Conference proceeding
Comparison of the active Bagnold dune field with other aeolian deposits observed at Gale using ChemCam data
American Geophysical Union Fall Meeting, Vol.2017
American Geophysical Union 2017 fall meeting
12/2017
Abstract
The Curiosity rover at Gale crater, Mars, had the opportunity to investigate an active dune field called Bagnold Dunes for the first time on another planet. The objectives of this campaign were threefold: Understand the present-day aeolian processes on Mars by investigating the grain size of the particles and their dynamics; Understand the past aeolian processes by looking at the morphology and texture of the dunes; and Investigate the source of the dunes material by measuring their chemistry and mineralogy. The ChemCam instrument acquired a large data volume during this campaign: 18 targets on barchan dunes, 15 targets on a linear dune and then 3 targets on a mega-ripple. In this study, we compare the Bagnold Dunes data to those acquired on soil patches (Aeolis Palus soils) along the traverse corresponding to 60 targets. We have observed that the major oxide composition of the dunes is similar to that of Aeolis Palus soils, with the exception of the FeO and MnO contents that are slightly more elevated in the dunes. Moreover, the material from the dunes and more particularly the coarser particles ( approximately 200 microns) are depleted in volatiles (mostly H) compared to the Aeolis Palus soils. The grain size analyses show that the dunes are depleted in fine-grained particles (<100 microns) compared to Aeolis Palus soils. The leading hypothesis to explain this depletion in volatiles and fine-grained particles is that the dunes, being active, have undergone physical sorting and therefore have lost their finest particles that seem to be the carrier of the volatiles (amorphous component and dust). Moreover, the dunes seem to be enriched in mafic minerals compared to the Aeolis Palus soils, as also shown by the CheMin and APXS instruments. However, thanks to the small footprint of ChemCam, we have shown that the coarsest particles were even more enriched in mafic minerals than the finer ones, in agreement with multispectral ChemCam passive and Mastcam observations. Therefore, the olivine abundance measured by CheMin (analysing only particles < 150 microns) could represent a lower limit with respect of the bulk of the dunes. Nevertheless, no significant difference has been observed with ChemCam between the barchan and linear dunes, even though the linear dunes seem to contain more pyroxenes according to the orbital observations.
Details
- Title: Subtitle
- Comparison of the active Bagnold dune field with other aeolian deposits observed at Gale using ChemCam data
- Creators
- A. Cousin - Institut de Recherche en Astrophysique et Planetologie Toulouse FRA FranceErwin DehouckP. Y. MeslinA. J. WilliamsN. SteinOlivier GasnaultNathan T. BridgesB. L. EhlmannS. SchroederValerie PayreWilliam RapinPatrick C. PinetV. SautterNina L. LanzaJeremie LasueSylvestre MauriceR. 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
- 9984318243702771
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