Debris Flows and Dikes: the impressive Absaroka Volcanics and Chimney Rock, east of Yellowstone NP

Team up with geology professor Shawn Willsey as he explores the picturesque Eocene volcanic and volcaniclastic rocks of the Absaroka Volcanics in Shoshone River canyon between Yellowstone NP and Cody, WY. Learn how subtle clues in layering reveal how these rocks were deposited and also check out one of the andesite dikes cutting these rocks.
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Shawn Willsey
College of Southern Idaho
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[@shawnwillsey]

You can support my field videos by going here. Thanks! www.paypal.com/donate/?hosted_button_id=EWUSLG3GBS5W8 Also, I apologize for mispronouncing "Shoshone" and "Absaroka". I have been properly corrected by several of you. Thank you. To be fair, I live near the iconic "Shoshone Falls" in southern Idaho where it is locally pronounced "show shown" not "Show show knee".

[@shawnwillsey]

@Brandan Weber Thanks for watching and learning with me. So much to learn about the world and its stories.

[@greatbarrierleaf4625]

Watching this triggered my field camp PTSD; I felt like I had to be feverishly taking notes in a wet field journal while not knowing what's going on at all. Jokes aside this was great. Thank you.

[@sdmike1141]

Best “hands on” field reporting in the land!! Nice niche! Lots of geology in small bites… so as not to dull the senses. Thanks much for your work!

[@Helix-ge1ld]

A good class of Geology. Greetings from Spain.

[@shawnwillsey]

Hola en Espana!

[@mikekilian5403]

Than you for doing this. Very interesting.

[@SkiSkillsMontana]

My mother used to be the educational specialist at Yellowstone National Park for many years. You do a great job with explaining stuff. Thanks for the great video

[@briandwi2504]

Excellent and informative description, thanks for that!

[@rogercarroll1663]

Thanks for the work.

[@peggieincolfaxca3818]

We do love your presentations!

[@leechild4655]

Volcanos are the scariest things really. They are most often the things that draw lines in time periods. And we see so many in the past you just know it will happen many more times than we will have existed. ;-)

[@ericclayton6287]

Wow a literal strat column.

[@rogercotman1314]

Thanks Shawn for the Normal and Reverse grading explanation!!!! Very nice informative video. 187 like ...................

[@stevewhalen6973]

Your highly knowledgeable descriptions paint a vivid picture of what was formerly present and grand in its past existence, at the many fascinating geological sites you examine .

[@maurinedoyle9964]

My son and I dove through there a year ago - took our breath away ❤

[@mehrzadm8899]

Thanks Shawn.

[@nitawynn9538]

I really like your road cut videos. The different rock formations are fascinating. Thanks.

[@RockEater-so6bd]

Fantastic series of videos, informative and delivered with enthusiasm. Thank you for the good you put out into the world.

[@stevehix1656]

Incredible another great video 👍

[@vetricara1149]

excellent shawn

[@michaelnancyamsden7410]

Especially like your pointing out the boundaries and types of rock layers.

[@chrisdooley1184]

Fascinating Scott. Thx for the geology lesson. Wyoming is utterly gorgeous and a beautiful place for rock hounds to see the progression of our formation

[@gretchenlhommedieu9246]

This is the most interesting and educational video I’ve ever seen of geology. I have enjoyed all your videos. Thank you.

[@shawnwillsey]

Wow. Thanks for the kind compliment. Hope you enjoy my other videos as well.

[@DavidHuber63]

I love learning from you, you are an excellent Teacher👍❤️

[@shawnwillsey]

Thanks David. Very appreciated. I love to share geology with folks.

[@williamlloyd3769]

Well you definitely didn’t want to be around when those layers were laid down above the sandstone layer.

[@christinedaly2694]

Thank you Shawn keep making yr videos they are very interesting

[@Josh1888USU]

I thought Absaroka was pronounced differently. Nice video, I'll have to take a drive through there to check it out for myself.

[@gerrycoleman7290]

I thought that also.

[@causeitsthere]

It is. My dad built buffalo bill dam. It’s more like Abb sor ka

[@Josh1888USU]

@@causeitsthere Found a video on how I have always pronounced it. The wife is from Wyoming and that is how she taught me. kzbin.info/www/bejne/aJetfYujmZ6lrJo To me it is 4 syllables. If you have ever watched the show Longmire, they say it on there like that too. However, the show has made it the name of a fictitious county in Wyoming. That drives my wife nuts, she prides herself on knowing all the county numbers on the plates in Wyoming so whenever they say Absaroka County on the show she has to interject "There's no damn Absaroka County in Wyoming!"

[@alro11]

it is- he said it incorrectly and Shoshone as well

[@shawnwillsey]

Yes, I was wrong with pronunciation. Although to be fair, I live near the iconic Shoshone Falls in southern Idaho where it is pronounced "show shown".

