Devils_Postpile_National_Monument

From Wikipedia, the free encyclopedia Devils Postpile National Monument Devils Postpile National Monument California. The postpile was created by a lava flow sometime between less than 100,000 years ago (according to current potassium-arIUCN Category III (Natural Monument) gon dating) to 700,000 years ago (according to other dating methods). The source of the lava is thought to have been somewhere near Upper Soda Springs campground at the north end of Pumice Flat on the floor of the Middle Fork of the San Joaquin River, from where it flowed to the site of the Postpile, was impounded by a moraine, and reached a thickness of 400 feet (newer estimate) to 600 feet (older estimate). In any event, the lava that now makes up the Postpile was near the bottom of this mass. Because of its great thickness, much of Madera County, California, USA Location the mass of pooled lava cooled slowly and evenly, which is why the columns are so long Nearest city Mammoth Lakes, CANearest city: and so symmetrical. Columnar jointing ocMammoth Lakes, CA curs when certain types of lava cool; the Coordinates 37°37′28″N 119°5′4″W / 37.62444°N joints develop when the lava contracts during 119.08444°W / 37.62444; -119.08444Coordinates: 37°37′28″N the cooling process. 119°5′4″W / 37.62444°N 119.08444°W / A glacier later removed much of this mass 37.62444; -119.08444 of rock and left a nicely polished surface on top of the Postpile with very noticeable gla798 acres (3.22 km²) Area cial striations and glacial polish. Established July 6, 1911 Established: July 6, 1911 Devils Postpile was once part of Yosemite National Park, but discovery of gold near 114,788 (in 2004) Visitors Mammoth Lakes prompted a boundary National Park Service Governing change that left the Postpile on adjacent pubbody lic land. A proposal to build a hydroelectric dam later called for blasting the Postpile into the river. Influential Californians, including Walter L. Huber, persuaded the federal government to stop the demolition and in 1911, President Howard Taft made the area into a United States National Monument. The John Muir Trail and Pacific Crest Trail pass through the monument. The Postpile’s columns average 2 feet (0.61 m) in diameter, the largest being 3.5 feet (1.1 m), and many are up to 60 feet (18 m) long. Together they look like tall posts stacked in a pile, hence the feature’s name. If The longer fragments of basalt at the base of the lava had cooled perfectly evenly, all of the cliff are much larger than a person. the columns would be expected to be hexagonal, but some of the columns have difDevils Postpile is a dark cliff of columnar ferent polygonal cross-sections on account of basalt near Mammoth Mountain in extreme variations in cooling. A survey of 400 of the northeastern Madera County in eastern Postpile’s columns found that 44.5% were Devils Postpile National Monument 1 From Wikipedia, the free encyclopedia Devils Postpile National Monument common volcanic feature, and they occur on many scales (faster cooling produces smaller columns). Other notable sites include Giant’s Causeway in Northern Ireland, Fingal’s Cave in Scotland, the Garni gorge in Armenia, the Cyclopean Isles near Sicily, Devils Tower National Monument in Wyoming, Sheepeater Cliff at Yellowstone National Park in Wyoming, Basalt Prisms in Hidalgo, Mexico, the "Organ Pipes" formation on Mount Cargill in New Zealand, Gilbert Hill in Mumbai, Organ Pipes National Park in Australia and the "Columnar Cape" (Russian: Mis Stolbchaty) on Kunashir, the southernmost of the Kurile Islands in Russia. Ancient basalt Post Piling can be seen in a high dessert dry river falls area just North, outside of Lajitas, Texas accessible on horseback, afoot or mtn. bike by trail. Basalt column on side 6-sided, 37.5% 5-sided, 9.5% 4-sided, 8.0% 7-sided, and 0.5% 3-sided.[1] Compared with other examples of columnar jointing, the Postpile has more hexagonal columns. Another thing that places the Postpile in a special category is the lack of horizontal jointing. Several stones from the Devil’s Postpile can be seen at the entrance to the United States Geological Survey headquarters lot in Reston, Virginia. See also • Gilbert Hill Bibliography • Roadside Geology of Northern and Central California, Alt, Hyndman (Mountain Press Publishing Company, Missoula; 2000) ISBN 0-87842-409-1 References [1] "Devils Postpile National Park Geologic Story". USGS/National Park Service. January 2, 2000. http://www2.nature.nps.gov/geology/ usgsnps/depo/dpgeol5.html. Rainbow fall at Devils Postpile National Monument External links Similar structures Although the basaltic columns are impressive, they are not unique. Basalt columns are a • Official NPS Site • The Devil’s Post Pile, Popular Science monthly, Feb 1916, page 178, Scanned by Google Books: http://books.google.com/ books?id=iSYDAAAAMBAJ&printsec=frontcover&sour Retrieved from "http://en.wikipedia.org/wiki/Devils_Postpile_National_Monument" Categories: IUCN Category III, Madera County, California, National Monuments in California, Sierra Nevada, 1911 establishments, Columnar basalts This page was last modified on 21 May 2009, at 23:27 (UTC). All text is available under the terms of the GNU Free Documentation License. (See Copyrights for details.) Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a U.S. registered 501(c)(3) taxdeductible nonprofit charity. Privacy policy About Wikipedia Disclaimers 2