"Old" Yellowstone in southern Idaho: amazing deposits of pyroclastic flows from explosive eruptions

[@shawnwillsey]

You can support my field videos by going here. Thanks! www.paypal.com/donate/?hosted_button_id=EWUSLG3GBS5W8

[@Maungateitei]

There are two mechanisms for pyroclastic flows, the low temperature low energy "eruption column collapse" mechanism you discuss here. Where an eruption pauses, allowing the mass of the ballistic ejecta column to collapse. And the FAR more deadly supersonic shock front driven mechanism of high energy explosive eruptions, where ejecta is super or hypersonic and the shockcone acts like an expanding conical wall confining the blast front. The first most always deposits material, the second, often can carve 50m to 100m of bedrock away from the surrounding landscape, and then deposits deep layers of fused welded ignimbrites and tephra conglomerates. Many of the examples here in New Zealand have been hot enough for many decades to centuries from the initial heat, and latent heat of hydration release from rainfall penetration, to generate hydrothermal spring features resulting In fields of silcrete hardened mounds on depositional plateaus such as the Mamaku's.

[@Anne5440_]

I'm thrilled learning about OLD Yellowstone. It really is a progression of eruptions.

[@Yojimbonh]

Another person who finds this fascinating. The diagram explanations followed up by real life illustrations are very illuminating.

[@shawnwillsey]

Glad you like it. Thanks for watching and learning with me.

[@hordboy]

These talks are fantastic! I travel to Idaho nearly every summer (from Ohio) to hike and climb. The geology is fascinating. Now I understand it better. Thanks!

[@toughenupfluffy7294]

Shawn Willsey is one of my favorite KZbin geology teachers!

[@hestheMaster]

Awesome explaination of what you are showing us professor. You, Nick Zentner and Myron Cook have taught me so much on the geology of the Pacific Northwest that I soon expect my mind to explode!

[@lonthrall5613]

My sentiments exactly!

[@gb57hevy3]

I didn't mind the "longer" video. Great explanation of these extremely interesting deposits. Old "yeller" left us something really worth seeing. Great video.

[@dennisdye7270]

Great video. Fascinating. It is nice to see beautiful landscapes, but if you can see the story told by the rocks, it adds so much! Explained so clearly. Thank you.

[@melodiefrances3898]

I love knowing the story of the rocks! Especially when I can see the bigger picture.

[@alanharwood1636]

Second time I have watched this vid, I enjoyed it 3 months ago, even more this time round. Thanks for your efforts from the UK.

[@shawnwillsey]

Awesome! Thank you for watching and learning with me. I was pleased with how this one turned out too.

[@101rotarypower]

Love the level of detail and descriptions you use, its just right to understand the subject without being too little or too much for me personally. Thank you

[@richardyoung5217]

Best explanation of geological procexxes i have seen. The physical examples make the explanations much better.

[@chucklearnslithics3751]

Fascinating! Browns Bench "obsidian" was very popular with the paleolithic and archaic Native Americans of the Great Basin, all the way south to at least Delta UT. When you work it into an arrowhead it clearly isn't an obsidian, but can certainly hold an edge like it is. I would love to go back in time and hang out with those guys and explain how it's a rheomorphic ignimbrite! I would be the coolest guy they know! 😁

[@shawnwillsey]

Yeah, the glassy stuff is vitrophyre and, in this case, part of an ignimbrite deposit. Impress away!

[@chucklearnslithics3751]

@@shawnwillsey Suhweet! Bonus word! Seriously though, thanks! You continue to shed light on so many things for me.

[@haroldwilkes598]

Doubt you would be cool but you might be dinner.

[@llloydhoffman3431]

More realistic lyrics burned at the stake...they hated smarty pants far more than this world🙄🤣😎

[@chucklearnslithics3751]

@@haroldwilkes598 _Never_ doubt my coolness.

[@schenkermeister]

Shawn! So good to hear your voice and see your smiling face! I met my wife in your 2005(?) CSI geology class. My first trip to Southern Utah and the Grand Canyon was with your class and you guided my efforts to apply to ISU where I eventually graduated with a Masters in Biology. Thank you for all you have done for us and allll the students you have supported. Thank you for sharing your love of geology with the interested minds of Idaho! hope you are doing well friend!

