Random Roadcuts #7: California Highway 158 near June Lake
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- Опубликовано: 8 фев 2025
- Learn to "READ" the rocks with this innovative video series. Join geology professor Shawn Willsey and investigate a random roadcut, make observations, and formulate basic interpretations. Here in Episode #7, we visit an interesting roadcut along CA-158 (June Lake Loop) at the foot of the Sierra Nevada. GPS Location: 37.76706, -119.09843
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Enjoying the spontainious geologic adventure of random roadcuts. Thanks for bringing us along Professor!
Keep the road cuts coming. Seeing a pro in field working through what he sees is helpful to me in my very amateur attempts.
You, Steve Baumann and Dr Nat are all doing great work with your insightful and accessible YT geology videos. I cannot over estimate the contribution you all are making to general understanding of such a vital branch of science. Essential viewing every time!!
I really liked this format. Geology unplugged. Thank you so much.
Glad you enjoyed it!
From what I was able to find, these rocks are Carboniferous aged marine rocks that is mostly chert, like you suspected in the video, argillite, hornfels, and sandstone.
My family and I used to camp and fish in the June Lake area every summer. It is beautiful there and still one of my favorite places I've been to. Neat to see part of it shown here.
I had several geology professors at the University of Montana in the early 70s who started the roadside geology series.........these videos take me back......great job!!!
This new series is definitely the Gift That Keeps on Giving: I find myself returning for second and third looks, like I would when visiting an art museum. But the really big surprise: my 'own' road cuts which I pass all the time are 'suddenly' taking on a new look, gaining personalities, and actually enticing me to stop for closer looks!
Love this
Love these Random Roadcuts, Professor Wilsey! It’s very instructive to see how you approach an unknown outcrop. Please keep these videos coming!
I do like the random road cut series.
"Good, well-behaved sedimentary rocks." Love it.
What I love about how you present this in this format is that you give the novices like me a chance to answer or have a hypothesis and when you give your professional hypothesis and it matches with mine i feel that i am learning so much by watching this series and the other programmes you have done. . I hope one day that you will come and do a few in the Uk
Hope to do so. Thanks for learning with me.
Retired Geologist - mostly east coast and southeast US - now living in CA. Thanks for these - nice to pick a little geology of my new neighborhood.
I like this roadcut series, you really get down to the nitty gritty of geology in trying to fathom out the makings of a terrain. I used to think a geologist could just take a quick look and he/she knew all about already.
I have enjoyed your videos, including the "road-cuts" series. You mentioned the "roof pendants" of the Sierra Nevada range. I would really appreciate a video on the "roof pendants" located above Convict Lake. They extend further south and from a geological perspective are fascinating. In the early 90's I participated in a 5 day Sierra Nevada geology field trip. Hearing and observing geology classes in the field is priceless. We had one class on the shores of Convict Lake and I have never forgotten it. There is a road cut just north of Tom's Place on 395 with vertical fractures filled with sediments. You are proving that new discoveries and understanding of geological processes can be found everywhere. Another place worth exploring is Lookout Mountain near Obsidian Dome. There are some great outcrops of obsidian and an overview of the Long Valley Caldera and Mammoth Mountain area.
Some sedimentary rocks do sometimes show up in the eastern sierras but they have long since ceased being anything like well behaved, lol! I swear being from California makes horizontal layering a novelty.
Enjoy your random road cut series a lot. I love looking at the road cuts out west with the highly variable rock types and fantastic exposure. With regard to the chert at your US 395 road cut in CA, my vote is metachert given the presence of boudins and what looked like a fold. Also given the proximity to the Sierras, hard to imagine those rocks could have escaped some level of metamorphism. Close inspection of the “dirtier” layers will likely also better reveal the metamorphic signature of rocks at this location.😊
Great road cut, absolutely loving this content. It helps a great deal when I see a road cut to identify what's happened. Again great video thanks.
Love your road cuts series. I'm learning a lot and at my age it's difficult to get out and explore as much as I'd like to do.
Yes I like this series. Plz continue
Great stuff
Love your Random Roadcut series !
I enjoy this series as well as your other videos. Nice to see this one on a feature in my neighborhood!
