Yellowstone's Obsidian Cliff: its amazing geologic story
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- Опубліковано 5 чер 2024
- Geology professor Shawn Willsey takes you up close and personal with the famous Obsidian Cliff in Yellowstone National Park. Learn more about how the silica-rich lava flow that formed this interesting rock.
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My great grandparents settled in Wyoming in 1895. My grandfather taught my siblings and I how to make arrowheads from obsidian. I still have some large pieces he gave me.
Just remember how sharp obsidian can be. Those edges can be sharper than anything in your kitchen.
I'm digging this channel! I have a geology degree but I've forgotten most of what I learned. These videos are like roadside geology refreshers.
Glad you enjoy it. I hope you subscribe and can check out the existing videos while waiting for new ones to launch.
Obsidian tend to develops inland volcanos. After all need rich silica’s low water.
remember you can’t take anything from the park - it’s illegal
but it must of been cool back before the colonizers showed up to find a stash of obsidian to make tools and arrows with ! awesome thanks!
It sure can be sharp, and its "cousin", rhyolite, also can have very sharp edges. I have gotten some nasty cuts opening boxes of both rocks that I'd ordered for tumbling so I have learned to be very careful when handling this material. I have also had rhyolite cut all the way through the rubber barrels of a rock tumbler during the first phase of tumbling. It is easy to see why this material was so sought after by ancient cultures the world over for making projectile points and tools.
Columns in obsidian............amazing!
Your reminder that the Obsidian Cliffs are within a national park does not "go without saying". In fact, I think it is important for your to remind your viewers of this fact and the implication of that. "Take only pictures and leave only foot prints"
I think that’s common knowledge except to a few dunderheads who don’t obey signs at the park. They are the ones dancing with bison.
@@drhyshek It's because of them the reminder is necessary.
One could add, 'don't even bring your rock hammer or gold pan in the car' as they are considered prospecting equipment which is forbidden.
thats for sheep, not PAYTREEUTS
@@wiregold8930 sorta makes it hard if youre a prospector and just passing through.
Obsidian Cliff is such an interesting and cool place, I've been there many times as I grew up in Greybull, WY just 60 miles east of there. I have also been a flintknapper for the past forty years and it always was very hard to resist colleting from this wonderfully massive source of lithic material. The National Park Service has NO sense of humor (none) if you get caught trying to take home even a small sample of this obsidian! Obsidian is, I believe, the sharpest material on earth because it fractures on the molecular level. They even use it for eye surgery!
Yes, The NPS has zero tolerance regarding collecting or even the possession ( even in your car) of prospecting equipment, such as a rock hammer, gold pan, or gem screen. If you are passing through the park system, be sure any equipment is stowed out of sight.
yeah, even though they could mine it and sell it to sucker...err, tourists and never run out
@@ThatOpalGuy Sure, mines are endless sources of minerals ... The country is full of obsidian localities were you are allowed to collect. The Mining Law of 1872 was written the same year National Parks were created. Your childish disregard for law is disturbing and not representative a Christian.
@@wiregold8930 Why bring religion into it? I see plenty of so called christian with a disregard for law & decency, who also lie, cheat and steal. I also people who aren't christians, who do the same. So I ask again, why bring religion into it?
Come on out to Oregon and visit Glass Buttes. You can pick up and surface mine 50 pounds… per visit. The obsidian is top quality.
So cool n informative Shawn
Thank you.
Our family lived near the Grand River near Ada Michigan back in the 1950’s and had a garden. The gravel road that ran by our house was an old Indian trail. There was a rock pile from rocks extracted from the garden. One of the rocks that was about 10 inches long and a shiny black glass appearance. At the time I thought it was real interesting, but when we move it was left behind. I’m quite sure the that rock was left by an Indian trader. The thought of it still impresses me that it had such long and arduous journey from the Yellowstone Park afoot.
obsidian can be found in many places all over the country not just this cliff
A nice geologist makes me love earth more and understand it. Thanks for making these videos.
Great vid! I was a park volunteer in 2020 and assigned to the Norris GB where I had the chance to work with geologists and physical science techs in surveying thermal features. My job also entailed doing a daily drive-by at Obsidian Cliff to thwart visitors from taking "samples" with them. A beautiful yet underrated Park feature.
I did a lot of forest research in the park. I would find a little of it here and there. How cool to learn there is a whole cliff of it.
Thank you, Shawn. Very interesting.
