The Kelso Dunes

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The Kelso Dunes

• Everything you wanted to know
• (and probably more)

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Quick Facts

• Active, 3rd highest dune system in the Western
  Hemisphere
• ?10,000-20,000 years old, best guess 14,000 (hard
  to tell because of the lack of datable matter)
• 45 sq miles in the Southeast of MNP
• Highest reach elevations of over 600 ft above the
  desert floor
• Lat/Long 115º 43 05W, 34 º 54 12N

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Setting

• Devils Playground bounded on all sides by raised
  terrain.
• -North Kelso Mts
• -South Granite Mts.
• -East Providence Mts.
• -West Bristol Mts.

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Formation

• Alluvium carried by the Mojave River system is
  deposited in Soda Basin
• Prevailing winds blow sand from the Afton Canyon
  35 mi. across Devils Playground
• Wind hits the Granite and Providence Mts (over
  7,000 ft high) and deposits its load
• Shifting winds keep the dunes from
  flatteningalmost perfect balance between erosion
  and deposition.

• Why did they form where they are?
• Perhaps a node among shifting winds

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Sand! Sand! Sand!

• 50-80 quartz and up to 50 feldspar, indicating
  sand is less mature than some thought
• Darker and denser minerals crown the dunes such
  as amphibole and the iron oxide magnetite
• Grains rounded, but pitted from impact

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Small-Scale Sand Transport

• Sand migrates downwind
• Grains usually travel at low heights (lt 1.5 ft
  off the ground)
• About 3/4 bounces and about 1/4 rolls

• Sand travels several feet with each hop
• If you stand on the lee side in a storm, you are
  deluged by falling sand as wind velocity ? 0 (no
  back eddies)

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Ripples and Transverse Dunes

• Perpendicular to wind direction, capturing the
  most sand
• Wind picks up sand from succeeding hollow and the
  windward slope of the next dune
• Upper windward side is firmly packed
• Dunes transverse ridges 200-300 ft. long

• Ripple- mini transverse dune- formation
  requires strong winds (gt25 mph)

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Winds

• Prevailing winds from the west blow sand from the
  Mojave River wash coming out of Afton Canyon
  across Devils Playground.
• Providence Mountains block further movement

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Shifting Winds

• Landscape channels winds to gentle prevailing
  west-northwesterlies
• Balanced by occasional strong storm winds from
  all directions
• Mountains create shifting local winds
• Shifts in wind direction over time can be seen
  in cross-bedding

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Angle of repose

• Windward face 10-15º
• The maximum angle of repose on the leeward face
  is 34º
• When the sand exceeds this angle, a
  mini-avalanche sends tongues of sand rolling down
  the leeward face

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The Influence of Water

• Floods renew the sediment supply, the Afton
  Canyon outwah plain
• When it rains, sand moves west again, the wind
  picks it up and transports it back
• Sand wicks water below the surface, remains moist
  just a few feet down

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Noisy Dunes
Musical

• Related to moisture content and grain type
• Possible Causes
• Quick compression of the sand and minerals in it
• Extreme dryness, wind-polished, well-rounded
  grains of sand
• Sand of polished quartz slides over the
  underlying surface

Barking
Booming
Singing
Diesel locomotive
1950s doo-wop
Tibetan Gong
Chorus
Kettle Drum
Low-flying airplane
Mythological Siren
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Dune Ecosystem
Flora

• 100 varieties of plants live on or near the
  dunes
• pink sand verbana
• yellow desert primrose
• grasses (galleta grass)
• mesquite and cresote on outer dunes
• Lepidopterans
• Clusters of willows on the dunes south face were
  probably established in a wetter period, but some
  continue to grow.

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Dune Ecosystem
Fauna

• Insects found nowhere else
• e.g. Jerusalem Cricket
• Kelso giant sand treader cricket

• Ground squirrel
• packrat
• sidewinders
• lizards
• kit foxes
• coyote
• antelope
• Several species of bird (including ravens)

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Conservation Issues and the Dunes

• BLM began its control of the dunes in 1946
• Off-roading in the area was popular between from
  the early 1950s to 1973
• Aerial photos show density of shrubs reduced by
  50
• Some mining of sand. With false claimes of
  precious minerals, owner held onto
  grandfathered-in claims after a 1972 law withdrew
  Kelso Dunes from mineral entry.
• Since 1973, has been a Wilderness Area with
  elimination of mining claims, it truly became one
  in the early 1990s.

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