PINGOS AS PLANETARY ANALOGS: THE GEOPHYSICAL PERSPECTIVE

On Earth, ice-cored hills found in frozen environments known as pingos are important indicators of groundwater systems and hydrogeologic properties. Potential pingo analogs have also recently been documented on Mars and the dwarf planet Ceres. These features represent unique science targets whose investigation may provide significant insights into the hydrogeological, astrobiological, and in situ resource potential of Mars and Ceres.

To prepare for the exploration of potential pingo and ground ice analogs the Pingo SubTerranean Aquifer Reconnaissance and Reconstruction project (Pingo STARR) is testing geophysical methods to investigate the internal structure of pingos in the North American Arctic. Pingo STARR’s key objectives are to:

1. Use ground penetrating radar, capacitively-coupled resistivity, and transient electromagnetic sounding to determine the structure of large pingos.
2. Assemble the largest complementary and comparable geophysical dataset of pingos collected to date.
3. Evaluate the advantages and disadvantages of our geophysical methods for investigating ground ice in a planetary analog environment.
4. Test the feasibility of deploying similar instrumentation on planets and asteroids in the future by both human and robotic explorers.

During our initial 2021 deployment, the Pingo STARR team performed 2D surveys over four pingos south of Deadhorse, Alaska. Initial geophysical observations clearly identified the subsurface pingo systems, delineating resistive ice cores or core fragments from the surrounding less resistive permafrost. Resistivity and electromagnetic data also revealed regions of relatively high ground conductivity underneath morphologically young appearing pingos. This suggests regions of unfrozen ground are present at relatively shallow depths even under large pingos inland from the Arctic coast. This deployment also demonstrated that a combination of radar and resistivity data can provide insights into the structure and hydrology of these features beyond what would be possible using any of the aforementioned techniques in isolation.

In 2022, the Pingo STARR team will return to the Arctic to further characterize pingo systems in 3D using our chosen geophysical techniques.

This work was made possible through NASA’s PSTAR program via grant #80NSSC20K1133.