¹Thomas Kenkmann et al. (>10)
Meteoritics & Planetary Science (in Press) Link to Article [DOI: 10.1111/maps.13048]
¹Albert-Ludwigs-Universität Freiburg, Institut für Geo-und Umweltnaturwissenschaften, Freiburg, Germany
Published by arrangement with John Wiley & Sons

This paper reviews major findings of the Multidisciplinary Experimental and Modeling Impact Crater Research Network (MEMIN). MEMIN is a consortium, funded from 2009 till 2017 by the German Research Foundation, and is aimed at investigating impact cratering processes by experimental and modeling approaches. The vision of this network has been to comprehensively quantify impact processes by conducting a strictly controlled experimental campaign at the laboratory scale, together with a multidisciplinary analytical approach. Central to MEMIN has been the use of powerful two-stage light-gas accelerators capable of producing impact craters in the decimeter size range in solid rocks that allowed detailed spatial analyses of petrophysical, structural, and geochemical changes in target rocks and ejecta. In addition, explosive setups, membrane-driven diamond anvil cells, as well as laser irradiation and split Hopkinson pressure bar technologies have been used to study the response of minerals and rocks to shock and dynamic loading as well as high-temperature conditions. We used Seeberger sandstone, Taunus quartzite, Carrara marble, and Weibern tuff as major target rock types. In concert with the experiments we conducted mesoscale numerical simulations of shock wave propagation in heterogeneous rocks resolving the complex response of grains and pores to compressive, shear, and tensile loading and macroscale modeling of crater formation and fracturing. Major results comprise (1) projectile–target interaction, (2) various aspects of shock metamorphism with special focus on low shock pressures and effects of target porosity and water saturation, (3) crater morphologies and cratering efficiencies in various nonporous and porous lithologies, (4) in situ target damage, (5) ejecta dynamics, and (6) geophysical survey of experimental craters.

¹Daniel M. Applin, ^1,2Matthew R.M. Izawa, ¹Edward A. Cloutis, ³Jeffrey J. Gillis-Davis, ⁴Karly M. Pitman, ⁵Ted L. Roush, ⁶Amanda R. Hendrix, ³Paul G. Lucey
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2018.02.012]
¹Dept. of Geography, University of Winnipeg, 515 Portage Avenue, Winnipeg, Manitoba, Canada R3B 2E9
²Institute for Planetary Materials, Okayama University, 827 Yamada, Misasa, Tottori 682-0193 Japan
³ Hawaii Institute of Geophysics and Planetology, University of Hawaii, 2525 Correa Road, Honolulu, Hawaii 96822
⁴Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, Colorado 80301 USA
⁵NASA Ames Research Center, Moffett Field, California, 94035-0001 USA
⁶Planetary Science Institute, 1700 East Fort Lowell, Suite 106, Tucson, AZ, USA 85719-2395
Copyright Elsevier

A number of planetary spacecraft missions carried instruments with sensors covering the ultraviolet (UV) wavelength range. However, there exists a general lack of relevant UV laboratory data to compare against these planetary surface remote sensing observations in order to make confident material identifications. To address this need, we have systematically analyzed reflectance spectra of carbonaceous materials in the 200-500 nm spectral range, and found spectral-compositional-structural relationships that suggest this wavelength region could distinguish between otherwise difficult-to-identify phases. In particular (and by analogy with the infrared spectral region), large changes over short wavelength intervals in the refractive indices associated with the trigonal sp2 π-π* transition of carbon can lead to Fresnel peaks and Christiansen-like features in reflectance. Previous studies extending to shorter wavelengths also show that anomalous dispersion caused by the σ-σ* transition associated with both the trigonal sp2 and tetrahedral sp3 sites causes these features below λ = 200 nm. The peak wavelength positions and shapes of π-π* and σ-σ* features contain information on sp3/sp2, structure, crystallinity, and powder grain size. A brief comparison with existing observational data indicates that the carbon fraction of the surface of Mercury is likely amorphous and submicroscopic, as is that on the surface of the martian satellites Phobos and Deimos, and possibly comet 67P/Churyumov-Gerasimenko, while further coordinated observations and laboratory experiments should refine these feature assignments and compositional hypotheses. The new laboratory diffuse reflectance data reported here provide an important new resource for interpreting UV measurements from planetary surfaces throughout the solar system, and confirm that the UV can be rich in important spectral information.

¹Antti Penttilä, ¹Julia Martikainen, ¹Maria Gritsevich, ^1,2KarriMuinonen
Journal of Quantitative Spectroscopy and Radiative Transfer 206, 189-197 Link to Article [https://doi.org/10.1016/j.jqsrt.2017.11.011]
¹Department of Physics, University of Helsinki, P.O. Box 64, FI-00014, Finland
²Finnish Geospatial Research Institute FGI, National Land Survey of Finland, Geodeetinrinne 2, FI-02430 Masala, Finland

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¹G.Maconi,¹A.Penttilä,¹I.Kassamakov,^1,2M.Gritsevich,¹P.Helander,¹T.Puranen,¹A.Salmi,¹E.Hæggström,^1,3K.Muinonena
Journal of Quantitative Spectroscopy and Radiative Transfer 204, 159-164 Link to Article [https://doi.org/10.1016/j.jqsrt.2017.09.005]
¹Department of Physics, University of Helsinki, Finland
²Institute of Physics and Technology, Ural Federal University, Ekaterinburg, Russia
³Finnish Geospatial Research Institute FGI, National Land Survey of Finland, Finland

