Tuesday, August 18, 2015

Canyonlands National Park

As I am sitting here and writing this post I am looking out at the sun setting on red cliffs and the La Sal Mountains beyond them.  It seems like large red walls are all around us here in Moab, Utah. Yesterday, Sunday, we took a drive on a scenic by-way along the Colorado River.  That river has carved out the many canyons in this area, as well as the Grand Canyon.  Pictured below are the cliffs along that highway.
As you may know from my last posting, we saw Arches National Park Saturday- and that was more red rocks.   The build-up of differing layers of sediment (sand and rock) started with inland seas which came and went over millions of years.  Large rock structures formed and changed over time as they were eroded by wind and water.  That is about as simplistic as I can make it!   After entering the park we drove a distance over a mesa covered with desert landscape until we came to the vista pictured below.  This part of the park is called Island in the Sky, and it is only section that is easily accessible to the public.  Two other districts of the park are called The Needles and The Maze. The latter is the most wildest, as well as remote.  At center stage of this park are two canyons carved out by the Green and Colorado Rivers.
A sign at this overlook notes that on a clear day it is possible to see as far as 152 miles.  As you can see, today was not a clear day, but we were glad it was overcast.  We did not want a repeat of Saturday when by late morning it was close to 100 degrees.  Today the sun did not show up until at least noon.  We had a pleasant hike to Upheaval Dome which is pictured below.
Here rock layers fractured and tilted forming a circular depression which is two miles wide.  Scientists do not know whether this is the result of a meteorite impact or the remnant of a salt dome.  An interpretive sign explained the latter phenomenon this way: when seas dried up they left thousands of feet of sand.  Sediment covered that.  Salt rose, fracturing and destroying rock layers in its path.  Water eroded the salt and over-laying sediment, exposing the crater we see today.  That is one explanation for this anomaly in the land of canyons.   By the way, we have seen a lot of red sandstone, but there is white also- as seen above.   The white sand came from ancient coastal sand dunes.
Just about in the middle of the picture above is the Green River.  Around that area is the confluence of the Green and Colorado Rivers.  The rivers and canyons here were explored by Major Powell, a one-armed Civil War veteran and geologist in 1969.   He wrote the following: "this is a strange weird region" of naked rocks with "cathedral-shaped boulders towering hundreds or thousands of feet, cliffs that cannot be scaled, and canyon walls that shrink the river into insignificance".   All information here that does not sound like my own brilliance came from information which the park provided!  More on this park tomorrow.

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