New Mexico offers some truly otherworldly experiences; it’s no wonder UFO and alien theories abound in the area (we thought about visiting Roswell to learn about UFOs, but ultimately decided not to take the time). I previously told you about touring Carlsbad Caverns, which makes me feel like I am in a sci-fi castle, now we go to
Mars Whitesands National Monument. I do not make the comparison of the monument to Mars lightly; researchers actually use this unusual landscape to understand how sand dunes at Mars’ north pole, Olympia Undae, migrate because they are so similar.
Tularosa Basin, a geographical feature in New Mexico, is a valley surrounded by mountains at the northern end of the Chihuahuan desert. Pure white hills rise from the heart of this basin, 275 square miles of white sand dunes. You must be wondering what material could possible form white sand dunes. This phenomenon can only exist in a desert; the sand is made of gypsum, a water soluble mineral. You may be familiar with it as the main component of plaster. But in the dry and windy desert, this material can form sand dunes!
Whitesands National Monument sits in the middle of a missile range, and hours of the park and access highway are subject to missile tests. The first atomic bomb test was detonated just north of the monument.
Rains falling on the surrounding mountains, the Sacramento range to the east and San Andres to the west, dissolve gypsum out of the stone and carry it into the Tularosa Basin. Once in the basin, the waters collect in lake and cease flowing – there is no drainage out of the basin towards the ocean. This lack of drainage is what makes this place so special. Everywhere else that rain dissolves gypsum out of stone, it is eventually carried away out to the ocean, but here it has no where to go. The waters collect in Lake Lucero during the monsoon season, then evaporate leaving behind giant gypsum crystals. The crystals are soft and easily flake off with a little weathering. Strong winds push them along, rolling and breaking into smaller and smaller fragments, from large crystals along the lake shore, to crystalline flakes that cover the alkali flats adjacent to the lake, to sand that forms the dunes of Whitesands National Monument, and finally to dust that blows up and out of the basin.
The few animals that inhabit the white sands have adapted to the white environment by turning white themselves. These include a couple species of lizard; a pocket mouse, several insects, and the top of the local food chain, the kit fox. Plants also have interesting adaptations to live in the ever shifting dune-field. The soaptree yucca elongates its stem to keep the leaves above a growing dune; this yucca meets its demise when the dune advances past it because the stem cannot support the plant without the surrounding sand; it falls over and breaks. The sumac bush forms a dense network of roots through the dune to tap into the ground water below. The roots are moist with the water they carry, which moistens the gypsum to form a plaster pedestal. Surprisingly, one species of tree even lives within these dunes; the cottonwood tree can survive being buried by gypsum as long as it keeps some branches and leaves above the surface to reach the sunlight and air. All these plants depend on the cyanobacteria to supply nitrogen. This bacteria forms the brown crust in the interdunal areas; when people break it by walking over it, it takes five years to reform.
At the edges of the dune fields more desert animals can be found, such as coyotes and jackrabbits. More plants grow on the edges to provide cover, and the animals can retreat away from the white sands for water. The interpretive nature trail in the park is at the edge of the dune field, and climbing up on the last dune offered amazing sunset views.
In many ways walking through gypsum dunes feels like walking through snow-coated hills. The color of the landscape, of course, but there are other similarities. The road is plowed and gypsum piles up on either side like plowed snow. You can play in the sands just like in snow! The gift shop sells plastic disk sleds, which we took advantage of. Sledding on sand is different than sledding on snow…much slower, so the trick is to find a slope that looks way to steep to possibly attempt, and then go for it! We had a wonderful time playing on sand dunes like school children on a snow day.