Southern Idaho's Balanced Rock area records an explosive and nonexplosive volcanic history
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- Опубликовано: 17 окт 2024
- Geology professor Shawn Willsey explains the fascinating story of two volcanic eruptions near Balanced Rock, a scenic attraction south of Buhl. This area near Salmon Falls Creek canyon records evidence of two contrasting eruptive styles, nonexplosive eruptions of pasty rhyolite lava and huge, explosive eruptions of ash. These eruptions occurred about eight million years ago as this part of Idaho moved over the Yellowstone hot spot.
You can learn more about southern Idaho geology by purchasing Geology Underfoot in Southern Idaho and Roadside Geology of Idaho. Both available locally or on Amazon.
GPS location: 42.54496, -114.95411
I love doing these videos and will continue to do so but if you want to provide support or much appreciated gas money, you can send support via:
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Shawn Willsey
College of Southern Idaho
315 Falls Avenue
Twin Falls, ID 83303
Fascinating. I’m now 70 and sadly regret being a turd in science and history classes as a kid. I think that had teachers had the internet in the 60’s I would have been motivated to study earth sciences. Great delivery and pretty awesome props (walking a highway in southern Idaho)
Thanks for watching and learning with me, Don. You're never too old to learn cool stuff. And yes, the current era of Google Earth, awesome graphics, videos, animations, etc certainly make my job as a geology professor much easier and more exciting. The hard part is keeping up with all the technology. Stay tuned for more videos soon.
I’m 66 and so wish I’d have known geology younger too… I’d have studied geology and archaeology wish I’d have had this passion then 😊
I've been living in the Northwest for a year and a half. The variety of rock formations and scenic landscapes has inspired me to learn more about geology. If I grew up here, I'd probably have become a geologist. Thanks for your videos, they are very educational.
So cool you are psyched about geology (better late than never) and geology as a hobby is great too. Thanks for watching.
After watching the video then reading the comments and your replies I'm struck by how much like a class field trip this is. I had a botany minor. We would take field trips. On those trips I learned as much from other students questions and the professors answers as I learned from lectures and the textbook. Today the questions in comments and your responses have added a lot to my experience. Thank you for taking the time to answer and explain!
I took 2 geology courses. Super fascinating stuff. It's really wonderful to hear a guy who's a real geologist explaining the landscapes. Brings the textbook material to life 😊
I grew up in Jerome and was essentially blind to the geology then. I moved to Lewiston in the mid 90s and after a few years began to notice all the different rocks. In the last couple of years I've really become interested in geology.
I would go as far as to say I've got the "geology bug" in the last couple months. I see all kinds of different rock formations when driving around and it is just so amazing. Thank you for providing all this information, especially from this area!
You bet and thanks for watching. So glad to hear you've got the geo bug. It's a good thing to have. Have fun looking through all my other videos and look for more new ones this spring and summer as I travel to Utah, Idaho, and Arizona. Be sure to subscribe. You might want to also check out my books: Geology Underfoot in Southern Idaho and Roadside Geology of Idaho. These will serve you well as you travel and explore.
@@shawnwillsey what I think is so funny is I hated anything to do with history in my early years. I've been a respiratory therapist since 1994 and absolutely love what I do. However, if I knew what I know and see now... Geology/Paleontology would be my desire.
I'm willing to learn and expand my hobby of the history of rocks.
@@AKUSUXs Geology as a hobby is a great choice. Keeps your mind and body active.
Totally awesome. I am a fan of Rhyolite and I really enjoyed this excursion. I was happy to learn from you that the toothpaste flow and the Ashfall material can actually look the same. One mile thick, that means it must have been a whopper of an eruption.
Indeed. A massive eruption. Differentiating rhylite lava flows from rheomorphic ignimbrites (hot pyroclastic flows that remelt) can usually only be done by microscopic analysis of rock to look for flattened pumice fragments.
So many forms of rhyolite in one place is interesting. I've heard from you and others info about rhyolite. Seeing the different forms it takes in one place along with the story of how each one formed is good. It helps me understand each type and the ranges of formation better. This illustrates how different influences of each eruption affects the final appearance. For me bits and pieces I've learned are making my understanding better of rhyolite. Thank you!
Amazing geology in Idaho so varied.. thanks Shawn
I find I'm learning so much Shawn. As soon as I saw the red layer, I thought that's paleo soil - a word/concept I picked up from one of your other videos. Welded tuff is another.
Awesome. Knowledge is power. Great to hear.
Shawn, If I understand the rhyolitic ash that was so hot when it settled on the ground it created the baked paleosol, all came from pyroclastic flows, right? It would be impossible for ash shot 10,000 to 40,000 feet in the atmosphere and still be hot enough to melt or bake the soil below it when it finally settled, right? That was an excellent video, you have an amazing mind. Thanks...
Great question. The initial eruption produced ash that blanketed the local region. This wasn't necessarily ash from the eruption column (directed vertically and pushed high into atmosphere) but likely ash blown out of vent. This is the white layer in the video. The red oxidation from the paleosol may be partly from the heat of the ash but also partly from the older brecciated rhyolite lava flow below oxidizing when it oozed to the surface. Hard to tell how much of each produced the red oxidation.