Very interesting to see the cliffs of obsidian. That Pumpkin Obsidian was really pretty.
Omg I really loved this one. I didn’t know anything about obsidian before this video, so incredibly interesting. Thanks for making these.
next to Glenn Rawson Stories posts I enjoy and learn the most from yours.
Excellent teaching presentation.
Wow! Very demonstrative for a hobbyist geology learner like myself. Really brings home a lot of the things I’ve been reading and watching.
Hi I love watching you ….. they enrichment stuff u get to see jealous ….. good night❤
The one place I regretted no getting to when I visited Yellowstone a couple of years ago was the Obsidian Cliffs. Thanks for taking us there!
Good video. It reminds me of the structure of Devils' Tower.
This was wonderful, thank you so much. Never seen obsidian "in the wild." The pumpkin obsidian was beautiful, too. Appreciate your videos very much.
Thanks for watching and learning with me. More Yellowstone (and other) videos coming soon.
I enjoyed stopping by those cliffs on a bicycle ride through Yellowstone in 1979. Thanks for the explanations and helping me to recall what I'd seen.
New Zealander here. I have some nice hand-sized chunks of obsidian I picked up just weathering out of a road cutting in the central North Island, a bit North of Lake Taupo, back in the Eighties. It is pretty common in that region.
I once found a big obsidian hide scraper (about 8 inches long, or ~10 cm) in Utah. It was a reddish-brown color. I did a little research and the closest place with brown obsidian like that was in Oregon. Some paleo-Native carried that scraper over 800 miles. Either that, or it was passed down somehow, making it far from its site of origin.
Thanks Shawn, another educational video. When I think of Obsidian, I think of conchoidal fracturing.
There are some obsidian cliff 20 to 30 feet high solid black, and house size boulders on the Valles callderas in northern New Mexico. Big piles of chips from arrow point making .
Prof. Willsey is a great guide. The high resolution is wonderful, makes you feel that you're right there at the cliff.
At 0.07 in the video you are panning across the wetland adjacent to the road. Partly hidden by a spruce (?) tree are two circular areas that are somewhat discolored and have some vegetative differences from the rest of the wetland. We were studying metal accumulations in thermal wetland sediments in Yellowstone and took some core samples in these zones.. The sediments lap on to the obsidian boulders at the base of the cliffs. They proved to be elevated in U, As and many other trace elements. We concluded that there were thermal spring plumes underlying these circular features and the organic matter was adsorbing the trace elements.
I love Obsidian and I never saw the other little things in them. They’re beautiful. Great video!
Super cool outcrop!! I have to get to the field man. We had started RV’ing two year ago but had another baby on accident and it screwed up our summer plans this year. He’s precious but babies in your 40’s 😂. Anyway, what an outcrop, wow.
Great information, Shawn. You take the sensory overload of looking at this sort of cliff down a notch by explaining the various parts. ( I see the need for a broad knowledge base!) Thank you.
Great stuff. Very awesome to see obsidian as something other than the usual hand sample! Mind blown! Thanks Shawn.
Fascinating. My 'rock hound' grandparents made Snowflake Obsidian jewelry. Beautiful. Thx kind Sir for the vid. Well done.
wow pieces of that mountain were traded across the northern hemisphere for thousands of years
Very informative, thank you brother.
Really cool. Needs to go on the bucket list of geologic sites to visit. Have never seen columns developing in obsidian and the size of those obsidian cliffs…awesome. Thanks.
The lava flow in the northeast park has petrified trees
If it isn't already on your list, go visit Glass Butte in Oregon. It's basically a small mountain of various colors of obsidian...and you're allowed to collect.
Very cool, thanks for the video!!
There are similar obsidian cliffs and house size boulders at the Jemez caldera in New Mexico.
A shame the close-ups are not focused. Otherwise, an excellent presentation! :)
agreed, autofocus can be a bane or a boon, it just depends on the day
Thank-you for demonstrating this Obsidian cliff. I was surprised that it was formed from rhyolite, and that it was black, as I expected it to be much lighter-coloured. I look forward to getting occasional geology ‘fixes’, as I retired from the field couple decades ago, and my body doesn’t want to go out there any more.
💕 Love your video!
Excellent video 👍👍
Just wow!!
Thanks for the informative videos.
Top of the cliffs has some of the largest glassy obsidian pieces (with conchoidally fractured surfaces) .
Great video! Thank you!
