Henrys Fork Caldera: Yellowstone's Last Caldera Eruption Completely in Idaho

[@shawnwillsey]

FYI: Graphics shown in video are from my two books, Geology Underfoot in Southern Idaho and Roadside Geology of Idaho. In fact, the content of this video is one full chapter in the Geology Underfoot book. You can order signed copies here: shawn-willsey.square.site/ or get from local booksellers or Amazon (of course).

[@keithweiss7899]

A great explanation! I love Geology and almost majored in it in the 70’s. I went to Southeast Missouri State and they are in the area of the great New Madrid earthquake. So lots of geologists were there because of that. Very interesting, and I thank you!

[@Vbluevital]

Simply love your content. Thank you for sharing.

[@briane173]

I was up and down US-20 through Island Park- Yellowstone twice -- once 40 years ago, another about 27 years ago -- and had no idea whatsoever that I was driving over a massive caldera. There is so much geology going on in Idaho that I missed while I was living in Idaho Falls it's a shame now that I'm finding all this out so late in life. But now that I know, I have more incentive to head back to the place I called "home" for 4 years back in the 1980s and view it all with a different pair of eyes.

[@shawnwillsey]

Better late than never. Enjoy!

[@Vbluevital]

How lovely, we hope you do.

[@briane173]

@@VbluevitalThere was a brief time when Island Park held the record for the all-time lowest temperature in the contiguous 48. I believe that was eclipsed either by West Yellowstone or Meacham Oregon, I'll have to look up the history.

[@estherlwhittle7568]

Yes. I lived in Idaho in the early 1960s in the Challis National Forest. We also traveled widely in Idaho.

[@PopsMdub]

You are always showing us the coolest stuff and explaining them in the most understandable way. That's why I love supporting you when I can.

[@shawnwillsey]

I appreciate that!

[@Anne5440_]

Excellent lesson! What I enjoyed the most was the Mesa falls tuff road cut. As you came up to it I recognized that it is tuff. I then remembered seeing the same thing in '82 along the Toutle River at st Helen's. I was confused that day by what I saw. But I really knew nothing about it. This spot was just above the lahar level along the river. Your explanation here and the layers told me what I had seen on a smaller scale that day. Comparing the two places really helps me realize what a large eruption that had been of the Yellowstone hot spot. I'm still glued to the Iceland current eruption cams. This video has also emphasized to me how much more complex explosive eruptions are compared to fissure eruptions. Both are fascinating in their own ways.

[@natcatsfarmlife]

I absolutely love the simplicity of “Let’s take a seat on the trail and have a quick lesson!” The clipboard and paper spoke to me. Felt like we were sitting with you on the ground reading along! Thank you for sharing with us.

[@user-wk1mw9nj3i76]

I agree!

[@robertmeyersMeyers-cm9fy]

You’ve got me super stoked about Geology. All your videos are great. I live in Hood River Oregon and was wondering if you have any videos on the Columbia River Gorge or Cascade Mountains.

[@williamdice2546]

Thank you for covering this area. I was in the area visiting a relative and she called the quartz crystals diamonds. I knew they were not, but I was not sure what they were. You answered my question while providing the background to how the area formed. Please continue making videos!

[@shawnwillsey]

I will. Thanks for watching.

[@ragnapodewski4694]

It is a complete description of the Supervolcano theory, Yellowstone is the unique place, where this theory is sure. Most caldera forming eruptions are different. America is lucky to have such a moving Hotspot under thick crust of a continental plate.

[@leswoodburn5764]

@@ragnapodewski4694 It maybe that the hot spot is stationery and the land mass is moving in a westward direction.

[@ragnapodewski4694]

That is the point,I have said!

[@beachbum200009]

I really enjoyed this video!!! Thank you Shawn.

[@shawnwillsey]

Awesome. Glad you liked it.

[@ja6995]

Seeing new uploads from this channel is really satisfying. I'm a fan at this point. Really great stuff

[@shawnwillsey]

Hey thanks so much and welcome aboard. Enjoy the existing videos and look for new ones soon!

