Quaternary Research Center

Late Quaternary Vegetation Associated with the Kirkland/Lakeview Elementary School Mammoth Site, Puget Lowland, Washington

Paul R. Kester (1) and Bax R. Barton (2)

(1) Geology and Paleontology Division, Burke Museum of Natural History and Culture
Box 353010, University of Washington, Seattle, WA 98195, USA
pkester@u.washington.edu

(2) Quaternary Research Center, University of Washington
Box 351360, Seattle, WA 98195, USA
baxbarton@collegeclub.com

Pollen and plant macrofossil analysis of samples associated with the Kirkland/Lakeview Elementary School mammoth site (Barton and Kester, 2001) provide information on the composition of parkland and periglacial steppe vegetation during the late Olympia non-glacial period. The exposed section ranges lithologically from a basal lacustrine clayey silt to a fibrous peat capped by a fluvial sand. The pollen assemblage from sediments directly associated with the mammoth tusk dates to 16,540+/-80 14C yr B.P. (19,710 cal yr B.P.)[CAMS-70709]. Pollen from this assemblage is dominated by Cyperaceae (46%), Poaceae (14%), Artemisia (4%), Pinus cf. contorta (12%), Picea cf. engelmannii (2%), and Populus (4%). The nonarboreal component accounts for roughly 78% of the total pollen count. Reconstruction of the paleoenvironment, using both pollen and plant macrofossils associated with this assemblage, suggests an oligotrophic lacustrine setting surrounded by a fen margin with distal parkland vegetation. A modern analogue for this assemblage is the present-day subalpine parklands of the northern Rocky Mountains. This analysis suggests a cold, dry climate for the Puget lowlands during this time interval.

GSA Abstracts with Programs Vol. 34, No. 5, April 2002.