Resolving the chronology of recent lake sediments: an example from Devils Lake, North Dakota

Abstract

Devils Lake was a closed, saline lake in North Dakota; it is typical of lake basins in the Great Plains Regions, where windy conditions and fluctuating water-levels disturb sediment and confound chronostratigraphy. Pollen analysis and 210Pb dating of two cores collected from bathymetrically contrasting embayments demonstrate (1) how certain agriculture-related pollen types differ in their value as chronostratigraphic markers, (2) how pollen and 210Pb stratigraphers can be reconciled to determine the approximate depth of sediment mixing, and (3) the importance of coring-site selection, especially in lakes and unstable sedimentary conditions.