West of the Guadalupes

PART 1:

The Gypsum Sand Dunes of Guadalupe Mountains National Park, Texas

1.  Orientation and Start

This map-photo (based on a Bing image) show you where we are going:

This next photo shows an interesting thing, to me: water running off the mountain range would tend to move things away from the mountain, but wind tends to move dust and sand toward the mountain --especially the peak-velocity winds from southwest to northeast that preceded frontal passages-- until the winds slow as they compress and lift across the mountain.  Hence the shape of the gypsum hills, pushed forward by these highest winds then ending abruptly.  Note the brownish dune area just ahead of the gypsum dune area (next photo shows a ground view):

If these peak winds bring these sand-size particles this far, what about the lighter silica-sand, silt, and clay sized particles?  They go a bit farther of course, but then also settle out and make dunes.  A line of those lighter-particle dunes, with tan silica sand (rather than white gypsum sand), silt, and clay, are visible here just a short distance away from the gypsum sand dunes:

This is obviously not the same scale as the White Sands National Monument west of here, that is a much bigger place and the gypsum sand is whiter.  But it is the same phenomenon that made these gypsum-sand hills.  Water from the mountains evaporates and lays down whatever salts it contains, and the first is gypsum which lines the dry lakes to the south and west of here.  As it precipitates it gets moved about by wind, and kernels of gypsum get carried away by the strongest winds coming up this valley and get dropped where the air-stream rises and slows, losing its carrying ability.

Finally this photo shows some of the detail, at about the limit to which these Bing satellite photos can be expanded:

So let's start our walk now, on a trail from the parking lot that was a road at one time:

That is Audrey on the trail, moving on and somewhat impatient with my just having to take cholla-cactus-flower-photos:

The trail is about two miles, and there is not much to see except for these beautiful denizens of the desert, and behind this particular one is the boundary of the gypsum hills:

 

Soon we are at the edge of the bowl with the dunes in it:

There are two trails from the access trail into the white dunes, this is the one we chose to go up (it is not the authorized trail, but gets plenty of use, the authorized trail is about a quarter mile further is all:

We will walk the dunes on the next dunes page linked below.

Go to the Gypsum Sand Dunes of Guadalupe Mountains National Park, Texas

2.  Walking the Dunes

3.  Peak Experience

4.  Denouement

Go to the Cornudas Mountains of Texas and New Mexico

1. Some Geology and Sociology Lessons

2. Cornudas Mountains Highlights

3. Leaving the Cornudas Mountains

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