Extensive deposits on the Pacific plate from Late Pleistocene North American glacial lake outbursts

Journal of Geology
By:  and 

Links

Abstract

One of the major unresolved issues of the Late Pleistocene catastrophic-flood events in the northwestern United States (e.g., from glacial Lake 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 Pacific 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 Lake Missoula and other latest Pleistocene 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 Late Pleistocene flood sediment reaching Escanaba Trough provides insight for understanding the extent of catastrophic flood deposits on the Pacific plate.

Publication type Article
Publication Subtype Journal Article
Title Extensive deposits on the Pacific plate from Late Pleistocene North American glacial lake outbursts
Series title Journal of Geology
DOI 10.1086/378334
Volume 111
Issue 6
Year Published 2003
Language English
Publisher University of Chicago Press
Description 21 p.
First page 617
Last page 637
Google Analytic Metrics Metrics page
Additional publication details