2017-2018 Antarctic

This project will study a large body of ice that is buried beneath approximately a meter of debris in the Ong Valley of the Transantarctic Mountains of East Antarctica. Preliminary analyses of this material suggest that it could be over a million years old. Most glacial ice contains tiny air bubbles that have trapped the atmospheric gases and other atmospherically transported materials existing at the time that the ice was deposited such as plant pollen, microbes, and mineral dust. Samples will be collected from this buried ice mass, down to a depth of 10 meters, and cosmogenic nuclide concentrations both in the overlying debris and in the till contained in the ice will be measured. The combined analysis of the target cosmogenic nuclides (Beryllium-10, Aluminum-26, and Neon-21) will allow the age of the ice to be uniquely determined and will enable determination of the rate that the ice is sublimating.

This project will utilize the Deep Logging Winch to log the Rapid Access Ice Drill (RAID) Antarctic field trial (AFT) borehole drilled during the 2017-2018 summer field season near Minna Bluff, Antarctica. The RAID AFT includes a new slim version of PI Ryan Bay's optical logging device for use in the 3.5-inch diameter RAID boreholes. The optical logger will enable rapid establishment of the ice chronology in a borehole, in a few hours after drilling. This field trial will be critical in determining whether or not the RAID borehole wall roughness, and cleanliness, permits optical logging at the level of detail needed for accurate dating of the ice.

In the context of the already planned field work at Minna Bluff for testing the Rapid Access Ice Drill in December 2017, this project will drill a 100-meter firn core to measure density and to pump firn air at a limited number of depths. The main science goals are to 1) obtain an accurate accumulation rate and density profile to add to the calibration of firn densification models, and 2) to pump firn air samples for testing whether noble gas isotopes exhibit gravitational disequiibrium as seen in other high-accumulation sites such as Law Dome. An ancillary goal is to test for the presence of melt layers during La Nina episodes, which were seen last season in a 18-meter deep core drilled at the same site.

This project will utilize the Intermediate Depth Logging Winch to lower a series of optical+UV and radio sensor packages into the South Pole Ice Core (SPICEcore) borehole to the full depth of the hole (1751 m). The science goals include measurements of the radio absorption length of the ice from 100-1000MHz, radio birefringence in the ice, and ice index of refraction, all measured as a function of depth and ice temperature. The science team is interested in the optical scattering, absorption lengths, and luminescence as a function of depth and optical wavelength from the visible into the ultraviolet.