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I'm a long haul truck driver who lived all my life in Florida. I love long runs out to the Northwest seeing all the beautiful landscape and rock formations. I love channels like this that explains how and why cuts in the earth and mountain ranges are the way they are. Thank You for taking the time going out to these locations and explaining to us that most of us will never get a chance to see.
By coincidence, "Practical Engineering" dropped a video today on rivers, and it makes a nice companion to this great video. I'm kind of humbled by all this, I had no idea how geologically dynamic Idaho is.
Thank you Shawn! I have wondered about that canyon for close to 50 years. I had no idea about Lake Idaho that explains the soil around Mtn Home. The soil turns to gumbo and dirt roads are virtually impassable when it rains. I was stationed there in the early 70's and have friends we like to visit which still live there. The USAF bombing range is along that same road. I spent many hours out there. For those interested, the overlook area has a trail with a fence so you don't have to go to the same spot as Shawn. The views are awesome! I watched a hawk soar in that canyon. Can you imagine going down into that canyon?
Great video as always professor Shawn, I think you, professor Nick, and Myron Cook are really putting out good content for the common person. Also watched your recent talk on The Geological Society of MN channel, great presentation on there
It is good to re-watch your videos. The first time I learned about Lake Idaho from you. This time, after all my months watching, my focus and understanding was better on your canyon cutting lesson. My geology knowledge has been growing from you, from Prof. Zentner and from Dr Cook. Now I grasp not only the cutting here in Idaho better and my understanding of the cutting of the Yakima River in Washington. I see now that the rivers you talked about today in Idaho are cutting down from gaining a lower base. I have learned that the cutting on the Yakima is from the uplift of the mountains at it's headwaters and along its length. I'm glad my understanding is growing. I thank you for your continuing teaching.
So uplift intensifies erosion :) Thank you for doing these Shawn, they are fantastic! Really enjoy these types of explanations and clarifications with "on location" examples to associate a concept with a real local place.
We can only repeat what others have said. Great video, wonderful explanation of geologic happenings. You are a great teacher. Thank you so much for these field trips.
think also that in the steeper gradients he's talking about, the force of gravity is not only moving the water fast downhill, but carrying sand, pebbles and even boulders along with it that really give the scouring needed to carve out the canyons, not just the water itself. Its also true in glacial valleys, the bottom of the glacier had rocks frozen in it with thousands of tons of ice above pressing down as it moves down the valley. That's one hell of a powerful scraper.
As always, you are an excellent teacher - thank you! I also thought that you were at Black Canyon of the Gunnison, Colorado at first! 😀 It would be interesting to compare the geological dynamics in its formation with this one.
@@shawnwillsey I will have to watch that! I camped near the rim of the Black Canyon once, it was an unforgettable sight. Thanks for your interesting videos, I really like the way you present the information. You had me confused at first on this one, when you said you were in Utah though! 😸
@@shawnwillsey Great, I will have to check it out. I love the Black Canyon. My wife and I watched two guys climb the shear wall. Even with powerful binoculars they were so small. It really put the size into perspective. They hung hammocks under a parapit right at dark. About 2:00 am it started sleeting very heavy. I could not sleep worrying about them. At the crack of light we raced to the overlook and low and behold...they had climbed out, apparently during the night. The pegmatite bands running through the walls are a beautiful sight.
More great story telling in deep time, thanks! It gives me the heebie-jeebies to see you perched out on what looks like a tiny point like that, though. Yikes, do I hate cliffs.
THere are marvelous flatlands to inhabit on the other side of the Rockies. Of course, having been a periodically desired belay-slave to Big Wall climbers, some of whom mention that days on vertical and overhanging cliffs make horizontal landscapes seem abnormal, I no longer venture into the horrible, terrorizing flatlands of that unrelieved millions of square miles!
@@shawnwillsey I'd be surprised if that covered the gasoline costs for you to get there. We should be thanking you for all the time and effort and thought that goes into these. Thanks again!
@@StereoSpace I appreciate whatever folks can provide. It all helps defer some of the costs. Ultimately, I just really enjoy sharing these places and stories with folks.
