Orbital and In-Situ Investigation of the Bagnold Dunes and Sands of Forvie, Gale Crater, Mars

The Bagnold linear dune field investigated by Curiosity at Mount Desert Island (MDI) is in Gale crater, north of the ~5.5 km high Aeolis Mons mound. False-color images (RGB, 2.4957, 1.8020, and 1.2365 µm, respectively) generated from Mars Reconnaissance Orbiter (MRO) Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) data show the dune field has a reddish-brown color. Sand sheets located south of the Bagnold dunes, such as at the Sands of Forvie (SoF), are darker and lack the reddish-brown color. Single scattering albedo (SSA) spectra retrieved at 12 m/pixel using along‑track oversampled CRISM observation FRT00021C92 show a long wavelength (1.7 to 2.5 µm) rise for the MDI dunes. Over the same wavelength interval, SoF is characterized by a broad ~2.2 µm absorption feature, consistent with color differences between the two deposits. Checkerboard unmixing of the SSA image cube isolated the spectral endmembers within the MDI dunes and SoF. Nonlinear modeling using Hapke (2012) theory implies finer grain sizes for MDI compared to SoF, with inferred abundances for MDI of basaltic glass > feldspar > olivine > pigeonite > augite, and SoF as basaltic glass > feldspar > augite > olivine. These results are similar for the mean spectra of each region and coincide with Curiosity‑based observations that MDI contains smaller ripples compared to large megaripples at SoF. These larger ripples at SoF concentrate coarser grains on their crests as compared to fine grain dominated smaller ripples in MDI.

This dataset contains the spectra of the synthesized glass endmembers used for spectral modeling in this study.