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Nick Zentner taught me that since a river never runs uphill, the river was always there first before the landscape uplifted and the present mountain eroded out of it, cutting down and preserving any meanders it originally came with, using the Yakima river as a particular example. In the dry landscape of the western US, Myron Cook showed me crossbedding from prehistoric streams and taught me that floods are what predominantly move the course of rivers. When you showed the picture at 1:55, I recognized both of those lessons and concluded that there was never a point in time where the river flooded in such a way to erode away a new, preferencial path around the narrow gorge. Lucky for us - because that canyoon is a beautiful sight! Thank you and all the other geologists on youtube for making these lessons readily available - I get to learn about geologic principles as well as a good look at the particular geology on the literal other side of the Earth!
@@ChaosEarth-p8i There will be significant changes in the amount of water at locations - some drier, some wetter, and *when* rainfall happens may change too. There should, however, be relatively minimal geological changes in the timescales we care about. Therefore, things like general drainage basins etc will not see any new potential major shifts (although some current potential shifts may be triggered) Following the principles mentioned in OC, we can generally group into some (non-mutually-exclusive) categories: Places that see more flooding, whether from changing precipitation patterns (more sudden rains, intense monsoons, etc) or just straight increased rainfall, may end up with more unstable river systems, as any major flood could cause rerouting of rivers. Without additional flooding, we don't really expect to see changes/new river systems beyond what normally happens. However, places that are drier and/or hotter, either seasonally or just in general, may see some parts of their system become seasonal or even completely insular as evaporation outpaces precipitation. Notably here are systems fed by meltwater. Should these sources completely melt away, their flow could become much more seasonal, as dry, hot seasons will no longer have meltwater to sustain flow.
Rivers never run uphill. Exceptions to every rule apply. Subglacial tunnel channeled rivers are pressurized and do indeed run uphill sometimes. Re:Lesemann
Climate change is not a new thing if you ever learned about things like "snowball Earth" or the temperature of the location seen here during the age of dinosaurs. That and the movement over long periods of time the continents have been moving which is also driving the climate of specific land masses. It is not just one thing like CO2 increases made by man. I guarantee another ice age is coming in 2000 to 3000 years. It's like you building a sandcastle at the beach and the tide comes in and wipes it all away. What we are doing now is that insignificant in spite all the doom and gloom climatologists are spreading via computer models and ancient ice core samples.
There you go! Another greatly appreciated explanation. I've lived here all my life and now just learning so much from you. Kind regards from your 78 year old "freshman" student.
I'll just echo the praise of the other commenters here. A clean, clear, crisp video, simple but clear pen-and-paper diagrams and beautifully supported using Google Earth (enabled by your new-found ability to do voice-overs! 🎉). I can't wait to see what how the new camera will enhance things further! I don't think that these videos are ever going to become slick videos such as National Geographic might make, but that's OK - that's not why we come here. We come here for some good old-fashioned learning! Thank you, Willsey. 👍
There's a similar formation on the San Juan River near Mexican Hat. While I was camping in Gooseneck with a group of other people I had them try to figure out which formed first, the river or the mountain. It was fun teaching them how to solve a geologic puzzle like that.
I remember years ago when I signed up for a rafting trip in Dinosaur. I'm in the rafting company's van driving to the put in. We were driving across relatively flat terrain. As we approach the put in the driver points towards split mountain and says the river is over there. I was thinking what the hell? Why would the river cut through a mountain rather than flow in this flat terrain. It was a mystery to me and didn't make sense. Thanks for clearing it up.
Holy crap, your channel is amazing Shawn. Just came across this a few nights ago, but I can't stop watching. You've answered so many questions I've had for years about random stuff. Thanks!!!