I found out local stream runs along a fault in our village. You made me dig deeper and now I’m going to find physical evidence. Thank you Shawn I’m loving this journey
That's an awesome place. I did a brief video there when I was just starting this channel: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-4Z-ux8_PB84.html
One of his other outdoors hobbies is rock climbing which generally speaking is always conducted on the edge, so for Shawn it better not be all that concerning as long as he keeps his safety close to mind.
There is a famous picture of Alex Honnold on Thank God Ledge, Half Dome, Yosemite taken by Jimmy Chin and used as the cover of the May 2011 National Geographic magazine (all good to google up). I use that image to reinforce a metaphor of life through the phrase "upon this (l)edge we are". In life straying just small amounts can measure the distance between safety and extreme to fatal danger, nearly always due to a momentary lapse into (or worse habitual) careless inattention. And so another phrase that can arise is "to the summit, or perhaps to plummet" and "be safe out there" and "be trained and use the proper PPE".
I have struggled to understand how and why rivers will cut thru the basalt, especially in the Columbia River Gorge. The gradient! Now I'm one step closer to understanding these deep gorges in the hard basalt. Thank you!
I have always wondered if the canyons south of Lake Mead were carved or fault canyons, similar the the Rio Grande Gorge in New Mexico. This was an excellent explanation of rapid erosion of canyons. Thank you.
Hi Shawn, I just found your channel about 10 days ago and truly enjoy the content (especially that you’re out at the sites, whilst explaining the processes showing physical examples/evidence either with actual strata or rocks and even your diagrams).. You have rekindled my intrigue in such landscapes that I haven’t had in over 30 years.. I am subscribing right now.. I unfortunately don’t have the funds to become a patron at the moment, but do intend to send you something as your videos provide me much enjoyment and I would think anything would help with the costs of driving all over the country.. I honestly had NO idea Idaho was such a geologically diverse state.. I do have a question if you can answer it.. As shown in the steepness of the canyon, you can clearly see the multiple layers of basalt flows (I don’t know how you date these flows, possibly charcoal embedded in the rock layers?), was the river continuously flowing at the time of some, all or none of these these flows? Just curious as I don’t believe you mentioned that. Thanks again for all your hard work, Tom
Hi Tom and welcome aboard. Hope you enjoy my content and teaching style. Any donation is appreciated, but certainly not required. I just love sharing geology. Idaho is awesome for geology and a good location for me to venture farther as well. Basalt layers in Bruneau canyon are mainly dated using other isotopes (not Carbon-14) such as Argon or Uranium. The lava-river relationship is complicated (like so many relationships). In general, its safe to say that the basalt layers are older, but in some instances, the lava pours into canyon (being the lowest point around), plugs up river and fills canyon, diverts elsewhere, and begins to downcut a new canyon. Tricky but fascinating stuff.
Great presentation Shawn, How far is this from the caldera of the same name? Without seeing more, the layers look like flood basalts, is it related to the CFB formation? I read that there are two types of basalts there; the range in compositions for basalts within the BJ eruptive center samples are consistent with basalts of the eastern Snake River Plain, and Basalts which erupted outside the BJ eruptive center are higher in Ti, Fe, and have much higher (La/Lu)N ratios, similar to basalts from the Western Snake River Plain.
Fascinating. Thank you for the review of river canyons. I really appreciated it. Had forgotten all that. Question: were any of the flows at the bottom from the Yellowstone Hotspot ?
It is places like this ( call it the canyon making standard) that made people not to believe for quite some time that the scablands of eastern Washington could have been created in just a couple hundred years when this canyon making took millions of years! As for ancient Lake Idaho it would be a great to cover in more detail professor since it existed for so long then drained away via the Snake River almost way too quickly thanks to vulcanism and crustal stretching. Maybe even cover Lake Bonneville and Lake McKinney with it to make the explanation as to events leading to their loss. Beat professor Cook to it! LOL
I didn't know about Lake Idaho. What created the lake? 3MA, hmm, I don't think that was a time of glaciation. I can see I need to learn more about NW glacial periods. I believe the last was 17 thousand BP. Another question that comes to me is how long did it take to form this canyon. Did take 3 MA years to form. Or was the formation catastrophic? This is an amazing canyon. Deep narrow canyons fascinate me. I've written down these places to look further into them. Thank you for an amazing view.
