Geomorphology and OSL Ages Estimates of a Nipissing Beach Ridge/Dune Complex Near Kangaroo Lake, Door Peninsula, WI

This study focuses on the geomorphology and geochronology of a beach ridge/dune complex near Kangaroo Lake, on the Door Peninsula of Wisconsin.   These features are located on a strand-plain ~800m inland from the present day level of Lake Michigan (~ 177 m) at the Nipissing highstand shoreline (~184 m).  Within the Nipissing strand-plain complex, smaller beach ridges and dunes are closer to Lake Michigan and have up to ~6 m of relief, while the largest ridge is furthest from Lake Michigan and is covered with parabolic dunes that have up to 25 m in relief.  Our investigation focused on eolian sand and included optically stimulated luminescence (OSL) dating, particle-size analysis (PSA), GIS analysis of a LiDAR-based DEM, and ground penetrating radar (GPR).

Preliminary OSL ages from eolian sand at Kangaroo Lake indicate that dunes were active between around 6.6 and 3.7 ka.  Previous research conducted at Clark Lake, located ~11 km to the southwest of our study site, indicates that dunes were active multiple times in the late Holocene from ~7 to 1 ka.  Unlike the results from Clark Lake, there is little evidence suggesting that dunes were reactivated in the late Holocene at Kangaroo Lake. Therefore, factors other than regional climate variability, such as sediment availability, may have influenced the differences in eolian activity at these two sites. This research was conducted by the Dune Undergraduate Geomorphology and Geochronology (DUGG) project, funded by the National Science Foundation Research Experience for Undergraduates program.