A Deformation Feature in Grand Gulch

March 2003

The Location

The feature, located at 12S 0590591/4148887 (WGS84), at the tip of the arrow in the inset map below, is along the main wash of Grand Gulch in Cedar Mesa. The circled "12" on the map is "Split-level Ruins". Access is from Todie Flat trailhead off Highway 261.

[map showing location of deformation]

The Feature

The feature is exposed in the vertical northeast side of the neck of an entrenched meander. The photos below were taken in May 2002 in the direction the arrow points in the inset map above. (The southwest side of the neck might be interesting too, but we didn't have time to look at it carefully -- it wasn't as nicely exposed as the northeast side.)

Not visible, above the frame of the left 'overview' photo, is a horizontal wedge of red 'shale' (or mudstone?) that is about 20cm thick to the right (north) side and tapers to nothing to the left (south).

What caused this?

Overview (click to expand)
Detailed view (click to expand)

Comments?