The lake filled the Western Snake River Plain, a low area bounded by faults and uplands during a period when the climate was much wetter. Lake Idaho (or at times, a series of smaller lakes) filled these area intermittently from 10 to 3 million years ago.
You mentioned in the beginning of the video that Bruneau Canyon is in Southwest Utah and, since I live in SW Utah, I was unfamiliar with such a canyon. So I figured that was an opps (been there done that!). But funny thing, Bruneau Canyon looks very similar to Timpoweap Canyon, which the Virgin River dug out between the towns of Virgin and Hurricane. Along the edge of Timpoweap is the Virgin Cracks, which as a geologist, you ought to check out the next time you're in this neighborhood. It's like a miniature example of plate tectonics.
Yep big oops right off the bat with the Southern Utah (instead of Idaho) intro. I'll add this place to my list. I should be in SW Utah this fall. Thanks!
@@shawnwillsey like I said, I've done that once or twice on my videos. Too bad RU-vid doesn't easily allow us to re-load corrected videos. I create videos with similar topics as yours, but more in road trip fashion. Whenever you plan on getting out here, I'd be happy to give you a tour of Timpoweap.
A vid on Black Magic Canyon would also be awesome if your ever near there. I have learned so much from you and your book Road Side Geology thank you very much!
It's very much like one of the old techniques for cutting glass, whereby you run a string charged with an abrasive (like carborundum) over a glass bottle.
Another way narrow canyons form is fault lines. If you look at the maps of the Appalachin mountains you will see many kinds of events. There are too many large dams built in ancient fault lines. The rock is black limestone in East Tennessee. If you think limestone is soft, you need to sink your teeth into black limestone as it will re-educate you. Take a look at the fault lines around Gate City, VA. The best education is traveling and the worst education is in the classroom!
Hi David. I don't think so. It's quite bony through most of the summer, fall, and winter but swells with spring runoff from snowmelt such that it can be rafted or kayaked. It is a Class IV river section with whitewater and hazards. There are some commercial outfitter companies that take folks through each year.
Could this be the results of mega flooding? I can't imagine this stream cutting a ravine this deep and wide without way more water. Are those signs of beaches in the canyon walls I wonder? It would be cool if you could link with Randal Carlson and get his thoughts on like features. I'm sure you know Randal has interesting ideas on erosion such as this caused by mega flooding. Another great video, thank you Shawn..
A likely important factor is the material solute, as well. Soft uplifted sediments from former sea bottoms would not obtain teh same cutting power as more crystalline hard matter. Certainly, water flowing onto hard basalt at first generates comparatively little incisive energy, and only the long-term cascading erodes the initial basalt. There's a place at Southern end of Owens valley before the (Los Angeles DWP-stolen) river exited into the Mojave, called Lava Falls, a narrow short, stunning precipice. When we think of Columbia River and the channeled scablands, through which the ice-dammed Lake Missoula some 40 times emptied, cutting through theColumbia Gorge, we get a sense of teh scouring from a lake that would fill to 500 cubic miles repeatedly. I often think of the Southeast California's Lake Cahuilla, a base level below sea level, that periodically formed from the lower Colorado River being large enough , or through some of those San Andreas fault system - earthquakes you noted in your beautiful Anza-Borrego videos of that tiny area. Cahuill formed a resource for the Kumeyaay seasonally nomadic people, whose fishing and other concentrations are now found hundreds of feet above the Imperial Valley level. There would even very likely be the large base lake now, were it not for the damming craze of the lower Colorado. Those huge dams are beginning to show, in less that 100 years, significant sediment deposit, as to harness hydroelectric power, water fall of some height is necessary for the efficiencies desired. This limits the lifespan of dams. I think and hope to the level of tentative belief, that rivers will be restored by nature, as the entire Colorado Delta, once a seasonal home for many diverse organisms, including arctic-summering birds in enormous numbers, will return. (the springtime blossoming of severe western deserts have always entranced me, and since summer can get into the 120s F ranger, from Death Valley and high desert 4k feet of Mojave, and fruit not quite ripe in the mornings, change into overripe and rotten, the biological mysteries of desert are magnificent. The Kumeyaay, like Mojave tribes might switch from sever deserts to seashore as seasons passed, and the sedentary lives to which we're accustomed pale in interest and adaptation = i really believe that our nature requires seasonal nomadism!)
