Thursday, August 5, 2010

Yosemite from a Slightly Different Perspective, Pt. 2

And we are off! Off the ground, off our rockers, and on the rocks. This is my former student on a ten-day journey up El Capitan in Yosemite Valley. Yesterday, we got a sense of the planning and logistics of a long climb on the big walls of Yosemite.
Kait and Ammon were following the Mescalito, which is route #14 in the picture above from SuperTopo (does that diagram look a bit like an LA freeway map?).
Rock climbers really are the ultimate geologists. Doing research on rock exposures is one thing, but it's quite another when your life depends on knowing the properties, and especially the weaknesses of the rock.
Climbers have to know a lot about the weathering properties of rock. On a face like El Capitan, climbing usually follows joints and fractures in the granite. Deeply weathered surfaces can't support or hold the gear in place. In some rocks (especially the Cathedral Peak granite), giant feldspar crystals (megacrysts) offer some convenient handholds and footholds, although the cleavage pattern of the mineral sometimes complicates things.
That's the "Nose" of El Cap below Kait.
El Capitan is one of the most extraordinary cliffs in the world because the
ganite is very solid with relatively few joints and cracks. It's actually been a long time since the cliff was scraped clean by glaciers, almost a million years. The two most recent glaciations reached the base of El Cap, but only a short distance up the cliffs. Moraines can be found on the valley floor below the cliffs. It is the effect of rockfalls and mass wasting that keeps the cliffs vertical (and providing "convenient" routes up the face).
That's the North America pluton behind Ammon. It's a darker rock that intruded into the El Capitan granite. From the valley floor, it looks vaguely like...North America. From this angle, not so much.
Thanks again for sharing the photos of your journey!
In the next post: The summit, and the view! Please remember, these pictures are the property of Kait and Ammon. Check with me for contact information.


Gaelyn said...

Looks very scary. But it would be fun to have your nose to the rocks like that.

Silver Fox said...

Great pictures, giving one a feeling of being there - which otherwise I wouldn't be likely to experience!

yosemite faith said...

great! on twitter follow @elcapreport - he posts daily during prime el cap climbs and posts photos too!