Evidence for Fluctuating Wind in Shaping an Ancient Martian Dune Field: The Stimson Formation at the Greenheugh Pediment, Gale Crater

Steven G. Banham (1) , Sanjeev Gupta (1) , David M. Rubin (2) , Candice C. Bedford (3, 4) , Lauren A. Edgar (5) , Alexander B. Bryk (6) , William E. Dietrich (6) , Christopher M. Fedo (7) , Rebecca M. E. Williams (8) , Gwénaël Caravaca (9) , Robert Barnes (1) , Gerhard Paar (10) , Thomas Ortner (11) , Ashwin R. Vasavada (12)

1 Department of Earth Science and Engineering [Imperial College London]
2 UC Santa Cruz - University of California [Santa Cruz]
3 LPI - Lunar and Planetary Institute [Houston]
4 JSC - NASA Johnson Space Center
5 Astrogeology Science Center [Flagstaff]
6 EPS - Department of Earth and Planetary Science [UC Berkeley]
7 Department of Earth and Planetary Sciences [Knoxville]
8 PSI - Planetary Science Institute [Tucson]
9 IRAP - Institut de recherche en astrophysique et planétologie
10 Joanneum Research Forschungsgesellschaft mbH
11 VRVis Research Center for Virtual Reality and Visualization
12 JPL - Jet Propulsion Laboratory

Temporal fluctuations of wind strength and direction can influence aeolian bedform morphology and orientation, which can be encoded into the architecture of aeolian deposits. These strata represent a direct record of atmospheric processes and can be used to understand ancient Martian atmospheric processes as well as those on Earth. The strata can: give insight to ancient atmospheric circulation, how the atmosphere evolved in response to global changes in habitability, and how ancient processes differ from modern processes. The Stimson formation at the Greenheugh pediment (Gale crater) records evidence of fluctuating wind across multiple temporal scales. The strata can be subdivided into three intervals-Gleann Beag, Ladder, and Edinburgh intervals. Internally, the intervals record changes of dune morphology and orientation, correlatable to wind fluctuations at multiple temporal scales. The basal Gleann Beag interval comprises compound cross-strata, deposited by oblique compound dunes. These dunes record a bimodal wind regime, resulting in net sediment transport toward the north. The Ladder interval records a reversal of sediment transport to the south, where straight-crested simple-dunes shaped by a seasonally variable winds formed. Finally, the Edinburgh interval records sediment transport to the west, where a unimodal wind formed sinuous-crested simple dunes. These observations demonstrate active and variable atmospheric circulation in Gale crater during the accumulation of the Stimson dune field, at multiple temporal scales from seasonally driven winds to much longer time-frames, during the Hesperian. These observations can be used to further understand ancient atmospheric conditions and processes, at a high temporal resolution on Mars.

Mots clés: Mars; aeolian; Gale crater; Mars science laboratory; stratigraph; climate

Domaines: Planète et Univers [physics]

Steven G. Banham, Sanjeev Gupta, David M. Rubin, Candice C. Bedford, Lauren A. Edgar, et al.. Evidence for Fluctuating Wind in Shaping an Ancient Martian Dune Field: The Stimson Formation at the Greenheugh Pediment, Gale Crater. Journal of Geophysical Research. Planets, 2022, The Curiosity Rover's Investigation of Glen Torridon and the Surrounding Area, 127 (9), pp.e2021JE007023. ⟨10.1029/2021JE007023⟩. ⟨insu-03867448⟩