EGU2020-13377
https://doi.org/10.5194/egusphere-egu2020-13377
EGU General Assembly 2020
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Identification and characterization of new feldspar-bearing rocks in the walls of Valles Marineris, Mars

Jessica Flahaut1, Marie Barthez1, Vincent Payet1, Frank Fueten2, Martin Guitreau3, Pascal Allemand4, and Cathy Quantin-Nataf4
Jessica Flahaut et al.
  • 1CNRS, CRPG Nancy, Vandœuvre les Nancy, France (flahaut@crpg.cnrs-nancy.fr)
  • 2Department of Earth Sciences, Brock University, St. Catharines, Ontario, Canada
  • 3LMV, Université Clermont-Auvergne/CNRS, Aubière, France
  • 4LGL,TPE, Université Lyon 1/CNRS, 69622 Villeurbanne, France

VNIR spectroscopy has previously led to many discoveries pertaining to Mars geologic history (e.g., the discovery of hydrated minerals associated to ancient terrains with OMEGA, Bibring et al., 2006). Plagioclase feldspar minerals can also be identified with spectroscopic techniques thanks to a 1.3 microns absorption in the VNIR domain (e.g., Adams and Goullaud, 1978). Previous lunar analog studies show however that when mixing powders of Ca plagioclase and a mafic component (olivine or pyroxene), the feldspars absorption band is quickly masked (e.g., Cheek and Pieters, 2014). This study further demonstrates that the 1.3 micron feature is only detectable if the plagioclase abundance is > 90 %. Based on this observation, previous feldspar absorptions on Mars have been interpreted as evidence for nearly pure anorthositic rocks (e.g., Carter and Poulet, 2013). A recent study by Rogers and Nekvasil (2015) however suggests that phenocryst basalts with less than 90% plagioclase could reproduce the 1.3 micron feature if large crystals are involved, although no whole rock measurements were made.

In the present study, we describe new feldspar signatures detected with the CRISM VNIR spectral-imager in the walls of the Valles Marineris grand canyon, on Mars. The associated rock textures and elevations were assessed from CTX and HiRISE images and DTMs. In parallel, we are collecting VNIR spectra of various (uncrushed) terrestrial rocks containing a large range of feldspar abundances and grain sizes. Analyses are carried out between 0.35 and 2.5 microns with an ASD Fieldspec at CRPG Nancy, France, and will be presented at the conference time. By combining laboratory measurements of a range of possible terrestrial analog rocks with the study of Mars feldspar-bearing outcrops, we should bring more clues on the nature and origin of these feldspathic rocks.

How to cite: Flahaut, J., Barthez, M., Payet, V., Fueten, F., Guitreau, M., Allemand, P., and Quantin-Nataf, C.: Identification and characterization of new feldspar-bearing rocks in the walls of Valles Marineris, Mars, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-13377, https://doi.org/10.5194/egusphere-egu2020-13377, 2020

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