[@felmlee1876]

Field trips with Willsey, what a treat. Make an application to Adams State University in Alamosa CO. Check out the Rio Grand Rift, the San Juans, the Sangre de Cristos, and why there are probably still grizzly bears in Colorado.

[@johnzinkowski6834]

Great job. Thank you.

[@RonHei]

Cody, Wyoming, my home town. When I was a kid I used to get behind Chimney Rock and push trying to topple it. It never worked.

[@haroldtanner9600]

Thanks for the video! I’ve been driving through the Park to Cody lots the last few years and I have wanted a geologist with me. This is the next best thing! (How do you say Absoroka???)

[@shawnwillsey]

I screwed up the pronunciation. Apparently it is "ab soar ka".

[@fredfleming8905]

How interesting I went by all of this on my way to Yellowstone. Unfortunately our schedule was limited and we did not get time to pull over and look at the rock formations. Your explanation is so helpful to the understanding the region. I wish I could go back and rearrange my life to become a Geologist I would spend all day and every day in the wilderness. There is so much to study and analyze. Thank you for taking time to make this video. Fred in Texas

[@stevewhalen6973]

Thanks!

[@morganrenner3122]

Shawn… Great Stuff! As a local native I’ve always been interested in the geology of the area. I must correct you on your pronunciation of Absaroka though… (nobody gets it right). It’s pronounced “Ubb Zor Kah” Thanks for putting these together; truly fascinating.

[@shawnwillsey]

Yes, I've been duly corrected. Thanks!

[@BlGGESTBROTHER]

Shawn, have you ever been to the Idaho Panhandle near Priest Lake? It would be awesome to see a video from you up there going over the geologic history of the Belt Supergroup. The reason I thought of that area is that there's also a Chimney Rock formation located there in the Selkirk Mountains, to the NE of Mt. Roothaan. It has several climbing routes bolted into it and could be an awesome climbing adventure for you!

[@shawnwillsey]

Sounds awesome. Only been to Northern Idaho once (shamed expression). It's such a big state and such a long drive.

[@66kbm]

So if this is Eocene in date...50 million ish, then are we talking about Volcanics from the after effects of Siletzia docking rather than the Yellowstone hotspot that would be still offshore ish at that time? Wonderful section through those rocks showing the flows. Thanks for posting.

[@shawnwillsey]

The Eocene volcanism in this area is thought to be caused by regional extension as the subduction slab steepened and stretched the overlying plate. However, several other hypotheses are out there.

[@66kbm]

@@shawnwillsey "Slab Rollback"?

[@haseo8244]

Oh debris flows. figures. Saw videos of massive boulders of limestone from the infamous Switzerland heavily eroded area. Then the mud kept them on top.

[@andyhampsten4252]

Ha ... I finally beat one of your puzzles. Reverse grading is why we wear inflatable bags when back country skiing or snowmobiling .. and a beacon in case you don't come out on top. If you're lucky, reverse grading will bring you on or very near the surface of the slide.

[@creed6.549]

several land slides as the rocks edgesare sharp

[@hunt4redoctober628]

Question, the assumption is that this is largely a debris flow. What would be different if these represented successive pyroclastic flows?

[@shawnwillsey]

Good question. Yes, a pyroclastic flow would be dominated by ash whereas this debris flow deposit is mainly clastic (rock fragments). Also, the heat of the pyroclastic flow would likely weld the material together more cohesively and/or "bake" the underlying rock.

[@hunt4redoctober628]

@@shawnwillseyGood points Shawn.

[@sharonseal9150]

Your videos are always so educational, and short enough to watch as soon as they are posted - thank you for all the wonderful content! Are these flows and dikes from extinct strato volcano Mt Sunlight similar age to the flows from Mt Washburn that created Specimen Ridge in north east Yellowstone? I am having trouble locating Mt Sunshine on a map but it sounds like it is in the vicinity to the east of Mt Washburn..

[@shawnwillsey]

Yes, Mt Washburn is also made of same Eocene volcanic rocks. I have a video from Specimen Ridge coming soon!

[@louiscervantez1639]

Thank you - I am in Spain right now and there “ain’t nufin” like this here.

[@drhyshek]

Really fascinating, Shawn. So these dikes were filled from lava flowing downwards?

[@shawnwillsey]

No, dikes are magma intrusions moving upward through cracks in rock.

[@davidk7324]

I enjoyed this, Shawn. Consider making a trip to upper and lower Mesa Falls on Henry's Fork in Idaho. I'll bet the rangers would let you get off the beaten path. During the Fall would be spectacular.

[@shawnwillsey]

Will do. It’s on my list. I covered that area in my book, Geology Underfoot in Southern Idaho.

