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Desert Diary
Fossils/Plate Tectonics


Most people now realize that the surface of the land may rise and fall through geologic time. Millions of years ago, the high desert country we call the Chihuahuan Desert was below sea level, thus resulting in the widespread presence of thick layers of sedimentary rocks—rocks now visible in our mountains after towering upwards thousands of feet.

But movements of the earth aren't limited to changes in elevation. Over the ages, the continents have done a slow, raucous dance, sometimes coming together, bumping and grinding against one another, then pirouetting away to join other partners. Sometimes sweating in the heat of the equator, else times retreating to icy, dark, faraway regions.

Alfred Wegener had the basic picture soon after the beginning of the 20th century, but scientists are reluctant to accept theories for which there are no believable mechanisms—and Wegener had none. Only some 50 years later did the cause, plate tectonics, become clear. Like ice flows swirling in slow currents, the plates making up the surface of the earth
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Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.

Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.