Question for Geologists

[Dover]

How are major canyons formed? Are they formed from a splitting of the Earth like a big tear, or are they formed by water?

The reason I ask is that a very large crack has appearred up in the panhandle area of Texas (just southeast of Amarillo). It just so happens that it's location is very near a huge 'crack' in the Earth called Palo Duro Canyon, and I'm wondering if that's coincidence, or if there is a relationship there.

Here's the story: http://www.firstcoastnews.com/news/usworld/news-article.aspx?storyid=39373

[DemSigns]

1. Short answer: Uplift and erosion

Uplift of continental crust and subsequent erosion are what cause the topography of mountains. Special circumstances lead to the formation of the greater canyons.

[Dover]

2. Thanks. Here is what I've found out so far on Palo Duro

It seems that it was erosion, primarily, according to this site:




Geology: The canyon is approximately 120 miles long, 20 miles wide, and 800 feet deep. Extending from Canyon to Silverton, Palo Duro Canyon was formed primarily by water erosion from the Prairie Dog Town Fork of the Red River, which began to carve the canyon less than one million years ago. The slopes of the canyon reveal the colorful natural history of the area.
Dating back 250 million years, the oldest layers of rock, Cloud Chief Gypsum, can only be seen in a few areas in the canyon. The next oldest and most prominent layer of rock is the Quartermaster Formation which can be seen with its distinctive red claystone/sandstone and white layers of gypsum.

The Tecovas Formation is located directly above the Quartermaster and is composed of yellow, gray, and lavender mudstone and sandstone. Together with the Quartermaster, they form the colorful triangular slopes called Spanish Skirts. Above the Tecovas, the Truijillo and Ogallala formations can be viewed. The Ogallala is composed of sand, silt, clay, and limestone, which compose the hard caprock.

http://www.tpwd.state.tx.us/park/paloduro/

[beyurslf]

3. God does it. The earth is only 6000 years old. He just reaches down and

scoops some out every once in awhile. (Maybe he uses it when they have mud wrestling contests with the angels in Heaven.)

[Dover]

4. Ya know.....the 'clever' responses about the fundy Creationist views

are getting pretty stale here in the Science forum. It was funny the first 100 posts, but now it's worn out. :eyes:

[beyurslf]

5. Sorry. Didn't notice this was in the Science room. It was on the main page

I am in KS so we are pretty used to the "God must have done it" approach. Ya know... we don't teach real science here.

[Kraklen]

6. Rivers and glaciers.

Uplift raises the land, erosion carves out the valley or canyon.

Occasionally continental drift can cause a large valley, the East Rift Valley is one such thing. If it fills with the ocean then you've got something resembling the red sea.

That crack Texas ddin't seem all that big to me. I would imagine it's just some subterranean feature that collapsed.

[Cicero]

7. Paul Bunyan's axe did it (nt)