[@shawnwillsey]

Matt! Hey so good to hear from you. Send me an email and let me know where you are, what you are doing and such. The trip was 2006 and I remember it well, especially the bus breaking down.

[@mariejackson325]

Thoroughly enjoyable. My Masters degree in geology concentrated in clastic sedimentology - and we didn't have volcanics in Louisiana. So all of this was new to me. Loved it. Thanks

[@boossersgarage3239]

Big words always impress the Ladies. good advice, thanks Shawn.

[@Yetibiker67]

What an amazing video Shawn. Thank you so much for educating us!! Please don't stop posting

[@thegoodscientistsdaughter7236]

I love binge watching your videos! Your so easy to understand and the places you visit are so close to home! Thank you for taking the time to make these awesome videos💚

[@MrFmiller]

I appreciate your illustrations. You tailor them to explain views you subsequently present which helps illustrate the subject. I’m learning a lot. Thanks.

[@davidd3441]

I had taken your geology class during your first or second year as a professor at CSI. One student asked the question, how do we know there was no/low oxygen on earth in the past? This video is great. First give some background on how the rock layers got there. Then give diagrams and definitions for us to follow along with. And finally giving proof through visual observations.

[@moonshiner5412]

If I remember correctly, the Bruneau area was once over the Yellowstone Hotspot, We were out there a couple years ago visiting in Mtn Home. We went out by the USAF bombing range and there is a canyon with some signs telling about the area. The rocks look totally different. It would be cool to hear your explanation about the formation of this area. Thank you for your videos explaining rocks and minerals. I have spent a lot of time in the mountains and am intrigued by how we think they formed and the rocks that make them up. The folds that I have seen throughout my travels in the Rocky Mtns make me wonder how that happened and the amount of energy.

[@pauldavis1943]

This was a great learning experience! Thanks

[@olddecimal2736]

Thank you for your work and making it accessible. Such a privilege

[@erich930]

Fascinating how a hot enough pyroclastic flow can kind of turn back into "lava" when pressed under itself! I can't even begin to imagine the utter scale of those super-eruptions...

[@valoriel4464]

Excellent video. Thanks. Yes, your diagrams are helpful 👏. Fascinating topic. Your hard work , Shawn, is greatly appreciated

[@maryseeker7590]

Excellent! I love the enthusiasm and the knowledge!!

[@Bloodknok]

Really informative, and those isoclinal folds are spectacular

[@bobbyadkins885]

Really like these longer vids, rheomorphic ignimbrite, definitely a new one to me, lol

[@bwc1007]

Great video-thanks for making these videos for the public to learn from.

[@TrainLordJC]

Absolutely awesome video and certainly very informative and educational adding so much more to my interest in geology having watched so many over the years of Nick Zentner and now you. I am actually in the process of building scenery for an HO scale train layout at my train club and even yesterday we painted many different colours on gouged out foam to represent much of the strata and layering that you show and describe. And having travelled all over the world including spending time in the Sawtooth Mountains of Idaho and the Wasatch geology and history is like doing a big jigsaw puzzle bringing answers to so many questions that our inquisitive minds ponder during our own journey through life (as a 71 year old). Your style of presentation is excellent and you certainly live in one of the beautiful places on this planet. In fact North America and it seems especially the US has so many geologists etc who have the knowledge and skills to present great KZbin videos for us all to learn from. It would be interesting if more geologists in other areas of the world could also present their local findings in similar fashion but so far they have been hard to find. For example the Siberian Traps and the Deccan traps and indeed even the geology of the Victoria Falls and Iguazú Falls (I have been to both and several more). I incorporate all of these memories into my scenery skills at the train club layout. Regards and cheers from the Train Lord in South Australia a long way away from this epic action.

[@LizWCraftAdd1ct]

Lots of new words to learn. Love the folds. Thanks Shawn.

[@Danika_Nadzan]

Thanks for another great geology lesson, with easy-to-remember diagrams and instant real-life reinforcement! The depth of the pyroclastic flows in the ignimbrite is both amazing and terrifying. The isoclinal folds are subtle at first, but the more you showed, the easier it was getting to pick them out. Maybe you should develop a special geology edition of Scrabble for all these great new terms...😁 Nice shirt, too!

