The channeled Scabland: Back to Bretz?

The Channeled Scabland, Washington State, United States, is only partly the result of erosion by the catastrophic drainage of Glacial Lake Missoula: t here were other sources of meltwater. Recent sedimentary investigations of some sites in the Missoula basin, and in the Channeled Scabland, support a single large late Wisconsin flood, as opposed to multiple floods proposed f or this time period. Sediment in the Glacial Lake Missoula basin records ra pid infill by jokulhlaups draining into Lake Missoula from upstream, punctu ating a long period of normal varve sedimentation. This was independent of sedimentation in the main Scabland tract, where proximal and distal rhythmi c beds are explained as resulting from multiple pulses, or surges, within a single flood. Geomorphic and sedimentary evidence supports the conclusion that drainage from the Cordilleran trunk valleys was important, and pulses were probably related to the drainage of these valleys.