Trenches through the Braid-scarp
From: Field studies of active faults in the Lake Iliamna region
The Braid-scarp is a step in a plain of tundra hummocks. The plain was left by braided rivers near an ancient glacier. In the thousands of years since the surficial sediment has been stirred by frost in the soil in a process called cryoturbation, which leaves the ground surface covered in mounds.
In an attempt to identify the origin of this step or "scarp," we dug two trenches across it. Part a shows the most likely of possible scenarios we considered for the formation of the scarp. Part b shows the stratigraphy (layering) that we observed when we dug the trenches. We were not able to conclusively eliminate either of our hypothetical scarp-forming scenarios, but what we saw in the trench was more consistent with faulting than with a fluvial scarp.
We discuss our interpretation of these trenches in our Braid-scarp technical notes page
| Data file | File type | File size |
|---|---|---|
| Field sketches of trench | 19.1 Mb |
| Data file | File type | File size |
|---|---|---|
| Vector-graphic original | Illustrator CS4 | 487 kb |
| Print version | 180 kb | |
| Flat image | .png | 135 kb |
| Flat image (small) | .png | 49 kb |
