Lake Great Falls

Coordinates: 47°30′14″N 111°17′11″W / 47.503784°N 111.286353°W / 47.503784; -111.286353
Source: Wikipedia, the free encyclopedia.
Lake Great Falls
Laurentide Ice Sheet
Primary outflowsAlong the face of the Ice sheet.
Basin countriesUnited States
Max. lengthabout 26 miles (42 km)
Max. widthabout 7.8 miles (12.6 km)
Surface areavaried
Surface elevation3,500 m (11,500 ft)
References[2]

Lake Great Falls was a prehistoric

Holter Lake.[6] At present-day Great Falls, the Glacial Lake Great Falls reached a depth of 600 feet (183 metres).[7]

Approximately 1.5 million years ago, the Missouri River, the

Cordilleran ice sheets pushed these lakes and rivers southward.[3][8] Between 15,000 BCE and 11,000 BCE, the Laurentide Ice Sheet blocked the Missouri River and created Glacial Lake Great Falls.[3][4][5]

About 13,000 BCE, as the glacier retreated, Glacial Lake Great Falls emptied catastrophically in a glacial lake outburst flood.[5] The meltwater poured through the Highwood Mountains and eroded the hundred mile-long, 500-foot-deep (150 m) Shonkin Sag—one of the most famous prehistoric meltwater channels in the world.[10]

Map of Montana showing glacial lakes.

Bibliography

  • Alden, W. C., 1958, Physiography And Glacial Geology Of Eastern Montana And Adjacent Areas, U. S. Geological Survey Professional Paper 174.
  • Colton, R. B., Lemke, R. W., and Lindvall, R. M., 1961, Glacial map of Montana East of the Rocky Mountains, U. S. Geological Survey Miscellaneous Geological Investigations Map I-327.
  • Lindvall, R. M., 1962, Geology Of The Eagle Buttes Quadrangle, Chouteau County, Montana, U. S. Geological Survey Miscellaneous Geological Investigations Map I-349.
  • Thornbury, W. D., 1965, Regional Geomorphology Of The United States, John Wiley & Sons, Inc., New York.

See also

References

  1. ^ dewiki
  2. ^ Physiography and Glacial Geology of Eastern Montana and Adjacent Areas; William C. Alden; United States Government Printing Office: Washington, D.C.; 1932
  3. ^ a b c Montagne J.L. "Quaternary System, Wisconsin Glaciation." Geologic Atlas of the Rocky Mountain Region. Denver: Rocky Mountain Association of Geologists, 1972.
  4. ^ a b Hill, Christopher L. and Valppu, Seppo H. "Geomorphic Relationships and Paleoenvironmental Context of Glaciers, Fluvial Deposits, and Glacial Lake Great Falls, Montana." Current Research in the Pleistocene. 14 (1997); Hill, Christopher L. "Pleistocene Lakes Along the Southwest Margin of the Laurentide Ice Sheet." Current Research in the Pleistocene. 17 (2000); Hill, Christopher L. and Feathers, James K. "Glacial Lake Great Falls and the Late-Wisconsin-Episode Laurentide Ice Margin." Current Research in the Pleistocene. 19 (2002); Reynolds, Mitchell W. and Brandt, Theodore R. Geologic Map of the Canyon Ferry Dam 30' x 60' Quadrangle, West-Central Montana: U.S. Geological Survey Scientific Investigations Map 2860, scale 1:100,000. Scientific Investigations Map 2860. Washington, D.C.: U.S. Geologic Survey, 2005.
  5. ^ a b c Feathers, James K. and Hill, Christopher L. "Luminescence Dating of Glacial Lake Great Falls, Montana, U.S.A." Archived 2014-11-29 at the Wayback Machine XVI International Quaternary Association Congress. Stratigraphy and Geochronology Session. International Quaternary Association, Reno, 2003.
  6. Helena Independent Record
    . June 20, 2004.
  7. ISBN 0-87842-202-1
    ; Stickney, Michael C. "Quaternary Geology and Faulting in the Helena Valley." In 1987 Guidebook for the Helena Area, West-Central Montana: Guidebook for the 12th Annual Field Conference. Richard B. Berg and Ray H. Breuninger, eds. Montana Bureau of Mines and Geology Special Publication 95. Helena, Mont.: Montana Bureau of Mines and Geology, 1987.
  8. ^
    ISBN 1-56037-037-8
  9. ISBN 1-59880-014-0
  10. ISBN 0-405-02659-5
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