Alamogordo, New Mexico

Our next stop was Alamogordo where we stayed at the Elks. Along the short drive to our destination, we could see the black streak of the malpais to the west. 

Not too much further, the contrasting white of the gypsum dunes started to appear. 

Here is a map showing the relative locations of Valley of Fires and White Sands NM, courtesy of GoogleMaps. The black "river" of malpais and the bright white gypsum deposits are clearly visible.

The attraction in Alamogordo is the White Sands National Monument, which we visited back in 2002 during our Eurovan fly-by touring days. The dunes were impressive then and even more so now because we spent more time exploring and learned more about their unique formation. 
We also went on a ranger-led hike across the dunes and watched a spectacular sunset while a full moon was rising. It was enchanting.

The impressive dunes started to grow 10,000 years ago in a process that continues today. The 250-million-year-old gypsum found in the surrounding mountains dissolves with snowmelt and rains. It drains, mostly underground, and settles here in the Tularosa Basin. With summer monsoons or heavy snows, groundwater levels will rise above the surface. Lake Lucero, a large mineral-rich temporary lake, reappears southwest of here. Wind and sun separate the water from the gypsum and form selenite crystals. Wind and water break down the crystals making them smaller and smaller until they are sand. Steady, strong southwest winds keep gypsum sand moving, piling it up and pushing dunes into various shapes and sizes. One constant about this area is that it is always transforming, often at a fast rate. 
Several information boards best explained an overview of the evolution of the geology that caused the dunes. The story is a familiar one, the result of inland seas retreating followed by tectonic plates pushing and pulling, then creating mountains with a basin, which in this case resulted in the phenomenon of the white gypsum dunes that cover an area of 275 square miles. It is the largest gypsum dunefield in the world. White Sands National Monument preserves more than half of this oasis, its shallow water supply, and the plants and animals living there.

We spent a pleasant sunny afternoon driving in the park. The approach to the dunes was pretty. 

But the dunes themselves were spectacular, an unreal mirage blinding you with its whiteness. Under a piercing blue sky, the white seemed even whiter.

We went on a short hike across the dunes. The gypsum made a squeaky sound as we tromped in our hiking boots, yet was soft and powdery.

Along the Interdune Boardwalk, I learned a few interesting facts about gypsum. 

It is also found on Mars.

Gypsum is the reason that many animals have adapted to a white color to survive better and this phenomenon provides scientists an opportunity to observe the evolutionary process. The lighter color reflects heat which keeps animals cooler and hides them better than their darker cousins just a few miles away.

The most fascinating fact is that gypsum continues to be a valuable mineral. It's the main ingredient in drywall and plaster of Paris, and a $100-million-a-year industry. It is also a mineral found in all kinds of household products, medicines, and food like bread, toothpaste, ice cream, beer, wine, cheese and is of course the main ingredient for casts to set broken bones. According to the information board, during my lifetime I will eat an average of 28 pounds of gypsum. 

pedestal formed by sumac

On our ranger-led dune hike, it was again surprising to see how many plants grow in this unfriendly and constantly changing  environment. Adaptation helps the few shrubs like skunkbush sumac grow dense, deep roots that help form a pedestal after the dunes move on. Animals find shelter in the pedestals. As sand buries the soaptree yucca, its stem grows longer to keep new leaves above the sand. Sadly after the dune shifts and moves on, the exposed yucca soon falls over and dies.

yucca

Our ranger-led hike was the highlight of this visit. Watching the sun setting was very memorable, the clouds glowing pink and bright. 


And the white moon rising over the white dunes was quite surreal.