Universität zu Köln

Elfers, Bo-Magnus ORCID: 0000-0003-0548-772X, Sprung, Peter ORCID: 0000-0003-4862-1415, Pfeifer, Markus ORCID: 0000-0002-2335-8860, Wombacher, Frank ORCID: 0000-0002-0755-8918, Peters, Stefan T. M. and Muenker, Carsten (2018). Variable distribution of s-process Hf and W isotope carriers in chondritic meteorites - Evidence from Hf-174 and W-180. Geochim. Cosmochim. Acta, 239. S. 346 - 363. OXFORD: PERGAMON-ELSEVIER SCIENCE LTD. ISSN 1872-9533

Full text not available from this repository.

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 Hf-17(4) and W-180. 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. (C) 2018 Elsevier Ltd. All rights reserved.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Elfers, Bo-Magnus UNSPECIFIED orcid.org/0000-0003-0548-772X UNSPECIFIED Sprung, Peter UNSPECIFIED orcid.org/0000-0003-4862-1415 UNSPECIFIED Pfeifer, Markus UNSPECIFIED orcid.org/0000-0002-2335-8860 UNSPECIFIED Wombacher, Frank UNSPECIFIED orcid.org/0000-0002-0755-8918 UNSPECIFIED Peters, Stefan T. M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Muenker, Carsten UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-169324
DOI:	10.1016/j.gca.2018.08.009
Journal or Publication Title:	Geochim. Cosmochim. Acta
Volume:	239
Page Range:	S. 346 - 363
Date:	2018
Publisher:	PERGAMON-ELSEVIER SCIENCE LTD
Place of Publication:	OXFORD
ISSN:	1872-9533
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language EARLY SOLAR-SYSTEM; SILICON-CARBIDE GRAINS; CARBONACEOUS CHONDRITES; IRON-METEORITES; LU-HF; STELLAR NUCLEOSYNTHESIS; PRIMITIVE METEORITES; INTERSTELLAR GRAINS; PRESOLAR COMPONENTS; NEUTRON-CAPTURE Multiple languages Geochemistry & Geophysics Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/16932