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Bruce Morris
Social climber
Belmont, California
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Yeah, like Scooter says, the Mirror Lake area has some good examples of glacier polish and striations. Quite a bit at the base of the Captain too.
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Klimmer
Mountain climber
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Topic Author's Reply - Apr 9, 2016 - 02:43pm PT
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Bruce,
There's a lot of glacial polish at the base of El Cap?
Really?
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NutAgain!
Trad climber
South Pasadena, CA
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Perhaps you are leaving Glacier Apron out of consideration?
Galactic Hitchhiker seems long enough to call a big wall, even if it's free.
Pretty smooth and shiny stuff over by Arches Terrace. Pretty smooth and shiny stuff all over the place really.
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Osprey
climber
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There is polish on the second half of Ugly Duckling. Yes, that's right, Swan Slab. Believe it or not?
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Bruce Morris
Social climber
Belmont, California
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Apr 10, 2016 - 12:23am PT
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Bruce,
There's a lot of glacial polish at the base of El Cap?
Yeah, on "Party Mix" (5.10b) and "Armageddon" (5.11 face).
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Klimmer
Mountain climber
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Topic Author's Reply - Apr 10, 2016 - 12:33pm PT
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You guys are awesome. I wasn't aware that there was so much residual glacial polish evidence still in Yosemite Valley proper. I was under the impression that most of it had weathered away, and there was little to be found.
There is a considerable amount and much more than most people probably imagine. Much more than I imagined.
Would be really cool to see a Yosemite National Park wide study, where glacial polish evidence still remains.
Glaciers acting as massive lapidary polishing grinders and getting granite as nearly polished as granite counter tops in kitchens and bathrooms. Simply amazing.
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bradL
Trad climber
Lake Tahoe, NV
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Apr 10, 2016 - 01:39pm PT
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I recommend checking out the ultra-classic USGS paper by Francois Matthes (1930). Yes, that Matthes. It's online here: https://pubs.er.usgs.gov/publication/pp160
The paper has a great geological map in Plate 27, which is available here: http://pubs.usgs.gov/pp/0160/plate-29.pdf.
As Greg pointed out, you'll want to look upstream of Bridalveil Meadows. The moraines there let you know that's how far down valley the glacier went (they're colored in blue). The boundaries of the last glaciation (blue dashed line) so you'll want to look inside of there.
Everything colored in yellow are more recently altered surfaces such as landslides that will probably have had their polished erased. This map also marks surfaces that were never glaciated (like Half Dome).
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Spider Savage
Mountain climber
The shaggy fringe of Los Angeles
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Apr 10, 2016 - 03:17pm PT
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Really great map in that last post.
Lots of bedrock polish on the rim up near Tamarack Flat campground. One of the previous ice ages was really big. Seems like the last one might have been lighter.
Really looking forward to the next one.
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Oplopanax
Mountain climber
The Deep Woods
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Nov 15, 2017 - 02:24pm PT
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When the polish starts to weather and gives you edges and holes, it's real good
(Yosemite of the north, i.e. Bella Coola)
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Scole
Trad climber
Zapopan
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Nov 17, 2017 - 10:04am PT
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Go look in Hetch Hetchy and the Grand Canyon of the Tuolumne. You will find great examples of polish on many formations.
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AP
Trad climber
Calgary
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Nov 17, 2017 - 10:23am PT
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Skaha is composed of gneiss with variable polish. Areas without polish can be a bit chossy in places. Polished areas are primo clean rock.
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donini
Trad climber
Ouray, Colorado
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Nov 17, 2017 - 10:32am PT
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Those glaciers were tireless.....grinding, ecavating, polishing. The kind of work ethic you just don’t find anymore.
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