fischer-Gödde et al., 2015) and Pd (Ek et al., 2017;Mayer et al., 2015), but have not previously been recognised for Pt (Hunt et al., 2017b;Kruijer et al., 2014aKruijer et al., , 2013aPeters et al., 2015;Wittig et al., 2013). The low-abundance isotope 192 Pt (0.79%) is the only major s-process nuclide of Pt, whereas the more abundant isotopes 194 Pt,195 Pt,196 Pt and 198 Pt are all almost uniquely produced by the r-process (Bisterzo et al., 2011). ...
The short-lived ¹⁸²Hf–¹⁸²W decay system is a powerful chronometer for constraining the timing of metal–silicate separation and core formation in planetesimals and planets. Neutron capture effects on W isotopes, however, significantly hamper the application of this tool. In order to correct for neutron capture effects, Pt isotopes have emerged as a reliable in-situ neutron dosimeter. This study applies this method to IAB iron meteorites, in order to constrain the timing of metal segregation on the IAB parent body. The ε¹⁸²W values obtained for the IAB iron meteorites range from −3.61 ± 0.10 to −2.73 ± 0.09. Correlating εⁱPt with ε¹⁸²W data yields a pre-neutron capture ε¹⁸²W of −2.90 ± 0.06. This corresponds to a metal–silicate separation age of 6.0 ± 0.8 Ma after CAI for the IAB parent body, and is interpreted to represent a body-wide melting event. Later, between 10 and 14 Ma after CAI, an impact led to a catastrophic break-up and subsequent reassembly of the parent body. Thermal models of the interior evolution that are consistent with these estimates suggest that the IAB parent body underwent metal–silicate separation as a result of internal heating by short-lived radionuclides and accreted at around 1.4±0.1 Ma after CAIs with a radius of greater than 60 km.
... [144][145][146][147] The major obstacles for the analysis of Pd stable isotope ratios are the isobaric mass interference caused by Ru ( 102 Ru and 104 Ru) and Cd ( 106 Cd, 108 Cd, and 110 Cd) and the molecular ion interference caused by the hydrides of Rh (RhH + ) and Ag (AgH + ), Ar compounds of Ni (NiAr + ) and Zn (ZnAr + ), and oxides of Zr (ZrO) and Mo (MoO). 148 Similar purication procedures with the Pt group elements could be used to purify the geological samples for the Pd concentration measurement. 149 Ek et al. developed an ion exchange separation method to achieve a highly efficient removal of Ru (Ru/Pd < 0.0005), Cd (Cd/Pd < 0.025), Ni (Ni/Pd < 0.04), Zr (Zr/Pd < 0.0002), and Zn (Zn/Pd < 0.06) from the samples for Pd isotopic analysis. ...
Non-traditional stable isotopes, with no clear definition yet, generally refer to isotopes beyond C, H, O, N, and S with small variations in natural stable isotopic composition, such as isotopes of transitional and heavy metal elements. With the rapid development in multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) technique, non-traditional stable isotopes have emerged as powerful tracers in geosciences, archaeology, anthropology, and environmental sciences. This article summarizes the recent advances in the analysis of non-traditional stable isotopes by MC-ICP-MS. We review recent efforts on improvement of the sensitivity of MC-ICP-MS and optimization of the sample preparation procedures. Special attention is paid to the “emerging” stable isotopes, e.g., vanadium (V), barium (Ba), potassium (K), platinum (Pt), palladium (Pd), silver (Ag), cerium (Ce), erbium (Er), and silicon (Si). We also introduce some novel aspects of application of non-traditional stable isotopes, e.g., in nanotechnology and environmental health studies. Finally, we discuss current challenges and give our perspectives in this active research area.
