Petaloid Organs Preserved in an Arctic Plant Macrofossil Assemblage from Full-Glacial Sediments in Southeastern Minnesota |
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| Authors: | R G Baker J A Mason L J Maher Jr |
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| Institution: | a Department of Geology, University of Iowa, Iowa City, Iowa, 52242;b Conservation and Survey Division, University of Nebraska, Lincoln, Nebraska, 68588-0517;c Department of Geology, University of Wisconsin, Madison, Wisconsin, 53706 |
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| Abstract: | A small suite of plant macrofossils indicates that southeastern Minnesota supported subarctic to arctic vegetation 18,700 yr B.P. Fossil tepals of Polygonum viviparum are exceptionally well preserved; they occur with more fragmentary remains of Dryas integrifolia, Vaccinium uliginosum var. alpinum, and probable species of arctic Salix, S. cf. herbacea, and S. cf. arctica. The pollen spectrum from this site is dominated by Picea, Pinus, and Cyperaceae, which are typical of midwestern full-glacial sequences. Tundra-like conditions with permafrost were present in southeastern Minnesota during full-glacial time. Local environments 18,700 yr B.P. reconstructed from both physical and paleobotanical evidence include wind-swept ridge tops with thin loess, outcrops of dolostone and sandstone on valley walls, colluvial slopes, sandy to gravelly floodplains, shallow floodplain pools, wet meadows, and peaty turfs, all in a treeless or nearly treeless environment. |
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