LATE QUATERNARY DUNE ACTIVITY IN THE CENTRAL AND LOWER WISCONSIN RIVER VALLEY

Dunes are commonly found on sandy glaciofluvial and glaciolacustrine deposits in the Wisconsin River valley. In Wisconsin's Central Sand Plain (CSP), dunes are found on Glacial Lake Wisconsin sediments that lie to the southeast of Wisconsin River terraces. In the lower Wisconsin River Valley (LWRV), near the town of Muscoda, dunes lie on two Wisconsin River terraces that have been attributed to Glacial Lake Wisconsin outburst flooding. We used optically stimulated luminescence (OSL) dating to provide age estimates for dune activity in both settings. In the CSP 18 OSL ages suggest that most of the dune activity occurred between 14-10 ka. Preliminary age estimates from the LWRV also suggest that most dunes were active between 14 to 10 ka. A total of seven OSL age estimates from the two settings suggest dunes may have moved between 10-4.8 ka. However, six of these samples were taken from within 2 m of the ground surface, suggesting that if dune activity occurred after ~ 10 ka it was likely limited to isolated dune crests.