Lake Michigan Coastal Dunes
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Lake Michigan Coastal Dune Home
Introduction to Lake Michigan Coastal Dunes
Features and Types of Dunes
Wind, Sand and Coastal Dunes
Climate, Dune, Lake and Seasonal Factors
Methods, Results and Research Students
References and Links to More Information


 
Dunes - Perched dunes    

Perched dunes exist on a surface that is above the level of Lake Michigan. Most perched dunes form when wind travels up a coastal bluff or cliff and removes fine material from the slope along the way. Sand-sized materials are deposited on top of the bluff to form a dune. Finer material (clay and silt) can be removed from the area entirely by the wind.

Sleeping Bear Dunes National Lakeshore has some spectacular examples of perched dunes. The dunes sit on top of glacial moraines which rise 30 to 120 meters (90 to 360 feet) above Lake Michigan.

  Perched dunes in Sleeping Bear Dunes National Lakeshore
Wind travels up the bluff (from right to left in photo), picking up sand along the way and depositing it on top of the bluff. The grass-covered mounds of sand are dunes; the rest of the slope from the dunes down is a glacial deposit.(Sleeping Bear Dunes National Lakeshore. Photo from R. Stearley, 1997).  

 

 

South of Grand Haven, dunes perched on lake terraces have their bases a mere meter (3 ft) or so above the lake. A tell-tale sign that these dunes are resting on something other than dune sand is the presence of clay layers or mixed sizes of materials at the bottom of the slope.
                

 

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Last updated 03/23/10.