Development of High-Resolution, Multi-Century Records of Trace Element Deposition in West-Central Greenland Using ICP-MS

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McConnell0221515The Principal Investigator will develop three spatially distributed, continuous, multi-century glaciochemical records of more than 20 chemical species, trace elements, and isotopes with unprecedented temporal resolution (~50 to 100 samples). These unique records will significantly expand possible applications of glaciochemical data to the study of a range of environmental and global change issues. This work builds on recent NSF-funded development at the Desert Research Institute (DRI) of a new method for continuous, high-resolution ice-core analyses called Continuous Flow Analysis with Trace Elements (CFA-TE). CFA-TE is a novel analytical approach in which a continuous ice-core melter is coupled directly with an Inductively Coupled Plasma Mass Spectrometer (ICP-MS) and traditional Continuous Flow Analysis (CFA) system. The apparatus makes possible continuous, high-resolution and exactly co-registered glaciochemical measurements of a broad spectrum of chemical species, trace elements, and isotopes. Measurements on an approximately 137meter core from Summit, Greenland demonstrate the potential of this new approach. Using sample handling and analytical protocols developed for the successful Summit analyses, CFA-TE will be used to measure more than 20 chemical species, trace elements, and isotopes on one archived and two new approximately140-m ice cores from high accumulation regions of the dry snow zone in west-central Greenland. This area is strongly influenced by large-scale changes in atmospheric circulation and anthropogenic pollution from North America. These new glaciochemical records will extend from around 1750 A.D. to the present and will be the highest resolution, multi-century elemental and isotopic glaciochemical records ever produced from Greenland ice cores.The application of ice-core chemical data in environmental, biogeochemical,and global change studies has been limited by 1) relatively coarse sample resolution in time even for high resolution studies, 2) inexact co-registration in depth for different chemical measurements, and 3) the limited number of chemical species, elements, and isotopes routinely measured in ice cores. The recent development of the CFA-TE method for ice-core analysis eliminates many of these issues and presents a new opportunity to develop very high-resolution, broad-spectrum glaciochemical records at relatively modest cost. Together with similar, recently completed measurements from Summit, these rich data sets will open new avenues for using glaciochemical data to investigate environmental and global changes issues ranging from anthropogenic, volcanic and biomass-burning-related trace element fallout to changes in hemispheric-scale circulation.