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Cataclysms on the Columbia: The Great Missoula Floods
 

Cataclysms on the Columbia: The Great Missoula Floods

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Geology lecture about the Missoula Floods and how they shaped the Columbia Gorge

Geology lecture about the Missoula Floods and how they shaped the Columbia Gorge

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    Cataclysms on the Columbia: The Great Missoula Floods Cataclysms on the Columbia: The Great Missoula Floods Presentation Transcript

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    • Cataclysms on the Columbia The Great Missoula Floods Dr. John Eliot Allen Dr. Marjorie Burns Dr. Scott Burns Portland State University Ooligan Press, PSU
    • 1) Name for the Floods is Missoula Floods not Bretz Floods 2) Dates are in Calendar Years not C-14 Years 3) Color Photos 4) Maps are shaded relief maps for easier reading 5) Rest of the Story added for history of the Floods 6) Totally updated science of the floods New Things in the Second Edition of the Book: Darryl Lloyd photo
    • In front of Mt. Rushmore “ Five great men in one picture – four of them don’t show” J Harlen Bretz
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    • Bretz et al in the Grand Coulee, ca 1928 Bretz, circa 1910
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    • Photo: Darryl Lloyd
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    • A “Palouse Island” along I-90, about 5 miles north of Sprague, Washington
    • Big whorls have little whorls, Which feed on their velocity: Little whorls have smaller whorls And so unto viscosity. JEA p31
    • Strand lines on the Washington side of the Columbia River Gorge
    • Bretz, 1933
    • USGS Controversy James Gilluly G.R. Mansfield O.E. Meinzer
    • Revisionists Ira Allison Richard Foster Flint
    • J.T. Pardee Breaks the Silence
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    • Vindication Before Bretz dies in 1981 at 98 years of age
    • The Rest of the Story 1979 photo
    • Richard Waitt
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    • Burlingame Gulch near Touchet, Washington Exposing 40 rhythmite beds
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    • Burlingame Gulch near Touchet, Washington Exposing 40 rhythmite beds
    • Set S Mt. St. Helens Ash near Mabton in the Yakima Valley
    • Brian Atwater
    • Close-up of 2 rhytmites showing varved annual layers of silt and clay
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    • Dating the Missoula Floods
      • Radiocarbon Dating: 15,300 – 12,700 BP
      • Calendar Years (Calibrated Dates: 15,000 – 18,000 years ago)
      • 40 events came to Portland area
      • 90 events came to Spokane
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    • Altai Mountains
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    • Glacial Lake Missoula : 1) 530 mi 3 water 2) 50 mi 3 ice 3) 2100 feet deep 4) Elevation: 4250 ft.
    • Ancient beach strand lines can still be seen Lake Missoula was ~ ½ the size of Lake Michigan
    • Nine Mile Section : 1) Pale: river deposits (36) 2) Dark: varves (1000) 3) oldest: 58 varves
      • 2400 ft. Elevation
      • 2) Up to 500 ft deep
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    • Grand Coulee Dam Spokane Odessa
    • Potholes in Quincy Basin
    • Palouse Falls
    • Wallula Gap
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    • Mt. St. Helens double ash layers, age 13,000 between 29th and 30th layer
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    • Columbia River, west of Philippi Canyon
    • Gravel bar formed at entrance to Philippi Canyon
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    • Bonneville
    • Beacon Rock – Columbia Gorge
    • Rooster Rock (has had different names in the past)
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    • Swan Island If the Missoula Floods were to occur today
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    • Willamette Meteorite ( 1902 photo) 1905 exposition
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    • Foreset beds in Durham Pits – now under Bridgeport
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    • 15,000 year old soil overlies on older paleosol in the loess
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    • 1935 Ira Allison map
    • Bellevue Erratic – argillite – 1950 measured approx. 160 tons, now approx. 40 tons
    • Irish Bend south of Corvallis
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    • Floodwaters, entrained sediments and turbid currents that swept across the Pacific Ocean floor for 700 miles (1100 km). Normark et al. (2000)
    • Ancient Cataclysmic Floods 5 Ancient Cataclysmic Floods exposed in paleosols near The Dalles
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    • Volcanic Soils on the hills of Dundee, Oregon Volcanic soils on the hills of Dundee, Oregon
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    • Terroir Differences in PNW
      • Washington: 95% of the vineyards are on Missoula Flood sediments; Vigor controlled by irrigation.
      • Oregon: 90% of vineyards are on upland vineyards and 10% are on Missoula Flood sediments; Vigor controlled by low nutrient, old soils.
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    • Conclusions - But Not The End of the Story
      • 89+ floods, with 40 getting to Portland
      • Velocities up to 60 mph
      • Flows = 10 x the total flow of all of the world’s rivers
      • Effects of the Floods: 16,000 square miles
      • Maximum Floods were the first ones: 530 mi 3 of water and 50 mi 3 of ice; biggest were first floods
    • Future
      • More information from Ancient Cataclysmic Floods
      • More information of time of the Floods passing the “Lakes”
      • More information from the deep sea record
      • New National Park will bring visitors to the region and new research will unlock further secrets