Geological Society of America

47 Quaternary Geology (Posters)

Monday, 21 March 2011
1:30 PM - 5:30 PM
Grand Ballroom

HOLOCENE OSL AGE ESTIMATES OF PARABOLIC DUNES ALONG THE WESTERN SHORE OF LAKE MICHIGAN, DOOR PENINSULA, WI, USA: INSIGHTS ON THE COASTAL DUNES GEOMORPHIC HISTORY

Paper number: 47-9
Program: Technical Sessions
Time: 1:30 PM – 5:30 PM

Authors

Irina Beal
Bates College, Lewiston, ME
Paul R. Hanson
University of Nebraska-Lincoln, Lincoln, NE
Brooke Burich
University of Wisconsin-Stevens Point, Stevens Point, WI
Nick Flinner
University of Wisconsin-Platteville, Platteville, WI
Nicole Grabos
Indiana University Northwest, Gary, IN
Eric Grazia
University of Wisconsin-Madison, Madison, WI
M.H. Hanson
Whitman College, Walla Walla, WA
Bethany Meskel Presenting Author
Slippery Rock University, Slippery Rock, PA
Jody Wycech
Grande Valley State University, Allendale, MI
J. Elmo Rawling
University of Wisconsin Platteville, Platteville, WI

Abstract

A detailed study of the geomorphology and geochronology of dunes on the northwestern shore of Lake Michigan at Whitefish Dunes State Park, Door County, Wisconsin was conducted. Three-meter LiDAR, aerial photographs, and field observations reveal a series of parabolic dunes superimposed on an 800 m wide strand plain that separates Lake Michigan from Clark Lake. There are two distinct sets of dunes, larger dunes (18-24 m relief) adjacent to Lake Michigan and smaller dunes (3-7 m relief) farther inland. Closer to Clark Lake are a series of approximately 1 m tall beach ridges. The parabolic dunes show a paleowind direction of SSW. Percent coarse sand composition along transects between the modern beach and dunes distinguish between eolian sediment (~2.7%) and beach sediment (~18%). Particle-Size-Analysis (PSA) along with Ground Penetrating Radar (GPR) distinguished dune and beach strata.

Sixteen samples were collected for Optically Stimulated Luminescence (OSL) from paleo-beach sediment (n=2) and dune crests (n=14). These samples were processed using the single-aliquot regenerative method with 90-180 mm quartz grains. OSL ages are 4.6 ka for a beach ridge landward of the dunes and 4.4 ka for beach sand underlying the dunes. OSL ages of the dune crests ranged from 7.8 to 1.9 ka. Eight dune ages fell between 5.2 and 4.0 ka, which correlates with the Nippising Lake Level High (6.0-4.3 ka). The similarity between the dune and beach sediment ages suggests rapid dune formation and stabilization. Three dune ages between 2.6 ka and 1.9 ka suggest that some dune activation may have been associated with the Algoma Transgression (3.3-2.3 ka). This research was made possible by the Dune Undergraduate Geomorphology and Geochronology Project, a National Science Foundation Research Experience for Undergraduates.