Deposition and erosion of a Light-Toned Yardang-forming unit of Mt Sharp, Gale crater, Mars

Gale crater is a large impact with ca 5 km thick sequence of stratified rocks in it, expressed today as central eroded mound (i.e., Aeolis Mons informally named Mt. Sharp). A goal the current Mars Science Laboratory mission to investigate processes that deposited, lithified, and this fill. The Light-Toned Yardang Unit (LTYu) unit, subject present research, one geological units Mt Sharp. Our specific purpose here refine interpret imaging documentation morphologic stratal components LTYu, at outcrop scale. In combination established orbital images, we use Remote Micro-Imager (RMI) ChemCam, remote sensing instrument currently operated onboard Curiosity rover, which provides several types context imaging. RMI capabilities now include “Long Distance” acquisitions targets kilometers away. these new acquisitions, substantial differences are visible LTYu yardang attitudes from lowest uppermost elevations allowing tentative subdivision into subunits. Bedding geometries lower consistent eolian dune foresets collectively prograde towards an average N134° direction. Based on architectures, viewed amalgamated stack least two, possibly four, ancient erg systems bounded by deflationary “supersurfaces”. Observations point multistory generation yardangs interpreted have been successively buried during stratigraphic building We conclude successive sequences deposition-erosion recorded generated cyclic changes semi-arid arid conditions, coupled climatic cycles, including wind regime change. regional unconformity tops Lower formation Sharp, subsequent emplacement express clear tendency toward sustained environments for region around Early – Late Hesperian transition. Given time scale involved few tens million years minimum), consider it likely local evidence increased aridity Sharp stratigraphy manifestation climate change affecting whole planet.