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Geology of Mojave National Preserve: Kelso Dunes

Kelso Dune view

The mystery of the missing sand

This extraordinary dune system has an unexpectedly mysterious history. Huge amounts of sand were needed to build Kelso's delicate wind-created sculptures, but geologists studying the Preserve discovered that no new sand is moving in to replenish the dunes. Where did the sand originally come from? What made it stop accumulating? The Kelso Dune sands remained a mystery until very recently.

Back to the source

By studying the mineral composition and shapes of sand grains that make up Kelso Dunes, we know that most of the sand has traveled all the way from the Mojave River sink east of Afton Canyon (map). Wind blowing from the northwest gradually carried the sand southeastward. In the path of the prevailing winds lie the Providence Mountains and the pink pinnacles of the Granite Mountains. The rocky crags and sloping fans of the two ranges block the moving sand. Sand piles up at the base of the mountains and along their flanks, forming dunes and sand sheets.

Stack 'em up

Where the sand piles up researchers found that the dunes are actually made up of several sets of dunes, stacked one on top of another. Each set formed in response to some past climate change! The Kelso Dunes depend upon times when the sand grain (sediment) supply is enhanced. This happens whenever the climate is dry enough to expose the raw material of dunes, sand, to the wind. In fact, most of the eastern part of the Kelso Dunes formed when water-filled Soda Lake and Silver Lake dried up, exposing the lake bottom sediment. The entire dune system was stacked up in five major pulses over the past 25,000 years.
There is a surprising variety of plant life living in the hollows and stabilized parts of the Kelso Dune complex
There is a surprising variety of plant life living in the hollows and stabilized parts of the Kelso Dune complex.

Plants move in

Over the past few thousand years plants have progressively covered and stabilized areas once covered by drifting sand. As you explore the dunes look for tracks left behind by the many creatures that call these dunes home.
How many different animals left their foot and tail prints here?  This photo was taken early in the morning. Most desert animals are active during the coolest time of day.
How many different animals left their foot and tail prints here? This photo was taken early in the morning. Most desert animals are active during the coolest time of day.

How many different animals left their foot and tail prints here? This photo was taken early in the morning. Most desert animals are active during the coolest time of day.

 

 

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Map of Kelso Dunes showing active and relict dunes and sand sheets

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