Peters, Stefan T. M.

[["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","Paleoceanography and Paleoclimatology"],["dc.bibliographiccitation.volume","36"],["dc.contributor.author","Fischer, Meike B."],["dc.contributor.author","Oeser, Martin"],["dc.contributor.author","Weyer, Stefan"],["dc.contributor.author","Folco, Luigi"],["dc.contributor.author","Peters, Stefan T. M."],["dc.contributor.author","Zahnow, Fabian"],["dc.contributor.author","Pack, Andreas"],["dc.date.accessioned","2021-06-01T09:41:37Z"],["dc.date.available","2021-06-01T09:41:37Z"],["dc.date.issued","2021"],["dc.identifier.doi","10.1029/2020PA004159"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/84980"],["dc.language.iso","en"],["dc.notes.intern","DOI-Import GROB-425"],["dc.relation.eissn","2572-4525"],["dc.relation.issn","2572-4517"],["dc.title","I‐Type Cosmic Spherules as Proxy for the Δ′ 17 O of the Atmosphere—A Calibration With Quaternary Air"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1495"],["dc.bibliographiccitation.issue","13"],["dc.bibliographiccitation.journal","Rapid Communications in Mass Spectrometry"],["dc.bibliographiccitation.lastpage","1504"],["dc.bibliographiccitation.volume","30"],["dc.contributor.author","Pack, Andreas"],["dc.contributor.author","Tanaka, Ryoji"],["dc.contributor.author","Hering, Markus"],["dc.contributor.author","Sengupta, Sukanya"],["dc.contributor.author","Peters, Stefan"],["dc.contributor.author","Nakamura, Eizo"],["dc.date.accessioned","2018-11-07T10:11:34Z"],["dc.date.available","2018-11-07T10:11:34Z"],["dc.date.issued","2016"],["dc.description.abstract","RATIONALE: The precise determination of Delta'O-17 values in terrestrial material is becoming increasingly important to understand the mass-dependent fractionation processes that cause variations in oxygen isotope ratios. San Carlos olivine is widely used as the reference material for oxygen isotope measurements of terrestrial and extraterrestrial materials. We report new Delta'O-17 values for San Carlos olivine that were independently determined in two different laboratories (Geoscience Center [GZG], University of Gottingen) and Institute for Study of the Earth's Interior [ISEI], Okayama University, Misasa) in direct comparison with VSMOW2 and SLAP2 water standards. METHODS: The delta O-17 and delta O-18 values of VSMOW2, SLAP2, GISP, and San Carlos olivine were determined relative to reference gas. In both laboratories, water and San Carlos olivine samples were prepared by BrF5 fluorination. In both laboratories, the O-2 released from water and olivine samples was passed through the same purification system and measured using the same mass spectrometer relative to the same reference gas. RESULTS: In both laboratories, the delta O-17(VSMOW2) and delta O-18 (VSMOW2) scales were slightly compressed with respect to the recommended composition of VSMOW2 and SLAP2. The new Delta'O-17(0.528) value (calculated from the VSMOW2-SLAP2 scaled 6 values) of San Carlos olivine from GZG was -36 +/- 9 ppm and, from ISEI, a value of -40 +/- 7 ppm (1(7 standard deviation) was determined. These values are similar to 50 ppm higher than previously reported from the same laboratories. Possible causes for the observed discrepancies are discussed. CONCLUSIONS: The results of this study in comparison with previous data from the same laboratories demonstrated that for high accuracy determination of Delta'O-17 values: (i) calibration of the reference gas relative to O-2 released from primary standards (VSMOW2, SLAP2) in the same laboratory is highly recommended, (ii) non-linearity of the mass spectrometer may not only affect delta O-17 and delta O-18 values but also Delta'O-17 values, and (iii) the VSMOW2-SLAP2 scaling should also be applied to analyses of rocks and minerals. Studies that are concerned with small differences in Delta'O-17 at similar delta O-18 values, however, are not affected by non-linearity of the mass spectrometer. Copyright (C) 2016 John Wiley & Sons, Ltd."],["dc.identifier.doi","10.1002/rcm.7582"],["dc.identifier.isi","000379974500007"],["dc.identifier.pmid","27321837"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/40075"],["dc.language.iso","en"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","1097-0231"],["dc.relation.issn","0951-4198"],["dc.title","The oxygen isotope composition