Surface Morphology and Subsurface Ice Content Relationships in Arcadia Planitia, Mars and the Canadian High Arctic
Doctor of Philosophy
Planetary Science and Exploration
Osinski, Gordon R.
As NASA and SpaceX prepare for future human missions to Mars as part of an In-situ Resource Utilization (ISRU) Space Act Agreement (SAA), we need more detailed characterization of ice at proposed landing sites to constrain ice accessibility, landing safety, and scientific value. Obtaining near-surface in situ water-ice can be used for rocket fuel and life support needs which would significantly reduce the mass needed for transport to and from Mars. Arcadia Planitia is the lowest-lying region in the northern hemisphere of Mars where abundant evidence exists for an ice-rich subsurface. Shallow Radar observations indicate a decameters-thick layer of water-ice (i.e., buried ice sheet) extends across much of Arcadia. The goal of my Ph.D. research is to characterize the ice-related features at Arcadia Planitia, a proposed future human mission landing site, in detail to assist in the identification of a safe landing site where water-ice is present and accessible for ISRU. By utilizing multiple orbital datasets (i.e., morphology, albedo, thermal infrared reflectance, thermal inertia, and subsurface radar reflections) and identification criteria for Viscous Flow Features (VFFs) on Mars, I mapped six glacial-related features in Arcadia. These units consist of conventional VFFs, such as Lobate Debris Aprons, and non-conventional VFFs. Three sinuous features in the flat-lying plains of Arcadia show surface morphologies and spectral properties indicating these are non-conventional VFFs of channelized ice that once flowed. I propose these sinuous features to be analogous to terrestrial ice streams. Brain terrain is proposed to represent a lag deposit formed atop thick glacial ice as a result of ice sublimation. However, we observe brain terrain to occur only within a narrow latitudinal band within the study site with minimal examples of brain terrain found on the six glacial-related features mapped. We utilize the Canadian High Arctic to investigate analogous brain terrain, that we have termed Vermicular Ridge Features (VRFs), to identify surface-subsurface relationships with ground-penetrating radar, photogrammetry, grain size analysis, and LiDAR. We interpret VRFs to be produced from the passive ablation of stagnant glacial ice. We interpret the lack of brain terrain on the six glacial-related features we mapped at Arcadia Planitia to represent regions where thick units of ice persist, have experienced less degradation than the surrounding terrain, and, therefore, where massive ice is shallower from the surface making our mapped regions areas where ice is more accessible for ISRU.
Summary for Lay Audience
As NASA and SpaceX prepare to send humans to Mars in the near future, we need to continue to study regions on Mars that are suitable to land. The landing site will need to be safe for landing, scientifically interesting to continue to learn about Mars, and provide significant mineable water ice as water can be used for life-support and fuel. One area of interest on Mars, called Arcadia Planitia, has abundant evidence that suggests it is both safe for landing and has a large amount of buried water ice. It has been suggested that an ice sheet was buried in the area which is scientifically valuable as glaciers act as physical records of past climate – something we are still trying to understand about Mars. My Ph.D. research aims to describe the surface of ice-related features at Arcadia Planitia in detail and infer areas of minable ice just below the surface to identify an ice-rich and safe landing site for future Martian astronauts to land. This is done by using multiple datasets from Mars to that provide information about the surface and subsurface to best locate shallow ice deposits. I mapped six units that I interpret to be buried glaciers on Mars. One unit includes three unique sinuous features in a flat-lying area that I suggest are analogous to ice streams found on Earth. Small-scale ice-related features were also mapped, one of which is called brain terrain and commonly found in the mid to polar latitudes of Mars. Brain terrain is proposed to represent glacial ice sublimation. I studied a similar landform in the Canadian High Arctic, termed Vermicular Ridge Features (VRFs), to understand the formation process and its relationship with buried ice. We interpret VRFs to form similarly to brain terrain. We found that brain terrain largely does not occur on the mapped glacial units, particularly on the sinuous features. We suggest brain terrain to represent areas where the greatest ice loss has occurred. Therefore, the sinuous features represent areas where less ice loss has occurred suggesting ice may be shallower, easily extractable, and an ideal area to land.
Hibbard, Shannon M., "Surface Morphology and Subsurface Ice Content Relationships in Arcadia Planitia, Mars and the Canadian High Arctic" (2021). Electronic Thesis and Dissertation Repository. 8120.