Pingo SubTerranean Aquifer Reconnaissance and Reconstruction
Mars, Ceres, and the Earth have abundant reserves of ground ice. On Earth, ice-cored mounds known as pingos are important indicators of extant and extinct near-surface groundwater systems, hydrogeologic properties, and local climate1. Spacecraft observations of Mars and Ceres have revealed a variety of deca- to kilometer scale hills with morphological similarities to terrestrial pingos in ice-rich environments2,3,4,5,. Domes observed on Europa, Ganymede, and Callisto also resemble these ice-cored structures6,7,8. These potential hydrologically controlled pingo-like features (PLFs) represent unique science targets that may contain information regarding groundwater history, hydrologic properties, and habitability due to their formation by liquid water. For these reasons, identifying, characterizing, and determining the origin of possible PLFs on Mars and Ceres are high priority science objectives related to the history of water in the solar system. They also represent potential resource deposits for future explorers. The difficulty in characterizing potential PLFs and their formation processes on Mars and Ceres is their small size and the buried nature of any supporting ice structure.
Pingo STARR will advance human and lander scale geophysical techniques specifically tailored to detect, characterize, and investigate the cryohydrology and genesis of possible PLFs on Earth, Mars, and Ceres. This systems-level field campaign will be the most comprehensive to date for any terrestrial pingos, and the first dedicated analysis of pingos from a planetary science perspective. Our science and technology objectives will provide valuable insight into detecting and characterizing ground -ice and -water systems on Mars and Ceres.
To understand PLFs and prepare for their direct exploration, we turn to pingos in the North American Arctic. Despite the existence of ~11,000 pingos on Earth9, only a handful have been studied for prolonged durations, and few have been surveyed using geophysical methods10,11,12. We will investigate the predominantly unexplored subsurface structures of some of the largest hydrostatic pingos on Earth in the North American Arctic. This field program seeks to identify the connections between the structural elements of pingos, their overlying morphology, and their underlying hydrology; and characterize a pingo ‘lifecycle’ as a process analog for past and present PLF generating hydrologic systems on Mars and Ceres by acquiring an unprecedentedly thorough and detailed geophysical data set.
Pingo STARR’s first field deployment was in spring 2021 south of Deadhorse, Alaska with the next deployment to Tuktoyaktuk, Northwest Territories scheduled for spring 2023. In 2021, the Pingo STARR team collected eight TEM soundings and nearly 2km each of resistivity and GPR transects at 50, 100, and 200MHz over our season 1 pingos. Initial data analysis suggests both confirmation of hydrostatic pingo formation theory and new unexpected insights into shallow talik formation in the high Arctic as well as pingo core disintegration mechanisms.
Pingo STARR is a four-year field campaign funded through NASA's Planetary Science and Technology Through Analog Research (PSTAR) Program.
How Ground Ice Loss Affects Slope Stability and Groundwater Flow in Arctic Watersheds
Permafrost environments in Alaska and throughout the polar regions of the Earth are changing rapidly as a result of climate forcing. Warming Arctic temperatures are leading to wetter surface environments in northern Alaska, as well as to significant permafrost thaw and degradation. The expeditious loss of ground ice and permafrost in Alaskan environments, particularly Arctic Alaska, is driving slope destabilization, mass movements, landform alterations, and changes in groundwater and surface hydrology. These changes cascade down through watersheds altering their physiography and impacting the quality of water resources. Nowhere in the Arctic are the impacts of permafrost thaw and shifting groundwater hydrology being felt more acutely than in watersheds located within Alaska’s western Brooks range. This is especially true near the Red Dog mine, a partnership project between Teck Resources and the NANA Regional corporation located ~50 miles inland from the village of Kivalina, where increased ground ice melt presents challenges for the responsible development of geologic resources.
In order to evaluate how ground ice loss is destabilizing and transforming landscapes in Arctic watersheds, and how these changes are affecting groundwater flow, my research group is undertaking a three pronged science program that is: (1) quantifying the physical characteristics of ground ice loss induced landslides and mass wasting in culturally and economically important stream watersheds using drone based photogrammetry, and (2) identifying the links that exist between periglacial landforms and ground ice/groundwater content using electromagnetic geophysics and surface probing. Combined, these approaches are helping to characterize the ever changing nature of permafrost, groundwater, and periglacial landforms in the Ikalukrok creek watershed near the Red Dog Mine.
This research is funded by the ConocoPhillips Arctic Science and Engineering Endowment Award in collaboration with Teck Resources and the NANA Regional Corporation.
Chill Hills: Exploring Ceres’ Hydrology and Geology Through Pingo-like Morphologies
High resolution Dawn spacecraft observations over Occator and Urvara craters on Ceres revealed an abundance of small, quasi-symmetric conical mounds, many of which bear significant similarities to terrestrial pingos. Similar features have also been observed on Mars, but their nature and origin remain open questions. These pingo-shaped hills on Ceres have diameters as large as approximately 1000 meters and are resolvable to as little as several 10s of meters. A large fraction of these features occur in areas suspected of melting, or of being covered by water-rich melt during or shortly after impact, and now contain high concentrations of subsurface ice. This further suggests a possible genetic similarity to pingos. These pingo candidates are unique science targets whose investigation may provide insights into the geological, hydrological, and astrobiological properties of Ceres.
The Chill Hills project is employing geologic mapping and spatial clustering techniques to identify and morphologically classify pingo candidates on Ceres. These mounds are being analyzed for context and correlation with geologic units and structures identified in published maps of Occator, Urvara, and the intervening region in order to determine their regional- and local-scale geologic affinities. Non-parametric clustering algorithms are being applied to identify major centers of hill formation and are determining if any of the hills are meaningfully correlated with surface geological structures or structure traces. We are also using high-resolution Dawn stereo topography to characterize various morphometric aspects of identified anomalous hills on Ceres. In the future we will collect similar morphometric data from potential terrestrial morphological analogues such as pingos, volcanic cones, karst hills, kames, and drumlins. We will then use these data to identify systematic morphological traits in common between the cerean hills and various potential terrestrial analogues through statistically driven comparative planetology. This analysis will increase our understanding of the origin of cerean hills and quantitatively estimate their morphometric similarity to pingos and other terrestrial hill-forms.
These potentially icy hills on Ceres represent a class of landform never before observed on a small body. By better constraining the structural and geological relationships, geospatial distribution, and morphometric affinities of these potential pingo candidates, this project is providing insights into the nature and evolution of possible hydrogeologic systems throughout the solar system.
The Chill Hills project is funded through NASA's Discovery Data Analysis Program (DDAP).