A TALE OF TWO TUNDRAS: HOW GEOPHYSICALLY DISTINCT PINGOS IN ALASKA AND THE CANADIAN ARCTIC CAN INFORM THE SEARCH FOR GROUND ICE THROUGHOUT THE SOLAR SYSTEM

Ground ice rich terrains are increasingly thought to be abundant in the near-surfaces of planets and small bodies throughout the solar system. Of particular interest are regions on Mars and the dwarf planet Ceres that appear to host geomorphic features that appear analogous to terrestrial periglacial structures such as polygonal terrain, frozen debris lobes, and ice-cored hills known as pingos. Such features represent important science targets whose morphology, internal structure, and composition may reveal significant insights into the regional hydrogeological, climatological, and astrobiological history of these planets.

With increasing interest in the search for planetary ground ice, we turn to two geologically and geophysically distinct populations of pingos in the Alaskan and Canadian Arctics to help prepare for the in situ geophysical investigation of periglacial terrains on Mars and Ceres. To better understand the internal structure and composition of these features, we deployed ground penetrating radar, capacitively-couple resistivity, and electromagnetic techniques. In spring 2021 we observed four pingos in a terrestrial setting on the North Slope of Alaska. Our spring 2023 field season focused on nine large coastal hydrostatic pingos within Pingo Canadian Landmark near the Mackenzie river delta in Canada’s Northwest Territories. We used these observations to characterize subsurface pingo systems, delineate resistive ice cores or core fragments from the surrounding less resistive permafrost, and identify potential hydrologic pathways within the permafrost. We also observed substantial differences in the range of ground conductivities between Alaskan and Canadian pingos with the coastal Canadian pingos displaying much higher mean conductivities, which impacted our ability to characterize them.

Our observations demonstrate that a multi-physics approach to ground ice surveying can provide insights into the composition and hydrogeologic structure of periglacial features that significantly exceed the science return from a single geophysical method. Furthermore, these results demonstrate that radar and electrical methods have great potential for characterizing ice-rich terrains in planetary environments.