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Intracrater Terminal Dune Fields in Arabia Terra, Mars

Citation

Dorn, Taylor; Day, Mackenzie (2020), Intracrater Terminal Dune Fields in Arabia Terra, Mars, Dryad, Dataset, https://doi.org/10.5068/D1WX0F

Abstract

Craters are the most prevalent basins and potential depo-centers of sediment on Mars. Within these craters and extending from them, terminal dune fields and wind streaks are abundant, indicating active sediment transport and providing a way to study how wind and sediment interact with crater topography. Here, we explore the role of craters as both sources and sinks in the modern martian sedimentary cycle. Our results show that craters with low albedo wind streaks (indicative of sediment transport out of a crater and downwind dust removal) have lower crater wall slopes (9.4° ±5.5°) compared to craters without wind streaks (17° ±5.8°). We interpret that crater wall slopes play a dominant role in whether sediment is transported out of a crater basin, and infer, from measurements of craters on Mars, that a crater transitions from being a net sediment sink to a net sediment source when crater wall slopes decrease to ~15°. This threshold value is consistent with limits of bedform climb observed on Earth and elsewhere on Mars.

Methods

The enclosed table contains data collected for the 116 craters in Arabia Terra, Mars that are referred to in this work. All included craters are >10 km in diameter and were selected based on terminal dune fields observed in their interior. Crater wall slopes were measured downwind of each terminal dune field using elevation data from the Mars Orbiter Laser Altimeter (MOLA) 128 ppd interpolated elevation map. The slope of each crater wall was measured at the closest location downwind of each terminal dune field from a wind-parallel elevation transect originating at the rim of the crater and ending at the dune field. The depth of the crater was estimated by subtracting the elevation of the downwind margin of the dune field from the elevation of the crater rim measured downwind of the dune field. Wind streak type was determined by observing the albedo contrast between the wind streak (if present) and the surrounding landscape. For more information on methods and data analysis, see the main text of this publication.