[@davidk7324]

@@shawnwillsey Thanks for the tip, I just ordered it.

[@SuperMontanamike]

Also, just to back you up, we say Shushown, (many people....not from/or have lived locally) Say Show show knee.....soooo, another good comparison to this compromise is Escalante in Utah....the locals from this area and town (salty Utah residents) say Escalant....most people say Esca lant "e"...... all of these things are just local knowledge or lingo or dialect..... Overall, I think you deserve an A+ for your ability to speak scientifically to the average layman!!!!

[@SuperMontanamike]

great content with awesome locations, would really love to see you do a video in, on and around the Henry Mountains in Utah! So much geology there...I've spent so many years there wondering how all the crazy rocks formed I wish I had your knowledge, perhaps it would then make sense. I think the Brushy Basin formation is my favorite there......;)

[@shawnwillsey]

I will be in that area in March so let me send me some specific locations or GPS coordinates of places that are worthy.

[@joecasalena8263]

Can you explain how those Basement Rocks got to exposed such that it was covered by sediments? Continental uplift, volcanic, meteor strike??

[@shawnamartin6118]

It's pronounced "Shoshoni", as far as I know. Thanks for the video.

[@shawnwillsey]

Yes, but where I live in southern Idaho (by Shoshone Falls), it is pronounced "show shown". Go figure.

[@shawnamartin6118]

@@shawnwillsey :-)

[@mar83161]

Well, I was taught that Shoshoni was the town, and "Show Shone" was the river. 4th Generation Park County.🤠

[@shawnamartin6118]

To me it all goes back to the Indian tribe I belong to. Sho-sho-nee we say. But whatever you call it, it's beautiful land. Thank you. Love to all.

[@kensanity178]

There is much to know about this world. Don't let the naysayers stop you. Some of us want to know.

[@stevehix1656]

Shawn have you ever done any work around My Shasta in California that area is filled with incredible stone.

[@stevehix1656]

Mt Shasta what the heck.

[@shawnwillsey]

Nope. Hoping to get over to Shasta next year. So much to see...

[@royolstad8532]

Around the town of Absaroka in Montana they pronounce it ab sor' ki

[@markvincent522]

Would debris flows have granular convection? I think that's what it's called, anyway... Is it the same process that happens in slab avalanches where the action of the avalanche almost "floats" big sections of slab?

[@bingosunnoon9341]

Are the rock faces we're looking at natural or were they created with the construction of the highway?

[@shawnwillsey]

As far as I could tell, all natural.

[@Anne5440_]

Could the debris flow be from a pyroclastic flow? I have heard of dikes. As I understand it they are from an intrusion. I can see I need to study those more. That study was back in the 80s when I was trying to learn about volcanos during and after my experience with Mt St Helen's. What a pretty canyon. I can't remember if I have been through it, but I don't think so. If I had it would have been nearly 50 years ago. I did treat myself to 2 geology books for c'mas. Each has several authors. Ron Blakey is in the list of authors of both books. During the next 2 weeks I am going to review and try to finish the geology 101 that I got part way through when I was sicker than I am now. I'm enjoying your videos. It really helps when you show and explain a feature.

[@shawnwillsey]

No ash in matrix of rock surrounding clasts so not a pyroclastic flow. I knew Ron Blakey at NAU and took classes from him while getting my MS in geology. Great guy and his paleogeographic maps are an amazing teaching tool. Thanks for watching and learning with me.

[@Anne5440_]

@Shawn Willsey OK, so the forces in a pyroclastic flow drive ash into the existing soils when they occur in addition to laying down a deposit layer? I am glad to know that about Dr Blakey. I was looking for fairly recent texts at a more affordable price. I have a degree in cultural anthropology with a biology minor (1971) and a masters in education(1992). So I know the importance of the quality of source material for study. Since I have been watching Professor Zentner I feel ready to tackle collegiate level reading again. Thanks for doing the rock identification series. You are giving great visual help that a beginner needs. I am slowly working through those videos.

[@shawnwillsey]

@@Anne5440_ The way I understand the process, the pyroclastic flow rides on a low friction cushion of air, enabling it to travel large distances. The ash is not driven into the soil which jives with observations I've made where the soil below is baked by heat but does not contain ash particles. Glad to see the rock videos are working for you. Hoping to record the next one tomorrow.

[@Anne5440_]

@@shawnwillsey thanks for explaining. That really does make good sense.

[@donmthg]

Could the red areas along the dikes be cinnabar? I live just north of Yellowstone Park and there is a prominent feature on Cinnabar mountain called The Devil's Slide. It is a red streak down the mountain. The red is cinnabar and there are two dikes there.

