Given their appearance, it's not surprising that they are made out of the same hard, monolithic granite as El Capitan itself.
The Cathedral Rocks form one side of a small subsidiary creek drainage. The sides and mouth of this valley have been sliced off by glaciers, leaving behind the classic example of a "hanging valley". Bridalveil Creek runs down the valley, and falls about 600 feet over the cliffs at its end. It's a fairly pathetic trickle in August, though.
The prominent knob to the right of the falls is the Leaning Tower. A more impressive picture of it (it really is "leaning") is here. I didn't know anything more about it than that, but poking around on the Internet I discovered that a fairly well-known rock-climbing guy, Todd Skinner, was killed in a fall while climbing it a few months after we were there. (Given the dangerous nature of the sport, it's interesting that most of the fatalities in Yosemite last year were hikers venturing off-trail in the wrong places, rather than rock climbers.)
One last glimpse of El Capitan as we headed down towards the heat and smog of the Central Valley. Stockton, here we come!
Posted by David Fleck at 17 January 2007 07:38 AM
Very cool.
Posted by: Jonathan on January 17, 2007 08:30 AM
Given their appearance, it's not surprising that they are made out of the same hard, monolithic granite as El Capitan itself.
Now is that granite, or granodiorite?
The whole granodiorite thing made me remember an interesting bit of trivia in which geology intruded into poetry.
In some versions of Kipling's classic poem "In the Neolithic Age" you find the lines:
But a rival, of Solutré, told the tribe my style was outré --
By a hammer, grooved of dolomite, he fell.
A Google search yields only a handful of hits for these lines, but that's how they appear in my 1913 edition of Departmental Ditties and Barrack-Room Ballads.
There are many more hits for a different version:
But a rival, of Solutré, told the tribe my style was outré --
’Neath a tomahawk of diorite he fell.
Someone must have told Kipling that diorite would make a much more satisfactory weapon. And it lead to a cleaner line. Hurray for geology!
I originally posted links to the actual Google searches, but your content filter did not like them since they referenced the naughty site google dot com.
Posted by: Angie Schultz on January 17, 2007 10:30 AM
Is El Capitan basically a ridge, or is the valley generally lower than the surrounding terrain?
Also, what will you do if you don't finish this before you start your next vacation?
Posted by: Annoying Old Guy on January 17, 2007 10:49 AM
A-
sorry about that. We tend to be vigorous in our spam-scrubbing. Google has been reclaimed from the outer darkness.
And yes, El C. is real, honest-to-God granite – except for the diorite intrusions, visible as some of the darker markings on the pale granite. In fact, there's a big splotch on the southeast face that looks like a very distorted outline of North America, and as a result that portion is known as the "North America Wall". So Kipling knew about diorite, eh? A man of hidden depths.
A.O.G.-
Here's an aerial photo I found - it shows that the valley is carved from a relatively level upland, and El Capitan / Cathedral Rocks is a resistant feature that hasn't been eroded back as much as the surrounding rock.
I suspect our next vacation will be less ambitious, e.g., a weekend in Dubuque or something similar.
Posted by: David Fleck on January 17, 2007 08:36 PM