Thursday, May 16, 2013

My 2013 Canyonlands River Trip - Part III

In Part I and II of this posting, we traveled from the put-in at Mineral Bottom through Stillwater Canyon and hiked on the Stovepipe Trail. Here in Part III, we arrive at the confluence of two great rivers - the Green and the Grand. (Before 1922, the upper part of the Colorado River was known as the Grand River. I just love the saying, "At the junction of the Green and the Grand" and so I plead for the state of Colorado to give up the mistaken notion that it's part of the river is "Colorado". How about by 2022, we begin again to refer to this branch as the Grand River!). From here we head downstream into Cataract Canyon, and its well regarded rapids. But first, we will take another hike to the outer rim of the Canyonlands.

The junction of the Green (left) and the Grand (right). Here the two rivers merge and become the true Colorado River. This is a fantastic place!

On the way home after the river, we took a scenic flight over the river we had floated. I can't resist adding two photos of the great confluence here, to give the bird's eye perspective. This first view is looking upstream with the Grand River being the darker of the two.

Another angle - the Green comes in from top center and the Grand enters the confluence from the right. It takes quite a distance for the waters to mix.

Rock and river heaven! Where the river disappears downstream is Spanish Bottom, the location of our next hike out.

Back on the ground at the confluence, we see an inscription from the Stanton Expedition in 1889. The inscription reads:

Sta 8489 + 50
D. C. C. & P. R. R.
May 4th, 1889

"Sta" stands for a station number assigned to this place. "D. C. C. & P. R. R." stands for Denver, Colorado Canyon and Pacific Railroad. This is one of the most historic inscriptions in all the southwest.

More colorful claret cup (hedgehog) cactus

Our first view of the Doll House from the river. This is the location of our next hike.

On the 5th morning we walked 3/4's of a mile upstream from Brown Betty Camp top Spanish Bottom, where a trail leads up to the Doll House. Here we begin the climb.

Spanish Bottom is an unusual "park" in the bottom of canyon country. We speculated if maybe this was once the site of a cut-off meander in the Colorado River? Or was it the site of a salt dome? More on that below.

Arrival at the top!

And a world of strange sandstone shapes. These are spires cut into the Permian Cedar Mesa Sandstone.

Once on the top, we could see the La Sal Mountains, across the entire width of Canyonlands. What a view

Cirrus clouds frame sandstone spires in the Doll House

There were many cracks to explore with narrow winding passages

Kids playing on ledges of sandstone - what fun!

We enjoyed lunch on this bench of sandstone overlooking Surprise Valley. The entire block of light-colored rock outboard of the viewer has broken away from the cliff he is standing on and slid down into Cataract Canyon. You can see the back tilting on the top surface of the Cedar Mesa Sandstone. Slumps like these are common in Cataract Canyon and serve to form rapids on the river where the slides are pinching the river channel.

Fantastically preserved granaries in a sandstone overhang

Making our way back to the beach through the Doll House

At the mouth of Lower Red Lake Canyon (where the small delta has formed in the Colorado River), a salt dome is exposed. Note how the usually flat-lying strata are unturned in a domal shape across the mouth of the canyon, with strata dipping away on the left and right. The salt has intruded upwards from the Paradox Formation, through to the overlying Honaker Trail Formation. See the next slide for a graphic illustration.

This is the same photograph with graphic aids added. The yellow dome highlights the location of the salt dome, now partially dissolved at the surface. The dotted red arrow shows its direction of movement. Layers of salt behave like flowing plastic when covered by heavy sediment. The other two red lines show deformed beds of the Honaker Trail Formation that were domed upwards as a result of salt intrusion. Compare the two photographs and see what geologists see!

A Princes' plume (Stanlea) frames our return to the bottom of Cataract Canyon. Now it is time to run the rapids after 5 days of gentle floating.

To be continued.....

No comments:

Post a Comment

If your comment will not post, email me with the problem.