[@paulwestenskow7302]

Hi Professor Willsey! This is one of the best presentations I have seen about geology in the Island Park area! I have to confess that I have binge-watched this serval times. There is just so much there to learn and understand! From now on, whenever I drive up there ( I am from Pocky), I will look at geology in a different light! Thanks again for this excellent presentation!!!

[@shawnwillsey]

Wow, thanks for the high praise. Happy to share what I know and love. Keep learning.

[@mickie7873]

Thank you for your overview of this caldera area. We midwesteners have such restrictive clues to this type of topography. I lived in Wyo. for 5 yrs.; got to visit Craters of the Moon and there abouts. The magma building period of our planet is so interesting. I'm enjoying all your videos.

[@jessespillman6754]

I have spent quite a bit of time in that area. Absolutely love it and love the geology. When I'm there i wake up on the edge of the caldera and sit and watch the sun rise over the mountains, watching sunlight fill the caldera acting like the magma that once rose from the depths below.

[@craighoover1495]

Thank you for this. I have a passing familiarity with this area in that years ago I "passed" over it for work ventures related to plants and animals in forests and waterways. Looking at it now and thru the lens of geologic time lends a perspective that is new and welcome to me.

[@lawrencetaylor4101]

Merci beaucoup. One of my favorite memories of my time in Wyoming was taking a Geology class in a Community College. My only regret was being colour blind. Great lecture, Professor.

[@Rachel.4644]

Another good one, Shawn, thanks. Your Guides are so practical and useful! Looking forward to exploring more of Idaho.

[@2flight]

Another outstanding field trip. Thank you!

[@LisaP-pd6nq]

We went to Yellowstone when I was 11 in 1973. No one mentioned we were all over a massive volcano:) This is so fascinating!

[@loisrossi841]

Yellowstone is a favorite; glad to have this information. Thank you.

[@godngunclinger]

thank you for including the GPS coordinates in the video I went ahead and researched the coordinates on google earth all around the outside of the caldera streams run every point of the compass🤠👍👍

[@shawnwillsey]

Yeah. It is by far the best preserved and most conspicuous landscape of the three recent caldera forming eruptions. The drainages are indeed radially, mainly on west and south side of caldera.

[@7inrain]

For the viewers used to the metric system: The Henry''s Fork Caldera eruption produced 280 km³ of ash, the Yellowstone Caldera had 1,000 km³ of ash and the Island Park Caldera eruption went off with 2,500 km³ of ash. The teeny, tiny Mount St. Helens eruption: 1 km³ of ash. Nothing to write home about. [/s]

[@Anne5440_]

But what St Helen's ash (2 3/8 inches) made a big impression on my life. No one wants to go through a super eruption for sure.

[@davidk7324]

Outstanding. Another trip to the area is on my agenda. Thanks Shawn.

[@shawnwillsey]

Awesome. This region offers so much geologically. I have more places to go for videos still too

[@michaelgeorgemcdonald5927]

Hi again! Excellent video. Really enjoyed it. You'd be happy to know that from watching your previous videos I was actually able to easily follow what you were describing! Quality education Professor!

[@shawnwillsey]

Awesome news. Glad to know that my videos have helped you learn.

[@altheacraig2904]

I know about it because a Geology Professor at Washington State University in Ellensburg, Washington named Nick Zentner has taught me all about things like plate tectonics and a lot of other things. Also that Yellowstone is a HOT SPOT just like Killowaya in Hawaii!

[@conniead5206]

That would be Central Washington University (CWU). I have learned a lot from Nick Zentner too. He makes Geology interesting.

[@angelalewis4213]

@@conniead5206he does, but so does Shawn!

[@naoakiooishi6823]

Thanks, as usual. and I personally want to know more about Colombia River Basalt as it was related to "basin & range" expansion mvement

[@altheacraig2904]

Ask Nick whom I mentioned a few seconds ago

[@stephenmorton8017]

excellent. thanks 'heaps' for the overview.

[@ahmedkunbargi8096]

Oh hell yeah. One of the few channels i got notifications turned on for. Thank you Shawn! You are goated.

