Detangling Flow Regimes and Paleoclimate in the Deepest Section of the EDML Ice Core using U-series Ages.

Determining the absolute age of ice in the absence of a continuous ice stratigraphy is an ongoing challenge to the cryosphere community. In this work, we implemented new physical and geochemical techniques to test a novel method for determining the age of ice in the Dronning Maudland ice core in coastal Antarctica. In collaboration with a private company, we installed a nano scale, a device that provides accurate and precise measurements of the reactive surface area of dust in ice cores. In order to confirm our analytical precision as we set-up the method in a new laboratory we tested a series of non-ice core samples, which resulted in a publication on modern dust. Combining the former techniques with the latter, we are able to calculate the age of ice. Our results indicate that this technique will be broadly applicable to ice samples of unknown age across Antarctica.

In addition, the surface area of dust has important implications for nutrient fluxes to ocean surface water – high surface area is correlated with higher dissolution rates and therefore higher nutrient availability. Changes in the reactive surface area of dust through time could be a key influence on drawdown of CO2 by marine organisms. Our technique will be able to provide a record of this important parameter for the first time.

This data set will be updated to include the surface area measurements and ages from the EDML ice core in Antarctica once the final measurements are complete. Data will include isotopic compositions (uranium, strontium and neodymium), uranium concentrations and surface area measurements using the nano scale.