Yay!!! Another random road cut! I love them! Thank you so much! Great to come home to after a hard evening shift work!
Once again, you were in my part of the world. The geology around here is so complicated, everything from glacial erratics to volcanic rocks to granite. I believe that June Lake was formed behind a terminal moraine. Anyway, fascinating. And boudin is a form of sausage in France. 😃
Thank you Professor Shawn, that’s one extremely tortured outcropping. I did a quick search and chert is a sedimentary rock although it can be chemically formed. I understand the Sierras were uplifted with the subduction of the Pacific plate and the North American plate. Was there an ancient ocean covering that region before it was added to the North American plate. So when the pacific plate started subduction and the Sierras started uplifting. The uplifted sea floor east of the present day Sierras were already folding from being crushed between the exotic terrain being pushed against the North American coast at that point in time. I hope I’m making some sense, I’m not a geologist, my education was Geology 101, but I watch a lot of RUclips channels about geology, especially yours. As well going out and exploring what I learned from the videos. Geology is fun and extremely exciting for me. Thank you
Thank you! I’ve been on that road before and rocks in that area are amazing. I have a piece of obsidian pumice from the obsidian dome near there.
Bedded cherts are a pelagic, deep-sea sediment, made of mostly of radiolarians and deposited out of reach of sediments shed off of land. Radiolarians are microscopic plankton and their skeletons are made of opaline silica. Over geologic time after they are deposited, the opaline silica transforms to microcrystalline quartz. There is a change in volume when this happens, and that may be the cause of the small-scale deformation you observed.
Thanks!
We go by many roadcuts through our journeys that we don't stop and study. But, of course, the rock showing tells the story of the land. Thanks for encouraging a thoughtful life.
Verry intresting video's thank you from the lowlands in Europe. The Netherlands/ Holland. We do not have this but next time I am traveling I wil keep my eyes open for any hil mountain or rock.
Gnarly fun rocks there! And once we get in close, very puzzling to me. I'm heartened to know it's tricky for pros sometimes too. Thanks, Shawn! ❤
I am very late getting to this video.
Thanks for all your time that goes into your videos. Very much appreciated. 😊
Once again, another great spot to stop and look at - Thanks for explaining it, I hope you stopped a Schat's Bakery being that close to Bishop! :-)
indeed!
I pull over for road cuts! I've been doing this since I was a teen driver.
Obvious but you mentioned movement. The beds are near vertical.
A very beautiful area. Thank you for posting this educational information.
Shawn, you are THE MAN....The road cuts have me hooked again!
I have been fascinated with California Road Cut Geology since I arrived in Cali in 1964!
You really need to see the Feather River Canyon (Hwy70) and (Hwy 89 between 70 and 36)
The sudden changes in the rocks is truly amazing.
Thank you so much.. I love watching your videos
Keep em coming Shawn. And thanks.
One of my favorite places. I am a mining consultant and get over there about twice a year. Very familiar with that area.
There is a roadcut I have always been fascinated by and its famous. Highway 14 at Avenue S in Palmdale, California along the San Andreas fault zone is just amazing.
Great ramdon roadcut!! I love seeing the rocks. Keep them coming!! You explain things so wonderfully and understandable. Thank you
Very interesting road cut!
Having been on a lot of these roads through Eastern CA, NV, ID, and OR it's nice to hear what the rocks are showing. Thanks for making these videos!
Such an excellent outdoor class on Geology ~ to touch pour water on rock is so much better than just a screen image or book ~tactile experience ~ really reading geology close up ~ assignments of either / and or sketching these ocurrences of the rocks their composition has got to be the best to learn characteristics ~ do students actually go on field trips to first hand witness to 'see' these Boudins etc. ~ all students of geology must witness the awsomeness of these roadside outcrops ~ amazing power of folding fracturng faulting ~ Thank You Shawn ~ very real & most interesting 🪨🪨🪨🤘⛰️
Hey Shawn thanks for the road cut videos. The next time you're in June Lake, check out the massive balancing erratic just below town at the fire station
That tilting seems to be generally increasing as you go to the right. It would be very revealing if you were able to investigate a wider field around that outcrop, to see where, and maybe even on which side of it, the intrusive rock lies. It could even be inclined beyond vertical, meaning that the rising magma could have erupted to the left, rather than to the right.
