Large Extraction of GAses and Compounds from Ice

Our project would drill two shallow 10cm diameter ice cores to ≈300 m depth at Dome C, Antarctica in collaboration with the University of Rochester (US). Trapped air would be extracted from most of the ice on site immediately after drilling. The oxygen isotopic anomaly of carbon monoxide (Δ17O of CO), Carbon-14 of CO (14CO) and methane (14CH4) would be analyzed in the extracted air samples. The Δ17O of CO would be used to investigate the past oxidative capacity of the atmosphere, the 14CO measurements would be interpreted with the aid of a model of in situ cosmogenic 14C production in glacial firn and ice and used to examine the galactic cosmic ray (GCR) flux history for the last 7000 years. The 14CH4 measurements would be interpreted with the aid of a 1-box atmospheric model and used to constrain the contribution of geologic methane, permafrost and marine methane hydrates to the Holocene methane budget. The melted water obtained from the gas extraction, would be filtered in order to collect micrometeorites to document the flux over the Holocene.
Some sections of the ice cores would be kept for the 10Be, 26Al and 36Cl cosmogenic nuclides to investigate their production rates in the atmosphere. The interpretation of these new 10Be, 26Al and 36Cl records would incorporate findings from in-situ 14CO and 14CO2 measured from the same ice core, in order to use the new reconstruction of the galactic cosmic ray flux, providing, in turn, an improved Holocene solar irradiance reconstruction. It is to mention that ice cores are the only ones to allow measuring cosmogenic nuclides produced in-situ and in the atmosphere, there is nothing equivalent. The advantage is that no assumption has to be made on the ages and each value of the galactic cosmic ray flux based on the 14CO and 14CO2 measurements, can directly be used for the solar reconstruction deduced from the 10Be, 26Al and 36Cl data.
An optimal use of the ice cores is planned, many other laboratories, including our French (A. Landais, LSCE, E. Capron, IGE) and Italian colleagues (M. Vecchiato, U. Venice, R. Traversi, U. Firenze, B. Delmonte, U. Milano-Biccocca), would work on these two new ices cores, for studies on the O2 and N2 isotopic composition, on gas content, on organic compounds, on dust and on bromine sea-salt.