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Episodic bedrock strath terrace formation due to meander migration and cutoff

Noah J. Finnegan and William E. Dietrich
Episodic bedrock strath terrace formation due to meander migration and cutoff
Geology (Boulder) (February 2011) 39 (2): 143-146


In order to explore mechanisms of bedrock terrace formation, we have developed a numerical model that couples vertical river incision and meandering. Model results illustrate that flights of unpaired strath terraces can form purely from the internal dynamics of bedrock river meandering in vertically incising channels. Specifically, knickpoints that propagate upstream following meander cutoffs enhance vertical incision, whereas channel lengthening and corresponding slope reduction during meander growth suppresses vertical incision. Analysis of topography from the Smith River, Oregon, USA, suggests terrace formation by this mechanism. Our results introduce an alternative mechanism to climatic or tectonic forcing, namely inherent instability triggered by meander growth and cutoff, that explains both oscillations in rates of vertical bedrock incision and the formation of longitudinally traceable, unpaired bedrock terraces. In addition, our results point to simple topographic criteria for identifying internally generated fluvial bedrock terraces.

ISSN: 0091-7613
EISSN: 1943-2682
Serial Title: Geology (Boulder)
Serial Volume: 39
Serial Issue: 2
Title: Episodic bedrock strath terrace formation due to meander migration and cutoff
Affiliation: University of California, Berkeley, Department of Earth and Planetary Science, Berkeley, CA, United States
Pages: 143-146
Published: 201102
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 27
Accession Number: 2011-019900
Categories: Geomorphology
Document Type: Serial
Bibliographic Level: Analytic
Annotation: With GSA Data Repository Item 2011068
Illustration Description: illus. incl. sketch maps
N42°00'00" - N46°19'60", W124°34'60" - W116°34'60"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201112
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