COLDEX 2022-2023 Antarctic Field Season: End of Season Summary

*Overview of COLDEX field locations in Antarctica, 2022-2023 field season (closed black circles and grid near South Pole). Red squares are established research stations.*

I-165 Allan Hills Shallow Ice Coring

A team of eight people – camp manager, two ice core drillers, five scientists – spent nearly 6 weeks at the Allan Hills blue ice area from December 2022 into early January 2023. They recovered two ice cores. One is a large-diameter (9.5”) borehole to 96 m depth at a site where 2.7 million year old ice has been previously recovered. The second is from a 4” diameter borehole completed to 205 m depth which should provide 100,000 to 1,000,000 year old ice near bedrock. Alllan Hills is a unique site where old ice is brought very close to the surface as the ice from deep in the East Antarctic ice sheet flows up against the Transantarctic Mountains. It is a 45 to 60 minute flight from McMurdo Station, the largest research station in Antarctica and the US Antarctic Program’s primary logistics hub.

*A windy morning at Allan Hills ice core camp, December 2022. Peter Neff.*

*Allan Hills ice coring team leader Sarah Shackleton (L) and US Ice Drilling Program driller Elizabeth Morton with the final core recovered for the season. Austin Carter.*

*A piece of bubbly ice core sitting on the snow surface at Allan Hills. Austin Carter.*

*Transporting ice cores in insulated boxes and replenishing extra empty boxes for more ice cores to be collected. Allan Hills, Antarctica, January 2023. Peter Neff.*

Two members of the I-165 team also took a day trip to another blue ice / old ice site, Elephant Moraine, collecting a 9-meter ice core to sample for age and consider whether to establish a camp for shallow ice coring at this site in future years.

I-165 field team members

Jonathan Hayden (camp manager)
Sarah Shackleton (science leader)
Michael Jayred (US Ice Drilling Program)
Elizabeth Morton (US Ice Drilling Program)
Julia Marks Peterson (graduate student)
Jacob Morgan (graduate student)
Austin Carter (graduate student)
Yuzhen Yan (scientist)
Peter Neff (COLDEX field director)
Jen Campos-Ayala (non-deployed alternate)

*Elephant Moraine, Antarctica, January 2023. Peter Neff.*

*Ice core drilling, Elephant Moraine, Antarctica January 2023. Peter Neff.*

I-188 Allan Hills Accumulation Area Intermediate-Depth Ice Core Site Selection

A team of five people – a field safety mountaineer and four scientists – spent about 6 weeks at the Allan Hills accumulation area (just 8 km from the blue ice area, team I-165) collecting ground-based radar data (7MHz, 200MHz, ApRES) to aid selection of a site to drill a 1100 m deep, 1,000,000 year old ice core in coming years (pending NSF approval). Distributed temperature sensing was also undertaken in several existing ice core boreholes. GPS stakes were resurveyed in the Allan Hills accumulation zone to constrain ice flow velocity. A Ski Landing Area Control Officer (SLACO) visit to the site was also completed to assess surface conditions for possible grooming of a skiway to support LC-130 aircraft needed for any intermediate depth ice coring operation at the site.

*The COLDEX Allan Hills radar team before leaving Allan Hills at the end of the season. January 2023. John-Morgan Manos.*

*Howard Conway (University of Washington), leader of the COLDEX Allan Hills radar team. December 2022. John-Morgan Manos.*

*COLDEX Allan Hills radar team member Annika Horlings of University of Washington. January 2023. John-Morgan Manos.*

I-188 team members

Howard “Twit” Conway (science leader)
Annika Horlings (graduate student)
John-Morgan Manos (graduate student)
Margot Shaya (graduate student)
Tim Farr (ASC field safety)
Tyler Bieneman (ASC field safety)
Julia Andreasen (non-deployed alternate)

I-185 South Pole Broad Airborne Geophysics Survey

A large team from the University of Texas, Scripps Institution of Oceanography, and University of Kansas outfitted a 1940’s era Kenn Borek DC-3 turbo (called a “Basler”) with radar, gravity, and magnetic instruments to explore ice thickness, internal stratigraphic structure, and bedrock characteristics between South Pole and Dome A. Outfitting and testing was completed in December 2022. This broad airborne survey is designed to help the COLDEX ice flow and modeling team hone in on two smaller regions in the coming Antarctic season for a follow-up airborne survey. This team then sent 6 scientists and a Kenn Borek Air crew on to South Pole Station, flying 13 successful survey flights (5 hours each) over an area approximately the size of Washington state. All flights were completed from January 7 to 29, 2023. Exploration of these regions will progress to ground-based radar and then “Ice Diver” probes that will melt their way to the bottom of the ice sheet, using laser optics to gain better understanding of depth-age relationships and thus confirm these sites’ utility as a possible location for deep ice coring and collection of a continuous 1.5 million year long ice core.

*The COLDEX airborne geophysics team and aircraft. Williams Field, McMurdo Station, Antarctica December 2022. Gonzalo Echeverry.*

*The COLDEX airborne geophysics aircraft, Kenn Borek Basler MKB, taking off from South Pole Station. January 2023. Shravan Kaundinya.*

*COLDEX airborne geophysics flights flown from 30 December, 2022 to January 29, 2023. Duncan Young.*

I-185 team members

Duncan Young
Jamin Greenbaum
Dillon Buhl
Megan Kerr
Shravan Kaundinya
Christian Chan
John Paden
Gonzalo Echeverry
Brad Schroeder

This work was supported by the Center for Oldest Ice Exploration, an NSF Science and Technology Center (NSF 2019719). We thank the NSF Office of Polar Programs, the NSF Office of Integrative Activities, and Oregon State University for financial and infrastructure support, and the NSF Antarctic Infrastructure and Logistics Program, the US Ice Drilling Program, the NSF Ice Core Facility, and the Lockheed Martin Antarctic Support Contractor for logistical support. We thank Kenn Borek Air and the 109th New York Air National Guard for airlift.