A diatom record of environmental change in Fryxell Basin,Taylor Valley,Antarctica, late Pleistocene to present |
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| Authors: | Matthew A Konfirst Charlotte Sjunneskog Reed P Scherer Peter T Doran |
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| Institution: | (1) Geology and Environmental Geosciences, Northern Illinois University, Davis Hall, DeKalb, IL 60115, USA;(2) Earth and Environmental Sciences, University of Illinois at Chicago, 845 W. Taylor St., Chicago, IL 60607, USA |
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| Abstract: | We present a diatom record from a sediment core taken in Lake Fryxell, Taylor Valley, Antarctica. Six zones were defined using
diatom assemblage changes that indicate varying limnological conditions. The early lake stage, ca. 35,000 cal years BP, is characterized by Mayamea atomus f. permitis, a species rarely reported in modern Antarctic Dry Valley environments. An extended period from ca. 35,000 to 19,000 cal years BP is characterized by low diatom abundance, with dominant taxa Luticola spp., Muelleria spp., and Diadesmis contenta. The modern assemblage was established ca. 13,000 cal years BP, after two relatively brief transitional stages. One key species
for this recent period, Navicula lineola var. perlepida, is absent in surface sediments and the modern environment, indicating an environmental change within the last several centuries.
The diatom assemblage is compared to modern diatom communities in Dry Valley streams, which provide the most complete information
on diatom distributions in this region. Although precise environmental interpretation of the core is hampered by limited knowledge
of environmental constraints on many of the diatom taxa present in the lake core, the data provide important new insights
into the history of Glacial Lake Washburn. |
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