Late Holocene lake-level and lake development signals in Lower Herring Lake, Michigan |
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Authors: | Julie A Wolin |
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Institution: | (1) Center for Great Lakes and Aquatic Sciences, University of Michigan, 48109 Ann Arbor, MI, USA;(2) Present address: Geobotany Division, Geological Survey of Denmark, Thoravej 8, Dk-2400 Copenhagen NV, Denmark |
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Abstract: | Paleolimnological investigations of a marginal lake in the Lake Michigan basin revealed signals of long-term lake-level changes primarily controlled by climatic forces. Multiple analyses identified concurrent signals in sediment chemistry, grain size, and the microfossil record. Coarse-grained sediments, benthic diatoms, and nutrient response species increased as lake levels rose or fell. Finer sediments and higher percentages of taxa associated with stable thermocline conditions occurred during high-lake periods. Sedimentary evidence revealed corresponding strong high-lake signals c. 2500–2200, 1800–1500, 1170–730, and 500–280 BP. Low-lake periods occurred c. 1500–1170 and 700–500 B.P. An additional signal of lake-level decline was apparent beginning c. 280 BP but was interrupted by anthropogenic effects. Evidence of extreme low-lake levels (c. 1400–1300 BP), and signals for a medieval warming period (1030–910 BP) and the Maunder minimum (370–325 BP) indicate occurrence of short-lived dry climatic conditions. |
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Keywords: | diatoms grain-size analysis lake-level changes Lake Michigan paleolimnology |
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