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Wind-driven particle mobility on Mars: Insights from Mars Exploration Rover observations at "El Dorado" and surroundings at Gusev Crater

Journal of Geophysical Research E: Planets

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Abstract

The ripple field known as 'El Dorado' was a unique stop on Spirit's traverse where dust-raising, active mafic sand ripples and larger inactive coarse-grained ripples interact, illuminating several long-standing issues of Martian dust mobility, sand mobility, and the origin of transverse aeolian ridges. Strong regional wind events endured by Spirit caused perceptible migration of ripple crests in deposits SSE of El Dorado, erasure of tracks in sandy areas, and changes to dust mantling the site. Localized thermal vortices swept across El Dorado, leaving paths of reduced dust but without perceptibly damaging nearly cohesionless sandy ripple crests. From orbit, winds responsible for frequently raising clay-sized dust into the atmosphere do not seem to significantly affect dunes composed of (more easily entrained) sand-sized particles, a long-standing paradox. This disparity between dust mobilization and sand mobilization on Mars is due largely to two factors: (1) dust occurs on the surface as fragile, low-density, sand-sized aggregates that are easily entrained and disrupted, compared with clay-sized air fall particles; and (2) induration of regolith is pervasive. Light-toned bed forms investigated at Gusev are coarse-grained ripples, an interpretation we propose for many of the smallest linear, light-toned bed forms of uncertain origin seen in high-resolution orbital images across Mars. On Earth, wind can organize bimodal or poorly sorted loose sediment into coarse-grained ripples. Coarse-grained ripples could be relatively common on Mars because development of durable, well-sorted sediments analogous to terrestrial aeolian quartz sand deposits is restricted by the lack of free quartz and limited hydraulic sediment processing. Copyright 2008 by the American Geophysical Union.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Wind-driven particle mobility on Mars: Insights from Mars Exploration Rover observations at "El Dorado" and surroundings at Gusev Crater
Series title:
Journal of Geophysical Research E: Planets
Volume
113
Issue:
6
Year Published:
2008
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Geophysical Research E: Planets