of San Carlos olivine on the VSMOW2-SLAP2 scale"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","15702"],["dc.bibliographiccitation.journal","Nature communications"],["dc.bibliographiccitation.lastpage","15702"],["dc.bibliographiccitation.volume","8"],["dc.contributor.author","Pack, Andreas"],["dc.contributor.author","Höweling, Andres"],["dc.contributor.author","Hezel, Dominik C."],["dc.contributor.author","Stefanak, Maren T."],["dc.contributor.author","Beck, Anne-Katrin"],["dc.contributor.author","Peters, Stefan T. M."],["dc.contributor.author","Sengupta, Sukanya"],["dc.contributor.author","Herwartz, Daniel"],["dc.contributor.author","Folco, Luigi"],["dc.date.accessioned","2019-07-09T11:43:29Z"],["dc.date.available","2019-07-09T11:43:29Z"],["dc.date.issued","2017-06-01"],["dc.description.abstract","Molten I-type cosmic spherules formed by heating, oxidation and melting of extraterrestrial Fe,Ni metal alloys. The entire oxygen in these spherules sources from the atmosphere. Therefore, I-type cosmic spherules are suitable tracers for the isotopic composition of the upper atmosphere at altitudes between 80 and 115 km. Here we present data on I-type cosmic spherules collected in Antarctica. Their composition is compared with the composition of tropospheric O2. Our data suggest that the Earth's atmospheric O2 is isotopically homogenous up to the thermosphere. This makes fossil I-type micrometeorites ideal proxies for ancient atmospheric CO2 levels."],["dc.identifier.doi","10.1038/ncomms15702"],["dc.identifier.pmid","28569769"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/14540"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/58894"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.relation.issn","2041-1723"],["dc.rights","CC BY 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/4.0/"],["dc.subject.ddc","550"],["dc.title","Tracing the oxygen isotope composition of the upper Earth's atmosphere using cosmic spherules"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","132"],["dc.bibliographiccitation.journal","Chemical Geology"],["dc.bibliographiccitation.lastpage","145"],["dc.bibliographiccitation.volume","413"],["dc.contributor.author","Peters, Stefan T. M."],["dc.contributor.author","Muenker, Carsten"],["dc.contributor.author","Wombacher, Frank"],["dc.contributor.author","Elfers, Bo-Magnus"],["dc.date.accessioned","2018-11-07T09:50:10Z"],["dc.date.available","2018-11-07T09:50:10Z"],["dc.date.issued","2015"],["dc.description.abstract","Analytical protocols for measurements of isotope ratios involving low-abundance isotopes Hf-174 (similar to 0.16%), W-180 (similar to 0.12%), and Pt-190 (similar to 0.014%) usingmulti-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) at ca. tenfold improved precision compared to previous studies are presented. The improvements in precision result in part from the use of Faraday amplifiers equipped with 10(12) Omega resistors for collection of the isotope beams of interest, as well as for the isotope beams used to monitor isobaric interferences. For ion currents >5 x 10(-13) A (>50 mV on an amplifier with 10(11) Omega resistor), uncertainties (2 s. d.) of better than 100 ppm are typically achieved for isotope ratios involving Hf-174, W-180 and Pt-190. Terrestrial isotope abundances (atomic percent +/- 2 s.d.) of Hf-174 (0.16106 +/- 0.00006; n=15); W-180(0.11910 +/- 0.00009; n=10); and Pt-190 (0.01286 +/- 0.00005; n = 9) were determined on reference solutions throughout multiple analytical sessions over similar to 3 years. The results, however, rely on the accuracy of the reference value chosen for the isotope ratios employed for mass bias correction and, to a lesser extent, on the accuracy of the exponential mass fractionation law used for mass bias correction. For the precise determination of isotope ratios involving Hf-174, W-180 and Pt-190 in natural materials, efficient chromatographic separation schemes for Hf and W from silicate-rich matrices, and for Pt from iron meteorite matrices, are presented that provide effective separation of the element of interest from interfering elements. First results for Pt suggest that IAB, IIAB and IIIAB iron meteorites exhibit terrestrial Pt-190 abundances within uncertainty. Three chondrite samples exhibit indistinguishable Hf-174 from terrestrial Hf. The isotope