Giant, ancient space rock helped shape Nevada

Recently a meteoroid exploded near the Ural Mountains in Russia, but Nevada has its own story to tell. Nevada’s impact event from the Devonian was featured in an article written by Keith Rogers of the Las Vegas Review-Journal. You can read the story here: http://www.sfgate.com/news/article/Giant-ancient-space-rock-helped-shape-Nevada-4321653.php

The Alamo impact breccia—“One fine day about 370 million years ago, an object from space splashed down into the Devonian sea that bordered western North America, almost instantly blanketing much of southern Nevada and surrounding areas with debris. The result of this event is a chaotic breccia unit within the Devonian Guilmette Formation known as the Alamo breccia (named for the town of Alamo). The meteor created a crater 30 to 50 miles in diameter and the impact debris and related tsunami deposits left a layer of shattered rock covering an area of some 39,000 square miles.” (excerpt from NBMG Special Publication 35, page 72—see below).

View the rock—You can visit us at the Gold Building (Great Basin Science Sample and Records Library) and view a sample of the breccia from this impact event in Nevada.

Plan a trip—Here are some publications available at the Gold Building and on our website that can help you plan a trip to see this impact site:

• NPS19 – Megabreccias and Impact Breccias of East Central Nevada – please call (775) 682-8766 to order

• 2004 Nevada Petroleum Society Fieldtrip Guidebook, C.W. Gillespie and S. Foster, editors. Five papers and road log focusing on the Alamo impact breccia, Ragged Ridge paleokarst breccia, and subsurface breccias in Railroad Valley. Seven reprints comprising the critical literature concerning the Alamo breccia, 196 pages. Contains articles by authors mentioned in the newspaper article mentioned above.

• SP35 – A Geologic and Natural History Tour through Nevada and Arizona along U.S. Highway 93, with GPS CoordinatesThis Highway 93 guidebook takes the traveler from Wickenburg, Arizona, through Las Vegas and up to three sites of the Alamo impact breccia, and then northward to the Idaho border.
  http://www.nbmg.unr.edu/sales/sp35_cart_details.pdf

Related reading:

• SP31 – chapter on meteorites (pages 84-90, by David Davis) from Minerals of Nevada
  http://www.nbmg.unr.edu/sales/pbsdtls.php?sku=SP31