McCall Glacier Upper Cirque ice core age model

Preliminary depth-age model for the McCall Glacier Upper Cirque ice core collected in summer 2008. Age scale is based on annual layer counting constrained by volcanic synchronization. The age model has been verified with comparisons to records of plutonium from nuclear testing fallout as well as heavy metal and other pollutant from well-dated Greenland ice cores. Estimated uncertainties are +/- 1 year in the upper ~37 m (1950 A.D. to present), increasing approximately linearly to +/- 4 years at ~1800 A.D. Age uncertainties are much larger prior to ~1800 because of flow thinning at the bottom of the glacier.