This award is in support of geochemical research on the Greenland Ice Sheet. The investigation's objective is to obtain temporal lead concentrations for the 2000=year period 600 BC to 1300 AD in the hard ice zone at about 200 to 600-meter depth. Temporal changes of lead in this period will be correlated with historic periods of maximum industrial production at about 450 BC, 50 BC and 1300 AD interspersed by minima at about 200 BC and 400 AD.