abundance of W-180 in meteorites is more variable due to radiogenic W-180 that was produced by Os-184-decay. (C) 2015 Elsevier B.V. All rights reserved."],["dc.description.sponsorship","DFG [MU 1406/10-1/2]"],["dc.identifier.doi","10.1016/j.chemgeo.2015.08.018"],["dc.identifier.isi","000361845700012"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/35653"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Bv"],["dc.relation.issn","1878-5999"],["dc.relation.issn","0009-2541"],["dc.title","Precise determination of low abundance isotopes (Hf-174, W-180 and Pt-190) in terrestrial materials and meteorites using multiple collector ICP-MS equipped with 10(12) Omega Faraday amplifiers"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","227"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Nature communications"],["dc.bibliographiccitation.volume","8"],["dc.contributor.author","Magna, Tomáš"],["dc.contributor.author","Žák, Karel"],["dc.contributor.author","Pack, Andreas"],["dc.contributor.author","Moynier, Frédéric"],["dc.contributor.author","Mougel, Bérengère"],["dc.contributor.author","Peters, Stefan T. M."],["dc.contributor.author","Skála, Roman"],["dc.contributor.author","Jonášová, Šárka"],["dc.contributor.author","Mizera, Jiří"],["dc.contributor.author","Řanda, Zdeněk"],["dc.date.accessioned","2018-06-28T08:55:56Z"],["dc.date.available","2018-06-28T08:55:56Z"],["dc.date.issued","2017"],["dc.description.abstract","Chemical fingerprints of impacts are usually compromised by extreme conditions in the impact plume, and the contribution of projectile matter to impactites does not often exceed a fraction of per cent. Here we use chromium and oxygen isotopes to identify the impactor and impact-plume processes for Zhamanshin astrobleme, Kazakhstan. ε54Cr values up to 1.54 in irghizites, part of the fallback ejecta, represent the 54Cr-rich extremity of the Solar System range and suggest a CI-like chondrite impactor. Δ17O values as low as -0.22‰ in irghizites, however, are incompatible with a CI-like impactor. We suggest that the observed 17O depletion in irghizites relative to the terrestrial range is caused by partial isotope exchange with atmospheric oxygen (Δ17O = -0.47‰) following material ejection. In contrast, combined Δ17O-ε54Cr data for central European tektites (distal ejecta) fall into the terrestrial range and neither impactor fingerprint nor oxygen isotope exchange with the atmosphere are indicated.Identifying the original impactor from craters remains challenging. Here, the authors use chromium and oxygen isotopes to indicate that the Zhamanshin astrobleme impactor was a carbonaceous chrondrite by demonstrating that depleted 17O values are due to exchange with atmospheric oxygen."],["dc.identifier.doi","10.1038/s41467-017-00192-5"],["dc.identifier.pmid","28794408"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/14651"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/15152"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","final"],["dc.relation.eissn","2041-1723"],["dc.rights","CC BY 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/4.0/"],["dc.title","Zhamanshin astrobleme provides evidence for carbonaceous chondrite and post-impact exchange between ejecta and Earth's atmosphere"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.contributor.author","Mußmann, Frank"],["dc.contributor.author","Hardwig, Thomas"],["dc.contributor.author","Riethmüller, Martin"],["dc.contributor.author","Klötzer, Stefan"],["dc.contributor.author","Peters, Stefan T. M."],["dc.contributor.editorcorporation","Kooperationsstelle Hochschulen und Gewerkschaften"],["dc.contributor.other","Fladung, Vanessa"],["dc.contributor.other","Seedorf, Wiebke"],["dc.contributor.other","Nitsche, Katrin"],["dc.contributor.other","Schrewe, Jan"],["dc.date.accessioned","2020-11-06T12:55:15Z"],["dc.date.accessioned","2021-10-29T09:42:04Z"],["dc.date.available","2020-11-06T12:55:15Z"],["dc.date.available","2021-10-29T09:42:04Z"],["dc.date.issued","2020"],["dc.description.abstract","Im Rahmen einer repräsentativen, empirischen Studie wurden die Arbeitszeit, die Arbeitsbelastungen und die Arbeitsbedingungen Frankfurter Lehrerinnen und Lehrer an öffentlichen Schulen untersucht. Die Studie zeichnet sich durch einen integrierten Ansatz der Ermittlung von Arbeitszeit und den