Episodic bedrock erosion by gully-head migration, Colorado High Plains, USA
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Abstract
This study explores the frequency of bedrock exposure in a soil-mantled low-relief (i.e. non-mountainous) landscape. In the High Plains of eastern Colorado, gully headcuts are among the few erosional features that will incise through the soil mantle to expose bedrock. We measured the last time of bedrock exposure using optically stimulated luminescence dating of alluvial sediment overlying bedrock in gully headcuts. Our dating suggests that headcuts in adjacent gullies expose bedrock asynchronously, and therefore, the headcuts are unlikely to have been triggered by a base-level drop in the trunk stream. This finding supports the hypothesis that headcuts can develop locally in gullies as a result of focused scour in locations where hydraulic stress during a flash flood is sufficiently high, and/or ground cover is sufficiently weak, to generate a scour hole that undermines vegetation. Alluvium dating also reveals that gullies have been a persistent part of this landscape since the early Holocene.
Study Area
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | Episodic bedrock erosion by gully-head migration, Colorado High Plains, USA |
| Series title | Earth Surface Processes and Landforms |
| DOI | 10.1002/esp.3929 |
| Volume | 41 |
| Issue | 11 |
| Year Published | 2016 |
| Language | English |
| Publisher | John Wiley and Sons |
| Contributing office(s) | Geologic Hazards Science Center |
| Description | 9 p. |
| First page | 1574 |
| Last page | 1582 |
| Country | United States |
| State | Colorado |
| Online Only (Y/N) | N |
| Additional Online Files (Y/N) | N |
| Google Analytic Metrics | Metrics page |