Geology of central Libya Montes, Mars: Aqueous alteration history from mineralogical and morphological mapping

1D. Tirsch, 2,3J.L. Bishop, 1J. Yoigt, 4L.L. Tornabene, 5G. Erkeling, 1,6R. Jaumann
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2018.05.006]
1Institute of Planetary Research, German Aerospace Center (DLR), Rutherfordstrasse 2, 12489 Berlin, Germany
2Carl Sagan Center, The SETI Institute, Mountain View, CA 94043, USA
3Exobiology Branch, NASA-Ames Research Center, Moffett Field, CA 94035, USA
4University of Western Ontario, London, ON, Canada
5German National Library of Science and Technology (TIB), Leibniz Information Centre for Science and Technology, Hannover, Germany
6Institute of Geological Sciences, Freie Universitaet Berlin, 12249 Berlin, Germany
Copyright Elsevier

We analyze the emplacement chronology and aqueous alteration history of distinctive mineral assemblages and related geomorphic units near Hashir and Bradbury impact craters located within the Libya Montes, which are part of the southern rim of the Isidis Basin on Mars. We derive our results from a spectro-morphological mapping project that combines spectral detections from CRISM near-infrared imagery with geomorphology and topography from HRSC, CTX, and HiRISE imagery. Through this combination of data sets, we were able to use the morphology associated with specific mineral detections to extrapolate the possible extent of the units hosting these compositions. We characterize multiple units consistent with formation through volcanic, impact, hydrothermal, lacustrine and evaporative processes. Altered pyroxene-bearing basement rocks are unconformably overlain by an olivine-rich unit, which is in turn covered by a pyroxene-bearing capping unit. Aqueously altered outcrops identified here include nontronite, saponite, beidellite, opal, and dolomite. The diversity of mineral assemblages suggests that the nature of aqueous alteration at Libya Montes varied in space and time. This mineralogy together with geologic features shows a transition from Noachian aged impact-induced hydrothermal alteration and the alteration of Noachian bedrock by neutral to slightly basic waters via Hesperian aged volcanic emplacements and evaporative processes in lacustrine environments followed by Amazonian resurfacing in the form of aeolian erosion.

An improved extraction chromatographic purification of tungsten from a silicate matrix for high precision isotopic measurements using MC-ICPMS

1,2,3Qing-Feng Mei, 1,2,3Jin-Hui Yang, 1,2Yue-Heng Yang
Journal of Analytical Atomic Spectroscopy 33, 569-577 Link to Article [DOI:
10.1039/C8JA00024G]
1State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
2Institutions of Earth Science, Chinese Academy of Sciences, Beijing 100029, China
3 University of Chinese Academy of Sciences, Beijing 100049, China

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Multi-element ion-exchange chromatography and high-precision MC-ICP-MS isotope analysis of Mg and Ti from sub-mm-sized meteorite inclusions

1K. K. Larsen, 1D. Wielandt, 1M. Bizzarro
Journal of Analytical Atomic Spectroscopy 33, 613-628 Link to Article [DOI:
10.1039/C7JA00392G]
1Centre for Star and Planet Formation, Natural History Museum of Denmark, University of Copenhagen, Denmark

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Er, Yb, and Hf isotopic compositions of refractory inclusions: An integrated isotopic fingerprint of the Solar System’s earliest reservoir

1Quinn R. Shollenberger, 1Jan Render, 1Gregory A. Brennecka
Earth and Planetary Science Letters 495, 12-23 Link to Article [https://doi.org/10.1016/j.epsl.2018.05.007]
1Institut für Planetologie, University of Münster, Wilhelm-Klemm-Straße 10, Münster, 48149 Germany
Copyright Elsevier

The oldest dated solids in our Solar System, calcium–aluminum-rich inclusions (CAIs), contain isotopic anomalies in a whole suite of elements relative to later formed Solar System materials. Previous work has reported differences in the proportions of nucleosynthetic components between CAIs and terrestrial rocks as a function of mass. However, the nucleosynthetic fingerprint of the CAI-forming region is still lacking significant data in the heavier mass range (A > 154). Therefore, we present the first erbium (Er) and ytterbium (Yb) isotopic data along with hafnium (Hf) isotopic compositions in a wide variety of CAIs derived from a variety of CV and CK chondrites. This work presents new methods for Er and Yb isotopic investigation that were explored using both thermal ionization mass spectrometry (TIMS) and multicollector inductively coupled plasma mass spectrometry (MC-ICPMS). Relative to terrestrial rock standards, CAIs—regardless of host rock, petrologic or chemical classification—have uniform and resolvable Er, Yb, and Hf isotopic compositions. The CAI isotopic patterns correspond to r-process deficits (or s-process excesses) relative to terrestrial values of 9 ppm for Er, 18 ppm for Yb, and 17 ppm for Hf. This new Er, Yb, and Hf data help complete the nucleosynthetic fingerprint of the CAI-forming region, further highlighting the systematic difference between the CAIs and later formed bulk planetary bodies. Such a systematic difference between CAIs and terrestrial rocks cannot be caused by different amounts of any known single presolar phase but is likely the result of a well-mixed reservoir made of diverse stellar sources.

Petrography and mineralogy of calcium-, aluminum-rich inclusions in an unequilibrated carbonaceous chondrite Y 81020 (CO3.05)

1,2Ritesh Kumar Mishra
Current Science 114, 1510-1519 Link to Article [doi: 10.18520/cs/v114/i07/1510-1519]
1Center for Isotope Cosmochemistry and Geochronology, Astromaterials Research and Exploration Science Division, EISD-XI,
NASA-Johnson Space Center, 2101, NASA Parkway, Houston, TX 77058, USA
2Oak Ridge National Laboratory Associated Universities, Tennessee 37830, Kentucky, USA

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Bacubirito: the longest meteorite in the world

1E Terán Bobadilla, 2J H Abundis Patiño, 3C Añorve Solano, 3C R Moraila Valenzuela,4F Ortega Gutierrez
Astronomy & Geophysics 59, 2.30-2.31 Link to Article [https://doi.org/10.1093/astrogeo/aty084]
1Facultad de Ciencias Físico Matemáticas, Universidad Autónoma de Sinaloa, Mexico.
2Electrical and Computing Engineering, Technical University of Munich, Germany.
3Facultad de Ciencias de la Tierra y del Espacio, Universidad Autónoma de Sinaloa, Mexico.
4Instituto de Geología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Delegación Coyoacán, Mexico.

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Oxidized conditions in iron meteorite parent bodies

1,2P. Bonnand, 1,3A. N. Halliday
Nature Geoscience (in Press) Link to Article [doi:10.1038/s41561-018-0128-2]
1Department of Earth Sciences, University of Oxford, Oxford, UK
2Laboratoire Magmas et Volcans, Université Clermont Auvergne, CNRS, Clermont-Ferrand, France
3The Earth Institute, Columbia University, New York, NY, USA

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