J.A. Reid
W. R. Normark
2003
<p><span>One of the major unresolved issues of the </span>Late<span> </span>Pleistocene<span> catastrophic-flood events in the northwestern United States (e.g., from </span>glacial<span> </span>Lake<span> Missoula) has been what happened when the flood discharge reached the ocean. This study compiles available 3.5-kHz high-resolution and airgun seismic reflection data, long-range sidescan sonar images, and sediment core data to define the distribution of flood sediment in deepwater areas of the </span>Pacific<span> Ocean. Upon reaching the ocean at the mouth of the Columbia River near the present-day upper continental slope, sediment from the catastrophic floods continued flowing downslope as hyperpycnally generated turbidity currents. The turbidity currents resulting from the </span>Lake<span> Missoula and other latest </span>Pleistocene<span> floods followed the Cascadia Channel into and through the Blanco Fracture Zone and then flowed west to the Tufts Abyssal Plain. A small part of the flood sediment, which was stripped off the main flow at a bend in the Cascadia Channel at its exit point from the Blanco Fracture Zone, continued flowing more than 400 km to the south and reached the Escanaba Trough, a rift valley of the southern Gorda Ridge. Understanding the development of the pathway for the </span>Late<span> </span>Pleistocene<span> flood sediment reaching Escanaba Trough provides insight for understanding the extent of catastrophic flood </span>deposits<span> on the </span>Pacific<span> </span>plate<span>.</span></p>
application/pdf
10.1086/378334
en
University of Chicago Press
Extensive deposits on the Pacific plate from Late Pleistocene North American glacial lake outbursts
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