The Distribution, Properties, and Implications of Ancient Bedforms on Mars
NASA Mars Data Analysis Program
Non PSI Personnel: Dr. Lauren Edgar (Co-Investigator, United States Geological Survey, Flagstaff, AZ), Dr. Christopher Edwards (Co-Investigator, Northern Arizona University, Flagstaff, AZ), Dr. Lori Fenton (Co-Investigator, Carl Sagan Center, SETI Institute, Mountain View, CA)
Project Description
Sedimentary rocks on Mars attest to a variety of aqueous and atmospheric processes throughout its history. Depositional features such as bedforms provide vital information regarding past and present environmental conditions. For example, surface investigations at the Meridiani Planum (Opportunity) and Gale crater (Curiosity) landing sites have firmly established that some of the ~4 Ga rock record is composed of sediment that was transported by flowing wind and water, as evidenced by abundant cross-bedding and alteration products. Across the surface other isolated occurrences that meet the morphologic criteria for dunes and ripples are evident in orbital data, yet appear degraded and superposed by craters, boulders, or geologic units. Some of these occurrences are hypothesized to be bedforms constructed in aeolian and fluvial depositional settings, yet they are largely preserved in an intermediate stage as part of the rock record, an uncommon circumstance on Earth. These landforms, hereafter termed paleo-bedforms – distinct groups of linear to crescentic, positive-relief features of a characteristic wavelength that show evidence for lithification – are the subject of this proposed study.
This proposed MDAP study is driven by the primary objective: Characterize the spatial distribution, origin, and geologic context of preserved ancient bedforms on Mars. Prior investigations have identified evidence for ancient bedforms in a continuum of preservation states (from partially lithified paleo-bedforms to cross-bedded sandstones preserved in outcrop) from both in situ and orbital data (e.g., Edgett and Malin, 2000a; Burr et al., 2004; Grotzinger et al., 2005, 2014, 2015; Fenton and Hayward, 2010; Edgar et al., 2012; Milliken et al., 2014). Ancient aeolian processes are responsible for some of these occurrences, but others are attributed to fluvial activity. However, many of these reports are only based on a few observations, are often restricted to old data sets, or are limited to isolated locations, yielding preliminary but incomplete information. Given the wealth of orbital data now available for these sedimentary landforms, this is an opportune time to conduct data analysis in this area of research, which may prove vital for uncovering clues to ancient surface processes on Mars.