[@shawnwillsey]

Awesome! Thanks for being a fan of my georamblings and geoventures.

[@cribbsprojects]

Explosive potential also relates to the amount of water present... Great explanation of the varied igneous geology, eruptive lavas we find in this location as well as, say, the San Francisco Volcanic Field further south.. Keep up the good work. Your videos spread the geo knowledge far and wide... in the same way that the Roadside Geology books have done for so many years.

[@shawnwillsey]

Thanks so much And as an aside, I co-wrote the updated and recently released Roadside Geology of Idaho. You can get a signed copy here if interested: shawn-willsey.square.site/

[@BoltonLass]

A very informative and interesting video.

[@Riverguide33]

Thanks for the vid…and the great illustrations. 👍

[@shawnwillsey]

Graphics are from my book, Roadside Geology of Idaho.

[@lars277]

I once watched a show or a video about how the Yellowstone caldera volcano actually started down by Sacramento, CA, then each successive eruption it moved northeast to its' present location in Yellowstone. They said there was at least 12 eruptions that they could verify by satellite pictures. We are talking about 40 million years that it took to get to its' present location.

[@papadopp3870]

That is an amazing story. Of course, for folks just getting into amateur geology, the hotspot didn’t move, the track we see today is the track of continent moving over the hotspot.

[@emilu5425]

Thanks for this most illuminating lecture on what most of us just pass by, without reflecting the least what the rocks might tell us. Prime enlightenment.

[@johnzinkowski6834]

Terrific presentation; clear visuals, enthusiastic explanation of technical details, and your pacing was perfect. As a novice I had no trouble following along. Thank you.

[@mattbillenstein]

Very good sir - as I pass through these areas in the west, I very much like understanding a little bit of the geology and topography.

[@brookeshaffer4377]

Thanks for a great show Shawn.Much appreciated.

[@shawnwillsey]

You bet!

[@BowlesTroy]

OK Shawn, I'm hooked. I find myself watching certain videos over and over again, sometimes 3-4 times so that I can: 1. Get all of the information in the first place. 2. Look again with new eyes after getting more information that you've given elsewhere. You're a stupendous educator. Aristotle would have been impressed.

[@shawnwillsey]

Many thanks. Glad you enjoy.

[@michaelgraham6682]

Hi Shawn thank you very much for this video and the one on Upper Mesa Falls. We are travelling from Ireland and will staying in this area in about 10 days time. The content is perfect for what I am aiming to see while we are here. Thank you for all your efforts posting the videos they are fascinating. Take care

[@shawnwillsey]

Awesome! Enjoy your travels. I highly recommend my books, Geology Underfoot in Southern Idaho and Roadside Geology of Idaho, as handy companions to help you find and understand the geology as you travel. Let me know if your travels bring you through Twin Falls.

[@michaelgraham6682]

@@shawnwillsey Thank you Shawn appreciate it, I sent you a quick email

[@d.gregorybrown7779]

It is so cool that the pyroclastic flow stopped before crossing the road. Great video.

[@shawnwillsey]

Glad you enjoyed it!

[@quill444]

Yes, roads built in the past few hundred years form excellent boundaries, often strong enough to prevent any lava from half a million years ago from flowing over them! - j q t -

[@d.gregorybrown7779]

wow, modern engineering solving problems happening hundred of thousand of years ago, life is good@@quill444

[@harleyanne3720]

@@quill444😅

[@torchiertorchier2273]

hahahaha

[@mistysowards7365]

Glad you did this. Not a lot of videos on the older eruptions. Thanks

[@schitz240sx]

I just did a road trip out to Yellowstone. Part of my trip was on US 20, its awesome to watch this video.

[@torchiertorchier2273]

Whenever I want my students to have an existential moment of their own insignificance, I find talking about the Yellowstone supervolcano far more impactful than meteors or the sun going nova. It seems so imminent! Thanks -- so helpful (and easy to listen to). I'll come back (I too, toured Yellowstone before we really knew what it was) and you can lead me on a tour. :-)

[@sarahb.6475]

I never would have guessed that the light loose "fluffy" ground / sandy looking stuff was ash! I would have presumed it was just dry old loose "dirt" (soil) of some type. And I have heard of pumice before but I had no idea they could be so big! Great video!!

