A time resolution methodology for assessing the quality of lake sediment cores that are dated by ¹³⁷Cs

Abstract

A methodology is proposed for grading the utility of lake sediment cores used to reconstruct pollution histories. The observed distribution of 137 Cs with depth in the core is compared to that expected from independent, historic measurements of fallout deposition. The width of the 137 Cs peak in the core profile that corresponds to the fallout maximum of 1963, or the combined maxima of 1959 and 1963, is used to infer the inherent time resolution of the core, i.e. the ability to distinguish events in the deposition history of the watershed. The method is applied to a number of core profiles from various lakes in the U.S. and appears to provide self‐consistent results.