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Episodic incision of the Colorado River in Glen Canyon, Utah
Author(s) -
Garvin Cristofer D.,
Hanks Thomas C.,
Finkel Robert C.,
Heimsath Arjun M.
Publication year - 2005
Publication title -
earth surface processes and landforms
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.294
H-Index - 127
eISSN - 1096-9837
pISSN - 0197-9337
DOI - 10.1002/esp.1257
Subject(s) - canyon , tributary , geology , colorado plateau , bedrock , plateau (mathematics) , navajo , hydrology (agriculture) , alluvium , physiographic province , geomorphology , archaeology , geochemistry , geography , mathematical analysis , linguistics , philosophy , cartography , mathematics , geotechnical engineering
Incision rates of the Colorado River are integral to understanding the development of the Colorado Plateau. Here we calculate episodic incision rates of the Colorado River based on absolute ages of two levels of Quaternary deposits adjacent to Glen Canyon, Utah, along the north flank of Navajo Mountain. Minimum surface ages are determined by a combination of cosmogenic radionuclide surface exposure ages, uranium series and soil‐development formation times. Bedrock incision rates of the Colorado River between c . 500 ka and c . 250 ka, and c . 250 ka to present are c . 0·4 m ka −1 and c . 0·7 m ka −1 , respectively. These rates are more than double the rates reported in the Grand Canyon, suggesting that the Colorado River above Lees Ferry is out of equilibrium with the lower section of the river. We also determine incision rates of two tributaries to the Colorado River. Oak Creek and Bridge Creek flow off Navajo Mountain into Glen Canyon from the southeast. Oak Creek and Bridge Creek both have incision rates of c . 0·6 m ka −1 over the past c . 100 ka at points about 9 km away from the main stem of the Colorado River. Copyright © 2005 John Wiley & Sons, Ltd.