[@shawnwillsey]

Thanks. FYI-in my world, there is no such thing as "dirt". There is soil, sediment (sand, gravel, silt, etc.), rocks, and minerals.

[@leor9252]

I learned more from this video than i ever did in geology class in school.

[@shawnwillsey]

Thanks for watching and learning with me.

[@gregrussell7704]

Excellent video Shawn, that is where we're planning to explore.

[@shawnwillsey]

It’s an amazing area.

[@sheilatruax6172]

Professor, thank you for your time. I am much more familiar with composite cones,Vesuvius, Eatna, the Peruvean peaks, Popcotapetl, the Cascades, etc. The hot spot shields are only familiar through Hawaii,and, now Iceland. Thank you for your updates on the activity in Iceland. Between you and Gylfi , I think I'm getting the whole picture. I learned from Prof Zetner, in Washington, about the successfully older calderas that track across to CA. And then a few slightly north. These are so interesting, I can't get enough!!

[@booshday]

I've lived in southeast Idaho for over thirty years and your videos are awesome and have taught me so much about the geology of the snake river plains and surrounding areas. I would love to see a video on the hells half acre volcano area in-between idaho falls and blackfoot.

[@susannell544]

You did a very nice video ....a first time for me that you included all three! Bravo👏💕

[@brittshepard9317]

Thanks, looking forward boondocking there and watching your video and reading your book.

[@lisaloy2011]

One of my favorite videos that you've done.

[@shawnwillsey]

Wow, thanks!

[@6806goats1]

Thank you for this. I own a home near Blackfoot but I work overseas most of the time. Always good to learn about the area. I’ll be glad when I move back.

[@jjensen551]

Thanks!

[@shawnwillsey]

Hey, thanks so much for your kind support.

[@micheleupchurch3725]

Thank you!❤ You always have such great information and on site!

[@drmichaelshea]

Thank you, Prof. Willsey.

[@shawnwillsey]

You are very welcome. Thanks for your kind donation.

[@jadesea562]

👏👏👏👏❤️my mind couldnt have been more excited about the thorough diagram description and explanation!! ✨️🌟thank you!!

[@shawnwillsey]

Glad it was helpful!

[@chasdegeofroy3091]

Very interesting the way you described the deposits of Pumice and the way the Caldera Forming eruption took place. I was in New Mexico this Spring and spent a lot of time in the Valles Caldera looking at the Resurgent Dome that Caldera and the Welded Tuff of the Bandelier National Monument fascinating.

[@jakelbies]

I live in Ashton - so cool to understand why the rock and soil looks like it does. Thanks for the info!

[@shawnwillsey]

You bet!

[@rjthurston5871]

thanks for a great video, also i really liked the paypal method of donating --this is the 1st time i have seen this type of method for supporting a you-tube channel, nice method, much better than patreon.

[@shawnwillsey]

Thank you for your kind donation. I agree that the PayPal link is simple and effective.

[@noeljohanson1979]

Outstanding Presentation!!!

[@causewaykayak]

Yet again we get a lesson in How to look at everyday landscape. Roadside geology is a good name for this. Book sounds intetesting ... must find out if it ships to Ireland

[@lilidiaconu9910]

Mr.Willsey i love your videos.Thank you,no matter haw old you can learn,my father used to tell me you cam learn from a5 years ,30,40 70 matter the age just pay attention.thank you.Lili.

[@joseangeltorresespinosa7997]

Excelente video didáctico, acerca de la petrologia en la caldera volcánica en el campo, esperemos más vídeos de estos fenómenos naturales, saludos desde México.

[@shawnwillsey]

Gracias amigo. Encantado de que disfrutes de los videos.

