^1,2Bo-Magnus Elfers,^1,2,3Sprung Peter,^1,2 Messling Nils,^1,2Münker Carsten
Geochimica et Cosmochimica Acta (in Press) Link to Article [https://doi.org/10.1016/j.gca.2019.12.008]
¹Institut für Geologie und Mineralogie, Universität zu Köln, Zülpicherstr. 49b, 50674 Cologne, Germany
²Steinmann-Institut, Rheinische Friedrich-Wilhelms-Universität Bonn, Poppelsdorfer Schloss, Meckenheimer Allee 169, 53115 Bonn, Germany
³Analytic Radioactive Materials, Hot Laboratory Division, Paul Scherrer Institute, 5232 Villigen, Switzerland
Copyright Elsevier

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 for the first time combined isotope data for acid leachates, residues, and bulk rock aliquots of several primitive chondrites for the geo- and cosmochemically similar elements Zr and Hf. Our analyses reveal significant Zr and Hf isotope anomalies that (i) are complementary between acid leachates and residues and (ii) well-correlated with each other. The observed Zr and Hf anomalies strongly suggest variable contributions of common s-process carrier phases to the different leachates and residues. Ratios of r- (and p-process) Zr and Hf isotopes appear to be uniform in leachates and residues. In contrast to the well-correlated anomalies found in our leaching experiments, nucleosynthetic Zr and Hf isotope signatures seem to be decoupled on the bulk rock scale. This contrast may result from the heterogeneous distribution of neutron-rich Zr material devoid Hf, or alternatively be caused by the presence of anomalous CAI material which overprinted s-process deficits that were initially correlated.

In contrast to a previous study, we find no direct evidence for the presence of a third isotopically distinct nucleosynthetic Zr component.

^1,2Samira Frey et al. (>10)
Planetary and Space Science (in Press) Link to Article [https://doi.org/10.1016/j.pss.2019.104816]
¹Space Research and Planetary Sciences, Physics Institute, University of Bern, Sidlerstrasse 5, 3012, Bern, Switzerland
²Laboratory for Astrophysics, Leiden Observatory, Leiden University, Niels Bohrweg 2, NL 2333, CA, Leiden, the Netherlands

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¹P.R.Kumaresan,¹J.Saravanavel,¹K.Palanivel
Planetary and Space Science (in Press) Link to Article [https://doi.org/10.1016/j.pss.2019.104817]
¹Departmentof Remote Sensing, Bharathidasan University -Khajamalai Campus, Tiruchirappalli, 620 023, Tamil Nadu, India

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¹K.Hadler,² D.J.P.Martin,³J.Carpenter,¹J.J.Cilliers,⁴A.Morse,¹S. Starr,¹J.N.Rasera,⁵K.Seweryn,³P.Reiss,³A.Meurisse
Planetary and Space Science (in Press) Link to Article [https://doi.org/10.1016/j.pss.2019.104811]
¹Department of Earth Science and Engineering, Imperial College London, London, SW7 2AZ, UK
²European Space Agency ECSAT, Fermi Avenue, Harwell Campus, Didcot, Oxfordshire, OX11 0FD, UK
³European Space Agency ESTEC, Keplerlaan 1, 2201, AZ Noordwijk, the Netherlands
⁴School of Physical Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6AA, UK
⁵Space Research Center of the Polish Academy of Sciences (CBK PAN), 18a Bartycka Str., 00-716, Warsaw, Poland

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¹P.Reiss,²F.Kerscher,³L.Grill
Planetary and Space Science (in Press) Link to Article [https://doi.org/10.1016/j.pss.2019.104795]
¹European Space Agency, ESTEC, Keplerlaan 1, 2201 AZ, Noordwijk, the Netherlands
²Technical University of Munich, Institute for Energy Systems, Boltzmannstr. 15, 85748, Garching, Germany
³Technical University of Munich, Institute of Astronautics, Boltzmannstr. 15, 85748, Garching, Germany

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¹Zeman, J.,¹Ješkovský, M.,¹Kaizer, J.,²Pánik, J.,¹Kontuľ, I.,¹Staníček, J.,¹Povinec, P.P.
Journal of Radioanalytical and Nuclear Chemistry 322, 1897-1903 Link to Article [DOI: 10.1007/s10967-019-06851-9]
¹Faculty of Mathematics, Physics and Informatics, Centre for Nuclear and Accelerator Technologies (CENTA), Comenius University, Bratislava, 842 48, Slovakia
²Faculty of Medicine, Institute of Medical Physics, Biophysics, Informatics and Telemedicine, Comenius University, Bratislava, 813 72, Slovakia

