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
Close-up of 2 rhytmites showing varved annual layers of silt and clay
Dating the Missoula Floods <ul><li>Radiocarbon Dating: 15,300 – 12,700 BP </li></ul><ul><li>Calendar Years (Calibrated Dates: 15,000 – 18,000 years ago) </li></ul><ul><li>40 events came to Portland area </li></ul><ul><li>90 events came to Spokane </li></ul>
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 <ul><li>Washington: 95% of the vineyards are on Missoula Flood sediments; Vigor controlled by irrigation. </li></ul><ul><li>Oregon: 90% of vineyards are on upland vineyards and 10% are on Missoula Flood sediments; Vigor controlled by low nutrient, old soils. </li></ul>
Conclusions - But Not The End of the Story <ul><li>89+ floods, with 40 getting to Portland </li></ul><ul><li>Velocities up to 60 mph </li></ul><ul><li>Flows = 10 x the total flow of all of the world’s rivers </li></ul><ul><li>Effects of the Floods: 16,000 square miles </li></ul><ul><li>Maximum Floods were the first ones: 530 mi 3 of water and 50 mi 3 of ice; biggest were first floods </li></ul>
Future <ul><li>More information from Ancient Cataclysmic Floods </li></ul><ul><li>More information of time of the Floods passing the “Lakes” </li></ul><ul><li>More information from the deep sea record </li></ul><ul><li>New National Park will bring visitors to the region and new research will unlock further secrets </li></ul>
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