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| Messages 1 - 34 of total 34 in this topic |
Klimmer
Mountain climber
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Topic Author's Original Post - Apr 9, 2016 - 07:00am PT
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There is plenty of evidence of glacial polish all throughout the High Sierra back country, but is there patches of glacial polish anywhere in Yosemite Valley proper? Is there any on Yosemite Valley Big Walls?
Do any of you know and then where?
Now I known of course the Valley was a U shaped glacial carved valley before sediment filled in the bottom of the valley. Just wondering if the glacial polish still exists in the valley somewhere?
Any one know? Thanks.
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Flip Flop
climber
Earth Planet, Universe
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Glacial Polish is caused by the plasma blasts of Starfighters during the last local battle in the Space War between the Lizzies and the Greys.
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FRUMY
Trad climber
Bishop,CA
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REALLY
Why don't you go and look for yourself
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overwatch
climber
Arizona
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Big surprise, Klimmer is being Klimmered (where everything you write is attacked and belittled)
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life is a bivouac
Trad climber
Bishop
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Hey, a little known fact... Back when John Muir drove sheep from the Bay area to the foot hills; and subsequently into the Yosemite, those jump bugs would flock from side to side along the Valley's walls eating sweet grasses.
With every passing summer more and more lanolin laden sheepies polished those walls to near mirror like finishes. And there you have it! :)
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Klimmer
Mountain climber
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Topic Author's Reply - Apr 9, 2016 - 08:41am PT
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Serious question. It's an Earth Science question. C'mon people. Focus. Get out of your ADHD induced hyper focus on making fun of people all the time.
I'm hoping some ST big wall gurus know and would be willing to share the info for the sake of pure science.
There is plenty of the valley being filled with sediment evidence. There are some small terminal moraine evidence in the valley, but is there any remaining patches or areas of glacial polish remaining on any big walls in Yosemite Valley proper?
I would ask John Muir but he's sadly no longer with us. And I'm pretty sure he didn't get onto the vertical big walls above the valley. But he would indeed be a great resource since this was one of his primary scientific studies beating out the geologists. Great story by the way.
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overwatch
climber
Arizona
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What an incredible tool and I don't mean you, sir, thanks for the link
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FRUMY
Trad climber
Bishop,CA
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I not making fun of anyone!
Go look for yourself - that's how science is done.
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Klimmer
Mountain climber
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Topic Author's Reply - Apr 9, 2016 - 08:55am PT
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WB,
Have you bumped into any in all your Valley big wall climbing and rescues?
I'll have to load the software to use the high definition imagery.
Personal experience is gonna trump remote sensing in this regard. I think you could look at patches of glacial polish in Toulomne Meadows in HD imagery and wouldn't be able to tell.
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Klimmer
Mountain climber
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Topic Author's Reply - Apr 9, 2016 - 09:25am PT
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This good general article indicates there might be some near Nevada Falls ...
http://www.indiana.edu/~sierra/papers/2012/klapperich.html
"Glacial polish, another visible marker seen on many rock features in Yosemite allows for a better understanding of which glacial period polished a specific areas as well as their possible age. "The deep weathering of the glacier polish found on the steeper slopes of the Nevada Fall area and on the low ridge that extends east from Liberty Gap into Little Yosemite Valley indicates that it is pre–Tioga in age" (Schaffer, 1977). If the Tioga age glacier had made it this far to the polish, the present day polish would have been obliterated or at least smoothed down much more so than is seen today."
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gstock
climber
Yosemite Valley
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The most recent glaciation in Yosemite Valley (the Last Glacial Maximum, locally called the "Tioga" glaciation, circa 18,000 years ago) terminated near Bridalveil Fall. In eastern Yosemite Valley the glacier was just below the rim, but it tapered to the terminus such that most of the walls in western Yosemite Valley were only slightly glaciated. Thus there is much more polish on the walls in the eastern portion of the Valley.
Large areas of glacial polish are visible on the walls of Tenaya Canyon around Mirror Lake, on the Glacier Point Apron, and on Middle Brother east of The Folly. There are smaller, easily accessible areas of polish at Church Bowl (Energizer), west side of Swan Slab, top of Manure Pile, and a tiny patch at the base of Pine Line.
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Klimmer
Mountain climber
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Topic Author's Reply - Apr 9, 2016 - 09:43am PT
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My best guess, hypothesis, is there must be some residual glacial polish on the massive vertical walls of Yosemite Valley somewhere.
Would be neat to find it, image it, map it, GIS it, and share it. Would be a really cool geology-glaciology study, and a great excuse to go climbing.
I suppose it could be expanded to the entire Yosemite National Park proper not just the Valley. Obviously there is great glacial polish in the High Sierra of course.
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Klimmer
Mountain climber
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Topic Author's Reply - Apr 9, 2016 - 09:46am PT
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Gstock, very cool. Thank you. Where is your resource, personal experience, published study? I see you're in Yosemite Valley. Thank you.
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Ed Hartouni
Trad climber
Livermore, CA
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gstock is The Valley Geologist...
he is the co-author of
Geology Underfoot in Yosemite National Park
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Spider Savage
Mountain climber
The shaggy fringe of Los Angeles
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Left side of Swan Slab. there is a wide ledge with a couple of short routes going up it. Go round to the top of this ledge and witness beautiful glacial polish on bedrock.
It is my belief that this is the spot where John Muir proved poor old Josiah Whitney was wrong about Valley origins.
It's quite clear.
I've seen other bits here and they're but not this good.
It is a significant site.
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scooter
climber
fist clamp
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If you go back near mirror lake on the North side, walk up to the Valley wall. You will find really nice glacial polish there.
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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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| Messages 1 - 34 of total 34 in this topic |
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