Thank you. Great information.
Never knew this about Yellowstone - shouldn't be surprised though. In Oregon we have a Big Obsidian Flow at the Newberry Monument in Central Oregon - great hike over the huge flow of beautiful glassy obsidian. Thank you!
Thanks for the explanation of obsidian. I had asked about it in one of your other vids. I had found some brown obsidian in the Red Deer River Valley Alberta. Must have been brought there by the indigenous.
Thanks!
Another great video!
A great lesson. I didn’t know about the Obsidian cliffs. Makes sense though since the Yellowstone hotspot has a lot of Feldsic magma.
I like to imagine that this guy was actually there when it happened, taking notes. Some people are a lot older than they look.
Thanks😊😊😊😊
Interesting, thanks.
Thank you
Shawn, I sure love your videos! I really enjoy geology, and I learn so much from your videos. Do you ever do field trips that non students can join you on? It would be great to meet up somewhere and learn from you live in the field! I'm in Utah, north if Salt Lake City, so I'm not terribly far away. Here's hoping. Thanks, Mark Lee
Hi Mark. Yes, I do field trips for UA-cam viewers throughout the year. In Oct, I ran two one day trips around Twin Falls. I’ll do some more this year in April and June. Look for announcements and sign ups soon. I also have a trip to Iceland in May for folks.
Awesome! I will definitely be watching for signups. However, I don't think Iceland is in the budget. 😅 thanks and keep up the great videos!
I noticed brecciation with the columns indicating the host magma erupted through and shattered an obsidian bed.
I'd really like to hear how these cliffs are dated. Like take us through the process. Thanks
So question: does obsidian form with any type of magma, or is it more prevalent in higher silica magmas like andesites and rhyolites? Or is its formation more a product of the circumstances of the eruption, i.e. the rate of cooling?
chemically its granite.. when he was pointing out that it was without minerals... there's still minerals in there just none of them have crystallized. but obsidian is chemically granite or rhyolite rhyolite is also granite I've got my own theories about that stuff but I'm not telling you anything that I'm not certain of
oh the first part of your question yes that would be felsic magma like a Mount St Helens it's very sticky so it doesn't flow which is why I have my own theories on its formation but I'll leave that for my channel at some point
Dave's reply here is good but I'll add a bit more. Obsidian forms when "dry" (low water content) felsic (meaning rich in silica) magma cools quickly at the surface. Mafic magmas like basalt do not make obsidian even when they flow into water or erupt beneath ice. Intermediate magmas like andesite would not form obsidian either. So, obsidian forms when you have the right magma type (dry and silica rich) cooling quickly at the surface. The elements are unordered and haven't combined to make minerals so it creates a glassy texture.
Glass is unstable, and technically a very viscous liquid, so it slowly devitrifies ("deglassifies") over time. The elements in the obsidian move very slowly, bond with other elements, and make crystals over time as elements move slowly and build crystals. These are the rounded spherulites seen in the video. Hence, the obsidian will slowly turn into a crystalline rock like rhyolite. Therefore, all obsidian is very young geologically (usually less than 15-20 million years at most). Hope this helps a bit.
@@shawnwillsey That makes sense, thanks!
@@shawnwillsey Thanks for an informative answer about this theme which I find very interesting. I was here ( on the road next to it ) 5 years ago, but unfortunately there were road works going on here, so I couldn't get to this outcrop. I did see some south of Madison, but it looked quite different than this.
One question I really wonder about is when obsidian have crystalized after some tens of millions of years, is it then possible to see from the new rock type - presumably rhyolite - that it previously was obsidian ? What features of the new rock type would reveal it to previously have been obsidian? I suspect some areas where I live originally were obsidian. They are several hundred million years old.
Now you only need a diamond pick axe and gather some to create a Nether Portal!
Obsidian Cliff sounds like a goth i used to know :)
It must have been a godsend for the Native Americans to have this material for tools.
Looking forward to some pumpkin obsidian pie.
For folks that would like to collect obsidian in the wild, go to Glass Butte in Oregon. Collecting is allowed, but you're permitted hand tools only. There are rough camping spots, but there is no shade and no water, and this is a desert area a long ways from the nearest town. Be prepared and you'll have a good time, there are many varieties and colors of obsidian available.
in other words, you can only collect obsidian in hell
We get the same in New Zealand ,but it was not used for weapons ,just flakes for crude Knives
Its almost like the volcano is a giant smelter and the different types of lava are the different minerals or substances of the smelt, obsidian reminds me of the slag that is on top of your precious metals.
