USAP-DC

In Antarctica, millions of years of freezing have led to the development of hundreds of meters of thick permafrost (i.e., frozen ground). Recent research demonstrated that this slow freezing has trapped and concentrated water into local and regional briny aquifers, many times more salty than seawater. Because salt depresses the freezing point of water, these saline brines are able to persist as liquid water at temperatures well below the normal freezing point of freshwater. Such unusual groundwater systems may support microbial life, supply nutrients to coastal ocean and ice-covered lakes, and influence motion of glaciers. These briny aquifers also represent potential terrestrial analogs for deep life habitats on other planets, such as Mars, and provide a testing ground for the search for extraterrestrial water. Whereas much effort has been invested in understanding the physics, chemistry, and biology of surface and near-surface waters in cold polar regions, it has been comparably difficult to investigate deep subsurface aquifers in such settings. Airborne ElectroMagnetics (AEM) subsurface imaging provides an efficient way for mapping salty groundwater. An international collaboration with the University of Aarhus in Denmark will enable knowledge and skill transfer in AEM techniques that will enhance US polar research capabilities and provide US undergraduates and graduate students with unique training experiences. This project will survey over 1000 km2 of ocean and land near McMurdo Station in Antarctica, and will reveal if cold polar deserts hide a subsurface pool of liquid water. This will have significant implications for understanding cold polar glaciers, ice-covered lakes, frozen ground, and polar microbiology as well as for predictions of their response to future change. Improvements in permafrost mapping techniques and understanding of permafrost and of underlying groundwaters will benefit human use of high polar regions in the Antarctic and the Arctic.

The project will provide the first integrative system-scale overview of subsurface water distribution and hydrological connectivity in a partly ice-free coastal region of Antarctica, the McMurdo Dry Valleys. Liquid water is relatively scarce in this environment but plays an outsized role by influencing, and integrating, biological, biogeochemical, glaciological, and geological processes. Whereas surface hydrology and its role in ecosystem processes has been thoroughly studied over the last several decades, it has been difficult to map out and characterize subsurface water reservoirs and to understand their interactions with regional lakes, glaciers, and coastal waters. The proposed project builds on the "proof-of-concept" use of AEM technology in 2011. Improvements in sensor and data processing capabilities will result in about double the depth of penetration of the subsurface during the new data collection when compared to the 2011 proof-of-concept survey, which reached depths of 300-400m. The first field season will focus on collecting deep soundings with a ground-based system in key locations where: (i) independent constraints on subsurface structure exist from past drilling projects, and (ii) the 2011 resistivity dataset indicates the need for deeper penetration and high signal-to-noise ratios achievable only with a ground-based system. The regional airborne survey will take place during the second field season and will yield subsurface electrical resistivity data from across several valleys of different sizes and different ice cover fractions.

Person	Role
Tulaczyk, Slawek	Investigator and contact
Mikucki, Jill	Investigator

Antarctic Earth Sciences	Award # 1644187
Antarctic Integrated System Science	Award # 1644187

USAP-1644187_1

Deployment	Type
C-516-M	airborne survey

None in the Database

Repository	Title (link)	Format(s)	Status
USAP-DC	ANTAEM project airborne EM resistivity data from McMurdo Region	None	exists

1. Tulaczyk, S. M., & Foley, N. T. (2020). The role of electrical conductivity in radarwave reflection. The Cryosphere Discussion. (doi:10.5194/tc-2020-9)
2. Foley, N., Tulaczyk, S.M., Grombacher, D., Doran, P.T., Mikucki, J., Myers, K.F., Foged, N., Dugan, H., Auken, E. and Virginia, R., 2019. Evidence for pathways of concentrated submarine groundwater discharge in east Antarctica from helicopter-borne electrical resistivity measurements. Hydrology, 6(2), p.54. (doi:10.3390/HYDROLOGY6020054)
3. Myers, K. F., Doran, P. T., Tulaczyk, S. M., Foley, N. T., Bording, T. S., Auken, E., … Virginia, R. A. (2020). Thermal legacy of a large paleolake in Taylor Valley, East Antarctica as evidenced by an airborne electromagnetic survey. (doi:10.5194/tc-2020-241)
4. Tulaczyk, S. M., & Foley, N. T. (2020). The role of electrical conductivity in radar wave reflection from glacier beds. The Cryosphere, 14(12), 4495–4506. (doi:10.5194/tc-14-4495-2020)
5. Grombacher, D., Auken, E., Foged, N., Bording, T., Foley, N., Doran, P. T., … Tulaczyk, S. (2021). Induced polarization effects in airborne transient electromagnetic data collected in the McMurdo Dry Valleys, Antarctica. Geophysical Journal International, 226(3), 1574–1583. (doi:10.1093/gji/ggab148)
6. Bierson, C. J., Tulaczyk, S., Courville, S. W., & Putzig, N. E. (2021). Strong MARSIS Radar Reflections From the Base of Martian South Polar Cap May Be Due to Conductive Ice or Minerals. Geophysical Research Letters, 48(13). (doi:10.1029/2021gl093880)
7. Myers, K. F., Doran, P. T., Tulaczyk, S. M., Foley, N. T., Bording, T. S., Auken, E., … Virginia, R. A. (2021). Thermal legacy of a large paleolake in Taylor Valley, East Antarctica, as evidenced by an airborne electromagnetic survey. The Cryosphere, 15(8), 3577–3593. (doi:10.5194/tc-15-3577-2021)
8. Dugan, H. A., Doran, P. T., Grombacher, D., Auken, E., Bording, T., Foged, N., Foley, N., Mikucki, J., Virginia, R. A., & Tulaczyk, S. (2022). Brief communication: The hidden labyrinth: Deep groundwater in Wright Valley, Antarctica. (doi:10.5194/tc-2022-91)
9. Dugan, H. A., Doran, P. T., Grombacher, D., Auken, E., Bording, T., Foged, N., Foley, N., Mikucki, J., Virginia, R. A., & Tulaczyk, S. (2022). Brief communication: The hidden labyrinth: deep groundwater in Wright Valley, Antarctica. The Cryosphere, 16(12), 4977–4983. (doi:10.5194/tc-16-4977-2022)
10. Gutterman, W. S., Doran, P. T., Virginia, R. A., Barrett, J. E., Myers, K. F., Tulaczyk, S. M., Foley, N. T., Mikucki, J. A., Dugan, H. A., Grombacher, D. J., Bording, T. S., & Auken, E. (2023). Causes and Characteristics of Electrical Resistivity Variability in Shallow (<4 m) Soils in Taylor Valley, East Antarctica. Journal of Geophysical Research: Earth Surface, 128(2). Portico. (doi:10.1029/2022jf006696)
11. Garza-Giron, R., & Tulaczyk, S. M. (2023). Brief communication: Significant cold bias in ERA5 output for McMurdo region, Antarctica. (doi:10.5194/tc-2023-44)
12. Neuhaus, S. U., & Tulaczyk, S. M. (2023). Mechanism for the subglacial formation of cryogenic brines. Annals of Glaciology, 1–4. (doi:10.1017/aog.2023.28)
13. Garza-Girón, R., & Tulaczyk, S. M. (2024). Brief communication: Significant biases in ERA5 output for the McMurdo Dry Valleys region, Antarctica. The Cryosphere, 18(3), 1207–1213. (doi:10.5194/tc-18-1207-2024)