Ice Core Analyses
The analyses of the Bona-Churchill ice cores are now underway in the laboratories at OSU�s BPRC. The primary measurements that are being made continuously along the length of all cores include the concentration and size distribution of insoluble microparticles (dust), δ18O, δD, and concentrations of the major anion and cation species. The upper sections of the cores have been analyzed for total Beta radioactivity. The annual accumulation rate has averaged ~1100 mm of water equivalent over the recent past. As of October 2003 we have analyzed 5600 δ18O, δD, dust and chemistry samples representing 320 meters of the 460-meter deep ice core. The dust and calcium concentrations show distinct annual variations and the preliminary results suggest that the annually resolved record will cover more than 2500 years. This bodes well for the recovery of a very high-resolution record of past climatic and environmental variability from these cores.
In November 2003 David Urmann, a graduate student in the Department of Geological Sciences, will complete his Master�s thesis entitled: �An Evaluation and comparison of ice core data from Bona-Churchill and Quelccaya, and lake level data for the Western United States, Alaska and Peru as proxies of El Ni�o events during the last one hundred years.