Belastungswirkungen verschiedener weiterer Belastungsfaktoren aus. Von 4.555 Frankfurter Lehrkräften nahmen 1.477 Lehrkräfte aus 69 Schulen an der Gesamtstudie teil. Davon konnten die Arbeitszeitdaten von 1.199 Lehrkräften nach Qualitätssicherung für die Arbeitszeiterhebung ausgewertet werden. Die Ergebnisse für Grundschule, Integrierte und Kooperative Gesamtschule sowie Gymnasium sind repräsentativ, für BBS nicht. Für die einzelnen Schulformen wurden der tatsächlichen Umfang, die zeitliche Lage sowie die Zeit- und Tätigkeitsstruktur in einem Zeitraum von bis zu 4 Wochen erhoben. Methodische Grundlage war ein normenkonformes und praxistaugliches Verfahren zur Erfassung und Systematisierung von Lehrer-Arbeitszeit, das in der Niedersächsischen Arbeitszeitstudie 2015/2016 entwickelt worden ist. Die Frankfurter Arbeitszeit-Daten wurden auf der Referenzbasis der Niedersachsenstudie auf Jahreswerte hochgerechnet und in einem Soll-Ist-Vergleich mit den Normvorgaben verglichen. Es liegen differenzierte Auswertungen vor (Schulformen; Klassenstufen, Beschäftigungsumfang; Geschlecht; Alter). 1.477 Lehrkräfte beantworteten zudem Fragen zur Arbeitssituation auf der Grundlage eines arbeitswissenschaftlichen Belastungs-Beanspruchungs-Modells und erprobter Erhebungsinstrumente (u.a. der „DGB-Index Gute Arbeit“). Differenziert nach Schulformen werden die psychische Belastung und Beanspruchung vorgestellt: Für die Arbeitsbedingungen, für spezifische aus der Tätigkeit einer Lehrkraft resultierende Anforderungen sowie Einflüsse aus der Schulsituation (Infrastruktur, soziale Herausforderungen). Darüber hinaus erfolgen Auswertungen zur Bereitschaft zur Digitalisierung, zum Spannungsfeld unterrichtlicher und außerunterrichtlicher Aufgaben, zu Motiven für Teilzeitarbeit und Frühpensionierung sowie zu Stress, Coping, Gesundheit und Personal Burnout. Die Arbeitsbedingungen von Frankfurter Lehrkräften unterscheiden sich von allen vergleichbaren Beschäftigtengruppen durch eine höhere Arbeitsintensität, höhere emotionale Beanspruchungen und ungünstigere Lage der Arbeitszeit sowie Problemen bei der Work-Life-Balance. Entsprechend sind auch schwächere Bindungen an den Arbeitgeber, schlechtere Einschätzungen zu Gesundheit und Burnout zu verzeichnen. Die Unterschiede zwischen Lehrkräften unterschiedlicher Schulformen und Bundesländern sind dagegen gering. Zentrales Ergebnis der Studie: Es besteht Handlungsbedarf, die Arbeitszeit und Arbeitsbedingungen humanverträglicher und gesundheitsförderlicher zu regeln. Dazu gehören eine Überprüfung und Anpassung der Arbeitsaufgaben von Lehrkräften, eine fairere Verteilung der Arbeitsbelastungen, die Verbesserung der Arbeitsbedingungen sowie präventive Maßnahmen zur Gesundheitsförderung. Dies kann im Rahmen einer ganzheitlichen Arbeitspolitik realisiert werden. Außerdem scheint eine grundlegende Überarbeitung von Arbeitszeitverordnungen für Lehrkräfte angezeigt."],["dc.format.extent","316"],["dc.identifier.doi","10.3249/ugoe-publ-7"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/17566"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/92407"],["dc.language.iso","de"],["dc.notes.intern","Migrated from goescholar"],["dc.publisher","Georg-August-Universität Göttingen, Kooperationsstelle Hochschulen und Gewerkschaften"],["dc.publisher.place","Göttingen"],["dc.relation.orgunit","Volkswirtschaftliches Institut für Mittelstand und Handwerk an der Universität Göttingen e.V."],["dc.rights","CC BY-SA 4.0"],["dc.rights.uri","http://creativecommons.org/licenses/by-sa/4.0/"],["dc.subject","Arbeitszeit; Arbeitsbelastung; Arbeitsqualität; Arbeitsbedingungen; Schule; Schulsystem; Frankfurt a. Main; Lehrkräfte; Lehrer und Lehrerinnen; digitale Zeiterfassung; Arbeitszeiterhebung; Psychische Belastung; Burnout; Coping; Gesundheitliche Belastung; Digitalisierung in der Schule; Brennpunktschule; Grundschule; Gesamtschule; Gymnasium; Berufsbildende Schule; DGB Index Gute Arbeit"],["dc.title","Arbeitszeit und Arbeitsbelastung von Lehrkräften an Frankfurter Schulen 2020"],["dc.title.alternative","Ergebnisbericht"],["dc.type","book"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","unknown"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","85"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Minerals"],["dc.bibliographiccitation.volume","10"],["dc.contributor.author","Whyatt, Laura"],["dc.contributor.author","Peters, Stefan"],["dc.contributor.author","Pack, Andreas"],["dc.contributor.author","Kirkland, Christopher