¹Josefine A.M.Nanne,²Francis Nimmo,³Jeffrey N.Cuzzi,¹Thorsten Kleine
Earth and Planetary Science Letters 511, 44-54 Link to Article [https://doi.org/10.1016/j.epsl.2019.01.027]
¹Institut für Planetologie, University of Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
²Department of Earth and Planetary Sciences, University of California Santa Cruz, Santa Cruz, CA 95064, USA
³Space Science Division, Ames Research Center, Moffett Field, CA 94035, USA
Copyright Elsevier

The isotopic composition of meteorites reveals a fundamental dichotomy between non-carbonaceous (NC) and carbonaceous (CC) meteorites. However, the origin of this dichotomy—whether it results from processes within the solar protoplanetary disk or is an inherited heterogeneity from the solar system’s parental molecular cloud—is not known. To evaluate the origin of the NC–CC dichotomy, we report Ni isotopic data for a comprehensive set of iron meteorites, with a special focus on groups that have not been analyzed before and belong to the CC group. The new Ni isotopic data demonstrate that the NC–CC dichotomy extends to Ni isotopes, and that CC meteorites are characterized by a ubiquitous ⁵⁸Ni excess over NC meteorites. These data combined with prior observations reveal that, in general, the CC reservoir is characterized by an excess in nuclides produced in neutron-rich stellar environments, such as ⁵⁰Ti, ⁵⁴Cr, ⁵⁸Ni, and r-process Mo isotopes. Because the NC–CC dichotomy exists for refractory (Ti, Mo) and non-refractory (Ni, Cr) elements, and is only evident for nuclides produced in specific, neutron-rich stellar environments, it neither reflects thermal processing of presolar carriers in the disk, nor the heterogeneous distribution of isotopically anomalous Ca–Al-rich inclusions (CAI). Instead, the NC–CC dichotomy reflects the distinct isotopic composition of later infalling material from the solar system’s parental molecular cloud, which affected the inner and outer regions of the disk differently. Simple models of the infall process by themselves can support either infall of increasingly NC-like material onto an initially CC-like disk, or infall of increasingly CC-like material in the absence of disk evolution by spreading. However, provided that CAIs formed close to the Sun, followed by rapid outward transport, their isotopic composition likely reflects that of the earliest infalling material, implying that the composition of the inner disk (i.e., the NC reservoir) is dominated by later infalling material, whereas the outer disk (i.e., the CC reservoir) preserved a compositional signature of the earliest disk. The isotopic difference between the inner and outer disk was likely maintained through the rapid formation of Jupiter, which prevented complete homogenization between material from inside (NC reservoir) and outside (CC reservoir) its orbit.

^1,5Noriyuki Kawasaki,²Changkun Park,³Naoya Sakamoto,²Sun Young Park,⁴Hyun Na Kim,⁵Minami Kuroda,^5,3,1Hisayoshi Yurimoto
Earth and Planetary Science Letters 511, 25-35 Link to Article [https://doi.org/10.1016/j.epsl.2019.01.026]
¹Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara 252-5210, Japan
²Division of Earth-System Sciences, Korea Polar Research Institute, Incheon 21990, Republic of Korea
³Isotope Imaging Laboratory, Creative Research Institution, Hokkaido University, Sapporo 001-0021, Japan
⁴Department of Geoenvironmental Sciences, Kongju National University, Chungcheongnam-do 32588, Republic of Korea
⁵Natural History Sciences, Hokkaido University, Sapporo 060-0810, Japan
Copyright Elsevier

Al–Mg mineral isochrons of three Ca–Al-rich inclusions (CAIs) that formed primarily by condensation, one fine-grained, spinel-rich inclusion and two fluffy Type A CAIs, from the reduced CV chondrites Efremovka and Vigarano were obtained by in situ Al–Mg isotope measurements using secondary ion mass spectrometry. The slope of the isochron obtained for the fine-grained, spinel-rich inclusion gives an initial ²⁶Al/²⁷Al value, (²⁶Al/²⁷Al)₀, of (5.19 ± 0.17) × 10⁻⁵. This is essentially identical to the Solar System initial ²⁶Al/²⁷Al determined by whole-rock Al–Mg isochron studies for CAIs in CV chondrites. In contrast, the isochron slopes for the two fluffy Type A CAIs from their Al–Mg mineral isochrons, (4.703 ± 0.082) × 10⁻⁵ and (4.393 ± 0.084) × 10⁻⁵, are significantly lower than the Solar System initial value. The range of (²⁶Al/²⁷Al)₀ values of the three CAIs, from (5.19 ± 0.17) to (4.393 ± 0.084) × 10⁻⁵, corresponds to a formation age spread of 0.17 ± 0.04 Myr. This formation age spread is similar to that of igneous CAIs from CV chondrites. The data suggest that condensation and melting of minerals occurred in the hot nebular gas contemporaneously for ∼0.2 Myr at the very beginning of our Solar System, if ²⁶Al was distributed homogeneously in the CAI forming region. Alternatively, the observed variations in (²⁶Al/²⁷Al)₀ among fluffy Type A CAIs would also raise a possibility of heterogeneous distributions of ²⁶Al in the forming region.

