Temporal dynamics of airborne lead-210 in Missouri (USA): implications for geochronological methods

Abstract

 Lead-210 (²¹⁰Pb) deposited from the atmosphere is used in the dating of certain geological materials such as glacial ice and lacustrine sediments, but its long-term atmospheric behavior has been little studied. The present investigation reports measurements of airborne ²¹⁰Pb at 21 monitoring stations in Springfield, Missouri, during 1975–1995. Seasonal and diurnal patterns of atmospheric concentrations are established, and the mean annual concentrations of ²¹⁰Pb in ground level air during the 20-year period are examined. Although airborne ²¹⁰Pb concentrations are found to vary diurnally and seasonally, mean annual concentrations in southwest Missouri have remained relatively constant during this time period. This finding is important for geochronological methods that assume a constant ²¹⁰Pb flux from the atmosphere.