Controlling Mechanisms for Late Holocene Arroyo Cut-fill Events in Southern Utah: A study from Kitchen Corral Wash
Location
ECC 201/203 & 205/207
Event Website
http://water.usu.edu
Start Date
4-9-2013 5:25 PM
End Date
4-9-2013 5:35 PM
Description
Arroyos, entrenched channels in valley-fill alluvium, from the semiarid southwestern United States are capable of capturing decadal- to centennial-scale fluctuations in watershed hydrology as evidenced by the Holocene cut-fill stratigraphy recorded within near-vertical arroyo channel walls. Kitchen Corral Wash (KCW), a tributary of the Paria River in southern Utah, has experienced both historic (ca. 1860-1910 AD) and prehistoric (Holocene) episodes of arroyo cutting and filling. During historic arroyo-cutting event, KCW and other regional drainages were entrenched up to 30m into their fine-grained alluvial fill, leaving former floodplains perched above new channel bottoms. Alluvial sediments preserved within the exposed arroyos walls record largely aggradational sequences interrupted by periods of incision. Although arroyo entrenchment and aggradation processes have been studied for over a century, exact causes of arroyo cutting are still not fully understood. Hereford (2002) argued that arroyo system dynamics over the last ~1000 years are climatically driven. This suggestion was based on the near-synchronous timing of arroyo cutting in drainages throughout southern Utah and the surrounding region. However, recent results from KCW and nearby drainages suggest a more complex pattern. While other studies have attempted to constrain the timing of arroyo cut-fill events in KCW, success has been limited by poor age control. In order to better understand the timing of arroyo events, this study aims to update and improve the existing arroyo cut-fill chronology from KCW using detailed alluvial stratigraphic descriptions and age control from optically stimulated luminescence (OSL) and AMS radiocarbon dating. Preliminary results from twelve study sites suggest at least five arroyo cut-fill cycles over the last ~5 ka. The newly developed KCW cut-fill chronostratigraphy is compared to regional alluvial and paleoclimate records to test hypotheses on whether arroyo system evolution is controlled by to climate or non-climate related forcing mechanisms.
Controlling Mechanisms for Late Holocene Arroyo Cut-fill Events in Southern Utah: A study from Kitchen Corral Wash
ECC 201/203 & 205/207
Arroyos, entrenched channels in valley-fill alluvium, from the semiarid southwestern United States are capable of capturing decadal- to centennial-scale fluctuations in watershed hydrology as evidenced by the Holocene cut-fill stratigraphy recorded within near-vertical arroyo channel walls. Kitchen Corral Wash (KCW), a tributary of the Paria River in southern Utah, has experienced both historic (ca. 1860-1910 AD) and prehistoric (Holocene) episodes of arroyo cutting and filling. During historic arroyo-cutting event, KCW and other regional drainages were entrenched up to 30m into their fine-grained alluvial fill, leaving former floodplains perched above new channel bottoms. Alluvial sediments preserved within the exposed arroyos walls record largely aggradational sequences interrupted by periods of incision. Although arroyo entrenchment and aggradation processes have been studied for over a century, exact causes of arroyo cutting are still not fully understood. Hereford (2002) argued that arroyo system dynamics over the last ~1000 years are climatically driven. This suggestion was based on the near-synchronous timing of arroyo cutting in drainages throughout southern Utah and the surrounding region. However, recent results from KCW and nearby drainages suggest a more complex pattern. While other studies have attempted to constrain the timing of arroyo cut-fill events in KCW, success has been limited by poor age control. In order to better understand the timing of arroyo events, this study aims to update and improve the existing arroyo cut-fill chronology from KCW using detailed alluvial stratigraphic descriptions and age control from optically stimulated luminescence (OSL) and AMS radiocarbon dating. Preliminary results from twelve study sites suggest at least five arroyo cut-fill cycles over the last ~5 ka. The newly developed KCW cut-fill chronostratigraphy is compared to regional alluvial and paleoclimate records to test hypotheses on whether arroyo system evolution is controlled by to climate or non-climate related forcing mechanisms.
https://digitalcommons.usu.edu/runoff/2013/AllPosters/11