Cliff-top dune

Cliff-top dunes, also known as perched dunes, are dunes that occur on the tops of cliffs. They are uncommon in most parts of the world, because they only develop under unusual geomorphological conditions. Processes by which they may be formed include:

a dune advances up a pre-existing slope, which is then eroded to form a cliff;
a dune forms during a period of high sea level, then sea level drops, exposing a cliff face.

They are most often seen as coastal landforms, but can also occur along lakes and rivers, and in deserts. Places where they are relatively common include the west coat of Jutland, Denmark. They can also be found in certain places along the shores of the Great Lakes in Michigan, including the Grand Sable Dunes in Pictured Rocks National Lakeshore and in the Sleeping Bear Dunes National Lakeshore, most dramatically on South Manitou Island.

References

Saye, Samantha E., Kenneth Pye and Lars B. Clemmensen (2006). "Development of a cliff-top dune indicated by particle size and geochemical characteristics: Rubjerg Knude, Denmark". Sedimentology. 53: 1–21. Bibcode:2006Sedim..53....1S. doi:10.1111/j.1365-3091.2005.00749.x.

Coastal geography

Landforms	Anchialine pool Archipelago Atoll Avulsion Ayre Barrier island Bay Baymouth bar Bight Bodden Brackish marsh Cape Channel Cliff Coast Coastal plain Coastal waterfall Continental margin Continental shelf Coral reef Cove Dune cliff-top Estuary Firth Fjard Fjord Freshwater marsh Fundus Gat Geo Gulf Gut Headland Inlet Intertidal wetland Island Islet Isthmus Lagoon Machair Marine terrace Mega delta Mouth bar Mudflat Natural arch Peninsula Reef Regressive delta Ria River delta Salt marsh Shoal Shore Skerry Sound Spit Stack Strait Strand plain Submarine canyon Tidal island Tidal marsh Tide pool Tied island Tombolo Windwatt

Beaches	Beach cusps Beach evolution Coastal morphodynamics Beach ridge Beachrock Pocket beach Raised beach Recession Shell beach Shingle beach Storm beach Wash margin

Processes	Blowhole Cliffed coast Coastal biogeomorphology Coastal erosion Concordant coastline Current Cuspate foreland Discordant coastline Emergent coastline Feeder bluff Fetch Flat coast Graded shoreline Headlands and bays Ingression coast Large-scale coastal behaviour Longshore drift Marine regression Marine transgression Raised shoreline Rip current Rocky shore Sea cave Sea foam Shoal Steep coast Submergent coastline Surf break Surf zone Surge channel Swash Undertow Volcanic arc Wave-cut platform Wave shoaling Wind wave Wrack zone

Management	Accretion Coastal management Integrated coastal zone management Submersion

Related	Bulkhead line Grain size boulder clay cobble granule pebble sand shingle silt Intertidal zone Littoral zone Physical oceanography Region of freshwater influence

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