[@3xHermes]

👍

[@kevintaunt4385]

I find that gravity tends to settle the larger matter, but vibration directly opposes that process? 🤷‍♂️

[@bobwinters6665]

Does the andesite at the contact zone fracture conchoidally?

[@valsummers5330]

Does reverse grading behave likea solution of cornstarch in water?

[@jeeperp3926]

The dikes are areas where lava/magma was injected into softer previously ejected clast?

[@shawnwillsey]

Yes, the dikes are vertical conduits in the rock that magma moved through.

[@outsider2222]

what was the tectonic cause of the absaroka volcanics?

[@stanfullerton8485]

Ab "sorkee" our Montana pronunciation

[@shawnwillsey]

Yes, I've been duly corrected. Thanks!

[@stanfullerton8485]

kinda like tourists calling a "crik" a creek

[@sarahb.6475]

I think the most shocking thing in here is the idea that a huge volcano could just disappear. from a huge mountain to nothing?? did it disappear because it blew its top like Mt St Helens and lost some height and the rest just blew away from erosion? why doesn't Yellowstone form a big cone / mountain if it is so powerful? did it ever have one at all? why do super volcanoes look like a lake / field instead of a big mountain?? they all seem to look that way, from Taupo in NZ to Campi Flagrei in Italy... It is mighty strange. and how did that chimney form? you explained the layers but what made the gap that makes it an actual "chimney". was it connected to the main hunk of rock and water cut the opening in between? I guess even volcanoes die. will Yellowstone die someday? or will it "move" to a different spot as the continents slowly drift via plate tectonics? just imagine how that debris must have looked flowing over the land to where it is now. must have been a horrid sight if anyone saw it. death coming. hot + steaming. probably stunk too. i would think a volcano must stink bad. did it stink at Yellowstone?? those gases. unfortunately I have a very sensitive nose! oh google does not know where that sunlight volcano is. i tried to look it up to see what was left. i did find this general area you are in thanks to the little map of Yellowstone + Cody. and wow... like nothing in that area..the whole area for huge distances seems to be just ... empty? mountains I guess?? a few towns and a few tiny places but mostly just nothing... never saw a place like that. did you know the majority of the US's population lives east of the Mississippi?

[@richarddavies7419]

Some really big volcanoes blow out so much material (cubic miles) that the very large surface area falls back into the hole, leaving just a depression or lake. That is represented at Yellowstone, and is what is called a "caldera". Volcanoes that spit out different kinds of rock, ash, or lava, also just a little bit at a time build cones, often unstable, that can erode away to nothing in a relatively short time. Mt Rainier near Seattle is a good example. The Cascade Range contains remains of many long-gone volcanoes.

[@russellhawn3499]

The thing you are calling a dike looks like a fissure. Here are facts that support my position. 1.) Material inside a fissure would be cooler around the edges ( where the material/magma in the fissure meets the non magma wall) and material at the middle would be warmer. 2.) Fissures make narrow columns just like that. 3.) Material in a fissure could potentially be different from the rock, material, structure that it is moving thru.

[@shawnwillsey]

I'm interested to know what your definition of a fissure is as compared to a dike.

[@russellhawn3499]

@@shawnwillsey Thank you for your reply and your question. It seems to me that perhaps a dike might be a result, geological formation, from a fissure. My understanding of a fissure is a " crack" in the ground where lava flows out or might be ejected. You have made a very strong case, for what I see as possible fissures, being little more than cracks in the rock. Thank you for your work and your videos. It seems that you might be a professor. I hope your classes are well attended as you are very insightful. Plus you have perked my interest in traveling to Idaho to see some of the features that you have shown. We have some interesting geological formations in my part of Indiana. One formation that supports you is fine layers of coal that I find embodied in layers of rock. Sometimes those layers are flat other times they look like a chocolate and vanilla cake batter that has been poured into a large glass test tube. I live near Turkey Run State Park. There are seams in the rock , maybe a couple 2-3 feet wide, where it appears that an upward flow occurred at some point in time there. There are what look like " pipe paths" down thru rock in other places. I say pipe as the size of the opening remains the same for at least 50 foot. There is rock that is tough, jagged, and filled with all various sized holes very similar to some form of lava. There is a seam of rock that will coat your hands with dust while other rocks in the area do not do so. The ground around the dust emitting rock is covered in the fine dust as well. Thank you for what you do. Thank you for questions my statement.

[@williamrowley4657]

I was a guilde in the 80s, up river, for a man who shares your family name ,though im not certain on the spelling..perhaps, do a show on camp Monaco.,Way up the north fork..I belive it has historic significance, and perhaps geologic significance..I found some amazing places there..not to mention rocks, that rocked..lol

[@stevewhalen6973]

Thanks!

[@stevewhalen6973]

Thanks!

[@frankcihak6623]

Thanks!

[@shawnwillsey]

Much appreciated.