The Bonneville Speedway – on Sea Salt!

Submitted by Deborah Cramer

The Bonneville Speedway – on Sea Salt!

Swamped in saltwater
© Bryan W. Jones

Fast cars make, and break, speed records on the flat, barren, dazzling white raceway at Utah’s Bonneville Salt Flats. The first record was set in 1914 at 141 mph, and there have been many since, including one in 1970 by the rocket-propelled Blue Flame, traveling at 622.4 mph. In 2006 a diesel engine traveling at 350.092 mph broke another record.

The long, flat straightaway and smooth surface are the speedway’s draws. Almost its entire surface, 90%, is made of common table salt, deposited millions of years ago in the nearby mountains when Utah was covered by a shallow sea. Some 15,000 years ago, rivers dissolved some of the salt and carried it into Lake Bonneville, a glacial lake once as large as Lake Michigan, and 1000 feet deep. Although Lake Bonneville has now drained away, (leaving the Great Salt Lake) the salt remains, in some spots, almost five feet thick. Groundwater continues to flow in, bringing more. Each year, the water floods the surface and then evaporates, coating the raceway with a fresh, smooth layer of salt.

Dry land may seem as if it is terra firma, but the salt flats are on the move. The Bonneville Salt Flats are part of the Great Basin, which began forming in the western United States some 17 million years ago as North America drifted west, colliding against seafloor from the Pacific. As the San Andreas Fault lengthens, tearing rock from California and sending it north, the Great Basin widens, creating the vast, flat, open space that attracts high speed auto racers.

In 1846, the Donner-Reed pioneers, seeking a short-cut to California, crossed the flats. Traveling much more slowly than today’s racers, they met with tragic result. Their route, along what was known as the Hastings Cutoff, cost them both time and provisions. Where their wagons were mired in mud just below the salt, the wheel tracks can still be seen today. Their late start and difficult passage brought the party into the mountains at the onset of winter. Trapped for months on a snowy pass on Truckee Lake, they desperately resorted to cannibalism, forced to eat their deceased to avoid dying from starvation.

References and more information

Utah Basin and Range Geology

Hintze, L.F. and Kowallis, B.J., 2009. Geologic History of Utah. Brigham Young University Geology Studies Special Publication 9, 225 pp.
http://geology.utah.gov/utahgeo/geo/geohist.htm
http://vulcan.wr.usgs.gov/LivingWith/VolcanicPast/Places/volcanic_past_utah.html

Lake Bonneville and the Bonneville Salt Flats
http://geology.utah.gov/online/PI-39/pi39pg01.htm
http://www.blm.gov/ut/st/en/fo/salt_lake/recreation/bonneville_salt_flats/Bonneville_Salt_Flats_History.html

Donner-Reed Story
http://www.nps.gov/cali/historyculture/donner-reed_story.htm

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