Friday Field Foto #48: Wall of plane- and ripple-laminated sandstone
If you ever find yourself around Guadalupe Mtns National Park in west Texas and southeastern New Mexico, take a day to do the hike up Shumard Canyon on the Western Escarpment. It’s a full day and parts of it quite strenuous, but worth it. To do it, you need to get a key from the park ranger for the Williams Ranch trail. The trailhead is at the end of 4-wheel drive road that can get washed out sometimes … takes about a half-hour to drive it.
When you get up into Shumard Canyon you’ll be within an ancient submarine canyon succession (the siliciclastic and turbiditic Brushy Canyon Formation overlying the carbonate Cutoff and Victorio Peak formations). One particularly spectacular exposure of the Brushy Canyon is a vertical cliff of nearly 100% plane- and ripple-laminated fine sandstone.
The photograph below is a vertical mosaic taking advantage of the vertical layout of a blog post. You’ll have to scroll down to see a person for scale. In addition to the within-bed sedimentary structures, there are a few intervals of inclined stratification that one might interpret as a large bedforms or barforms. For a slightly bigger version, click on photo.
For you turbidite geeks, one thing to consider … if you didn’t have the context of this area being within a submarine canyon-fill, do you think you would interpret it that way?
check out more photos from a trip to this region last September