The Primal Desert Next Door
Land of Black Volcanoes and White Sands
The primal desert next door is the land of black volcanoes and white sands
located at the north end of the Gulf of California, approximately between
Ajo, Arizona and Puerto PeÃ±asco (Rocky Point), Sonora, Mexico. In Mexico the
land is protected within the Pinacate and Gran Desierto de Altar Biosphere
Reserve and in the United States by the Cabeza Prieta National Wildlife
Refuge. The area is easily identified in satellite photos of the region.
Visitors enjoy the murals of volcanoes, dunes and vegetation in the
The area is part of the basin and range province of southern Arizona and
northern Sonora. Discover the processes that create the basin and
The basin and range structure is formed by faulting, which causes lowering
of valleys, called grabens, with the ranges (horsts) remaining in place.
Turn the wheel and see horsts and grabens forming before your eyes.
Volcanic craters are characteristic of the landscape. Molina Crater is
149 meters wide and 30 meters deep. Photo Bob Sharp.
Volcanoes are formed when molten rock, called magma, comes to the surface of
the earth. If there are no obstructions or other forces applied to
them, volcanoes may be shaped as cones. Here, visitors crawl through a
replica of a lava tube.
Winds sculpture the sands into spectacular dunes. The dune fields of the
Gran Desierto de Altar cover about 4,800 square miles. Much of the
sand comes from the Colorado River, which carries the particles from the
Colorado Plateau and Grand Canyon and deposits them at the top of the Gulf
Young scientists explore the formation of dunes.
The area is known for its namesake Pinacate beetle, living here in the
terrarium. In the exhibition, see images of local flora and fauna, including
amphibians and reptiles, birds, arthropods, mammals, wildflowers, cactus and
Sidewinder, the rattlesnake Crotalus cerastes, named for its sideways
Teddy Bear Cholla. Courtesy Arizona Sonora Desert Museum.
The area seemed so foreign and forbidding, Apollo astronauts trained here,
1965-1970. Apollo 14 Commander Alan B. Shepard (second from right), Apollo
10 lunar module pilot and Apollo 17 Commander Eugene H. Cernan (far left),
X-15 pilot and Space Shuttle Discovery Commander Joe H. Engle (second from
left), and geologists Richard H. Jahns (far right) and James T. Gutmann
(center). Image (S70-29573) SAL, NASA, Johnson Space Center.
At the opening, Larry Marshall and Clark Blake sign copies of their book on
which the exhibition is based, Land of Black Volcanoes and White Sands,
which is available in the museum store. Photo courtesy of Peter L.
53 N. Macdonald
Mesa, AZ 85201
(One block north of Main Street in downtown Mesa. Take US 60 or 202 to
Country Club Drive, go to Main Street, and proceed one-half mile east to