¹S.S.Hopkins,^2,3J.Prytulak,¹J.Barling,⁴S.S.Russell,²B.J.Coles,⁵A.N.Hallidaya
Earth and Planetary Science Letters 511, 12-24 Link to Article [https://doi.org/10.1016/j.epsl.2019.01.008]
¹Department of Earth Sciences, University of Oxford, OX1 3AN, United Kingdom
²Department of Earth Sciences and Engineering, Imperial College, London, SW7 2AZ, United Kingdom
³Department of Earth Sciences, Durham University, DH1 3LE, United Kingdom
⁴Natural History Museum, London, SW7 5BD, United Kingdom
⁵The Earth Institute, Columbia University, Hogan Hall, 2910 Broadway, New York, NY 10025, USA
Copyright Elsevier

We present the first high-precision vanadium (V) isotope data for lunar basalts. Terrestrial magmatic rock measurements can display significant V isotopic fractionation (particularly during (Fe, Ti)oxide crystallisation), but the Earth displays heavy V (i.e. higher ⁵¹V/⁵⁰V) isotopic compositions compared to meteorites. This has been attributed to early irradiation of meteorite components or nucleosynthetic heterogeneity. The Moon is isotopically-indistinguishable from the silicate Earth for many refractory elements and is expected to be similar in its V isotopic composition.

Vanadium isotope ratios and trace element concentrations were measured for 19 lunar basalt samples. Isotopic compositions are more variable (∼2.5‰) than has been found thus far for terrestrial igneous rocks and extend to lighter values. Magmatic processes do not appear to control the V isotopic composition, despite the large range in oxide proportions in the suite. Instead, the V isotopic compositions of the lunar samples are lighter with increasing exposure age (te). Modelling nuclear cross-sections for V production and burnout demonstrates that cosmogenic production may affect V isotope ratios via a number of channels but strong correlations between V isotope ratios and te^⁎ [Fe]/[V] implicate Fe as the primary target element of importance. Similar correlations are found in the latest data for chondrites, providing evidence that most V isotope variation in chondrites is due to recent cosmogenic production via Fe spallation. Contrary to previous suggestions, there is no evidence for resolvable differences between the primary V isotopic compositions of the Earth, Moon, chondrites and Mars.

¹Y.Zhao,^1,2J.de Vries,^1,2A.P.van den Berg,³M.H.G.Jacobs,¹W.van Westrenen
Earth and Planetary Science 511, 1-11 Link to Article [https://doi.org/10.1016/j.epsl.2019.01.022]
¹Faculty of Science, Vrije Universiteit Amsterdam, the Netherlands
²Dept. Earth Sciences, Utrecht University, the Netherlands
³Institute of Metallurgy, Clausthal University of Technology, Germany
Copyright Elsevier
The ilmenite-bearing cumulates (IBC) formed from the solidification of the lunar magma ocean are thought to have significantly affected the long-term evolution of the lunar interior and surface. Their high density is considered to trigger Rayleigh–Taylor instabilities which allow them to sink into the solidified cumulates below and drive a large-scale overturn in the lunar mantle. Knowledge of how the IBC participate in the overturn is important for studying the early lunar dynamo, chemistry of surface volcanism, and the existence of present-day partial melt at the lunar core–mantle boundary. Despite early efforts to study this process as Rayleigh–Taylor instabilities, no dynamical models have quantified the degree of IBC sinking systematically. We have performed quantitative 2-D geodynamical simulations to measure the extent to which IBC participate in the overturn after their solidification, and tested the effect of a range of physical and chemical parameters. Our results show that IBC overturn most likely happened when the magma ocean had not yet fully solidified, with the residual melt decoupling the crust and IBC, resulting in 50–70% IBC sinking. Participation of the last dregs of remaining magma ocean melt is unlikely, leaving its high concentrations of radiogenic elements close to the surface. Our simulations further indicate that foundered IBC can stay relatively stable at the core–mantle boundary until the present day, at temperatures consistent with the presence of a partially molten zone in the deep mantle as inferred from geophysical data. 30–50% of the primary IBC remain at shallow depths throughout lunar history, enabling their assimilation by rising magma to form high-Ti basalts.