I was given a big piece that had brown swirls and was told it was called Mahogany obsidian. Forgot what I did with it.
arrowheads and clubs...obsidian actually was the knife of the old world. Sure, makes great piercing weapons. But I would like the sciences to lean more towards how obsidian changed the cultures around it...finally having a sharp edge to cut leather, plant material, lance boils, etc. etc. And trade with obsidian was huge.
I have seen columnar basalt. I have seen columnar andesite. And I believe I have seen columnar rhyolite. But I have never seen columnar obsidian. Quite the sight/site.
we have tons of these columns in the boise area, on the way to Lucky Peak. climbers love to climb them
Awesome as usual! What's the age of the Yellowstone obsidian cliffs? I've heard obsidian oxidizes down geologically fast and so there are few obsidians older than ~40 million years. Any idea if that's true?
Hi Chuck. See my detailed reply to "No Thanks" below. Age is 105,000 years old.
glass lasts a long time. but geologically i guess it does weather as fast, or faster, than rock
Can the pumpkin obsidian only form in the presence of water? Great video, as always. Thanks.
The pumpkin obsidian has the reddish color due to some of the iron being oxidized. I don't think it is due to increased water content.
I’m guessing obsidian doesn’t get climbed much??
Uh yeah, shredding your hands is counterproductive. I'm sure it would hold a cam or nut though.
I was just looking at the obsidian In Africa....videos of course.
That iron infiltration specimen and the last were something I'd probably have taken decades ago but I realized how selfish that would be and as many times as I've lost everything from personal bad decisions I find sentimental to be nothing more than a reason of hindrance. Just imagine if there wasn't a national park system or even if there were imagine nothing to see because everyone took part home.
Anyway, instantly subscribed and thanks for expanding our horizons.
Welcome aboard and enjoy the existing videos in the collection.
never mind that it would take thousands of years for that to happen. the actual danger are the capitalists
@@ThatOpalGuy Like communists never used steel with forced labor. There's always one that has to bring politics into everything and it's always the one that does the least.
I hope you washed your hands well when you got home. There is poison ivy all over that cliff. I really enjoyed the video, I think obsidian is so cool.
I think not. Here is what Big Wild Adventures says about poison Ivy in Yellowstone. Bear in mind that the elevation of the Obsidian Cliffs is 7,400 feet.
". . . “rare” is not the same as “absent”! Poison ivy is a deciduous shrub with a skin-irritating oil with which most folks are familiar. It grows in temperate climates with adequate moisture, which excludes much of the arid and high altitude West. Since most of the Yellowstone and Tetons region is above 7,000 feet, and those areas that are lower are mostly semi-arid, this region is not conducive to robust populations of poison ivy . . . ."
Why do the columns form with 120 degree angles? You said it was not crystalline, so how do the angles form? Is it the same as the Giant's Causeway in Northern Ireland?
👍
Sounds as if obsidian is the odd child out of it's "category" rocks.
For some reason the algorithm has sent me vids on slime molds recently; they're the odd one out in their category. Turns out there's plants, animals, fungi,, and slime molds. Just their own category.
"Knowing" stuff is fun!
just a side note... while obsidian cliff is impressive and has some amazing high quality deposits... don't collect anything from inside park boundaries. it's also a common enough mineraloid that you shouldn't need to; plenty of other deposits of similiar or better quality exist on BLM lands where it is permitted to collect specimens.
Did you see any indication of actual mining on the part on Natives, or did they just pick at the natural scree? In Europe, the Paleontologist have mapped all of the knapping material out crops and matched found worked items to the out crops. Very interesting I must say.
There is another obsidian cliff in the park some distance from any road and it is kept secret as there are deep pits dug by natives extracting obsidian. This obsidian was considered the finest of all and traded as far as 1000 km away.
all this time they were breaking the white mans law
Wonder justwhat they would look like had humans NOT harvested for tools for tens of thousands of years and just how far it was traded
Cooling time? You say....slower....but what's that geologically? Four hours or 400 years to cool?
Was this cliff underwater or under ice for it to cool quickly?
so is it considered an amorphous solid? that's what they told us in school many years ago that glass was ?
Yes. Obsidian is technically an amorphous solid.
@@shawnwillsey thank you! nice to see some definitions stay the same,, rock solid ? lol cheers!
