GSA Annual Meeting in Phoenix, Arizona, USA - 2019

Paper No. 246-11
Presentation Time: 10:35 AM


BANKS, Maria E.1, BAKER, Mariah M.2, WARNER, Nicholas H.3, NEWMAN, Claire E.4, LORENZ, Ralph5, GOLOMBEK, Matthew P.6 and WILLIAMS, Nathan R.6, (1)NASA Goddard Space Flight Center, Greenbelt, MD 20771, (2)Department of Earth and Planetary Sciences, The Johns Hopkins University, Baltimore, MD 21210, (3)Department of Geological Sciences, SUNY Geneseo, 1 College Circle, Geneseo, NY 14454, (4)Aeolis Research, Pasadena, CA 91107, (5)Applied Physics Lab, Johns Hopkins University, Laurel, MD 20723, (6)Jet Propulsion Laboratory, California Institute of Technology, M/S 183-301, 4800 Oak Grove Dr., Pasadena, CA 91109

The Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) spacecraft landed in western Elysium Planitia. The landing ellipse surface consists primarily of impact-fragmented regolith overlying Hesperian-aged basalt flows, with a near-surface covering of dust and unconsolidated fine sand particles. The surface has been predominantly modified by eolian and mass wasting processes, and impacts that dot the surface with craters varying in age and associated stages of degradation. Here we focus on eolian bedforms associated with relatively fresh craters ≥100 m in diameter, which contain most of the bedforms. Initial observations reveal bright bedforms along the W and NW outside edges of the rims of fresh and moderately fresh craters. These bedforms are typically oriented NW/SE or W/E. Similarly bright bedforms, but often smaller in scale and wavelength, appear roughly centered on the floors of fresh and moderately fresh craters. Significantly darker bedforms and accumulations of sediments are observed in some of the freshest to moderately degraded craters. These dark sediment accumulations/bedforms are predominantly located in the western half of the crater floor and wall; dark bedforms are oriented W/E or SW/NE. The bright albedo of bedforms is typically indicative of stability and mantling by dust deposition; these bedforms are likely currently inactive or have low rates of activity. Some dark sediments/bedforms have small superposing craters or appear indurated and are also less likely to be active. However many of the dark bedforms are morphologically crisp and, where collocated, superpose the bright bedforms. These observations, plus the lack of dust mantling, suggest the dark bedforms have been active more recently than the bright bedforms, and at least some may be currently active. We perform detailed mapping of the orientation and location (with respect to the crater) of these bedforms associated with craters of different ages to assess their formation and timing of activity and the influence of crater degradation and/or shifts in the regional wind regime over time. Observations are compared with our understanding of the current wind regime at the lander using InSight APSS-TWINS meteorological data, along with atmospheric models to extend the dataset over a broader region.