I visited South Stack on Anglesey (the main offshore island of Wales, a few kilometres away from Great Britain, United Kingdom) a number of times, and could not help but notice the extreme folding which the rocks below the lighthouse had undergone. Those rocks are like folds of toffee; folded back and forth upon themselves.
The folds of rock at your June Lake site are even more tightly folded. A very intriguing outcrop, indeed! Thanks Shawn.
Like #300 satisfies that OCD part of my brain 😂. Love this seried thanks Prof!
Great new destination for Mariposa rock nerds! Tons of obsidian across the 395 not far away, lots of volcanism etc.
Very interesting . I have never seen rocks like that . Native of NE FL, now live in SE GA. Guess we don’t have anything like this ? Thank you for teaching us !
Head up to far north east Georgia or Western North Carolina, and you'll see similar geology, just much older and more eroded.
Yippeee. Random road cut!
Hwy 58 through Tehachapi is loaded with different rock types in the road cuts
I am from south of Salton Sea and can't wait to hear what you have to say about the geology of that area. If you happen to go between Ocotillo, CA and Jacumba, CA on Interstate 8, I would love to know what happened in that area geologically. Thank you so much for explaining and making geology so interesting.
I know how to read them rocks...the plot twists are awesom
Thank you, I will look out the car window with more interest now!
Great videos shawn aka steve. 🤔. Very interesting and enlightning. I always enjoy wandering Devon and checking out our rocks, how they might have formed etc. It's even better armed with more knowledge, thanx to you. Cheers
I too, spent many a summer camping and fishing in June lake area, beautiful! So these Cherts were metamorphosed because they were sitting under the Sierra Nevada Batholith? Great video!
Cars going by, wondering what kind of Rambo dude this might be. :)
So much to see on the eastern side of the sierras.
Got some great rdcuts up in Redding ca too
interesting as always. In my area of sw OR/nw CA there are some old chrome mines in which the chromite apparently forms or is made up of boudins. Chert is relatively common here as well.
At first, living in Minnesota, Anorthosite came to mind, but when you showed the orange spot, i revised my thinking towards serpentinite which weathered patina is orange
Before I dive into any literature on this, I do know that there was a load of metamorphic rock that got pushed out and away by the granite batholith there, most of which were the product of the subduction zone that resided there before the Farallon Plate completely subducted beneath CA. Most of the roof pendants on some of their geologic cross-sectional maps are to the west of the crest of the Sierra Nevada, but I don't know why there wouldn't also be roof pendants EAST of the crest that survived the eruption of the Long Valley Caldera. This will be interesting reading. There's so many different rock types in this area the list is practically endless.
Yay more Sierras!
This was a very good Random Roadcut. Sometimes answers can be found with other investigations like to possibly the
area due north on a trail called the Reversed Peak Loop Trail. ;)
Thanks for another one. My favorites are the feather river canyon Hwy 70 in Calif. A most amazing roadcut in idaho is hwy 17 between Garden valley and Lowman. Just dike after dike.
I have found what appears to be the same rock as the quartz rich rock you displayed in the beginning next to old granite fields in Currawinya NP. Would love to hear an update and deeper dive on this one.
Thanks, Shawn! Some of the rocks appear to be somewhat smooth and have a greenish tint in the video. Possibly a serpentinite if they were actually greenish?
CPG here: Serpentinite is much softer, 2.5 to 6 on the MOHS scale, vs 6.5 for chert. Plus, the wrong mineral set for the precursor to serpentinite (ie: quartz rich vs more mafic ). Chert is often greenish, white, grey, blue.
@@91F2Z Cool, and thanks! 🙂
I have a list of the road cuts that I want to visit from Annals of a former world, John McPhee. It starts on the east coast and goes to the Pacific, just in the Sierra foothills with Eldridge Moores would be great.
That whole I-80 series was just plain wonderful-(like all John McPhee's books)-
Great book
Maybe uplifted metamorphosed rocks. We have similar folding and cracking on the Balcones Escarpment in Central Texas right on the edge of an uplift and on a old fault zone. Karst landscape mostly but the uplift has some neat rocks as well.
People write books, and rocks write their own history as well.
