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3.1.2: Phase 1 - Barchan Dunes

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  • Phase 1 focused on investigations of barchan dunes on the northwest border of Bagnold dunes (Figure \(\PageIndex{1}\)). The team spent about 3 months during the low-wind season during Phase 1 investigating High and Namib dunes.

    Annotated satellite image showing the area of the Phase 1 investigations

    Figure  \(\PageIndex{1}\): Satellite image of the Phase 1 investigation area showing the Curiosity rover path (white line) with the sols (martian days numbered from landing) where key data were collected as part of the dune campaign.  Dune names are shown, with Namib and High dunes the focus of most of the observations. (Dunes were informally named after areas in Namibia, which has a large sand sea.) Image credit: Lapotre et al., 2018.

    Anaglyph satellite image of High dune

    Figure  \(\PageIndex{2}\): Satellite images combined to provide a 3d view of the Phase 1 field area. Use red-blue 3d glasses. North is about 7 degrees to the left of up. Image credit: NASA/JPL/University of Arizona/Phil Stooke/Emily Lakdawalla

    Observations from orbit demonstrated that High dune has migrated to the south over six years of satellite observations (Figure  \(\PageIndex{3}\)). Thus, the team expected to evidence of active sand transport with bedforms that reflect the average modern wind conditions in this part of Gale Crater.

    Animated gif showing the motion of High dune.

    Figure  \(\PageIndex{3}\): An animation of two HiRISE images of High dune. The first image was taken on August 22, 2008, the second on April 16, 2014. Comparisons of the images show that the dune migrated slightly to the south and ripples on the dune also moved southward. The two images were taken at slightly different angles, making parts of the bedrock appear to shift when it was actually static. Image credit: NASA/JPL/University of Arizona/Emily Lakdawalla

    A summary of activities during Phase 1 is provided by Emily Lakdawalla in two blogs (sols 1166-1217 and sols 1218-1249) and in section 2.1 of Lapotre et al. (2018). Early on, the MSL team had Curiosity perform some drive tests on sand and characterize the elemental composition of the sand. Curiosity then imaged the back (stoss or upwind) side of High dune, documenting beautiful, and unusual, bedforms. The team wanted to monitor the slipface of a barchan dune, but it was not reasonable for Curiosity to observe the downwind side High dune due to the bedrock topography and the distribution of sand. Thus, the team had the rover drive to the slipface of Namib dune for several weeks over the US December holidays. After the holidays, Curiosity sampled the sand, characterizing its mineralogical composition. Some excellent images from Phase 1 are compiled here.