[@d2sfavs]

im really beginning to enjoy your videos so fascinating the size of volcanoes

[@paulwestenskow7302]

Professor Wolsey! I don’t know if you take a request to do Geology shows,! Have you ever considered doing a program that would cover the Geology around in and Pocatello? Could you explain how we got the lava bed in Rosses Park? Could you explain, possibly what it was like when the Bonneville flood came in and went out the Inkom gap, what is the geology of scout mountain, and how that formed? I thought it was a volcano by shape just an idea for you. Thanks again for everything.!👍

[@MyMemphisable]

Thanks!

[@shawnwillsey]

Thank you for your kind donation. Much appreciated.

[@evandean3944]

Hey Shawn, could you help me clarify how much ash a cubic mile is? Like, what density is the ash considered? Is the volume measured/estimated at the density it leaves the caldera during the eruptive process, or soon after it's airborne, or once it's in the stratosphere? It seems like it is going to be a lot less dense once aloft, and a single cubic mile of ejecta could be many in the sky. The unit a cubic mile, when applied to something that's changing from a burning solid into an aerosol, is confusing for me. Can you elaborate? Thanks!

[@shawnwillsey]

Good question. I believe these estimated volumes are erupted ash volumes (uncompacted).

[@kathiwright4849]

shawn - do you have videos ( or maybe covered in one of your books?) - about the river canton around malad? the dark blocks of rock above the river are stunning formations. this was a great vid, by the way. i never knew there were 3 separate calderas

[@noeljohanson1979]

The Hot Spot has never moved, it is plate tectonics that has carried the older erupting sequences into No. Nevada and Eastern Idaho. Future areas that will erupt over the Yellowstone Hot Spot are now in South Central Canada….NE Johanson MD

[@daveisnothere]

The crater I am curious about is one I found while looking at google maps a few years ago. It is located just south of Blackfoot, ID at [ 43.104994, -112.343015 ]. If you look at google maps, either with the satellite view or terrain view it is obvious. I figure it was part of the Yellowstone Hotspot migration from about the same time as the Picabo Volcanic Field era.

[@altheacraig2904]

See the comment I made just a few seconds ago about Nick Zentner and his talk about Yellowstone and the one in Idaho. He is worth watching!

[@marchcyr1811]

Cool thanks for the short lecture, Hope your book goes well,

[@robertmeyersMeyers-cm9fy]

You’re a rockstar! Great video, thanks for posting.

[@shawnwillsey]

You can support my field videos by clicking on the "Thanks" button just above (right of Like button) or by going here: www.paypal.com/donate/?hosted_button_id=EWUSLG3GBS5W8

[@sraiken]

Love geology. Excellent lesson, thanks

[@vickihubach4388]

"you knew it was going to be a rough day" and your "superhuman grip" made me laugh out loud! loved it, thanks!

[@vickihubach4388]

(just got your book)

[@shawnwillsey]

Glad you enjoyed it!

[@WayneTheSeine]

Absolutely amazing the story this material tells if you know how to read the book. I love the Island Park area....gorgeous place. They have great, world class fly fishing. I did notice that the invasive mullen plant has managed to eke out a living there as well. What a tenacious plant.

[@raymondimbro2769]

Very interesting and well explained

[@Bigandrewm]

Concerning that last stage of the caldera eruption being basaltic flows: because the ash and tuff from the explosive eruption haven't been buried by basalt at the Henrys Fork Caldera, does this mean that there are still some forthcoming basaltic eruptions that can happen there?

[@shawnwillsey]

Absolutely. The Pinehaven flow by Mesa Falls is only 29,000 years old and there may be younger ones (don't have map in front of me at moment). Future eruptions of basalt are very possible (and more likely than an explosive ash eruption). If this occurs in my lifetime, I'll be there!

[@sarahb.6475]

"You'll be there??" Won't it instantly incinerate a whole bunch of people ? You'll be the only one running towards it. Sounds dangerous. I have heard there is a spot directly above the magma chamber in Idaho that keeps getting earthquakes.

[@kayakingirl7252]

O M G, I'm a beginning, self- taught geology lover. I'm so happy I found you! I'm headed to some family property on the Sun River, outside of Augusta, MT. I'm so curious about this area. Do have any good resources for me to check out so I can be a bit more informed? Thank you so much!!!

