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- Title
Measuring Ripple and Dune Migration in Coprates Chasma, Valles Marineris: A Source to Sink Aeolian System on Mars?
- Authors
Boazman, S. J.; Davis, J. M.; Grindrod, P. M.; Balme, M. R.; Vermeesch, P.; Baird, T.
- Abstract
Active aeolian systems are present across the martian surface, with active dune fields commonly found in depressions such as craters and valleys. There are many dune fields within the equatorial region of Mars, including Valles Marineris, but the effects of topography on wind regimes and consequently dune migration in Valles Marineris is poorly understood. We investigated both the ripple and dune migration in a dune field in Coprates Chasma using High Resolution Science Experiment Images (HiRISE) and Context Camera (CTX) images. Migration rates of dune brinks and ripples were measured over varying time scales, between Earth years 2007–2014. The dunes here are some of the tallest on Mars, with heights of up to 182 m. The dune brinks are migrating eastwards at a rate of 0.1–0.3 m/EY through the valley due to topographical influences on the local winds. Potential sediment sources for the dune field were identified and investigated by studying thermal inertia and mineralogy. The topographic slope‐related katabatic winds travel down the valley walls and converge with the dominant winds traveling through the center of the valley, causing overall eastwards dune migration. Topography is likely the dominant control on the local wind regime; slope winds travel down the sides of the valley walls and are funneled through the center of the valley. These local winds subsequently facilitate the migration of the large dunes in Coprates Chasma, thus expanding our understanding of local winds in the Martian environment. Plain Language Summary: Sand dunes and dune fields are common on Mars. Wind erosion and the formation of dunes and ripples are one of the dominant active surface processes on Mars. Localized winds allow dune movement to occur and measuring how fast the dunes and ripples are moving is important for understanding the martian environment. We can monitor the movement of dunes and ripples by using high resolution (0.25 m/px) and medium resolution (5–6 m/px) satellite images. Measuring the migration of the dunes and ripples in Valles Marineris (the largest canyon in the solar system) allows inferences to be made about present‐day wind regime. We found the valley topography and steep slopes may accelerate the winds traveling eastwards through the valley, which converge with winds traveling down the valley slopes. It is likely that these combined winds facilitate the erosion of several source regions, supplying sand to the dune field enabling the migration of the large dunes and ripples. These results highlight the effects of topography on local winds and the influence a wind regime has on large dunes. Key Points: Dune brink and ripple migration in Coprates Chasma quantified for both short and long time periods for Earth years 2007–2014Potential sources for the dune field evaluated using thermal inertia and mineralogyCanyon topography may influence the local wind regime and thus the activity of bedforms
- Subjects
SAND dunes; MARTIAN craters; MARTIAN valleys; VALLES Marineris (Mars); MARTIAN atmosphere
- Publication
Journal of Geophysical Research. Planets, 2021, Vol 126, Issue 3, p1
- ISSN
2169-9097
- Publication type
Article
- DOI
10.1029/2020JE006608