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

We currently do not have a copyright agreement with this publisher and cannot display the abstract here

^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.