[@shawnwillsey]

Maybe look at some published geologic maps or just Google things like "Augusta Montana geology" or "Sun River Montana geologic guide". Here is one thing I found with a quick search: pubs.usgs.gov/pp/0663b/report.pdf

[@Toasterleavins12]

This is such a great video, thank you!!!!!!

[@theoneyoudontsee8315]

this is awesome thank you Shawn!

[@sgtpepperz25]

Great explanation, thank you!

[@ActinOut]

Better than my earthquakes and volcanoes college geology class.

[@m.j.mateyka7350]

I lived inside the caldera for four years when stationed at the Island Park Ranger Station. The whole area was geologically interesting. I put up a timber sale along Thurmon Ridge which is the common edge of the Henry's Fork and Island Park Calderas. (It was a salvage sale that harvested trees killed by a mountain pine beetle epidemic that stretched from Montana to the escarpment North of Aston.) There had been a salvage sale in the area that harvested over a 1000 acres of wind thrown trees. They were blown over by hurricane force wind in the lat 1960's. My wife had a plastic raised relief map that really showed the calderas. (Ashton, ID 1 in 250,000) The Moose Creek Plateau basalt flow covered much of the Island Park Caldera all the way into Idaho. There was a huge obsidian outcrop along the Fish creek Road. Locals said that Native Americans came a long way to get the obsidian for projectile points. You should do a video on Upper and Lower Mesa Falls on the warm River that are exceptionally scenic.

[@m.j.mateyka7350]

Oops. Just got further down the list of your videos and see that you have one on Upper Mesa Falls.

[@shawnwillsey]

Thanks!

[@noeljohanson1979]

Excellent!!!! Discussion!!!!

[@BretBerger]

A family member has a home on the hill above Ashton, adjacent to Highway 20. His basement slab shattered after a water pipe leak beneath the slab. I guess the tuff/ash has hydro-expansive properties?

[@shawnwillsey]

Hmm, older ash layers might do this if ash is altered to clay and prone to shrink-swell. I doubt these young ash layers would expand much in water

[@HollyLewallen-Smith]

Thank you so much for sharing your research with the World. ❤🌎🌏🌍. Love ❤. Shared ❤. Saved on KZbin ❤.

[@susannell544]

I saw a video from a Professor in Washington State that did a video. He explained that it was actuality in Washington State and moved to where it is at now. The Caldera is 30 by 45 miles.

[@loisstanford8736]

Fascinating ❤

[@TrainLordJC]

Excellent presentation again. A question came to my mind about the huge eruption of 2.1 million years ago? Was the planet at the time of that eruption already in this current Ice Age or could this eruption have dropped temperatures so much to influence the Ice Age, or do you think that it has nothing to do with the current Ice Age that we are in? Or did this Ice Age start as a result of North America and South America joining up around 2.5 million years ago thereby changing the Thermal Haline current and helping to start the Ice Age?

[@LizWCraftAdd1ct]

Yellowstone is fascinating.

[@cacogenicist]

I'm curious how the previous magma chambers sort of migrate away from the current ones, as the NA plates moves -- are there discrete chambers, or a continuous line of increasingly crystalized felsic rock (in the case ofnthe upper chamber) extending to the E-SE of the current partially molten chamber?

[@johnnash5118]

Hi Shawn, How do you explain the deviation of the West Snake River Plain from the YHS track? The WSRP continues West across Oregon’s High Lava Plains, with a string of calderas aging from East to West and ending at Newberry Caldera. The aging is the opposite of the YHS. Is that caused by slab rollback or perhaps a rift associated with the B&R extension?

[@shawnwillsey]

You read my mind. Planning a video on this very topic. Can I keep you in suspense longer?

[@shawnwillsey]

Also WSRP does not tie into high plains volcanic field in central idaho.

[@lawrencet83]

I'm curious, to the best of your knowledge when do you think the next eruption of any kind will and where might occur in either Idaho, Wyoming. or any other of the lower 48 states?

