Conference proceeding
From Aeolis Palus to the Bagnold dunes field; overview of martian soil analyses performed by ChemCam in Gale Crater
American Geophysical Union Fall Meeting, Vol.2017
American Geophysical Union 2017 fall meeting
12/2017
Abstract
In situ analysis of the chemical and mineralogical composition of the martian soil, and the determination of its volatile inventory, can provide important constraints on the bulk composition of the martian crust, on its igneous diversity, but also on the physical and chemical weathering processes that have altered its primary igneous constituents. Transport processes that have occurred over long geological time scales, however, make this analysis quite complex, as constituents from different unknown sources are mixed together, and may have been sorted according to grain size or density. A meteoritic contribution is also present. Disentangling the influence of each of these processes requires the use of different analytical techniques, at different spatial scales, and at different locations over the planet. We will present an overview of the soil analyses obtained over the past 5 years by the ChemCam instrument on board MSL/Curiosity. Their specificity lies in their small spatial scale ( approximately 300 mu m), close to the average grains' size. At this scale, chemical trends are observed, resulting from the mixing of different end-members with different grain sizes: coarse felsic grains of likely local origin, fine grains with a basaltic composition close to soil compositions observed at other landing sites, but distinct from local rocks, and a fine-grained, Si-poor, volatile-rich component probably associated with the XRD-amorphous component detected by the CheMin instrument. The thin ablation depth associated with each laser shot ( approximately 1 mu m) enables us to analyse the surface of the grains, which is characterized by a strong, but variable hydrogen signal. These analyses provide constraints on the composition of a possible alteration rind or coating present at their surface. An extensive, multi-instrument investigation of active dunes (barchan and linear dunes) has also been carried out, revealing slight chemical differences with surrounding soils, and a more homogeneous composition, although chemical variations as a function of grain size are observed, with coarser grains enriched in mafic minerals. These results illustrate the still ongoing influence of aeolian transport on the physical sorting of loose, unconsolidated sediments. These results also provide ground truth for orbital IR observations of aeolian bedforms.
Details
- Title: Subtitle
- From Aeolis Palus to the Bagnold dunes field; overview of martian soil analyses performed by ChemCam in Gale Crater
- Creators
- A. Cousin - Institut de Recherche en Astrophysique et Planetologie Toulouse FRA FranceP. Y. MeslinErwin DehouckGael DavidWilliam RapinSusanne SchroederOlivier ForniOlivier GasnaultA. J. WilliamsJeremie LasueN. SteinB. L. EhlmannValerie PayreR. B. AndersonDiana L. BlaneyNathan T. BridgesB. C. ClarkJ. FrydenvangP. J. GasdaJeffrey R. JohnsonNina L. LanzaJonas L'HaridonNicolas MangoldSylvestre MauriceH. E. NewsomAnn M. OllilaPatrick C. PinetV. SautterN. H. ThomasR. C. Wiens
- Resource Type
- Conference proceeding
- Publication Details
- American Geophysical Union Fall Meeting, Vol.2017
- Conference
- American Geophysical Union 2017 fall meeting
- Publisher
- American Geophysical Union
- Alternative title
- AGU 2017 fall meeting
- Language
- English
- Date published
- 12/2017
- Academic Unit
- Earth and Environmental Sciences
- Record Identifier
- 9984318246302771
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