[@astrialindah2773]

That is so helpful! Thank you for bringing geology to life!!!!!

[@shawnwillsey]

Glad it was helpful!

[@ericfavre2301]

these geology treks are awesome !

[@candise9063]

It’s absolutely gorgeous there. Definitely putting this on the road trip list. Very interesting video as always.

[@alaskajdw]

Amazing video Shawn 👊

[@Yetibiker67]

What an amazing video!!!! Absolutely fabulous Shawn! Keep posting and educating!

[@Tatterdemalion-77]

That was pretty dang cool. What a beautiful spot. Some day, I’m going to need to do a nice long road trip…

[@ThomasEckhardt]

Thanks Shaw, this segment helped solve a mystery for me, now I understand the origin of the flow structures I noticed in some float samples from the Caliente-Indian Peak caldera area. Here the layering is fine, just 1-2 millimeter but nicely folded and twirled!

[@KA7EII]

Very informative! Can't wait until my next Rabbit Springs geode collecting trip - will definitely take a ride to Salmon Falls to look at this interesting geology.

[@timothycivis8757]

Good video! Very informative.

[@brookeshaffer4377]

Very intriguing!You explain things well Shawn 🌟

[@briandwi2504]

Excellent lesson there. Thanks for putting all that together.

[@Raptorman0909]

I mentioned in a previous video that I'm reminded of the HBO program "From the Earth to the Moon" and in particular the show titled "Galileo Was Right" -- one of my two favorite shows in the series. In it, geologists Lee Silver and Farouk El-Baz teach the Apollo astronauts how to read the landscape and identify the various rock types they might encounter. The actor who played Lee Sliver, I forget his name, portrayed the geologist-as-teacher beautifully. I think we've found the one of the geologists to teach the next generation of astronauts to read the landscape. Oh, my second favorite show from the series is "Spider" -- about the Grumman team that designed and built the LEM. Both episodes are deeply inspiring...

[@SarahS1214]

Really interesting! My parents were geologists & I had no interest in rocks! 50+ yrs later I’m interested! Thanks for the great video! So neat to see the layers.

[@user-wk1mw9nj3i76]

Amazing to think of the originally different characteristics of the rock all around you. (I couldn’t help thinking, “don’t slip!”) Your summation at the end is so true.

[@AKUSUXs]

Just awesome to watch and see. I drive up and down the Lewiston Hill and others places in the area quite a bit. Watching these videos, I can now better understand what I see. Thank you!

[@josephcline370]

Hi Shawn, This is really great! It helps to answer quite a few questions I have had about some of the igneous rock formations that I have encountered in the Hagerman valley area! Thank you! ...You are the best!!!

[@vintagelady1]

Fascinating, I'm still awed by the idea of seeing & touching something that's 10 million years old & that tells the story of how it was made. Thank you, you rock (bet you never heard that before!).

[@shawnwillsey]

Glad you enjoyed it

[@maryt2887]

I found the contacts and their different colors and textures very interesting, probably because I can see them clearly! Appreciate your helpful diagrams followed by the rocks that support the diagrams.

[@jaimecastells4283]

Thank you for the geologic descriptions. You provide a solid level of technical detail with exactly the amount of definitions and background to clarify and inform, rather than obscure. Early in your description you gave dates for these deposits of 10.5-8.6 Ma which is interesting since, as I understand it, the Salmon Creek Reservoir is on the edge of the area of the Bruneau-Jarbridge eruption which is dated roughly 12-10.5 Ma. The dates you gave would be for the Twin Falls eruptive period. Am I right to understand that this is a younger pyroclastic flow on top of the older caldera? Makes me wonder if the creek valley below the falls shows direct evidence of both eruptions stacked one above the other. Sounds dramatic!

[@shawnwillsey]

Thanks for your kind words and comments. The Salmon Falls Creek Reservoir area (or Rogerson graben) does lie just near the edge of the mapped boundary of the B-J eruptive center as you note and there are deposits from this center (and its slightly older age) in the area. However, the particular unit I highlight in the video is the Grays Landing member of the Rogerson Formation which is inferred to have erupted from the Twin Falls eruptive center. Other members in the formation are likely linked to the B-J center.