[@shawnwillsey]

It's anyone's guess. Most likely would be a Cascade volcano eruption, possibly St Helens, Lassen, or South Sister. Another eruption at Craters of the Moon is likely. Less likely is the huge Yellowstone eruption that folks get super worked up about.

[@Davidbirdman101]

Hey Shawn, what are the chances of this thing going off anytime soon?

[@shawnwillsey]

An eruption of basaltic lava is possible and much more likely than another explosive, caldera-forming eruption. Chances of either happening within out lifetime is quite low.

[@stevenatkinson7443]

Have you ever taken the Fish Creek Road out to the East of the Warm River. I was up there last summer and found some really neat rock. Black but not obviously basalt with small bubbles coated with ash. They were in a rock scree right off the road. Watch out for bears though.

[@RomoRooster]

What's cool is because the north American plate is moving east, there should be old Yellowstone caldera's dotted all the way to oregon

[@SM4724_]

Have you been to the crater rings near mountain home? Looks like a cool area near I84

[@shawnwillsey]

I know of it but haven’t been yet.

[@candui-7]

Nice rhyolite columns @ 11;30. Does that mean slow cooling?

[@3xHermes]

Well done thx!

[@martinwhalley3286]

Now, what have you confirmed about the former Farallon tectonic plate (now remnants are Juan de Fuco). I heard that the bottom of the Yellowstone caldera meets the mantle lava separated by the plate.

[@Michael-rg7mx]

All 3 eruptions were during the Ice Ages. I wonder if pressure flexing the plate had any effect. A few quadrillion tons of ice may have just squashed it.

[@Redfour5]

I could argue with you but it would be semantics in that it did occur in Yellowstone National Park...but due to plate tectonics, the National Park literally moved east over time. In fact, human verbal/written designations are of no consequence except to provide a frame of reference for humans. The Hawaii island chain including many now under water is a result of the same plate tectonics. Go look at Google maps and the undersea items and look west at the underwater "mountains." AND, the next islands are already forming east of the Hawaii islands. But you would have to believe in things like evolution, earth is a globe and not flat and the fact that the earth is billions of years old and I know that's pushing it for many people. Great video actually. I'm just a grumpy old man.

[@conniead5206]

Actually, the continent has been moving kind of southwest over the hot spot for at least 16 million years. The oldest caldera from it is in northeast Oregon, if I remember correctly. There is debate over its origins. Did it used to be in the Pacific and got added on when our continent ran into a huge mass or did it pop up independently. The basaltic land mass did not subduct. About the time when the first caldera was formed a heck of a lot of lava started bleeding out from fissures north of there. Covered lots of Oregon and Washington under up to 3 miles of basalt before it stopped.

[@briane173]

@@conniead5206 There's an operating theory (more of a hypothesis in the absence of direct evidence) that the Yellowstone hotspot was under the Pacific and was at least partially responsible for the formation of the Siletzia terrane. It's now thought that Siletzia didn't run into North America, North America ran into Siletzia; and that once it was docked to the continent the continent just continued to ride over the stationary hotspot. The most interesting part of this process is that the first caldera formed in NE Nevada/SE Oregon happened almost simultaneously with the hundreds of fissures that began opening up just west of the craton margin, which are responsible for the CRBG. I have to think that to some degree, Basin & Range extension had _something_ to do with the hotspot feeding basalt magmas erupting from the fissures; but the fissures in the Blue Mountains and eastern WA aren't impacted by Basin & Range extension, so I consider it a happy accident that these fissures in eastern WA formed along the suture between the NA craton and the series of terranes that docked there. Since the fissures north of the B&R are lined up north of the axis of the clockwise rotation and WA is more or less being squeezed between the Oregon block and Canadian Buttress, those fissures might have gotten some help forming out of the squeezing process -- kinda like opening up a coin purse -- the soft plastic ones with the slit that opens wide as you squeeze the ends. Just me spitballing as a hopeless geology nerd living in WA. I'd love to follow how these ideas take shape over time; Basil Tikoff and others are working on this problem as a consequence of their search for the mystical "fault line" along which "Baja/BC" might've taken shape.