How the Southern Snake Range Formed: Three Episodes of Stretching

New geological research shows that the mountains of Great Basin National Park took millions of years to form. The southern Snake Range, the range at the heart of the park, was built over the past 50 million years by periods of intense extension — the stretching of the Earth's crust.

Stretching the crust created many faults, breaks along which rocks move up and down. The faults brought rocks from below up to the surface, and rain, snow, ice and wind then carved them into the range seen today.

One episode or several?

Geologists had not been sure whether the range formed in a single period of stretching or in several. To find out, Sarah Evans of the University of Nevada, Las Vegas, and her colleagues combined computer modelling with new laboratory analyses of rocks from the park and similar analyses by other researchers, to work out when faulting happened. The answer: several episodes.

Still stretching

The crust is still stretching along faults in and near the park. The time involved is hard to grasp, but the research has helped geologists understand a little more about how this range came to be.

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Sources

• Sarah Evans, University of Nevada, Las Vegas, "Figuring out How the Southern Snake Range Formed," The Midden (Great Basin National Park), vol. 15, no. 2, winter 2015, National Park Service. https://www.nps.gov/articles/000/figuring-out-how-the-southern-snake-range-formed.htm
• The article's photograph, supplied by the author, is not reproduced here.