Wind in Jezero Crater, Mars

Abstract

Wind generates erosional and depositional morphologies across Mars, including in Jezero crater, the planned landing site for the Mars 2020 rover. Known for subaqueously formed sedimentary features, Jezero crater also hosts wind‐formed features that provide insights about the local wind regime. We combine interpretations from dunes, wind streaks, transverse aeolian ridges, and yardangs to holistically understand the recent history of wind in Jezero crater. Together, these features describe modern easterly winds trending toward 263° ± 8° and older southwesterly winds that formed small yardangs. Previous research has suggested that aeolian processes eroded the delta deposit in Jezero crater. We propose early southwesterly winds removed the majority of material, exposing the more lithified units seen today. Modern easterly winds continue to cause erosion, but lithologic heterogeneities remain the dominant control on delta deposit evolution. Aeolian erosion has accentuated existing sedimentary structures, leaving the striking delta remnant seen today.

Geologic map of Jezero crater and the Nili Planum region, Mars

“…Eolian erosion formed the ridged surface in the northeastern portion of unit Nue (fig. 3A) and the ridges are interpreted as yardangs (Day and Dorn, 2019). Erosion of local or regional units continued to contribute to the deposition of the dark-colored mantle overlying units Njf and Nnp 1 and collecting in topographically lower regions.…”

“…In contrast to other linear features in the map area, such as the "ridge crest" feature in unit Nnp 1 , the ridges in the ridged surface of unit Nue tend to be shorter-on the scale of a few hundred meters in length at mostand are more closely spaced (tens of meters to a hundred meters). These ridges are interpreted as yardangs (Day and Dorn, 2019). Although texturally distinct from the other parts of unit Nue, we could not confidently place the stratigraphic transition between the ridged surface and the rest of unit Nue, thus we mapped this surface texture as part of unit Nue and used the "ridged surface" to indicate the extent of this texture.…”

“…Throughout the Amazonian, erosion and eolian transport processes contributed to the formation of the eolian unit Aeb, which overlies many of the aforementioned geologic units and is interpreted as the youngest unit deposited in the map area. Unit Aeb is interpreted to be composed of transverse eolian ridges (Day and Dorn, 2019), whose bedforms are oriented orthogonal to prevailing wind directions (Balme and others, 2008). The bedforms in the map area are primarily oriented north-south, implying dominantly east-west wind directions (Day and Dorn, 2019).…”

“…Unit Aeb is interpreted to be composed of transverse eolian ridges (Day and Dorn, 2019), whose bedforms are oriented orthogonal to prevailing wind directions (Balme and others, 2008). The bedforms in the map area are primarily oriented north-south, implying dominantly east-west wind directions (Day and Dorn, 2019). Unit su was emplaced on top of the other map units, typically occurring along slopes or collecting in local topographic lows and is marked by a smooth surface texture at map scale.…”

Boulder Fall Activity in the Jezero Crater, Mars

“…The approximate position of the landing ellipse of the rover Manuscript submitted to Geophysical Research Letters and the potential traversable routes of the rover to regions of interest within the landing site surrounds the partially eroded delta deposits (also known as western delta deposit) at the mouth of the western inlet channel (Figure 1b; Fassett and Head, 2005;Goudge et al, 2015Goudge et al, , 2017Farley, 2018;Mangold et al, 2020;Williams et al, 2020). Presence of aeolian landforms such as yardangs and transverse aeolian ridges (TARs) has been reported over the volcanic deposits on the front of the delta deposits (Chojnacki et al, 2018;Day and Dorn, 2019), and aeolian erosion has been suggested to have extensively eroded the delta deposits (Fassett and Head, 2005;Schon et al, 2012). In addition, the front of ~50-60 m high western delta deposit hosts numerous boulders on its top surface, over its talus slope and at the base of the talus slope.…”