Random Roadcuts #23: Deformed Rocks near Alta Ski Resort in Little Cottonwood Canyon, Utah

[@shawnwillsey]

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[@lauragibson4864]

I love all rocks they’re awesome. Thank you for sharing this beautiful education and information with us

[@LizWCraftAdd1ct]

Wow, loving all those folds. Amazing to see a slice through a mountain essentially, and don't forget the Sparklies. Thank you Shawn.

[@YewtBoot]

A fun exploration. Lots of variety in a such a small area! A couple of memories I have of the area: the geneological storage "cave" at the bottom of the canyon. I never got in when the tours were open. It would be fun to see. Also, when I toured Timpanogos Caves, the geology inside that cave system was really awesome!

[@davidk7324]

Thanks Shawn. Marvelous geology ~20 minutes from my front door on most days. Sometimes Big is my favorite, sometimes Little.

[@xwiick]

Thanks for all the hard work on these videos!

[@Steviepinhead]

I've skied both areas, when the rocks were buried in snow. Appreciate your making them visible for us all!

[@wendygerrish4964]

Snowbird almost killed me, Alta was wonderful.

[@seanwelch007]

So much amazing geology in both Big and Little Cottonwood Canyons! Thanks for explaining it all!

[@sueellens]

Amazing that not very long ago I would’ve passed by a roadcut like this and thought it just a mess of jumbled rocks, but these random road cut episodes with your explanations and teaching has piqued my curiosity! Thank you.

[@stephenc1111]

Those were simpler times.

[@garygraham6020]

I really enjoy this road cut series. Keep the series going. I live in the western foothills of the southern Appalachians in East Tennessee. Our geology where I live is primarily sedimentary.

[@juanvasquez9561]

Great info Shawn!🤠⛏️🤘🌵

[@runninonempty820]

I really like that you do a summary of what you saw and also how you come up with possible explanations. Good stuff.

[@Pace-Imagery.]

That is some awesome layering!!

[@susiesue3141]

Thank you for sharing! Very much appreciated. 😊

[@Janer-52]

Stunning! The folds and fractures, the diverse colors, the fizz - no fizz. This has got to be one of the most beautiful and fun roadcuts I've seen you explore. I could see you publishing a "Roadcut Identification Guide" for non-geology students. Or it could be a beautiful coffee-table book full of unique pictures. We are enriched by every roadcut you bring to us.

[@sandrine.t]

Many thanks for another Random Roadcut, Shawn! This one is intriguing, yes... There's so much going on here! There are so many fractures, faults, folds, bends, beds, swirls, 'sparklies' ;) and lots of different textures and colors and angles (which you did a great job of capturing with the camera) that for me, a non-geologist, this outcrop is complex to "read"… so thank you for explaining these sexy rocks! :)

[@eaglepursuit]

That place has clearly seen some wild stuff over the past several million years

[@marcialoofboro306]

Thanks for showing us those cool rock formations!!

[@tuboe777]

Boy those rocks look like how my body feels. The rocks look so horribly tortured. A very beautiful and interesting road cut, Prof. Shawn.

[@lhaaa1059]

So interesting. Got so involved I felt the traffic when it whizzed by. Sure appreciate the trips you take us on, Willsey ! Thank you.

[@stellaandstone2348]

The folding was very visible, and very interesting! Thanks for this random road cut!

[@YOICHIHAGIWARA]

ありがとうございます！

[@carloscorreia8928]

Amazing! Thank you Prorfessor.

[@Riverguide33]

Thanks, Shawn. As you describe these sites, I can’t help but imagine a time-lapse of the chaos that led to these folds and random bedding. 👍

[@briankirton9636]

Shawn, the hellgate cliffs area in little cottonwood canyon is right on the strike of the sevier overthrust. Metamorphism is present as this acted as a conduit for mineralizing fluids. This area of the canyon is geologically complex and fascanating.

[@mbvoelker8448]

That was wonderful! So many interesting structures.

[@1607rosie]

Hey Shawn you ought talk about what’s going on in palos verdes Calif just a thought

[@reginatonetti7421]

Greetings from Brazil. Some rocks look like petrified trees. Very interesting, Professsor. Thanks a lot.

[@niinaperkkio2356]

Oh, saw only part of the title and thought that the place was Alta in Norway. 😅 We just came down from Finland to the sea level in Norway yesterday and I wanted to know about the road cuts and the beautiful layering and buckling they revealed.

