Evidence for widespread glaciation in Arcadia Planitia, Mars

Viscous flow features, including lobate debris aprons and lineated valley fill, are common ice-related features found across the mid-latitudes of Mars. These features are commonly found along the dichotomy boundary and around massifs where snow and ice can accumulate and flow to topographic lows during periods of higher obliquity. We have identified and mapped glacial-related features reminiscent of lineated valley fill and lobate debris aprons in the lower mid-latitudes of Arcadia Planitia based on morphology, thermal infrared reflectance, thermal inertia, and subsurface radar reflections. Three sinuous features show surface morphologies and supporting spectral properties indicative of massive buried ice, including distinct boundaries, arcuate and linear banding, deep radar reflections, dielectric constants similar to water-ice, expanded secondary craters, and proximity to lobate debris aprons. We interpret the sinuous and lobate features of Arcadia Planitia to be buried debris-covered glaciers formed during higher obliquity periods in Mars’ recent past. These sinuous features appear to be channelized ice that once flowed but currently reside in a flat-lying region. Although their origin is unclear, we consider an ice stream or subglacial history due to a lack of obvious topographic dependence. The abundant evidence of widespread near-surface ice in a flat-lying lower mid-latitude region of Mars makes Arcadia Planitia a potentially favorable site for future missions due to the high potential for in situ resource utilization.