The National Parks on the Colorado Plateau include Arches and Canyonlands, which I've already blogged about. The other national parks on the plateau are the Petrified Forest, Grand Canyon, Zion, Bryce Canyon, and Capitol Reef. The reason so many parks are in this single area is because of an amazing series of geological events. Many layers of rock have been formed over millions and millions of years from a variety of climates and events. Huge inland seas left buried sediment, time passed then expansive deserts with huge sand dunes were covered, more time passed to bury a tropical landscape with volcanic ash and lava ... coral reefs ... river sediment ... glaciers ... etc ... layer upon layer was buried and turned to stone by the weight of subsequent layers and the mineral laden waters that filtered down. It kind of reminds me of a layered rock cake. 
Then, the 140,000 square mile area that is the Colorado Plateau uplifted due to one tectonic plate going under another, forcing up the land ... this area of the "layered rock cake" was now higher, angled and askew in many places. With lots of rain, the softer soil "frosting" on top of the "layered rock cake" eroded away, exposing the bare rock layers.
Some layers of rock are softer than others so that rain can slowly make holes in them called "windows," "arches," "bridges" or "grottos." This softer rock is usually a sandstone which use to be sand dunes millions of years ago. Arches NP has lots of examples of these odd rock shapes created by water dissolving the sandstone. Similarly rain water (think flash floods) eroded the cliff faces of Canyonlands NP, creating the labyrinth of canyons for as far as you can see.
The next park I visited was the Petrified Forest and Painted Desert. Here the minerals present in the rock layers made for beautiful colors in the hills and rocks (1st pic) of the Painted Desert Bad Lands. Just as colorful was the petrified wood, turned to stone through time and pressure (2nd pic). Inside the fossilized wood sometimes showed a beautiful rainbow of semi-precious gems (3rd pic). As mineral laden water seeped down through volcanic ash, it provided the ingredients to turn the wood to quartz, milky quartz, purple amethyst, yellow citrine, and jasper.
I love seeing the big picture. So, when I was told that the next 3 parks I was to visit formed a "staircase," I paid attention. The Grand Canyon is the lowest step in this staircase, having the oldest rock layer exposed at the bottom of the canyon. It's Precambrian, 3,800 million years old! The top rock layer of the Grand Canyon is the bottom layer of rock exposed at Zion ... but, I'm getting ahead of myself.
The views at Grand Canyon NP are beyond words ... and definitely beyond my photographic ability ... absolutely stunning. The breadth and depth of this hole in the ground is extraordinary ... GRAND indeed! I explored the south rim (5th & 6th pics), and then did some lounging and people watching on the veranda of the El Tovar (7th pic).
The next day I visited the north rim which had just opened for the season. In fact, there was still snow on the ground in many places (8th pic). The Grand Canyon is no less stunning from the north side. It's less developed and you must drive to the view points. The highest point on the canyon is almost 9000 feet (9th pic).
The next park I visited was Zion NP. As I said earlier, its bottom layer of rock is the top layer of exposed rock at the Grand Canyon. So, Zion was the second step up on the staircase of the Colorado Plateau National Parks.
I arrived at Zion via the east entrance at sunset. Checker Board Mesa was an amazing site (10th pic). The rock of the mesa has horizontal lines of an alternating type of rock, and vertical lines etched by water run off ... making a checker board appearance ... wow!
I must have been hungry coming into the park that evening because I kept thinking that the color and texture of the rock looked just like a huge cooked salmon! (11th pic)
Whereas I looked down into the Grand Canyon, in Zion I looked up at the huge sandstone cliffs. Many of the monoliths had bible-inspired names. Here (12th pic), the flat top on the left is the West Temple (7810 ft.), next to it is the almost white Sundial (7590 ft.), and further to the right the red stained peak is the Alter of Sacrifice (7505 ft.). Zion means "place of refuge;" and it definitely fit as I enjoyed my peaceful camping spot (13th pic).
Zion has several "life zones," including a small marsh on the hike to the Narrows (14th pic). The Narrows is a place along the Virgin River where the rock faces are very high, and you can hike in the water, up-river, in the late summer and fall when the water level is low and going slow. I'd love to go back to hike the Narrows some day.
The next step up on the rock-layer staircase is Bryce Canyon NP. As you might have guessed, Zions' top rock layer is Bryce's bottom layer of exposed rock.
In Bryce, the operative word is "hoodoo" ... canyons and canyons of hoodoos! (15th pic) A hoodoo is a pinnacle or spire rock formation from 5 ft to 150 ft tall.
Hoodoos are made from fins of layered rock. Water seeps down into the cracks of the rock then freezes over night, expanding and breaking the stone. Because Bryce gets over 200 days per year where it freezes at night and thaws during the day, the stone gets broken and washed away at a fairly rapid rate. The edge of the canyon recedes 1 to 4 feet every 50 years. This tree, nick named "tickle toes," demonstrates that loss. (16th pic)
Because some of the layers of rock are harder than others, the hoodoos can develop some familiar shapes (17th pic).
Some of the names of the hoodoos in the park include -- poodle, lion, hunter and the rabbit, horses head, the queen, the sentinel ...
So, there's my staircase of national parks, Grand Canyon up to Zion up to Bryce ... from oldest exposed rock layer to youngest exposed rock layer.
One of the facts that puzzled me, however, was that the highest point at the Grand Canyon was just about level with the highest point at Bryce, both about 9000 feet. The reason? When the Colorado Plateau was uplifted, the Grand Canyon area was forced to a higher elevation than either Zion or Bryce ... mystery solved!
The other national park on the Colorado Plateau is Capitol Reef NP. So named for a rock formation that someone thought looked like a capitol dome (18th pic, formation on left).
When the Colorado Plateau was uplifted some folds in the earth's crust were created (monocline). Capitol Reef's fold is over 100 miles long and is called the Water Pocket Fold ... a sight to behold. Capitol Reef NP also has hoodoos, arches, and colorful rock. But, but my favorite geological views were from the bottoms of Grand Wash and Capitol Gorge, looking up between shear cliff walls (19th pic).
Capitol Reef NP has also preserved the orchards, pastures and some buildings from a small Mormon pioneer community, Fuita. The campground was set among the orchards. The pastoral setting of Historical Fuita and the Fremont River juxtaposed with the harshness of the rock cliffs and desert was wonderful (20th pic).
That's it for my tour of the Colorado Plateau National Parks, but it's not the last about a staircase on the plateau ... more to come ...
originally posted 5/29/10
Great Geology lesson-- I've never been there-- just flown over it. Someday......
ReplyDeleteIt's cool stuff. I keep thinking about all of those geology teachers I know and how it'd interesting just to tag along as they explore these parks.
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