Publication Date:
2018-08-01
Description:
We measured sand sizes and shapes on diverse eolian bedforms in Gale crater to help constrain models of eolian sediment transport on Mars. All grains are subangular to rounded with circularities of ~0.93–0.97, indicating an extensive abrasion history. There are two types of active bedforms based on grain size: (1) ripples composed of 50- to 150-μm grains and (2) ripples that also include 250- to 500-μm grains along their crests, in some cases with small amounts of even coarser grains (up to 1.4 mm). The smallest grain sizes (50–150 μm) are volumetrically the most abundant at all active bedforms. Inactive bedforms have surfaces of 350- to 2,000-μm grains with finer-grained interiors, consistent with observations made by rovers at other landing sites. Grains coarser than ~300 μm are less prone to mobilization driven by smaller saltating grains, making bedforms with concentrations of coarser grains more susceptible to surface stabilization and inactivity. ©2018. American Geophysical Union. All Rights Reserved.
Print ISSN:
0094-8276
Electronic ISSN:
1944-8007
Topics:
Geosciences
,
Physics
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