I'd rather see the "weathered out" bits enjoyed by collectors than just get timeworn into oblivion.
The narrator hefts and admires what he describes as "a nice piece" and then just callously chucks it to the ground. I'd say most rockhounds have more respect and awe for the material.
That would deprive future visitors the chance to discover and view "a nice piece". Most rockhounds I know have more respect for the material than you have displayed.
Dumb question: if it's not crystalline, why do you see distinct circular/planar cleavage patterns when it breaks? Wouldn't that imply that there was some kind of order?
Hey that's a solid question so thanks. Obsidian lacks mineral crystals and so it breaks along curved surfaces called conchoidal fracture. This is also how man-made glass (also lacking crystals) breaks. The larger fractures forming the columns in Obsidian Cliff are related to how this silica-rich lava cooled. The top (in contact with the air) and bottom (in contact with the ground) cooled quickly, causing the lava to contract and form fractures which propagated through lava and linked to form continuous fractures.
Part of why obsidian forms no minerals is because the highly viscous lava inhibits atomic migration and diffusion, keeping nucleation sites from forming. This, along with the quick cooling, forms glassy obsidian.
en.wikipedia.org/wiki/Obsidian#:~:text=Obsidian%20is%20formed%20from%20quickly,contact%20with%20water%20or%20air.
I found a small amount of obsidian much of which is covered with a dark grey fiberous material. It appears to grow out of the cracked obsidian itself. Is this weathered obsidian? I cannot any pictures of weathered obsidian or any mineral or rock that match what I am seeing.
Probably rhyolite. Basically the same material but where minerals nucleated.
I relly like your videos. I just should have taken some Dremamine first though on this one. Motion sickness
According to the signs you’re not supposed to be up there. Some rules are meant to be broken 😉
Would you find agates in those cavities?
Send a raven to the King in the North!
Can this source of obsidian be traced by scientific study? In other words, can we prove that obsidian arrowheads, spear tips or scrapers that are found far away actually came from these cliffs? I thought that I heard once that this obsidian was traded far and wide across America.
Yes, I've read chemical signatures identified Yellowstone obsidian in Illinois. There is another obsidian cliff with deep pits dug by natives but the park service keeps that location a secret.
There is an interesting book on the topic of the Native American presence in the area that became Yellowstone NP. “Before Yellowstone” by Douglas H. MacDonald from the University of Washington Press. (2018)
The book mentions how X-ray fluorescence can be used to determine the amount of silica in the obsidian and consequently determine a signature for obsidian from different locations. So a found obsidian tool can be traced to its origin!
Good to know when the White Walkers come!
cool vid - maybe a little more steady on the camera or recommend dramamine
Tapping with a rock hammer?
Devitrification?
Why disclose this obsidian cliff, to you tube. Some things are sometimes left alone.
It will now be dismantled.
There is another larger obsidian cliff in the park which is kept secret. It's not near any roads.
It's inside a National Park, and the rangers take their job very seriously. Attempt to take some chips home and you'll be facing legal troubles of a Federal nature.
Do you know how crazy your statement is? There is literally a mountain of obsidian at Obsidian Cliff, and that's just at that one site! There are many places to find obsidian in the western states and Mexico. Also, Obsidian Cliff is inside Yellowstone National Park! Get it, its a National Park! It was made a national park by Theodore Roosevelt, it belongs to the citizens of the US and for all to enjoy (for a small fee)! It's also shown on the maps the Park Service hands out to all vehicles as they enter the park!
Try dismantling a cliff in a National Park.
How can such a thick flow of molten material cool so quickly? Does not make sense! Simply saying it formed no crystals, stayed a glass as it cooled, proves it had to cool quickly; what would the mechanism be for cooling molten rock perhaps a 100 feet thick, and several hundred meters long, quickly? There's something basic to obsidian and how it formed that is missing from the discussion! There is no way to quick quench massive amounts of red-hot, molten rock...period!
…even when lava flows-out under water, even at depths around spreading centers where the water temperature is barely above freezing, where it forms “pillow “ lava there is only the thinnest of obsidian rimes over what quickly cools into pillow basalt, not pillow obsidian. Even in In arctic regions where temperatures are much colder, still, than at the bottom of the ocean, lava cools into basalt not obsidian. There has to be another process involved other than rapid cooling. What is this process?
No minerals. Un-ordered elements??? This is gonna take a little extra reading.