[@PopsMdub]

Just imagine if these sorts of events occurred today. The earth is so much more calm than it was just a few million years ago. Thanks for the great lesson as always.

[@davidpnewton]

No we just have a sample bias. Events of this scale are rare enough that one simply hasn't occurred in recorded human history. Even the number during the entire existence of homo sapiens sapiens is relatively small. Only two in the last 75,000 years: Taupo 26 ka and Toba 74 ka. The recurrence rate is tens of thousands of years: recorded human history is only 5 ka.

[@melodiefrances3898]

It is SOOOOOO helpful to be able to see what is being talked about right there in the field. And, of course, your natural teaching ability helps even more. And the diagrams are great! They totally clarify what you are explaining. Thank you KZbin for a recommendation that I actually REALLY like!!! I would LOVE to see you do the San Francisco Bay Area in California which is the wreckage of a subduction zone that has been sliced and diced by the San Andreas fault zone. I live here and am trying to understand the big picture. Your ability to explain what can be seen is some of the best I have ever seen.

[@shawnwillsey]

I've got plans to get to Yosemite/Eastern Sierra next year and Cascades in Northern California. Not sure I'll make it over to the SF Bay region.

[@dianebriggs8797]

Nick Zentner has covered this area with other experts...I believe you will absolutely appreciate what they have highlighted over the last 5 years. Fascinating area.

[@robclawson2931]

Nice job showing the layers and the inner workings of the caldera,I am a firm believer of geology in the field.Bretz teachings were short lived by the educational system in Washington state due to pressure to teach in a classroom.Well done sir

[@66kbm]

Is there such a thing as Andesitic Tuff? Fabulous scenery, fabulous commentary, fabulous stratigraphy shown. I still dont know how things stick together with great heat. Too technical for me. Keep up the good work sir. Many thanks.

[@davidpnewton]

Certainly. Tuff is any rock consolidated from volcanic ash. Andesite can produce pyroclastic flows and so it can produce a tuff. Heck even a basaltic tuff is possible. A big enough basaltic phreatomagmatic eruption could certainly produce an ash fall tuff. A basaltic welded tuff ignimbrite would be pushing it however! That said Tarawera in 1886 might just have achieved that very feat. Such eruptions are referred to as Big Basalt Blasts in a series of blog posts at Volcanocafe.

[@jenb.6440]

Great video! Thank you! We really enjoy your work

[@skyedog24]

Thank you in support of all things with geology it's a very good flight to jump into an ultralight and go to the end of the flow or close to it around halfway Oregon there are a lot of bubbles that have popped and they are sometimes 50 60 ft wide and great big Bowls in the middle of this flow it is such a beautiful sight to fly over this in an ultralight

[@lorenmorelli9249]

Beautiful... I have made many a trip into the Jarbidge Wilderness with my Friend Lowell Prunty and have always been taken back by the natural order of this awesome area..

[@edwardhanson3664]

I like the 2ne model, it recognizes the physics of fluid flow.

[@timdienhart3738]

Very informative video Shawn, Thanks I enjoyed it

[@joaniewillow]

such a good teacher. Thank you for sharing your knowledge and obvious passion .

[@samuelcarstens6152]

Interesting content sir. Thanks for sharing this knowledge. Have you considered creating content that shows how to read the rock to find sources of the eruptions?

[@samuelcarstens6152]

Meaning, show where the eruptions took place?

[@shawnwillsey]

Usually linking eruptive products to a source and event involves lab data such as chemical analysis and dating.

[@samuelcarstens6152]

@@shawnwillsey I see. I didn't know if there are simple visual indications of direction of flow.

[@cherylwood5202]

Wow! That was incredible! Thank you for the tour and great explanations.

[@sdmike1141]

“Wow, your gravy flows like rheomorphic iignimbrite…”. things to say over a holiday gathering…and hope no one’s a geologist. 🤣. Great description of volcanic flow other than basalt. Thanks!

[@shawnwillsey]

That's great!

[@danbh3981]

Very excited to see the Grey's Landing ignimbrite on a KZbin thumbnail! I did my master's project on this eruption

[@shawnwillsey]

I'd love to read through it if you can send a copy or a link.

