Geologic History of Red Rock Canyon and Valley of Fire
Valley of Fire and Red Rock Canyon
Red Rock Canyon is presently located 5 miles west of Las Vegas, Nevada. It is 197,000 acres within the Mojave Desert. The canyon is one of several in the state with the name Red Rock, this one is located on the east side of Spring Mountain, the flat land rises to a great colorful escarpment, formed along a fault zone (the Keystone Thrust) with several peaks over 8,000 feet, and including huge cliffs and ravines composed of bands of gray Paleozoic carbonates, white and red Jurassic sandstone, all heavily eroded. The wide empty plains beneath the hills are studded with Joshua trees and other plants typical of the Mojave Desert, contributing to a most impressive spectacle. Red rock canyon has a fairly complex geologic history. The now national conservation area was at the bottom of a deep ocean basin and the western coast of North America was in present day Utah. Around 542 million years ago, Paleozoic, the area was under a deep ocean. Thick deposits of sediment, about 9,000ft, were lithified. This lithified sediment eventually formed limestone and other similar carbonate rocks. Preservation of marine invertebrate fossils provides evidence for a marine setting for the Paleozoic. Starting around 250 million years ago, the Mesozoic era, the earths crust rose due to tectonic shifts. This forced water out of the area leaving behind rock formations of salt and gypsum, this lead to the exposure of the former sea bed causing the rock to oxidize to the now characteristic red-orange color. The Paleozoic carbonates are dominantly gray in color and only red-orange locally. These pre-existing carbonate deposits were dissolved and oxidized due to sea level drop and sub aerial exposure, creating an unconformable surface (unconformity). The seabed rose slowly somewhere around 225 million years ago, causing streams to enter shallow waters, depositing mud and sand. This later became shale and marine sandstones of the Triassic
Red Rock Canyon is presently located 5 miles west of Las Vegas, Nevada. It is 197,000 acres within the Mojave Desert. The canyon is one of several in the state with the name Red Rock, this one is located on the east side of Spring Mountain, the flat land rises to a great colorful escarpment, formed along a fault zone (the Keystone Thrust) with several peaks over 8,000 feet, and including huge cliffs and ravines composed of bands of gray Paleozoic carbonates, white and red Jurassic sandstone, all heavily eroded. The wide empty plains beneath the hills are studded with Joshua trees and other plants typical of the Mojave Desert, contributing to a most impressive spectacle. Red rock canyon has a fairly complex geologic history. The now national conservation area was at the bottom of a deep ocean basin and the western coast of North America was in present day Utah. Around 542 million years ago, Paleozoic, the area was under a deep ocean. Thick deposits of sediment, about 9,000ft, were lithified. This lithified sediment eventually formed limestone and other similar carbonate rocks. Preservation of marine invertebrate fossils provides evidence for a marine setting for the Paleozoic. Starting around 250 million years ago, the Mesozoic era, the earths crust rose due to tectonic shifts. This forced water out of the area leaving behind rock formations of salt and gypsum, this lead to the exposure of the former sea bed causing the rock to oxidize to the now characteristic red-orange color. The Paleozoic carbonates are dominantly gray in color and only red-orange locally. These pre-existing carbonate deposits were dissolved and oxidized due to sea level drop and sub aerial exposure, creating an unconformable surface (unconformity). The seabed rose slowly somewhere around 225 million years ago, causing streams to enter shallow waters, depositing mud and sand. This later became shale and marine sandstones of the Triassic
Cited: 1)"GEOLOGY." Red Rock Canyon. 30 Apr. 2009 . 2)"Red Rock Canyon Geology." Prodigy 's Personal Web Pages. 30 Apr. 2009 . 3)"Red Rock Canyon National Conservation Area -." Wikipedia, the free encyclopedia. 30 Apr. 2009 . 4)"Thrust Fault." About Geology - The Complete Guide to Geology. 30 Apr. 2009 . 5)"Valley of Fire State Park, Nevada." Desert Biomes by DesertUSA. 30 Apr. 2009 . Interview Kelsey McNamara, grad student at Montana State University, May 2, 2009 via Email