- Glacial Lake Missoula
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Glacial Lake Missoula was a prehistoric proglacial lake in western Montana that existed periodically at the end of the last ice age between 15,000 and 13,000 years ago. The lake measured about 7,770 square kilometres (3,000 sq mi) and contained about 2,100 cubic kilometres (500 cu mi) of water, half the volume of Lake Michigan.[1]
The Glacial Lake Missoula National Natural Landmark is located about 68 miles northwest of Missoula, Montana at the north end of the Camas Prairie Valley, just east of Montana Highway 382 and Macfarlane Ranch. It was designated as a National Natural Landmark in 1966 because it contains the great ripples, (often measuring 25 to 50 feet high and 300 feet long), that served as a strong supporting element for J Harlen Bretz's contention that Washington State's Channeled Scablands were formed by repeated cataclysmic floods over only about 2000 years, rather than through the millions of years of erosion that had been previously assumed.[2]
The lake was the result of an ice dam on the Clark Fork caused by the southern encroachment of a finger of the Cordilleran Ice Sheet into the Idaho Panhandle (at the present day location of Clark Fork, Idaho at the east end of Lake Pend Oreille). The height of the ice dam typically approached 610 metres (2,000 ft), flooding the valleys of western Montana approximately 320 kilometres (200 mi) eastward. It was the largest ice-dammed lake known to have occurred.[3]
The periodic rupturing of the ice dam resulted in the Missoula Floods – cataclysmic floods that swept across Eastern Washington and down the Columbia River Gorge approximately 40 times during a 2,000 year period. The cumulative effect of the floods was to excavate 210 cubic kilometres (50 cu mi) of loess, sediment and basalt from the channeled scablands of eastern Washington and to transport it downstream.[4] These floods are noteworthy for producing canyons and other large geologic features through cataclysms rather than through more typical gradual processes.
See also
- Missoula Floods
- Glacial lake outburst flood
- Ice Age Floods National Geologic Trail
- List of prehistoric lakes
- Glacial Lake Agassiz
- Glacial Lake Ojibway
- Deluge (prehistoric)
Cited references
- ^ Bjornstad, Bruce N. (c2006). On the trail of the Ice Age floods : a geological field guide to the mid-Columbia basin / Bruce Bjornstad.. Sandpoint, Idaho: Keokee Books. pp. 4. ISBN 9781879628274.
- ^ Soennichsen, John (c2008). Bretz's Flood : The Remarkable Story of a Rebel Geologist and the World's Greatest Flood / John Soennichsen.. Seattle, Washington: Sasquatch Books. pp. 215–248. ISBN 9781570616310.
- ^ Alt, David (c2001). Glacial Lake Missoula and Its Humongous Floods / David Alt. Missoula, Montana: Mountain Press. pp. 27–28. ISBN 0878424156.
- ^ Allen, John Eliot; Burns, Marjorie and Sargent, Sam C. (c1986). Cataclysms on the Columbia : a layman's guide to the features produced by the catastrophic Bretz floods in the Pacific Northwest. Portland, OR: Timber Press. pp. 104. ISBN 0881920673.
External links
- USGS Site on Glacial Lake Missoula
- US Park Service Site for Glacial Lake Missoula National Natural Landmark
- PBS's NOVA (TV series): Mystery of the Megaflood for information on the Missoula Floods
- The Seattle Times' Pacific NW magazine - "Trailing an Apocalypse" - 30-Sep-2007
- The Ice Age Floods Institute
- U of Montana publication, The Montanan, "Sedimental Journey: Following the Path of Glacial Lake Missoula's Flood Waters."
- Giant current ripples
Ice Age Floods National Geologic Trail in the Pacific Northwest Ice Age Glacial Floods Glacial Lakes Glacial Lake Missoula • Glacial Lake ColumbiaTemporary Lakes Lake Lewis • Lake Condon • Lake AllisonIce Age Floods Glacial Residue Ice Age Floods Erosion & Deposition Features Related contemporaneous events Bonneville FloodPleistocene proglacial lakes and related seas Africa Asia Europe North America Lake Admiralty · Lake Albany · Lake Algonquin · Lake Bonneville · Lake Bassano · Lake Cahuilla · Lake Chicago · Lake Columbia · Lake Connecticut · Early Lake Erie · Lake Frontenac · Lake Great Falls · Lake Hitchcock · Lake Iroquois · Lake Lahontan · Lake Manly · Lake Maumee · Lake Minong · Lake Missoula · Lake Ojibway · Lake Passaic · Proglacial lakes of Minnesota (Lake Agassiz · Lake Duluth) · Lake Souris · Lake Stowe · Lake Tight · Teays River · Lake Tonawanda · Tyrrell Sea · Lake WisconsinSouth America Lake BalliviánMissoula, Montana Education High SchoolsBig Sky • Hellgate • Sentinel • Loyola Sacred Heart High School • Valley Christian • Willard Alternative High School • Sussex School • Clark Fork School • Next Step PrepHigher EducationUniversity of Montana • UM-College of TechnologyMuseumsFort Missoula • Montana Museum of Art & Culture • Missoula Art MuseumGeography MountainsRiversHistory Glacial Lake Missoula • Fort Missoula • Missoula CemeteryMedia TelevisionPrintBreweries Bayern Brewing • Big Sky Brewing • Kettle House Brewing • Taproom only: Tamarack Brewing • Flathead Lake BrewingServices Health CareSt. Patrick Hospital and Health Sciences Center • Community Medical CenterTransportationSports TeamsMontana Grizzlies • Osprey (baseball) • Phoenix (semi-pro football) • Maulers (hockey) • Hellgate RollergirlsVenuesWashington–Grizzly Stadium (football) • Ogren Park at Allegiance Field (baseball) • Glacier Ice Rink (hockey) • Dornblaser Field (soccer) • Dahlberg Arena (basketball) • Western Montana Fair Grounds (horse racing)University of Montana Category • People from MissoulaCoordinates: 46°56′20″N 114°08′37″W / 46.93889°N 114.14361°W
Categories:- Former lakes
- Geology of Montana
- Geology of Idaho
- Natural history of Montana
- Natural history of Idaho
- National Natural Landmarks in Montana
- Proglacial lakes
- History of Missoula, Montana
- Geography of Missoula County, Montana
- Inland seas
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