Sunday, August 31, 2008

Below the Wingate

Today I had the chance to be in my favorite part of the Colorado Plateau. It's not a specific place but rather a place in time. In many places throughout the canyon country of Western Colorado and eastern Utah, there is a cliff-forming formation called the Wingate Sandstone. It seems in Triassic times, this area was quite the sandy desert, reminiscent of the Sahara desert of modern times. This wind blown sand accumulated a few hundred feet of depth before the next major climatic change came in to produce the Kayenta Formation, a great caprock keeping the Wingate from blowing away...again.

These reddish cliffs make a heck of a barrier when trying to cross the area and there are only select places where you can safely make your way through the cliffs.


The cliffs themselves are the greatest red color and show remarkable cross bedding indicating their origins as sand dunes. Today the desert varnish colors the walls with stripes of black making amazing works of art. I just wish my camera would do justice to what I really see.

As I get older, desert hiking is quickly replacing my mountain adventures as what I do for entertainment. I enjoy walking through the canyons and dissecting their geologic history. I can look at the cross bedding and conchoidal fractures way up on the wall and I can understand how the sand grains were moved by wind those long eons ago... but, when I reach the bottom of the Wingate and start walking through the Chinle, I also just get mesmerized by the beauty in the rocks. So, when you get a chance, spend some time, even a night below the Wingate and you will see what I mean.

Wednesday, August 13, 2008

Sand bar camping

As the last post explains, we had plenty of sand bar camping and only small amounts of Teva sucking mud on our Geology of the Green River class. The flow of the river had dropped to its not-runoff-minimum just the week before and we were expecting to see lots of stagnant mosquito filled back water eddies behind the best camping sand bars... but no. The camping was awesome.

It was interesting to look for changes in sand bar location and size after a banner snow year across the west. The Green River, although dam controlled, still boasted a larger than normal spring discharge that we hoped would translate into lots of sand transport, at least from the channel centers to the river's edge. The upper stretches of the river (between Green River UT and the start of Labyrinth Canyon proper) saw just that, a healthy crop of not new, but certainly beefier sand bars than the year before. However, once we were in the narrower portions of the canyon, the sand bars were certainly just as numerous as other years but also all showed evidence of terrain loss. The focus on the class did not allow any quantitative measurements so this is all anecdotal.

One fun exercise was that we examined the sorting of particles across each sand bar to see how the flow of water changed as the discharge dropped and the sand bar was exposed above water. Mostly however, the class seemed to find a need to memorize each formation name as we floated by and they were less enthralled with studying the energy regime that created the rock they are looking at.

Monday, August 4, 2008


Just back from the Green River (Labyrinth Canyon). Discharge was about 3100 cfs and the sand bar camping was amazing. The Teva sucking mud was at a minimum.

I'll tell more when I catch up on sleep.