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arXiv · 1703.10997

Evolution of major sedimentary mounds on Mars

Edwin S. Kite·Jonathan Sneed·David P. Mayer·Kevin W. Lewis·Timothy I. Michaels·Alicia Hore·Scot C. R. Rafkin
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Abstract

We present a new database of $>$300 layer-orientations from sedimentary mounds on Mars. These layer orientations, together with draped landslides, and draping of rocks over differentially-eroded paleo-domes, indicate that for the stratigraphically-uppermost $\sim$1 km, the mounds formed by the accretion of draping strata in a mound-shape. The layer-orientation data further suggest that layers lower down in the stratigraphy also formed by the accretion of draping strata in a mound-shape. The data are consistent with terrain-influenced wind erosion, but inconsistent with tilting by flexure, differential compaction over basement, or viscoelastic rebound. We use a simple landscape evolution model to show how the erosion and deposition of mound strata can be modulated by shifts in obliquity. The model is driven by multi-Gyr calculations of Mars' chaotic obliquity and a parameterization of terrain-influenced wind erosion that is derived from mesoscale modeling. Our results suggest that mound-spanning unconformities with kilometers of relief emerge as the result of chaotic obliquity shifts. Our results support the interpretation that Mars' rocks record intermittent liquid-water runoff during a $>$10$^8$-yr interval of sedimentary rock emplacement.

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Edwin S. Kite, Jonathan Sneed, David P. Mayer, Kevin W. Lewis, Timothy I. Michaels, Alicia Hore, Scot C. R. Rafkin. 2017-03-31. Evolution of major sedimentary mounds on Mars. https://doi.org/10.1002/2016je005135

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