Widespread Middle Holocene Dune Formation in the Eastern Upper Peninsula of Michigan and the Relationship to Climate Outlet-Controlled Lake Level

 

 

Alan F. Arbogast, Ann G. Wintle, and Susan C. Packman

 

            Dating of five widely spaced (noncoastal) dunes in eastern upper Michigan by optically stimulated luminescence (OSL) of quartz establishes that eolian sand was last mobilized between ca. 7 and 5.5 ka in the region. Although this interval corresponds to the drier Altithermal-Hypsithermal period, climate alone may not have been sufficiently arid to cause dune formation in this area. Instead, it appears that dune formation may also be linked to depressed water tables, associated with outlet-controlled low levels in Lakes Michigan and Superior. Following dune stabilization, peat began to accumulate in interdune areas at ca. 4.4 ka.