Broadcast: February 19, 2003
(THEME)
VOICE ONE:
This is Steve Ember.
VOICE TWO:
And this is Mary Tillotson with the VOA Special English program
EXPLORATIONS. Today we tell about one of the world¡¯s
great natural wonders, White Sands National Monument. It is
in the southwestern American state of New Mexico. Nature has
created huge moving hills of pure white sand.
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VOICE ONE:
At White Sands National Monument, winds have formed great hills
of sand called dunes. The sand dunes cover more than seventy-thousand
hectares of desert.
It is one of the largest sand dune fields in the United States.
The bright white sand dunes are always changing, always moving,
like waves on the ocean. Driven by strong winds, the sand moves
and covers everything in its path. It is like a huge sea of
sand.
VOICE TWO:
Oryx
(Photos - National Park Service)
The sand dunes have created an extreme environment. Plants and
animals struggle to survive. A few kinds of plants grow quickly
to survive burial by the moving sand dunes. Several kinds of
small animals have become white in color in order to hide in
the sand.
White Sands National Monument protects a large part of this
dune field. It also protects the plants and animals that live
there. More than five-hundred-thousand people visit White Sands
National Monument each year. They climb on the dunes and observe
the moving sea of sand.
VOICE ONE:
You may wonder how all this sand arrived in the area. To understand
that, you would have to travel back in time two-hundred-fifty-million
years. An inland ocean once covered the area. The minerals calcium
and sulfur were at the bottom of the ocean. Over time, the water
slowly disappeared. The calcium and sulfur remained. The minerals
formed gypsum rock.
Then, seventy-million years ago, the Earth¡¯s surface,
or crust, pushed upward. The rocks formed two groups of mountains.
Later, the crust pulled apart. The area between the mountains
broke and fell down. It formed a half-circle shape of a bowl.
This bowl of rock is known as the Tularosa Basin.
VOICE TWO:
About twenty-four-thousand years ago, it rained a great deal
in the area. The rain filled the Tularosa Basin and formed Lake
Otero. The rain and snow that washed down the mountains into
Lake Otero carried gypsum with it.
Later, Lake Otero almost completely dried up. Gypsum remained.
A strong wind moved into the area. It blew across the land for
thousands of years. Pieces of gypsum broke off. The wind wore
them away to a size small enough to pick up and carry for short
distances. Wherever the wind dropped sand, dunes formed.
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VOICE ONE:
The sand dunes at White Sands National Monument are unusual
because they are made of gypsum. Gypsum sand is different from
common sand. Most sand is made of quartz, a hard silicon crystal.
Gypsum sand is made of softer calcium sulfate. It dissolves
easily in water. So it is rarely found in the form of sand dunes.
Most gypsum would be carried away by rivers to the sea. But
the Tularosa Basin is enclosed. No rivers flow out of it. So
water with dissolved gypsum has nowhere to go.
Gypsum sand is being made all the time. The dunes continue
to form and move under the influence of water and wind. Water
continues to wash down from the mountains carrying dissolved
gypsum into the Tularosa Basin. Wind continues to blow across
the Basin carrying the gypsum.
The gypsum sand grains crash into each other. The crash creates
tiny lines or scratches on the surface of the sand. These scratches
change the way light shines off the surface. This makes the
sand appear white. The sand dunes look like great masses of
bright white snow. But they are not cold and wet. It only rains
about eighteen centimeters each year.
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VOICE TWO:
There are four kinds of sand dunes at White Sands National
Monument. Some of the dunes are small and fast-moving. They
are called dome dunes because they are shaped like a half-circle.
Few if any plants grow on them. These dunes move the fastest,
up to twelve meters a year.
Other dunes are called transverse dunes. They form in long
lines across the dune field. They can grow to be one-hundred-twenty
meters thick and eighteen meters high.
Another kind of dunes are barchan dunes. They form in areas
with strong winds but a limited supply of sand. These dunes
have sand in three parts, like a body in the center and two
arms on the sides. The sand in the two arms moves faster than
the sand in the center.
Parabolic dunes are the opposite of barchan dunes. They form
when plants hold sand in the outer parts of the dune but the
center of the dune continues to move.
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VOICE ONE:
You may wonder how anything can live in this extreme environment
of a white sand desert. There is not much rain. The heat in
summer is intense. The sand lacks nutrients.
Yet almost four-hundred kinds of animals live in White Sands
National Monument. Many of them are birds or insects. There
are also twenty-six kinds of reptiles, including rattlesnakes
and lizards. And there are more than forty kinds of mammals.
They include rabbits, foxes and coyotes.
Scientists know that plants and animals often change to be
able to live in extreme environments. For example, they change
color to protect themselves from enemies. Many of the animals
that live in the sand dunes have become white. So it is difficult
to see the animals in the sand.
There is another reason why you may not be able to see the
animals. Many of them remain underground during the day when
it is very hot. They come out at night when it is cooler. You
may be able to see their footprints.
VOICE TWO:
Plants do grow in the White Sands dune field. But even plants
that grow in most deserts have trouble surviving. A major reason
is that the dunes bury any plants in their way as they move
across the desert. Yet, a few plants have developed techniques
to avoid being buried by moving sand.
For example, some plants grow taller and their roots grow deeper
into the sand. The soaptree yucca plant can make its stem grow
longer to keep its leaves above the sand. The plant grows up
to thirty centimeters a year.
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VOICE ONE:
White Sands National Monument is about twenty-four kilometers
southeast of the city of Alamogordo, New Mexico. In the visitor
center at the entrance of the park, you can find out about special
activities and guided walks. From the visitor center, you can
drive about thirteen kilometers into the center of the dunes.
It is like driving on a lonely white planet. Along the way there
is information that tells about the natural history of the white
sands.
You can also explore the dunes on foot. There are four marked
trails. Signs along the trail tell about the plants growing
in the sand. You can see some unusual and beautiful plants and
flowers growing in the sand dunes. But you may not remove or
destroy any plants or animals at White Sands.
You can even camp there overnight. But you must be careful.
It is easy to get lost in the waves of moving sand especially
during sandstorms. There is no water to drink. The temperature
can rise to thirty-eight degrees Celsius in summer. There is
no shelter from the sun¡¯s rays.
VOICE TWO:
There is another reason to be careful at White Sands National
Monument. The White Sands Missile Range completely surrounds
the park. It covers one-million hectares. The missile range
was first used as a military weapons testing area after World
War Two. It was used to test rockets that were captured from
the German armed forces. The missile range continues to be an
important testing area for experimental weapons and space technology.
These tests take place about two times a week. For safety reasons,
both the park and the road from it south to Las Cruces, New
Mexico may be closed for an hour or two while tests are taking
place.
VOICE ONE:
White Sands National Monument is part of America¡¯s
National Parks System. The park system includes more than three-hundred-seventy
protected areas. White Sands National Monument is just one of
the more unusual examples of America¡¯s natural and
cultural treasures.
(THEME)
VOICE TWO:
This program was written by Shelley Gollust. It was produced
by Paul Thompson. I¡¯m Mary Tillotson.
VOICE ONE:
And I¡¯m Steve Ember. Join us again next week for
EXPLORATIONS, a program in Special English on the Voice of America.
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This V-O-A Explorations Report is published
courtesy of VOAnews.com
