The distribution of putative periglacial landforms on the martian northern plains

Abstract

In this investigation, HiRISE images were surveyed across three regions of the Northern Plains of Mars; Acidalia, Arcadia and Utopia Planitiae. A sample of HiRISE images within each of these areas was examined. The aim of the investigation was to determine the distribution of three varieties of landform; clastic patterned ground, lobate hill-slope features and scalloped depressions. These features are of importance, as they are morphologically similar to terrestrial periglacial features. Examples of these landforms were found across the study areas. Scalloped depressions are common at mid latitudes in each of the three regions. Sorted patterned ground was not as widespread. Some examples of sorted patterned ground were found in all three study areas, but the main concentration occurs in the north-western region of Acidalia Planitia. Lobate hill-slope features were the least common of the three landform types. Despite occurring infrequently, several possible examples of lobate features were found to occur in proximity to other putative periglacial features. It was found that lobate hill-slope features and clastic patterns occurred further south than expected, beyond the southern extent of many previous studies. These features, and by extension the processes that form them, could thus occur more widely than previously thought. It also appears that although putative periglacial features are often found in crater interiors they are not limited to these environments. Extensive areas of patterned ground were found on the inter-crater plains. Lobate features and sorted stripes were often found on crater walls, which would support the hypothesis that they are analogous to hill-slope features on Earth. Scalloped depressions were most often found in crater interiors, or on crater ejecta, although examples on the inter-crater plains were not uncommon.