BRN 9-4 - Flipbook - Page 63
3) Guadalupe National Park, Texas. All three are in the
Chihuahuan Desert.
San Andres Mountains Access
As noted in the article by Ken Logan and Linda Sweanor,
access to the San Andres Mountains is severely restricted.
For the most part only researchers are allowed into the area.
Whether they be naturalists like Logan and Sweanor;
historians, like Laumbach; or anthro-archeologists like the
teams doing excavations at Lake Lucero, the nature and
extent of the work being done is carefully deÞned and
delineated by the military.
That is not to say that there is no access, however. What
follows are two examples, one a recurring opportunity, the
other of the type which requires vigilance to ferret out.
Reprint of an article from
the April 2025 Issue of BRN
Lake Lucero & White
Sands National Park
The gypsum dunes of White Sands National Park are not
unique, but they are one of the most dramatic
manifestations of this land form. They cover 275 square
miles of the Tularosa Basin. To the west of the dunes lies
the Alkali Flat, whose southwestern end is the area now
known as Lake Lucero covering an area of about 10
square miles. The dunes, the ßat, and the lake are all part of
a dynamic geologic process which may have started 24,000
years ago. At that time gypsum was dissolved in water, in
both the San Andres Mountains to the west and in the
Sacramento Mountains to the east of the Tularosa
Basin. This runoff formed Lake Otero, which is estimated to
have been about 1,600 square miles in area. By about
12,000 years ago the inßuence of the last glacial period had
waned and Lake Otero began the slow process of
evaporation, concentrating the gypsum in the Basin. Lake
Otero gradually diminished in size, and its remanent is what
we now call Lake Lucero.
Rainwater (from the sky and as runoff) periodically pools in
Lake Lucero and then evaporates out. The concentrated
gypsum in the area forms selenite (CaSO¤á2H¢O) crystals.
These crystals break down into the white sand which forms
the dunes to the east of the lake. (Prevailing winds in
the area are to the east and north.)
Selenite is very soft (a hardness of 2 on the Mohs scale - you
can scratch it with your Þngernail) and it readily forms
beautiful crystals. See images on this page of the playa
(Lake Lucero when it is wet) and crystals from the
playa.
End of Reprint
Ed. note: DonÕt expect a solitary experience on
the National Park outings. Additional photos from Lake
Lucero are shown on the following two pages, several with
the San Andres Mountains in the background.
Tours of the lake, which is in a restricted zone, occur
periodically. Contact the White Sands National
Park headquarters for details.
The dunes of White Sands National Park are the largest
concentration of gypsum dunes in the world. The three
largest gypsum dune complexes are located at: 1) White
Sands; 2) Cuatro Cienegas, Coahuila, Mexico; and
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