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^1,2Ponomarev, D.S.,^1,2Litasov, K.D.,³Ishikawa, A.,¹Bazhan, I.S.,⁴Hirata, T.,¹Podgornykh, N.M.
Russian Geology and Geophysics 60, 752-767 Link to Article [DOI: 10.15372/RGG2019055]
¹V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russian Federation
²Novosibirsk State University, ul. Pirogova 2, Novosibirsk, 630090, Russian Federation
³Dept Earth Science and Astronomy, University of Tokyo, Komada, Meguro, Tokyo, 153-8902, Japan
⁴Geochemical Research Center, University of Tokyo, Hongo, Bunkyo, Tokyo, 113-8654, Japan

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¹Bogusz, P.,¹Gałązka-Friedman, J.,²Brzózka, K.,¹Jakubowska, M.,³Woźniak, M.,⁴Karwowski, Ł.,¹ Duda, P.
Hyperfine Interactions 240, 126 Link to Article [DOI: 10.1007/s10751-019-1659-7]
¹Faculty of Physics, Warsaw University of Technology, Koszykowa 75, Warsaw, 00-662, Poland
²Faculty of Mechanical Engineering, Department of Physics, University of Technology and Humanities, E. Stasieckiego 54, Radom, 26-600, Poland
³Faculty of Biology, University of Warsaw, Miecznikowa 1, Warszawa, 02-096, Poland
⁴Faculty of Natural Sciences, Institute of Earth Sciences, University of Silesia in Katowice, ul. Będzińska 60, Sosnowiec, 41-200, Poland

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¹Flynn, G.J.,²Durda, D.D.,³Molesky, M.J.,³May, B.A.,³Congram, S.N.,³Loftus, C.L., Reagan,³J.R.,³Strait, M.M.,⁴Macke, R.J.
International Journal of Impact Engineering 136, 103437 Link to Article [DOI: 10.1016/j.ijimpeng.2019.103437]
¹SUNY-Plattsburgh, 101 Broad St., Plattsburgh, NY 12901, United States
²Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, CO 80302, United States
³Alma College, Alma, MI 48801, United States
⁴Vatican Observatory, V-00120, Vatican City State

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¹Elsa Amsellem,^1,2Frédéric Moynier,^1,3Brandon Mahan,^2,4Pierre Beck
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2019.113593]
¹Université de Paris, Institut de physique du globe de Paris, CNRS, F-75005 Paris, France
²Institut Universitaire de France, Paris, France
³Department of Earth and Planetary Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
⁴Institut de Planétologie et d’Astrophysique de Grenoble, Univ. Grenoble Alpes, CNRS, CNES, 38000 Grenoble, France
Copyright Elsevier

Carbonaceous chondrites are often considered potential contributors of water and other volatiles to terrestrial planets as most of them contain significant amounts of hydrous mineral phases. As such, carbonaceous chondrites are candidate building blocks for Earth, and elucidating their thermal histories is of direct importance for understanding the volatile element history of Earth and the terrestrial planets. A significant fraction of CM type carbonaceous chondrites are thermally metamorphosed or “heated” and have lost part of their water content. The origin and the timing of such heating events are still debated, as they could have occurred either in the first Myrs of the Solar System via short-lived radioactive heating, or later by impact induced heating and/or solar radiation. Since Rb is more volatile than Sr, and some heated CM chondrites are highly depleted in Rb, a dating system based on the radioactive decay of ⁸⁷Rb to ⁸⁷Sr (λ⁸⁷Rb = 1.393 × 10⁻¹¹ yr⁻¹) could be used to date the heating event relating to the fractionation of Rb and Sr. Here, we have leveraged the ⁸⁷Rb/⁸⁷Sr system to date the heating of five CM chondrites (PCA 02012, PCA 02010, PCA 91008, QUE 93005 and MIL 07675). We find that the heating events of all five meteorites occurred at least 3 Ga after the formation of the Solar System. Such timing excludes short-lived radioactive heating as the origin of thermal metamorphism in these meteorites, and relates such heating events to ages of collisional families of C-type asteroids.