Jones, Lawrence S. and Rosenburg, Margaret and del Mar Figueroa, Maria and McKee, Kathleen and Haravitch, Ben and Hunter, Jenna (2010) Holocene valley-floor deposition and incision in a small drainage basin in western Colorado, USA. Quaternary Research, 74 (2). pp. 199-206. ISSN 0033-5894 http://resolver.caltech.edu/CaltechAUTHORS:20101022-090954139
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The valley floor of a 33.9 km^2 watershed in western Colorado experienced gradual sedimentation from before ~ 6765 to ~ 500 cal yr BP followed by deep incision, renewed aggradation, and secondary incision. In contrast, at least four terraces and widespread cut-and-fill architecture in the valley floor downstream indicate multiple episodes of incision and deposition occurred during the same time interval. The upper valley fill history is atypical compared to other drainages in the Colorado Plateau. One possible reason for these differences is that a bedrock canyon between the upper and lower valley prevented headward erosion from reaching the upper valley fill. Another possibility is that widespread, sand-rich, clay-poor lithologies in the upper drainage limited surface runoff and generally favored alluviation, whereas more clay-rich lithologies in the lower drainage resulted in increased surface runoff and more frequent incision. Twenty-two dates from valley fill charcoal indicate an approximate forest fire recurrence interval of several hundred years, similar to that from other studies in juniper–piñon woodlands. Results show that closely spaced vertical sampling of alluvium in headwater valleys where linkages between hillslope processes and fluvial activity are relatively direct can provide insight about the role of fires in alluvial chronologies of semi-arid watersheds.
|Additional Information:||© 2010 University of Washington. Published by Elsevier Inc. Received 17 August 2009. Available online 31 July 2010. Support was provided by NSF-REU Grant #0453264, Murdock Charitable Trust Grant No. 2005188, Mesa State College, and Rocky Mountain College. Reviews by Joel Pederson, Dan Albrecht, and anonymous reviewers are greatly appreciated. Special thanks go to Quaternary Research Associate Editor James Knox for careful, patient, and insightful reviews.|
|Subject Keywords:||Holocene; Incision; Aggradation; Geomorphology; Colorado; Sedimentation; Arroyo; C-14; Forest fire; Recurrence interval; Charcoal|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||25 Oct 2010 16:23|
|Last Modified:||26 Dec 2012 12:32|
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