¹Loroch, D.,¹Klemme, S.,¹Berndt, J.,¹Rohrbach, A.
Data in Brief 21, 2447-2463 Link to Article [DOI: 10.1016/j.dib.2018.10.100]
¹Institute for Mineralogy, University of Münster, Corrensstrasse 24, Münster, 48149, Germany

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^1,2Dieter Stöffler, ¹Christopher Hamann,³Knut Metzler
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13246]
¹Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, , 10115 Berlin, Germany
²Humboldt‐Universität zu Berlin, , 10099 Berlin, Germany
³Institute of Planetology, University of Münster, , 48149 Münster, Germany
Published by arrangement with John Wiley & Sons

With this addendum we provide some correction and additional information regarding the above cited publication. It addresses the following two topics. (1) Clarification for a correct application of the criteria for certain shock stages of chondrites, in particular stage C‐S6. (2) Correction of a printing error in the table that contains the shock classification system of chondrites.

¹Yoko Kebukawa,²Hanae Kobayashi,²Norio Urayama,²Naoki Baden,³Masashi Kondo,⁴Michael E. Zolensky,²Kensei Kobayashi
Proceedings of the National Academy of Sciences of the United States of America 116, 753-758 Link to Article [https://doi.org/10.1073/pnas.1816265116]
¹Faculty of Engineering, Yokohama National University, 240-8501 Yokohama, Japan;
²Nihon Thermal Consulting Co., Ltd., 160-0023 Tokyo, Japan
³Instrumental Analysis Center, Yokohama National University, 240-8501 Yokohama, Japan
⁴Astromaterials Research and Exploration Science, National Aeronautics and Space Administration Johnson Space Center, Houston, TX 77058

Organic matter in carbonaceous chondrites is distributed in fine-grained matrix. To understand pre- and postaccretion history of organic matter and its association with surrounding minerals, microscopic techniques are mandatory. Infrared (IR) spectroscopy is a useful technique, but the spatial resolution of IR is limited to a few micrometers, due to the diffraction limit. In this study, we applied the high spatial resolution IR imaging method to CM2 carbonaceous chondrites Murchison and Bells, which is based on an atomic force microscopy (AFM) with its tip detecting thermal expansion of a sample resulting from absorption of infrared radiation. We confirmed that this technique permits ∼30 nm spatial resolution organic analysis for the meteorite samples. The IR imaging results are consistent with the previously reported association of organic matter and phyllosilicates, but our results are at much higher spatial resolution. This observation of heterogeneous distributions of the functional groups of organic matter revealed its association with minerals at ∼30 nm spatial resolution in meteorite samples by IR spectroscopy.

¹Jordan A. Hachtel,^1,2Jingsong Huang,³Ilja Popovs,³Santa Jansone-Popova,^1,4Jong K. Keum,^1,2Jacek Jakowski,⁵Tracy C. Lovejoy,⁵Niklas Dellby,⁵Ondrej L. Krivanek,¹Juan Carlos Idrobo
Science 363, 525-528 Link to Article [DOI: 10.1126/science.aav5845]
¹Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
²Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
³Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
⁴Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
¹Nion R&D, Kirkland, WA 98034, USA.
Reprinted with permission from AAAS

The identification of isotopic labels by conventional macroscopic techniques lacks spatial resolution and requires relatively large quantities of material for measurements. We recorded the vibrational spectra of an α amino acid, l-alanine, with damage-free “aloof” electron energy-loss spectroscopy in a scanning transmission electron microscope to directly resolve carbon-site–specific isotopic labels in real space with nanoscale spatial resolution. An isotopic red shift of 4.8 ± 0.4 milli–electron volts in C–O asymmetric stretching modes was observed for ¹³C-labeled l-alanine at the carboxylate carbon site, which was confirmed by macroscopic infrared spectroscopy and theoretical calculations. The accurate measurement of this shift opens the door to nondestructive, site-specific, spatially resolved identification of isotopically labeled molecules with the electron microscope.

^1,2Qi, Y., ^1,2Zhang, Z.
Scientia Geologica Sinica 53, 714-725 Link to Article [DOI: 10.12017/dzkx.2018.039]
¹Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China
²University of Chinese Academy of Sciences, Beijing, 100049, China

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¹Łuszczek, K.
Mining Science 25, 71-83 Link to Article [DOI: 10.5277/msc182506]
¹Wrocław University of Science and Technology, Faculty of Geoengineering, Mining and Geology, Department of Geology and Mineral Waters, Poland

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