A Caltech Library Service

^(10)Be dating of late Pleistocene megafloods and Cordilleran Ice Sheet retreat in the northwestern United States

Balbas, Andrea M. and Barth, Aaron M. and Clark, Peter U. and Clark, Jorie and Caffee, Marc and O’Connor, Jim and Baker, Victor R. and Konrad, Kevin and Bjornstad, Bruce (2017) ^(10)Be dating of late Pleistocene megafloods and Cordilleran Ice Sheet retreat in the northwestern United States. Geology, 45 (7). pp. 583-586. ISSN 0091-7613. doi:10.1130/G38956.1.

Full text is not posted in this repository. Consult Related URLs below.

Use this Persistent URL to link to this item:


During the late Pleistocene, multiple floods from drainage of glacial Lake Missoula further eroded a vast anastomosing network of bedrock channels, coulees, and cataracts, forming the Channeled Scabland of eastern Washington State (United States). However, the timing and exact pathways of these Missoula floods remain poorly constrained, thereby limiting our understanding of the evolution of this spectacular landscape. Here we report cosmogenic ^(10)Be ages that directly date flood and glacial features important to understanding the flood history, the evolution of the Channeled Scabland, and relationships to the Cordilleran Ice Sheet (CIS). One of the largest floods occurred at 18.2 ± 1.5 ka, flowing down the northwestern Columbia River valley prior to blockage of this route by advance of the Okanogan lobe of the CIS, which dammed glacial Lake Columbia and diverted later Missoula floods to more eastern routes through the Channeled Scabland. The Okanogan and Purcell Trench lobes of the CIS began to retreat from their maximum extent at ca. 15.5 ka, likely in response to onset of surface warming of the northeastern Pacific Ocean. Upper Grand Coulee fully opened as a flood route after 15.6 ± 1.3 ka, becoming the primary path for later Missoula floods until the last ones from glacial Lake Missoula at 14.7 ± 1.2 ka. The youngest dated flood(s) (14.0 ± 1.4 ka to 14.4 ± 1.3 ka) came down the northwestern Columbia River valley and were likely from glacial Lake Columbia, indicating that the lake persisted for a few centuries after the last Missoula flood.

Item Type:Article
Related URLs:
URLURL TypeDescription
Balbas, Andrea M.0000-0002-4855-3507
Konrad, Kevin0000-0002-4349-1618
Additional Information:© 2017 Geological Society of America. Received 12 January 2017; Revision received 2 March 2017; Accepted 3 March 2017; First Published on May 08, 2017. We thank Nick Zentner, Ralph Haugerud, Ken Lacy, and Karl Lillquist for field support. The Purdue University Rare Isotope Measurement Laboratory provided funding for 10Be ages. M.W. Caffee acknowledges support from the U.S. National Science Foundation grant EAR-1153689. Richard Waitt, Jack Oviatt, Sanjeev Gupta, and an anonymous reviewer provided helpful reviews.
Funding AgencyGrant Number
Purdue UniversityUNSPECIFIED
Issue or Number:7
Record Number:CaltechAUTHORS:20170508-153433204
Persistent URL:
Official Citation:Andrea M. Balbas, Aaron M. Barth, Peter U. Clark, Jorie Clark, Marc Caffee, Jim O’Connor, Victor R. Baker, Kevin Konrad, and Bruce Bjornstad 10Be dating of late Pleistocene megafloods and Cordilleran Ice Sheet retreat in the northwestern United States Geology, July 2017, v. 45, p. 583-586, first published on May 8, 2017, doi:10.1130/G38956.1
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:77268
Deposited By: Tony Diaz
Deposited On:12 May 2017 22:41
Last Modified:15 Nov 2021 17:29

Repository Staff Only: item control page