Ice Age Floods Touchet Bed Rhythmites

The Touchet Beds at Burlingame Canyon, White Bluffs, and Granger, WA are stacked lake deposits (rhythmites) from temporary lakes that formed as Ice Age Flood waters backed up behind the hydraulic dam constriction at the narrow Wallula Gap. Sediment thicknesses and sedimentary structures in each of the beds give a sense of the tremendous sediment load and the low velocity of the ponded flood waters. Up to 40 floods are documented at Burlingame Canyon where a couple of 16,000 year old ash layers give a sense of the age of the floods. Video produced by Bruce Bjornstad for Ice Age Floodscapes

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