Article Dans Une Revue Journal of Geophysical Research. Planets Année : 2017

Martian aeolian activity at the Bagnold Dunes, Gale Crater: The view from the surface and orbit

Résumé

Thefirst in situ investigation of an active dunefield on another planetary surface occurred in2015–2016 when the Mars Science LaboratoryCuriosityrover investigated the Bagnold Dunes on Mars.High Resolution Imaging Science Experiment images show clear seasonal variations that are in goodagreement with atmospheric model predictions of intra-annual sandflux and migration directions thattogether indicate that the campaign occurred during a period of low wind activity.Curiositysurface imagesshow that limited changes nevertheless occurred, with movement of large grains, particularly on freshlyexposed surfaces, two occurrences of secondary grainflow on the slip face of Namib Dune, and a slump on afreshly exposed surface of a large ripple. These changes are seen at Martian solar day (sol)-to-sol time scales.Grains on a rippled sand deposit and unconsolidated dump piles show limited movement of large grainsover a few hours during which mean friction speeds are estimated at 0.3–0.4 m s1. Overall, the correlationbetween changes and peak Rover Environmental Monitoring Station (REMS) winds is moderate, with highwind events associated with changes in some cases, but not in others, suggesting that other factors are alsoat work. The distribution of REMS 1 Hz wind speeds shows a significant tail up to the current 20 m s1calibration limit, indicating that even higher speed winds occur. Nonaeolian triggering mechanisms are alsopossible. The low activity period at the dunes documented byCuriosityprovides clues to processes thatdominated in the Martian past under conditions of lower obliquity

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hal-02343906 , version 1 (03-01-2022)

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N. Bridges, R. Sullivan, C. Newman, S. Navarro, J. van Beek, et al.. Martian aeolian activity at the Bagnold Dunes, Gale Crater: The view from the surface and orbit. Journal of Geophysical Research. Planets, 2017, 122 (10), pp.2077-2110. ⟨10.1002/2017JE005263⟩. ⟨hal-02343906⟩
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