Palaeohydrology of the southwest Yukon territory, Canada, based on multiproxy analyses of lake sediment cores from a depth transect
Anderson, Lesleigh, Abbott, Mark B., Finney, Bruce P. and Edwards, Mary E. (2005) Palaeohydrology of the southwest Yukon territory, Canada, based on multiproxy analyses of lake sediment cores from a depth transect. The Holocene, 15, (8), 1172-1183. (doi:10.1191/0959683605hl889rp).
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Lake-level variations at Marcella Lake, a small, hydrologically closed lake in the southwestern
Yukon Territory, document changes in effective moisture since the early Holocene. Former water levels,
driven by regional palaeohydrology, were reconstructed by multiproxy analyses of sediment cores from
four sites spanning shallow to deep water.Marcella Lake today is thermally stratified, being protected from
wind by its position in a depression. It is alkaline and undergoes bio-induced calcification. Relative
accumulations of calcium carbonate and organic matter at the sediment/water interface depend on the
location of the depositional site relative to the thermocline. We relate lake-level fluctuations to down-core
stratigraphic variations in composition, geochemistry, sedimentary structures and to the occurrence of
unconformities in four cores based on observations of modern limnology and sedimentation processes.
Twenty-four AMS radiocarbon dates on macrofossils and pollen provide the lake-level chronology. Prior
to 10 000 cal. BP water levels were low, but then they rose to 3 to 4 m below modern levels. Between 7500
and 5000 cal. BP water levels were 5 to 6 m below modern but rose by 4000 cal. BP. Between 4000 and
2000 cal. BP they were higher than modern. During the last 2000 years, water levels were either near or 1 to
2 m below modern levels. Marcella Lake water-level fluctuations correspond with previously documented
palaeoenvironmental and palaeoclimatic changes and provide new, independent effective moisture
information. The improved geochronology and quantitative water-level estimates are a framework for
more detailed studies in the southwest Yukon.
|Keywords:||Lake-level, effective moisture, palaeoclimate, palaeolimnology, carbon isotopes, nitrogen isotopes, Yukon Territory, Canada, Holocene|
|Subjects:||G Geography. Anthropology. Recreation > G Geography (General)
G Geography. Anthropology. Recreation > GE Environmental Sciences
G Geography. Anthropology. Recreation > GB Physical geography
|Divisions:||University Structure - Pre August 2011 > School of Geography > Environmental Processes and Change
|Date Deposited:||01 Aug 2008|
|Last Modified:||27 Mar 2014 18:38|
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