@@shawnwillsey Thanks for helping me understand the ash deposition more clearly. New subscriber here!
Thanks for another incredible presentation. Did you walk up on top and see all those rock structures that someone has stacked?
Thank you. Up above Balanced Rock? I didn't go up on this visit but have on others.
I have. Nature vandals are truly a sick breed.
Love your vids. I live in geologically boring Louisiana and your vids let me see neat rocks I never would normally.
I noticed on Google Earth the Snake River plain looks pretty flat through the Rockies in Idaho that pretty much parallel the hotspot path, and I recall an article in NatGeo about the Yellowstone hotspot that 'Volcanoes build mountains - super volcanoes erase them.'
Fascinating geology Proffessor, thank you!
Hey, Shawn! When things die down in Iceland, would you (or have you) make/ made a video of the different types of volcanoes? I’ve tried watching a few on RUclips but none compare to your videos and expertise. I find volcanoes fascinating (as long as no one loses their life or home). Thanks!
Four years ago I went out west for the first time and visited 32 National Parks. I wish so much that I had had a travelers guide to the geology of the places I went to, which included lava flows in South Idaho. I had no idea the whole west was so volcanic so recently. Please write that geologic guide to the west and the national parks. Im a first year geology student who fell in love and have traveled the world wishing I knew more!
Two books I wrote or co-wrote that will help you are Geology Underfoot in Southern Idaho and Roadside Geology of Idaho. This should help considerably. Enjoy!
Really fantastic videos. Thank you. Keep them coming for us geologist wannabes.
Hi Shawn, thanks for the great video. Are you familiar with the area in southern Wyoming named Vedauwoo? Absolutely amazing formations. Was that area formed in the same way? There is very little noticeable stratification, at least to my eyes. The rock is mostly reddish -pink and very gritty like sandpaper. Thanks.
Thanks for watching. Yes, I know of Vedauwoo. As a long time rock climber, this is a classic location. The rock type there is granite and it is 1.4 billion years old. The stratification you noticed is actually fractures which formed when the magma cooled and crystallized. The color of the rock is due to the abundance of potassium feldspar, a pinkish mineral that forms small squares and rectangles in the rock.
Other than heaping on more platitudes to those below, I can only add one more exclamation of WOW. What a great way to start my day.
Excellent job well done. I can tell you are in shape to walk fast and talk fast
Ha! Thanks. It never feels like I'm in great shape but I do try.
Do we know where the eruption/ground zero was?
Great question and I should have included this information in the video. The source of the huge, explosive supervolcanic eruption is the Twin Falls volcanic field, a poorly defined region up to 40 miles in diameter around the city of Twin Falls. The Kimberly borehole (mentioned in video) intersected an amazing 1.3 km thick, unbroken succession of the same rhyolite which erupted as super hot pyroclastic flows. This same unit is found in the Cottrel Mountains near Albion and the Mount Bennett Hills north of Gooding. Combining this data provides an estimate for the volume of ash erupted, making it as big or possibly larger than the largest known Yellowstone eruption (about 2.1 million years ago). The eruption likely produced a caldera which may have ponded the ash, accounting for the thickness found in the Kimberly borehole.
@@shawnwillsey Thank you for this amazing information of the area. I was born/raised in Burley Idaho and had visited ALOT of the areas you discuss. I wished I knew this as I would appreciate it even more. Guess that makes a re-visit necessary... ha
@@RBOWWOW Indeed. Come on back and enjoy it again.
interesting story Wilsey always wanted to know how Balanced Rock was formed. Everyone knows Balanced Rock I went here for the first time in 4th grade later I camped her and did some dutch oven in the park.
Did the Yellowstone hotspot produce the final cataclysmic eruption? Alternate wording: Was this part of Idaho over the hotspot 8.1 MYA?
Yes, these rocks and deposits were produced when this part of Idaho was above the Yellowstone hot spot.
Amazing! A volcanic eruption of this magnitude could have affected the entire planet, or so I think.
I want to watch another one but my wife is telling me to get up and go to work !
Ha! Plenty of time later. Glad you are enjoying catching up with these videos.
The Paleosol is likely to be red also due to the extreme age of the soil, having developed into an Oxisol.
Did the area have a tropical climate when that red layer was formed? Oxisols develop in tropical climates typically.
Balanced rock looks like a chess piece, specifically the knight.
Do you have a lab at your school that can date ash?
Hi there. No CSI does not have any instrument to determine isotopic ages of rock. These pricey instruments are usually at much bigger universities like University of Utah.
Because of the earthquake in San Francisco, which knocked dishes off the shelves in my great-grandparents house, Orlando Calhoun, mu great-grandfather, got some ranchers together to put a cement collar around the base of Balanced Rock. They thought it would prevent it from falling over. Guess it might have worked, if it had not eroded away. LOL This rock is in my very Soul.
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a mile thick !