Day 51 April 24

We went to White Sands National Monument today.  White Sands has the largest deposit of gypsum sand in the world.  Here is a short explanation of how they form from the National Park Website

"The largest gypsum dune field in the world is located at White Sands National Monument in south-central New Mexico. This region of glistening white dunes is in the northern end of the Chihuahuan Desert within an "internally drained valley" called the Tularosa Basin. The monument ranges in elevation from 3890' to 4116' above sea level. There are approximately 275 total square miles of dune fields here, with 115 square miles (about 40%) located within White Sands National Monument. The remainder is on military land that is not open to the public. This dune field is very dynamic, with the most active dunes moving to the northeast at a rate of up to 30 feet per year, while the more stable areas of sand move very little. The pure gypsum (hydrous calcium sulfate) that forms these unusual dunes originates in the western portion of the monument from an ephemeral lake or playa with a very high mineral content. As the water evaporates (theoretically as much as 80" per year!), the minerals are left behind to form gypsum deposits that eventually are wind-transported to form these white sand dunes. Many species of plants and animals have developed very specialized means of surviving in this area of cold winters, hot summers, with very little surface water and highly mineralized ground water."

Basically this means that it is like a gypsum sand making machine.  Water washing down the local mountain dissolves the gypsum.  The water collects in a shallow lake called a playa.  The sun evaporates the water and leaves the gypsum behind.  The wind than blows the gypsum crystal into the dune area. In the process breaking down the crystals into very fine sand. The process is very efficient having created 275square miles of dunes in a few thousand  years.

 Climate change led to this interesting system to develop.  Also in the park are found fossilized foot prints of Mammoths.  Mammoths and camels were hunted to extinction by the local Indians which forced them to take up farming.  This led to the cliff dwellings and petroglyphs we see in the area.

Jane on her way with a little help.

There is a lot of sand.

The other fun thing you can do is slide down the dunes on sleds like they are snow.  The sand is so fine it acts similar to fine snow.