The mystery of the missing sand
This extraordinary dune system has an unexpectedly mysterious history. Huge amounts of sand were needed to build Kelsos 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.