This is a Preprint and has not been peer reviewed. The published version of this Preprint is available: https://doi.org/10.1029/2019JE006191. This is version 1 of this Preprint.
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The distribution of cross-set thicknesses is important field-collected data for reconstructing ancient aeolian dune fields from the strata they accumulated, but most aeolian strata on Mars must be observed with remote sensing. We hypothesize that remote sensing resolution limits will affect cross-set thickness measurements and the dune field reconstructions that follow. Here, we test this hypothesis using a numerical experiment mimicking the effects of remote sensing resolution limits performed on a distribution of aeolian cross-set thicknesses measured in the field from the Page Sandstone, Arizona, USA. Page set thicknesses are exponentially distributed, representing the accumulations of dry (no water table) dune fields in a state of net-sediment bypass. Set-thickness measurements are progressively blended into adjacent sets based on the map-view distance between their upper and lower bounding surfaces on exposures with different dips. This is termed the “exposure distance” of a cross set, and in this experiment is a function of (1) set thickness, (2) the dip of the outcrop surface, and (3) assumptions of the number of remote sensing image pixels required to detect a set (detection limit). Using outcrop dips from 1° to 60° and detection limits from 3 to 10 HiRISE pixels, gently sloping surfaces (< 13°) allow most of the Page Sandstone sets to be measured, conserving the bypass interpretation made from the true set thicknesses at all detection limits. Although these results are specific to the Page, they can be used as a rule of thumb for future Mars work.
Physical Sciences and Mathematics, Planetary Geology, Planetary Sciences
remote sensing, Mars, Aeolian, cross set, dune
Published: 2019-09-09 17:46