Cataclysms on the Columbia: The Great Missoula Floods

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

Bretz et al in the Grand Coulee, ca 1928 Bretz, circa 1910

Photo: Darryl Lloyd

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

Vindication Before Bretz dies in 1981 at 98 years of age

The Rest of the Story 1979 photo

Richard Waitt

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

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

Altai Mountains

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

Grand Coulee Dam Spokane Odessa

Potholes in Quincy Basin

Palouse Falls

Wallula Gap

Mt. St. Helens double ash layers, age 13,000 between 29th and 30th layer

Columbia River, west of Philippi Canyon

Gravel bar formed at entrance to Philippi Canyon

Bonneville

Beacon Rock – Columbia Gorge

Rooster Rock (has had different names in the past)

Swan Island If the Missoula Floods were to occur today

Willamette Meteorite ( 1902 photo) 1905 exposition

Foreset beds in Durham Pits – now under Bridgeport

15,000 year old soil overlies on older paleosol in the loess

1935 Ira Allison map

Bellevue Erratic – argillite – 1950 measured approx. 160 tons, now approx. 40 tons

Irish Bend south of Corvallis

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

Volcanic Soils on the hills of Dundee, Oregon Volcanic soils on the hills of Dundee, Oregon

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.

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

Cataclysms on the Columbia: The Great Missoula Floods

by OMSI Science Pub on Oct 20, 2010

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