Crystal White Waves

How the Glistening Dunefields of White Sands National Monument Came to Be
Double rainbow through rains on sunlit white sand dunes
Raymond Lee, Share the Experience

Love to sled, but hate the cold and wet of snow? Maybe it’s time to put White Sands National Monument onto your winter travel itinerary. In fact, it’s possible to go sledding on the beautiful, soft, white sand dunes in the heart of New Mexico’s Tularosa Basin year-round.

A man walking up white sand dunes with his daughter and a sled in White Sands National Monument
National Park Service

The sand dunes here are special because they’re made up of gypsum, a mineral rarely found as sand and more commonly found as large crystals or dissolved in water. It's so ubiquitous, it can be found in your drywall, shampoo, and even in tennis court clay.

It all started with the Pangaea 280 million years ago when parts of what we now call New Mexico were covered by the ancient Permian Sea, rich with minerals including gypsum.

The moonrise over White Sands National Monument
John Fowler (snowpeak, flickr)

Things began to shake up about 70 million years ago as the tectonic plates collided to create tall mountain ranges while other parts of the earth’s crust pulled apart, making fault zones and basins, including the Rio Grande rift, which trapped gypsum deposits in the Tularosa Basin nestled between the newly-formed ranges.

Gaint gypsum crystals in the evaporated lake bed of Lake Lucero at White Sands National Park

Gypsum crystals in Lake Lucero

National Park Service

During the last Ice Age, rain and snowmelt carried even more gypsum from the surrounding landscape into the basin, settling onto the lakebed of ancient Lake Otero. After the Ice Age ended, Lake Otero evaporated, leaving concentrations of crystalline gypsum, selenite, in the dry lake bed, or playa.

Over time, freezing and thawing broke selenite into progressively smaller chunks, eventually turning it into gypsum sand. These grains of sand moved a few inches at a time over thousands of years, eventually forming the famous white sand dunes.

Today, the white sand dunes are still being formed (albeit much slower) as the gypsum crystals in modern-day playa, Lake Lucero, are exposed and broken down.

View of White Sands National Monument from space

The deposit of gypsum sand is so large, it can be seen from space


Thinking of visiting the ever-changing landscape of this New Mexican national park? Learn more about ways you can explore the wave-like dunes of White Sands National Monument here.

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