L."],["dc.contributor.author","Balic-Zunic, Tonci"],["dc.contributor.author","Szilas, Kristoffer"],["dc.date.accessioned","2020-11-05T15:10:58Z"],["dc.date.available","2020-11-05T15:10:58Z"],["dc.date.issued","2020"],["dc.description.sponsorship","Villum Fonden"],["dc.identifier.doi","10.3390/min10010085"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/68505"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-352.8"],["dc.publisher","MDPI"],["dc.relation.eissn","2075-163X"],["dc.rights","https://creativecommons.org/licenses/by/4.0/"],["dc.title","Metasomatic Reactions between Archean Dunite and Trondhjemite at the Seqi Olivine Mine in Greenland"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","70"],["dc.bibliographiccitation.journal","Earth and Planetary Science Letters"],["dc.bibliographiccitation.lastpage","79"],["dc.bibliographiccitation.volume","459"],["dc.contributor.author","Peters, Stefan T. M."],["dc.contributor.author","Muenker, Carsten"],["dc.contributor.author","Pfeifer, Markus"],["dc.contributor.author","Elfers, Bo-Magnus"],["dc.contributor.author","Sprung, Peter"],["dc.date.accessioned","2018-11-07T10:28:07Z"],["dc.date.available","2018-11-07T10:28:07Z"],["dc.date.issued","2017"],["dc.description.abstract","Some nuclides that were produced in supernovae are heterogeneously distributed between different meteoritic materials. In some cases these heterogeneities have been interpreted as the result of interaction between ejecta from a nearby supernova and the nascent solar system. Particularly in the case of the oldest objects that formed in the solar system - Ca-Al rich inclusions (CAls) - this view is confirm the hypothesis that a nearby supernova event facilitated or even triggered solar system formation. We present Hf isotope data for bulk meteorites, terrestrial materials and CAIs, for the first time including the low-abundance isotope Hf-174 (similar to 0.16%). This rare isotope was likely produced during explosive 0/Ne shell burning in massive stars (i.e., the classical \"p-process\"), and therefore its abundance potentially provides a sensitive tracer for putative heterogeneities within the solar system that were introduced by supernova ejecta. For CAls and one LL chondrite, also complementary W isotope data are reported for the same sample cuts. Once corrected for small neutron capture effects, different chondrite groups, eucrites, a silicate inclusion of a JAB iron meteorite, and terrestrial materials display homogeneous Hf isotope compositions including 174Hf. Hafnium-174 was thus uniformly distributed in the inner solar system when planetesimals formed at the <50 ppm level. This finding is in good agreement with the evidently homogeneous distributions of p-process isotopes W-180, Os-184 and possibly Pt-180 between different iron meteorite groups. In contrast to bulk meteorite samples, CAls show variable depletions in p-process 174Hf with respect to the inner solar system composition, and also variable r-process (or s-process) Hf and W contributions. Based on combined Hf and W isotope compositions, we show that CAls sampled at least one component in which the proportion of r- and s-process derived Hf and W deviates from that of supernova ejecta. The Hf and W isotope anomalies in CAls are therefore best explained by selective processing of presolar carrier phases prior to CAI formation, and not by a late injection of supernova materials. Likewise, other isotope anomalies in additional elements in CAIs relative to the bulk solar system may reflect the same process. The isotopic heterogeneities between the first refractory condensates may have been eradicated partially during CAI formation, because W isotope anomalies in CAls appear to decrease with increasing W concentrations as inferred from time -integrated (182)w/W-184. Importantly, the Lu-178-Hf-176 and Hf-182-W-182 chronometers are not significantly affected by nucleosynthetic heterogeneity of Hf isotopes in bulk meteorites, but may be affected in CAls. (C) 2016 Elsevier B.V. All rights reserved."],["dc.description.sponsorship","DFG [MU1406/10-1/2]; Gottingen University [6125/3917543]"],["dc.identifier.doi","10.1016/j.epsl.2016.11.009"],["dc.identifier.isi","000393006500007"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/43354"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","PUB_WoS_Import"],["dc.publisher","Elsevier Science Bv"],["dc.relation.issn","1385-013X"],["dc.relation.issn","0012-821X"],["dc.title","Distribution of p-process Hf-174 in early solar system materials and the origin of nucleosynthetic Hf and W isotope anomalies in Ca-Al rich inclusions"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","346"],["dc.bibliographiccitation.journal","Geochimica et Cosmochimica Acta"],["dc.bibliographiccitation.lastpage","362"],["dc.bibliographiccitation.volume","239"],["dc.contributor.author","Elfers, Bo-Magnus"],["dc.contributor.author","Sprung, Peter"],["dc.contributor.author","Pfeifer, Markus"],["dc.contributor.author","Wombacher, Frank"],["dc.contributor.author","Peters, Stefan T. M."],["dc.contributor.author","Münker, Carsten"],["dc.date.accessioned","2019-07-24T07:38:21Z"],["dc.date.available","2019-07-24T07:38:21Z"],["dc.date.issued","2018"],["dc.description.abstract","The stepwise acid digestion of primitive chondritic meteorites allows the identification of nucleosynthetic isotope anomalies that are otherwise hidden on the bulk rock scale. Here, we present combined Hf and W isotope data for acid leachates, residues, and bulk rock aliquots of several primitive chondrites that include highly precise analyses of the heavy p-process isotopes ¹⁷⁴Hf and ¹⁸⁰W. Including data for these two p-process isotopes enables, for the first time, the clear-cut discrimination between s- and r-process contributions to the Hf and W isotope inventory. Our analyses reveal Hf and W isotopic homogeneity at the bulk rock scale, but significant Hf and W isotope anomalies that are complementary between acid leachates and residues. Since both r- to p-process isotope ratios are invariant in leachates and residues, the observed anomalies can unambiguously be tied to variable contributions of carrier phases enriched in s-process nuclides, as previously inferred for, i.e., Mo and Ru in leaching experiments. Hafnium and W isotope anomalies co-vary in leachate and residue fractions from CM chondrites, whereas CO and CV chondrites are characterized by distinctly larger Hf isotope anomalies compared to W. This observation is most likely explained by more efficient homogenization of s-process W carrier(s) or, alternatively, by local redistribution of anomalous W into secondary less resistant phases during parent body and/or nebular processing. This implies the presence of different s-nuclide carrier phases for Hf and W. Several carriers of s-process-material appear to have been selectively dissolved by our leaching protocol, while contributions from r- and p-process Hf and W carrier phases appear invariant, possibly due to the generally more labile nature of their carrier phases during solar nebula and/or parent body processing."],["dc.identifier.doi","10.1016/j.gca.2018.08.009"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/61964"],["dc.language.iso","en"],["dc.relation.issn","0016-7037"],["dc.title","Variable distribution of s-process Hf and W isotope carriers in chondritic meteorites – Evidence from 174Hf and 180W"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","236"],["dc.bibliographiccitation.journal","Geochimica et Cosmochimica Acta"],["dc.bibliographiccitation.lastpage","239"],["dc.bibliographiccitation.volume","169"],["dc.contributor.author","Peters, Stefan T. M."],["dc.contributor.author","Muenker, Carsten"],["dc.contributor.author","Becker, Harry"],["dc.contributor.author","Schulz, Toni"],["dc.date.accessioned","2018-11-07T09:48:55Z"],["dc.date.available","2018-11-07T09:48:55Z"],["dc.date.issued","2015"],["dc.identifier.doi","10.1016/j.gca.2015.06.030"],["dc.identifier.isi","000362975700015"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/35406"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Pergamon-elsevier Science Ltd"],["dc.relation.issn","1872-9533"],["dc.relation.issn","0016-7037"],["dc.title","Comment on \"Cosmogenic W-180 variations in meteorites and re-assessment of a possible Os-184-W-180 decay system\" by Cook, DL, Kruijer, T., Leya, I., Kleine, T."],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.subtype","letter_note"],["dspace.entity.type","Publication"]]