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A geochronology-supported soil chronosequence for establishing the timing of shoreline parabolic dune stabilization

Fulop, Emma C.F., Johnson, Bradley G., Keen-Zebert, Amanda
Catena 2019 v.178 pp. 232-243
B horizons, E horizons, barium, chronosequences, coasts, cobalt, dunes, iron, leaching, luminescence, magnesium, shorelines, soil chemistry, zinc, Lake Michigan
Detailed dune chronologies are required to understand the complex drivers of dune stabilization and activation. Stabilized parabolic dunes provide ideal study sites to examine dune stabilization because their geomorphic histories are more straightforward than other dune types. Here, we present optically stimulated luminescence (OSL) stabilization chronologies for two complexes of fully stabilized, parabolic dunes along the eastern coast of Lake Michigan with the goal of clarifying the timing and consistency of dune stabilization along the shoreline. Further, we use this chronology to calibrate a soil chronosequence for use in future dune chronologies. We found periods of stabilization at 4.0 ka, 2.8–2.0 ka, and 1.2–0.4 ka that complement existing periods of stabilization identified as the Nipissing, the Algoma, and Modern. Soils in the area appear to develop consistently and predictably over the last ~4000 years. The strongest indicators of age are depth to the B horizon and thickness of the E horizon. Well-developed E horizons also appear to form between the Algoma and Modern stabilization periods creating a useful proxy for quickly differentiating between otherwise similar landforms. The impact of leaching is also evident in the soil chemistry as Zn, Co, Mg, and Fe all decrease in the eluvial zone through time while Ba steadily increases. Overall, our study closes a gap between chronologies further to the north and south, clarifies the consistency of stabilization periods along the coastline, and creates new tools for quickly estimating dune stabilization ages.