Whtie Sands Administrative History

The geologic history of the dunes began millions of years ago, when natural forces created the Tularosa basin. The basin extends for 150 miles in length, and averages fifty miles in width. The area of the White Sands dunes (within and outside the monument boundaries) stretches some 275 square miles, with average dimensions of 27 miles long and ten miles wide. Some forty percent of the dunes are within the monument itself, while the remainder lie on the property of the White Sands Missile Range (WSMR), the U.S. Army's huge weapons testing center to the north and west of the monument. [9]

Natt N. Dodge, chief naturalist for the Southwest Regional Office (SWR) of the park service, compiled in 1971 the research of many of the scientists attracted to the basin and dunes since the mid-nineteenth century. He noted that the Tularosa basin had once been part of the vast "Delaware basin," dating back some 230 million years. High in salt content, the Delaware basin collected saline deposits over the millennia that became the basis of the "Yeso formation," with the term "yeso" translated from the Spanish word for "gypsum." About 70 million years ago, the event called by geologists the "Laramide revolution" lifted the Rocky Mountains and their southwestern spine, exposing the gypsum-rich rock. Over the course of many centuries, the forces of wind and rain eroded the San Andres Mountains to the west, and the Sacramento Mountains to the east, causing the accretion of gypsum on the basin floor. [10]

Often a visitor to the dunes in his long career with the service, Dodge spoke highly of their unique ecological character in a region noted for its breathtaking environmental phenomena. White Sands was "a striking example of geology in action," said the naturalist, "unnoticed by most people yet . . . a fundamental process of nature." Contributing to their singular character were the extremes of heat and cold, moisture and aridity, and the surprisingly complex and populous flora and fauna of the region. Annual rainfall rarely exceeded ten inches, yet the water table lay only three to four feet below the surface of the dunes. Temperatures ranged from zero degrees Fahrenheit in January to 110 degrees-plus in the summer. The whiteness of the sands, a function of their purity (over 99 percent gypsum), reflected rather than absorbed the heat of the desert, creating temperate conditions in the midst of summer or the depths of winter. [11]

The naturalist Dodge also catalogued in the "harsh" dune ecosystem no less than 144 species of birds, 23 small mammals, 371 species of insects, and several types of reptiles. Dodge marvelled at the adaptability of the insects and rodents, including the fur color of the "Apache pocket mouse," which was lighter in tone and shade than its cousins amid the Valley of Fires, a lava flow north of the monument. [12]

Figure 2. Selenite crystal formation at Lake Lucero.
(Courtesy White Sands National Monument)