[@daveyblackg]

I’m interested in the dolomite’s down a bit from there.

[@Eastonwasatch]

If you go up the south ridge of Mount superior, the layering is super obvious. Its really cool to see the different rock type on the summit vs farther down

[@tomday7309]

Some of those rocks remind me of the eruptions in Iceland where the lava cools and swirls. Oddly some of those figures you show look like petrified trees!

[@patrickkillilea5225]

Maybe like some Regional Metamorphism?

[@marknovak2413]

Major faults are notoriously hard to see in outcrop b/c the rocks at the fault are usually busted up and easily eroded. But there is an old mining road directly above that outcrop that goes up maybe 500' or so vertical that has the best-exposed fault I've ever seen. In this case, the Alta Thrust where Cambrian quartzite has been thrust over Missippian limestone. The outcrop in the video is so deformed b/c it is near the thrust, Cambrian Ophir Shale and Maxfield Limestone in the lower plate.

[@mch8172]

did the Z-folds in the different layers form at the same time?

[@J0hnC0ltrane]

I was interested in the age of the Sevier orogeny, with my friend google, which is approximately 160 mil yrs old. It's pretty old but still young compared to areas in the Canadian shield. Thanks for the time you spend making this video for the community.

[@sixfigureskibum]

The geology in both cottonwood canyons changes every 400 yards at most. Just up slope from ypu are displays of glacier polish and riparian aluvium. Prety sure the dark stuff is dolomite or magnesium limestone vs the white stuff being straight limestone. In this particular cut i personally am fascinated by the very decomposed powdery layers in the sedimentary layers.

[@skyedog24]

I was going to ask this a long time ago and maybe you have covered this. what is the acid ?

[@williamedwards1528]

I believe he has said it is hydrochloric acid

[@shawnwillsey]

Dilute hydrochloric acid.

[@madmaddie4956]

Wonderful road cut lesson, once again! Question: why at the change of rocks @ 11:50 you tested the acid on “fresh” rock instead of the rocks at the onset you didn’t use “fresh” rock but just the rocks lying around?

[@bearrivercacheco.435]

Any books you recommend so I can try to identify rock types in the field? Love this series!

[@gltchatx]

But what does the Z fold signify? Was it that it was a fault?

[@shawnwillsey]

Rocks were compressed to form Z fold.

[@matthewkrall9124]

Those are intrusive but extrusive. Those granite deposits are the roots of ancient strato volcanoes.

[@andseefor]

Is sparkily a geologic term?

[@timpointing]

Another great video in Prof Willsey's series. Here's the proper title for this video: "University Professor Drops Acid in Utah Mountains - Exclusive Video! 😲🤣 Everything that he wondered whether or not it'd show up in the video, did show up. The only glitch i was was when one or two of the acid tests were somewhat or completely off camera to the right. I understand that it is not easy to juggle hammer, camera and acid, but something to keep in mind for future videos.

[@shawnwillsey]

Clickbait!

[@stephenhudson8739]

That may well be a secondary fault to the Wasatch fault

[@cynthialeadavidson8847]

Amud clay when is was being first formed in fresh? Water?

[@leegreen4165]

Any thoughts about age on this unit? Up here in the Canadian Rockies I’d be thinking Cambrian-Ordovician but is that reasonable there?

[@slidefirst694]

What's amazing is the 10.million year old cobblestone garages just above the limestone

[@ZebaKnight]

How does rock get "folded"? Is heat involved? Wouldn't even a very slow compression process break rock into sharp-edged fragments? It's hard to imagine even _one_ "fold", let alone a Z shaped series (especially one that is so small).

[@shawnwillsey]

Yes, rocks must be somewhat "warm" to deform by bending without breaking. This would happen when rocks are buried and not at surface.

[@ZebaKnight]

@@shawnwillsey Thanks... Seems like magic to me! ☺

[@stevekolstad4445]

So what kind of rock is it. Not limestone and all the folding so it a metamorphic rock. But which one

[@shawnwillsey]

Possibly argillite.

[@3xHermes]

[@DisVietVetUSA]

I love sexy rocks

[@BobKeefe]

Is that a geology nerd kid's right of passage: Getting their first bottle of acid? Sort of like getting the keys to your first car for other teens😅