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¹Hsin-Wei Chen, ²Jennifer L. Claydon, ¹Tim Elliott, ¹Christopher D. Coath, ^1,2,3Yi-Jen Lai, ²Sara S. Russell
Geochimica et Cosmochimica Acta (in Press) Link to Article [https://www.sciencedirect.com/science/article/pii/S0016703718300814]
¹Bristol Isotope Group, School of Earth Sciences, University of Bristol, Bristol, BS8 1RJ, UK
²Natural History Museum, Meteoritic and Cosmic Mineralogy, Cromwell Road, SW7 5BD, London, UK
³Institute of Geochemistry and Petrology, ETH Zürich, Zürich, Switzerland
Copyright Elsevier

We have analysed the petrography, major element abundances and bulk Al-Mg isotope systematics of 19 ferromagnesian chondrules from the CV3 chondrites Allende, Mokoia, and Vigarano, together with an Al-rich chondrule and refractory olivine from Mokoia. Co-variations of Al/Mg with Na/Mg and Ti/Mg in our bulk chondrules suggest their compositions are dominantly controlled by reworking of different proportions of chondrule components (e.g. mafic minerals and mesostatis); their precursors are thus fragments from prior generations of chondrules. Our samples show a range in fractionation corrected 26Mg/24Mg (Δ’26Mg) ∼60ppm, relative to precisions <±5ppm (2se) and these values broadly covary with 27Al/24Mg. The data can be used to calculate model initial 26Al/27Al, or (26Al/27Al)0, of the chondrule precursors. Our resolvably radiogenic chondrules yield model (26Al/27Al)0 ∼1-2×10-5, equivalent to model “ages” of precursor formation ≦1Ma post CAI. However, many of our chondrules show near solar Δ’26Mg and no variability despite a range in 27Al/24Mg. This suggests their derivation either from younger precursor chondrules or open system behaviour once 26Al was effectively extinct ((26Al/27Al)0<0.8×10-5, given the resolution here). Evidence for the latter explanation is provided by marked rims of orthopyroxene replacing olivine, indicating reaction of chondrules with a surrounding silicate vapour. Concurrent isotopic exchange of Mg with a near chondritic vapour during late reworking could explain their isotopic systematics. One ferromagnesian object is dominated by a high Mg# olivine with elevated Ti and Ca abundances. This refractory olivine has a markedly negative Δ’26Mg = -16±3 ppm (2se), reflecting its early removal (model age of <0.5Ma post CAI), from a reservoir with evolving Δ’26Mg. If representative of the chondrule forming region, this grain defines a minimum interval of radiogenic ingrowth for CV chondrites commensurate with (26Al/27Al)0>3.4±0.6×10-5. Overall, our samples record a sequence of events from the formation of ferromagnesian objects within 0.5Ma of CAI to re-equilibration of chondrules and silicate vapour >2Ma post CAI, assuming an initially homogeneous 26Al/27Al. Metamorphism on the asteroid parent body may have played a subsequent role in affecting Mg isotope composition, but we argue this had a minor influence on the observations here.

¹Julia Martikainen, ¹Antti Penttilä, ^1,2Maria Gritsevich, ³Hannakaisa Lindqvist, ^1,4Karri Muinonen
Journal of Quantitative Spectroscopy and Radiative Transfer 204, 144-151 Link to Article [https://doi.org/10.1016/j.jqsrt.2017.09.017]
¹Department of Physics, P.O. Box 64 (Gustaf Hällströmin katu 2a), FI-00014 University of Helsinki, Finland
²Institute of Physics and Technology, Ural Federal University, Mira str. 19, 620002 Ekaterinburg, Russia
³Finnish Meteorological Institute, Erik Palménin aukio 1, FI-00101 Helsinki, Finland
⁴Finnish Geospational Research Institute FGI, National Land Survey of Finland, Geodeetinrinne 2, FI-02430 Masala, Finland

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¹I. Weber,²U. Böttger,²S. G. Pavlov,^2,3H.-W. Hübers,¹H. Hiesinger,¹E. K. Jessberger
Journal of Raman Spectroscopy 48, 1509-1517 Link to Article [DOI: 10.1002/jrs.5083]
¹Institut für Planetologie, Münster, Germany
²Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institut für Optische Sensorsysteme, Berlin, Germany
³Institut für Optik und Atomare Physik, Humboldt Universität, Institut für Physik, Berlin, Germany

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¹C. Stangarone,²U. Böttger,¹D. Bersani,¹M. Tribaudino,³M. Prencipe
Journal of Raman Spectroscopy 48, 1528-1535 Link to Article [DOI: 10.1002/jrs.5127]
¹Physics and Earth Science Department, University of Parma, Parma, Italy
²Institute of Optical Sensor Systems, DLR, Berlin, Germany
³Earth Science Department, University of Turin, Torino, Italy

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¹Imanol Torre-Fdez,¹Julene Aramendia,¹Leticia Gomez-Nubla,¹Kepa Castro,¹Juan M. Madariaga
Journal of Raman Spectroscopy 48, 1536-1543 Link to Article [DOI: 10.1002/jrs.5148]
¹Department of Analytical Chemistry, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Bilbao, Spain

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¹Lucie Riu,¹Jean-Pierre Bibring, ¹Cédric Pilorget, ¹François Poulet, ¹Vincent Hamm
Planetary and Space Science (in Press) Link to Article [https://doi.org/10.1016/j.pss.2018.01.009]
¹Institut d’Astrophysique Spatiale, Université Paris-Sud 11, 91405, Orsay, France

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