Laboratory spectroscopy of meteorite samples at UV-vis-NIR wavelengths: Analysis and discrimination by principal components analysis

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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Non-destructive controlled single-particle light scattering measurement

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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Chronology of formation of early solar system solids from bulk Mg isotope analyses of CV3 chondrules

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.

Spectral modeling of meteorites at UV-vis-NIR wavelengths

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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Laser alteration on iron sulfides under various environmental conditions

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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Ab initio simulations and experimental Raman spectra of Mg2SiO4 forsterite to simulate Mars surface environmental conditions

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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Geochemical study of the Northwest Africa 6148 Martian meteorite and its terrestrial weathering processe

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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