How well do sediment indicators record past climate? An evaluation using annually laminated sediments

The reliability of paleoclimatic inferences from lake-sediment records rests on the understand- ing of how various sediment indicators respond to environmental changes. Despite the recent prolifera- tion of paleoclimatic records, only a limited number of studies have rigorously evaluated potential indi- cators by comparing lake-sediment records with instrumental weather data. We analyzed annually laminated sediments of the past 100 years from a lake in north-central Minnesota for a suite of variables commonly used for climatic reconstructions. Results were compared with time series of climatic or climate-derived variables, as well as with indices of climate modes thought to influence the regional climate of the midwestern United States. The oxygen- isotopic composition of calcite (d 18 Oc) shows trends