Las Vegas is a city build upon sand. Somewhere, far beneath, underground streams once ran to the ocean, but to the naked eye, it's simply an oasis in the desert.
The first time I flew to Vegas from Canada was only my second trip ever by airplane. I was buffeted by the turbulence over Utah and then, suddenly, more mountains yet. As we approached, passengers started craning their necks to peer out the windows. Being on the wrong side of the plane (of course), I had to wait until we swung around to get my first glimpse of this neon metropolis. And there she was, glittering and beckoning for us to “come on down.” For me, it was love at first sight.
What first impressed this plains dweller were the palm trees and the stark mountains. Everywhere I looked, there was excavation; and everywhere there was construction, there was also white sand. In the Prairies where I grew up, construction meant thick black loam and the granite underscoring of the Cambrian Shield. When I had visited the Maritime Provinces as a teenager, it had been dense, red clay. This was something new and fascinating.
After I moved here, married my husband and had time on my hands, I decided to research the prehistory and history of the area. The history of the city of Las Vegas is legend, but the Mohave Desert and the mountains ranges were still a mystery to me. I have always loved a good mystery.
The Prehistory of Nevada
Nevada was named after the Spanish word for "covered with snow," a strange translation for those of us who now reside in the Valley. Years before anyone civilized this state, it was a barren region of desert and mountains, occasionally relieved by a spring or two. Many parts of our state still are unclaimed wasteland!
Millions of years previous to that, Nevada had a lot of movement going on under the earth. Tectonic plates shifted, vast mountains erupted in various stages, giving the variety of colors that you can clearly see if you look carefully at our landscape.
According to Russell Elliot, a combination of underground seismic activity, streams and volcanoes gave us instability, ever shifting the sand and changing the lay of the land throughout hundreds of thousands of years. But this activity has also granted great finds of silver (hence The Silver State), gold, silver, copper, lead, zinc, mercury, barite, tungsten and oil.
These same shifts and seismic 'burps' are what cause the activity which some experts like Hubert Howe Bancroft say may one day cause Nevada to experience an earthquake of considerable magnitude. Instability breeds instability, and this city is certainly not built upon the great Canadian Shield where I lived for so many years.
The Basin and Range Effect
Here in Nevada, we have a natural phenomenon known as the 'basin and range' effect. Millennia of plate shifting, rhythmic faults and folding of our earth’s crust have caused what looks (from a topographical view) like north and south ridges, valleys and peaks, reminding one of the symmetrical folds and ridges caused by pushing a cloth across a flat rough tabletop. In this way, the distance between Reno and Salt Lake City has increased by 50 miles and it’s still expanding.
Mountains are stretching ever higher along major fault zones because of the broken plates of our Earth’s lithosphere (uppermost brittle solid mantle and crust), which floats on the asthenosphere welling beneath us like brittle ice on a fast-moving river, or even like an egg shell resting upon a cracked egg. We are a land of constant shifting and movement.
Climactic Changes
Cave Rock near Lake Tahoe dramatically shows that there was volcanic activity here within the last two million years. You can see the different benches, or strand lines, cut by former waves as high as six hundred feet above the current lake level. Glaciers shaped the lake area’s terrain, sometimes reaching the shoreline, though never filling the basin itself.
Because of the rain and shadow effect, glaciers could only form on the shaded sides of the highest peaks on the Carson Range. Because of the cooler climate in North America, so much snow fell during the long bitter winters that it couldn’t all melt during the short, cool summers. Snow accumulated on the peaks, recrystallizing as ice that thickened with time. This ice began to move and flow under its own weight, picking up rock and sediment that scraped the surface, leaving jagged peaks on the Sierra Nevada while leaving the less glacially iced Carson Range more rounded in shape by erosion.
The Great Basin
Those of us who have lived here have experienced the hot, dry winds of summer and the chilly winter evenings. We have also experienced days that are “good breathing days” and those during which the air seems less light, denser. Because we live in an enclosed area, the Great Basin, water can only escape by evaporation. Our warm air meets the cooler air above us, is trapped by the mountains surrounding our valley and eventually the inversion cap bursts. Once a weather pattern is established in our valley, it can take a considerable amount of time to leave again, for better or for worse.
Sometimes it’s difficult to believe that way up on the mountains in Nevada, there are, indeed natural lush trees and vegetation. It’s equally difficult to believe that hundreds of thousands of years ago, our entire Great Basin was covered with water. According to Bancroft, four hundred and sixty million years ago, geologists believe that a huge sea may have reached from Elko, Nevada to Salt Lake City.
You could speculate that at that time, dry land and sea alternated across the majority of the USA, caused by shifting plates and water welling through the cracks. This resulted in dramatic collisions in terrains where the plates once again ground against each other. In fact, even our earth’s equator has moved.
So welcome to Nevada, the land of shifting sands, mountains and plates, a fascinating region where the pulling and tugging of our earth, and the resulting collisions, are still causing mountains to grow and landscapes to change.
References:
- Bancroft, Hubert Howe (1832-1918), 1967, History of Nevada, Colorado and Wyoming, 1540-1888, New York: Arno Press in cooperation with McGraw-Hill.
- Elliot, Russell R., 1973, History of Nevada, Lincoln, University of Nevada Press.
Sharon Damon - Writing is my passion. I have published poetry and write for Examiner and other publications. I love my fascinating home, Las Vegas!
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