There is something profound with the nature of crystals
In the habitable zone, crystals form in a certain way.
Likely on Mercury, crystals have a vastly different arrangement to tackle higher temps.
More rock cuts please.
Roctor-Dub would look so gangster with a full geologist beard.
You should do CA Hwy 16 along Cache Creek. Not sure why, but mountains on west side are all brush, and the east side of the river is all grass and sparse trees. The road cuts show near vertical layers of rock.
Interesting roadcut, but I wonder how layers can fold nicely without breaking or fracturing. were they molten. Thanks.
Is it just me, or do the small plants growing there seem to change color to match the color of the rock it's growing on?
Imagine prehistoric man standing upon the rocks in that area, and the silence surrounding him.
What was the blue color (around 12 min in)?
I watched all the way to the end to see if the SHERIFF at 13:27 didn't return to card you for a wilderness pass and or a field sobriety test to know your fitness-to-drive after your time in the sun stumbling around high on a road cut so near a 55mph roadway🤔
Shawn, do you play Minecraft? Forgive me, but when you used your hammer, it reminded me of Steve placing blocks or wielding a sword. And I did enjoy the geology as well.
I don't. A few of my kids do (or did).
Why do we use dilute hydrochloric acid for the carbonate test? Why not use dilute sulfuric acid so we have it to test for copper as well? Yes, Hydrochloric is slightly safer but at the dilute levels used, both ok. Both cheap and easy to buy. Both strong acids.
😎
👍
would chert show a conchoidal fracture?
Yes. Same fracture properties as obsidian.
I'm a little confused now because I thought basalt was what was left over after volcanic eruptions and now you're telling me that granite is left behind? Can you please clear that up for me?
Good question. This is a generalization of what may happen: In subduction zones (such as produced the Sierra Mountains) the magma chemically and physically seperates into layers. The least dense are the 'felsic' (light colored) granitic or rhyolite magmas, quartz rich, and they rise to the top. The next might be what's called 'intermediate' magma, often grey in color, that produce andesite or diorite. The last are the 'mafic' (dark colored) magmas, and produce gabbro or basalt. In other volcanic zones, like backarc basins, spreading centers or rifts (think Iceland), the crust pulls apart giving unfettered conduits to basaltic magma, and differentiation occurs less frequently. Hot spots, such as that underlying the Hawaiian Islands or Yellowstone Park, also erupt basaltic magma. There's a lot more to magma classification, but this is the basic scheme.
A big difference is granite is solidified magma below the volcano and never surfaced, was pushed up later or eroded out. Basalt is lava that flowed out on the surface.
Granite forms from felsic (silica rich) magma that cools underground very slowly. Basalt forms where mafic (low silica) lava erupts onto surface. Very different chemistry and cooling history.
Thank you all for chiming in. I think I'm getting a little bit better picture, especially since I watched professor Willsey's rock identification video that explained some things the different types of granite. Thanks hanks for clearing the why and how!
@@shawnwillsey thank you for getting back with me personally professor. I have an interesting spot that I'd like to learn more about. If I sent you the coordinates and a little detail, do you think you might plan a trip there someday? It's in Utah on the San Rafael Swell. I suppose I should look at some of your past videos. You might have covered it, but it's like nothing I've ever seen before anywhere. Thanks for sharing your knowledge 🤙🏼
I love your experimental/observational approach to teaching geology. However, Sierra is already plural, so saying Sierras is similar to saying deers. Keep up the delightful work. More scientific literacy is really needed at this time.
Last Sizable Earthquake within 30 miles of June Lake : 1980 6.1. |. At high risk status remaining ~
Just an FYI, Mono is pronounced such that the “Mo” rhymes with “no.”
the dude passing at 15:04 seems want to learn about road cuts
I caught on to this road cut thing here. just be careful. it becomes addictive and distracting.
California cherts are sort of a mystery, even for us chert aficionados. Maybe it's all fractured because of all the movement.
1:14 The fully competent geologist holds the hammer with thumb only, and manipulates it while gesturing like a cigarette in the smoker’s hand…
ha
Did you see evidence of the 1980 6.1 30 miles near June Lake Earthquake ?
No.
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Thanks!
Thank you!
Thanks!