This Article Full Text (PDF) References Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Add to Saved Citations Download to citation manager Request Permissions Request Reprints Add to My Marked Citations Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Anderson, L. Articles by Edwards, M. E. Search for Related Content GeoRef GeoRef Citation Social Bookmarking                   What's this?

Palaeohydrology of the Southwest Yukon Territory, Canada, based on multiproxy analyses of lake sediment cores from a depth transect

Department of Geosciences, University of Massachusetts Amherst, Amherst MA 01003, USA; U.S. Geological Survey, Box 25046 MS-980, Federal Center, Denver CO 80225-0046, USA land{at}usgs.gov

Mark B. Abbott

Department of Geology and Planetary Science, University of Pittsburgh, Pittsburgh PA 15260-3332, USA

Bruce P. Finney

Institute of Marine Science, University of Alaska Fairbanks, Fairbanks AK 99775, USA

Mary E. Edwards

Institute of Arctic Biology, University of Alaska Fairbanks and School of Geography, University of Southampton, Highfield, Southampton S017 1BJ, UK

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.

Key Words: Lake-level • effective moisture • palaeoclimate • palaeolimnology • carbon isotopes • nitrogen isotopes • Yukon Territory • Canada • Holocene

CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?