[@annewandering]

Interesting. I live on the Oakley side of this area. You answered some questions I had all my life. Especially the black crystal like rock. Never could figure out what that was. Thanks!!

[@shawnwillsey]

I'll be over around Oakley sometime soon to do some other videos.

[@DragonHeartTree]

Absolutely fascinating! And explains many things I’ve wondered about. Thanks so much!

[@timbush7850]

Thank You for this! Great explanation.

[@balesjo]

Loved seeing a video from one of the older "Yellowstone" eruption sites. Very interesting, easier to see the geological structures with less vegetation.

[@SueFerreira75]

Love your videos - thank you for making geology so clear and interesting.

[@room5245]

I said rheomorphic ignimbrite aloud twice and my peers were much impressed

[@room5245]

Great videos mate, absolute treasure for a yt connaiseur and new nerd in geology

[@donnaw9040]

♥️🌋, so interesting, loved the curvy rocks. I bet you and the family had a lovely time hauling those rocks home!! haha, done that a couple times myself. Wished I had a burrow.

[@7hilladelphia]

This is mad interesting, thank you 🎉🎉🎉

[@hapagirl79]

Mahalo for sharing!!!! This was a wonderful video. Your diagrams were perfect!

[@sharonseal9150]

Excellent! So informative.

[@grud66]

Really well explained thank you

[@joetrueblood7663]

Wow that's awesome, great information 👍

[@roneldridge7991]

I could see a few folds they looked pretty Awesome. One you pointed at and one above. 👍

[@Aghorri]

Absolutely brilliant.

[@packrat2569]

Interesting! Thanks for showing us these amazing features.

[@gerrycoleman7290]

Are there thicker exposures of the former Paleosol? Does the color stay generally the same reddish hue with depth? Was the climate when the ash fall deposit occurred tropical? The former Paleosol looks like it was an old depleted soil called an Oxisol. Typically found in tropical settings.

[@guiart4728]

Great communicator!

[@stephenjacks8196]

My Geo classes showed the "first" Yellowstone hot spot was west of Moses Lake where basalt features disappear (from Eastern Washington basalt flows) towards Mount Baker volcano. Earliest known flows from Yellowstone hot spot 50-60 million years ago.

[@ronjlwhite8058]

Awesome video explaining them layers. Always found that fascinating and usually look when I see them on trips.

[@BrianSmithCanman]

Thanks for the great video

[@toughenupfluffy7294]

Pyroclastic flow: terrorizing, but not for long.

[@edwardhanson3664]

Great presentation. Watch that ledge.

[@SomeDumUsrName]

We are truly just barely a spec in the timeline of all this. Amazing to think about. Kind of like pondering the size and contents of the known universe.

[@fromkorriban7369]

Thank you for these amazing video !

[@shawnwillsey]

Glad you like them!

[@mickie7873]

Thank you for your explanations.

[@shawnwillsey]

You are welcome!

[@jdean1851]

FANTASTIC " VIDEO ! Thanks 4 Posting! Cheers from Lewis County"jd

[@piotrrajmundkoprowski4732]

Simply brilliant

[@robertgoble2491]

Great video. Very simple and clear explanation.

[@hunt4redoctober628]

A fantastic explanation. Really fascinating. Thankyou!

[@shufflerp3868]

Great video! Very interesting. I have always enjoyed geology.

[@shawnwillsey]

You and me both!

[@LizWCraftAdd1ct]

Love the isoclinal folds.

[@stevewhalen6973]

Thanks!

[@tonylatham5915]

I've also got a couple layers of sedimentary rock running through the igneous rhyolite (?). So I assume the Challis volcanic eruptions caused a lake or large inland sea to form here fifty or sixty million years ago... fascinating stuff.

[@SkinnyVinnyLive]

What an excellent video!

[@jackprier7727]

Thanks, Shawn--very fun and informative, I'll have more to ponder as I go to Twin Falls as I do. What causes/allows the layering/exfoliation of the welding/welded flow? Is it intrinsic to the crystal-type of the silica-rich semi-lava?

[@rufusmclean9770]

i learned something new...thanks.