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
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.