2024-2025 Antarctic

Cores drilled through the Antarctic ice sheet provide a remarkable window on the evolution of Earth’s climate and unique samples of the ancient atmosphere. The clear link between greenhouse gases and climate revealed by ice cores underpins much of the scientific understanding of climate change. Unfortunately, the existing data do not extend far enough back in time to reveal key features of climates warmer than today. COLDEX, the Center for Oldest Ice Exploration, will solve this problem by exploring Antarctica for sites to collect the oldest possible record of past climate recorded in the ice sheet.

This component of COLDEX will recover a suite of shallow (16 x < 200 m) ice cores from the Allan Hills and other Antarctic Blue Ice Areas (BIAs) that contribute towards our understanding of how Earth's climate system operated during warmer periods in the past and why the periodicity of glacial cycles lengthened from 40,000 to 100,000 years approximately 1 million years ago. These ice cores will be dated using a newly developed array of dating methods to establish a preliminary depth/age time scale. Subsections of the cores will be imaged and analyzed for stratigraphic orientation using ECM and a suite paleoclimate properties (e.g. CO2, CH4, O2/N2/Ar, water isotopes, etc.).

This project will collect a novel dataset to determine how the West Antarctic Ice Sheet (WAIS) responded to a warmer climate during the last interglacial period (~125,000 years ago) by reconstructing the glacial history at the Mt. Waesche volcano in Marie Byrd Land, Antarctica. The researchers will use the Winkie Drill to drill through the ice sheet and recover bedrock that can be analyzed for its surface exposure history to help determine when the surface became overridden by the ice sheet. Reconstructing WAIS geometry when the ice sheet was smaller than present is difficult, and data are lacking because the evidence lies beneath the present ice sheet. The scientists will use the Winkie Drill to drill through the ice sheet and recover bedrock that can be analyzed for its surface exposure history to help determine when the surface became overridden by the ice sheet. The research will provide constraints on the past maximum and minimum spatial extent of WAIS during the last glacial-interglacial cycle.

Previous field expeditions to the Mt. Waesche volcano in Marie Byrd Land, Antarctica, used ground-penetrating radar to map the area's sub-ice topography and internal glacial layering. These radar profiles revealed discontinuities within the ice that represent lower ice levels that may have occurred in the past. This project aims to enhance the team’s rock core drilling program at Mount Waesche (see Constraining West Antarctic Ice Sheet Elevation during the last Interglacial) by dating the discontinuities in the ice. Using the Badger-Eclipse Drill, the team will collect ice cores from above and below the discontinuities to constrain the ages of the discontinuities. Isotopic and tephra analysis will be used to provide age constraints on the ice cores. These data will be correlated with other, well-dated West Antarctic ice cores to obtain a local chronology and date the discontinuities. This exploratory work aims to provide data that complement the results from subglacial rock cores to better constrain surface-elevation change, including both retreat and readvance, since the last interglacial.

This project aims to examine the response of the flow of an Antarctic Peninsula outlet glacier (Flask Glacier) to surface meltwater. Satellite observations suggest that Antarctic Peninsula outlet glaciers speed up during surface melt events. The researchers will make field observations of surface melting, ice dynamics, and surface conditions on Flask Glacier to investigate if Antarctic Peninsula outlet glaciers speed up during surface melt events. The researchers will use an IDDO Hand Auger to drill several shallow firn cores. The firn cores will be used to constrain firn stratigraphy to help determine how temporal changes in near-surface water content affect satellite-based velocity measurements.

Solar activity is an important driver of Earth’s climate, and glacier extent is an important part of the Earth’s climate system. As such, the historical rate at which cosmic rays reach Earth’s solar system is important to understand for studies of past solar activity and glacier extent. The main goal of this project is to improve the understanding of the variability in the galactic cosmic ray flux on millennial timescales. Using the 4-Inch Drill, this collaborative project with the French Polar Institute will drill two ~300-meter-long ice cores from the Dome C region of Antarctica. Past variations in cosmic ray flux will be examined via measurements of carbon-14 of carbon monoxide (14CO) on large samples from the ice cores. 14C of methane will also be measured to improve understanding of the Holocene methane budget.