I wonder if the north American continent is unique in it`s errosion and deposition cycles. Everywhere we look we see exposed features that show how old the ground was all the way back over a billion years ago? Think how much errosional forces had to have happened to reveal that billion-year-old rock, which wasnt a rock then. it was dirt, water, and air. Its just amazing I think. Maybe each continent is unique because no two really evolve the same exact way.
How in the world do you stand on the edge like that? I would be cutting button holes. At Black Canyon where they have the overlooks with fencing and rails, I approach in a half-crouch, grab the railing and slowly rise up....leaving dents in the railing. 😬
Great stuff. But: your description implies that headwaters "seek" their base level. You imply that if the head is uplifted its waters will "work harder" to reach their old base. I know you didn't mean that but it sort of comes across that way.
Growing up in Idaho, I have always been curious about the iconic twin butes of eastern Idaho. I was once told as a child that they are actually much taller than they appear..that at least half to two thirds of their actual height has been buried by their own lava. I have always wondered if that were true, or even possible.
@Shawn Willsey I am not sure, I have only known them as the twin butes. They are the two most prominent butes you see to the west as you are heading north on I-15 out of Pocatello.
@@randypowell3180 Yep, East and Middle Buttes. These are rhyolite lava domes, although the rhyolite lava pushed the overlying basalt up but did not break through to the surface. That's why East Butte has white rocks (rhyolite) and Middle Butte has black rocks (basalt). I'll try to do a video on these this summer.
At whatever gradient, it's hard for me to imagine iriver cutting through all that solid basalt. Have geologists done lab or experimental research to prove this in the normal course of streamflow? And what does the process look like? Is the abrasion uniform along the stream or does it cut back from a waterfall after the base falls?
Tricky question as both have vied for the same real estate for several million years. For a place like the Grand Canyon, its easy. The rocks were there first and the river cut through them. In southern Idaho, its not so straightforward. Eruptions create lava which flow to the lowest point which often has a river or stream. If enough lava inundates the drainage, the river is forced elsewhere and begins carving a new canyon. The next eruption can fill in this new canyon, diverting the river, etc. Its a crazy cycle.
It was freshwater because the climate was wetter and cooler. Salty lakes form when evaporation far exceeds precipitation, concentrating the salts in the water to make it saline.
I don't see how the draining of Lake Idaho affected the Gradient of the Bruneau river in the gorge area. Call point 'B' the location of where the Bruneau river entered Lake Idaho before the lake drained and point 'A' the source of the Bruneau river. This will give a certain gradient. Now drain the lake. The gradient from point A to Point B has not changed (Assuming point B is not in the gorge but further down stream). So the gradient of the river IN THE GORGE AREA has not changed. Also, when Lake Idaho drained, the new base layer point 'C' would be lower but it is now farther away from point 'A', so it is entirely possible that the gradient from point 'A' to point 'C' is Smaller than the gradient from 'A' to 'B'.
If a steeper gradient results in a canyon and a less steep gradient results in a wider valley then the canyon should be in the mountains from which the river originates and not in the rather flat area shown in the video.
Yes indeed. Just downstream of here, the canyon ends and widens dramatically as it approaches the confluence with the Snake River. Much of the wide valley floor has been filled in with deposits.
You should look into the spill way at canyon dam at canyon lake Texas . A short but very deep canyon was formed in just hours when their was a huge flood that actually over ran the spill way. Some of these events that people think took millions of years could have actually happened in days not years. Glaciers dams failing eat.
3 million years ago? It's possible or likely no humans were in the Americas at that time. Perhaps the whole thing was a bit closer to Europe too. I do no know obviously.
Thanks for making these videos. I really enjoy learning geology, especially in the Utah/Idaho area. I recently watched this video about rivers and think it compliments this video well. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-UBivwxBgdPQ.html
