Geomorphological Study of Late Holocene Lake Michigan Strandplain Sediment in the Door Peninsula, WI

Understanding shoreline systems in the Great Lakes helps us understand more complicated coastal systems. Our study focuses on the geomorphology and geochronology of a late Holocene Lake Michigan shoreline complex on the Door Peninsula of Wisconsin. These features are located ~1 km inland from modern Lake Michigan and include dunes, beachridges and strandplains.  We used optically stimulated luminescence (OSL) dating, particle-size analysis (PSA) and ground penetrating radar (GPR) to estimate ages and determine past depositional environments of these landscapes.  Previous investigations indicated that the dunes were active between approximately 6 and 4 ka, and the PSA revealed that eolian sediment at this region was primarily medium sand that directly overlies coarse gravelly sand. This project seeks to further understand the evolution of the shoreline complex by optically dating strandplain sediments. By linking near shore or littoral sediment with dune sediment, we want to determine the depositional past that led to the stabilization of these dunes. In addition, our new age estimates will help us determine if these dunes were a result of sediment supply at the time of deposition or simply a matter of prolonged accumulation through the years in a dynamic climate. Preliminary ages indicate that there could have been more sediment supply at the time of deposition due to the close proximity of lake sediment ages and dune sediment ages. This research was conducted by the Dune Undergraduate Geomorphology and Geochronology (DUGG) project, funded by the National Science Foundation Research Experience for Undergraduates program.