Current Projects

Major ion chemistry of WAIS Divide Ice Core

A major US ice core research program is under way. An ice core to bedrock will be drilled at central West Antarctica (WAIS Divide site) to obtain detailed climate and environmental records for the last 100,000 years. The ICECL group is part of this program. A current project funded by NSF is developing, testing and finalizing a new ice core chemical analysis technique (CFA-IC, continuous flow analysis with ion chromatography detection). This technique will then be used to perform high-speed, high-resolution major ion analysis on the WAIS Divide ice core, as it is drilled and becomes available for analysis over the next 3-4 years.

Study of atmospheric oxidation chemistry using volcanic sulfate in ice cores

Explosive volcanic eruptions put large amounts of sulfur dioxide into the atmosphere where the sulfur dioxide (S(IV)) undergoes oxidation to become sulfuric acid or S(VI). While the final product of the oxidation is certain, the mechanisms by which S(IV) is converted to S(VI) may be complicated and several oxidants (e.g., OH radical, ozone) and reaction media (e.g., gas phase and heterogeneous) may be involved. Exactly how the oxidation is accomplished and under what atmospheric conditions are important for us to understand, for the processes are part of the atmosphere's ability to oxidize (i.e., oxidative capacity) and to remove minor and trace chemical substances in their biogeochemical cycles.

The isotopic composition of the final oxidation product of volcanic S(IV) can tell us the oxidants and the mechanisms in the oxidation process. This requires careful measurement of oxygen (16O, 18O and 17O) and sulfur (32S, 34S, 32S and 36S) stable isotopes in sulfate. Further, to understand oxidation in the stratosphere, sulfate produced by SO2 oxidation in the stratosphere must be found, separated from sulfate from other sources, and then analyzed for isotope composition.

We search in ice cores for sulfate produced by atmospheric oxidation of sulfur dioxide from past volcanic eruptions. Very large eruptions may have emitted sufficient sulfur dioxide which, after rapid oxidation in the atmosphere, falls and is preserved in polar snow.

We have collected multiple ice cores from South Pole, Antarctica, and from Summit, Greenland, from which to extract sufficient quantities of volcanic sulfate for isotope measurement. We hope that comparison of data from the two opposite polar regions will yield information on how the atmospheric dynamics, which operates differently in the two hemispheres, and its effect on the oxidation process.

Reconstruction of 2000-Year Record of Explosive Volcanic Eruptions from Antarctic Ice Cores

With new (2004) ice cores from the South Pole, we are compiling detailed and quantitative records of volcanic eruptions covering the last 2000 years. This is building on our previous work of reconstructing volcanic records over the last 1000-1500 years.
We hope to use deep Antarctic ice cores (e.g., the WAIS Divide deep ice core) to extend ice core volcanic records beyond the 2000 years from South Pole cores and the 4100 year record from East Antarctica cores. The next objective is to reach 10,000 years using the WAIS Divide core.

Collaborative Research to Analyze Snow and Ice Core Samples from East Antarctica

The Chinese Antarctic Research Expedition (CHINARE) has been collecting snow and ice core samples on a traverse between the Zhongshan Station and Dome A in East Antarctica.
Snow and ice core samples from CHINARE are being analyzed in ICECL at South Dakota State University.