Back in the late Pliocene, when I was a geology undergraduate, we called the Green River flowing through Split Mountain a classic example of an "antecedent river." The ancestral river superimposed its self on buried geologic structures as they were excavated by the river's downcutting and thereby preserving the ancient meanders of what was once a mature river system. The landscape would be described as "rejuvenated" as the lowering of the base level of erosion allowed erosional down-cutting while preserving the original course of the once mature river system. You want to see something "older than the hills?" Look at the river, it's much older than today's landscape. Where I live on the Central California Coast, we have the Cuyama River that flows through the San Rafael mountains to the East of here. Highway 166 follows that river until it broadens out in a pull-apart valley (Cuyama Valley just West of the San Andres Fault). That valley is filled with sediments of temporary lakes that formed from time to time as the rising San Rafael Mts. temporarily dammed the ancient Cuyama River. The scenery along Hw. 166 is rather nice and the roadcuts West of the Mts. that reveal the lake sediments are interesting, but nowhere near as spectacular as Split Mountain and, truth be told, the Cuyama River is certainly no Green River. However, before the San Rafael's pushed up to create a severe Rain Shadow to the East, the huge drainage area the river today encompasses must have made it a erosional force to be reckoned with and the ancestral Cuyama River probably would have been fun to raft down. Even so, I really don't think the early Australopithecines were into rafting and they lived a long way off besides.
Is that similar for the San Rafael river and Muddy Creek cutting through the San Rafael Reef? I've floated both of those rivers and wondered how they ended up in their current paths.
Thanks. Yes I did enjoy this episode. I had looked at that exact location last spring when my wife and I did a short trail walk in the area. It is certainly an impressive cut through the rocks, even not knowing which are more or less resistant. Cool place to visit.
I have privately rafted Ladore and the Yampa probably 15 times over the years. Always a great trip. Split Mountain is a great ride at high water. Your thoughts on the geology makes sense because the river is a straight shot down Split Mountain. I once flipped a boat inside the cave near the bottom of the canyon on river right.........another story for another time........
For most of my guiding life, i was a whitewater snob, Westwater, Cataract and the Grand Canyon. Then i was asked to take a Green River trip to the confluence of the Green and Colorado. One trip and i couldn't get enough of the Green .
Dinosaur is such an underrated national monument. The vault is amazing, of course, but the Colorado portion of the monument (upriver from this video) is just gorgeous and definitely worth the effort to visit.
I was at Echo Park campground this summer at the Yampa and Green rivers. We accidentally came upon the trail when exploring Dinosaur. An interesting and fun ride down, and you could clearly see the different rivers water well after they combined.
Thanks for explaining this. A nearly identical situation exists in the Smokehole Canyon in West Virginia, where the South Branch of the Potomac River takes a seemingly impossible jag through the most unlikely mountain path, while by passing the immediately adjacent stream valley. A superposed stream would explain Smokehole Canyon, but this is the first time I've seen it explained in any other geologic context.
This is excellent. I was born and raised in Craig, CO and so when I have flown over the area I look for familiar landmarks. On one flight back to Reno, I crossed over this feature and took an image of it. I wondered how it could have formed and now I have my answer. Thank you!
Thank you. I've always heard "superimposed" and "superposed" synonymously, it's nice to hear that we're all agreeing on one term. Such superposed drainages are wonderfully common on the Colorado Plateau, including being the cause of Paradox Valley, which has got to be about the best named landform on the plateau. Video subject idea: A related topic that I know just enough about to be curious and confused is the geomorphic history of the Green River. I understand that at one point the Green River was part of the Mississippi River drainage basin; I take it that it was a tributary to either the Sweetwater River or North Platte River, I don't know which. I understand that eastward movement of the Yellowstone hotspot has caused all sorts of drainage reorganizations, this being one. I also don't know the timing of the river's capture into the Colorado River drainage basin, but it would obviously be before the river become entrenched in the Unita Mountains. I'm also curious about the evidence for the river's earlier course, can there really be river terrace remnants still around? Thanks!
Many years ago, traveling west on Highway 20 across Wyoming with my nine-year-old son, we came to the Boysen Reservoir and to this day he remembers how I pulled over on the side of the road, and sat on the hood of the truck, staring at the impossible and moaning that I didn't understand. The Wind River runs north, up into the mountains. It was getting dark when Alex finally convinced me that we'd never get a good campsite near Thermopolis if we stayed there longer. On our return home to Iowa City, Holmes Semken, professor of geology at the University of Iowa, lent me John McPhee's book Rising from the Plains, which is, decades later, still one of my favorite rereads every couple of years. Same phenomenon, of course. I highly recommend the entire Annals of the Former World series by McPhee, as well as all his other books on science. Rising From The Plains is his best, I think. Thanks for this fun video.
That's the stuff I gotta learn how to do on YT so I can make coherent videos describing and studying the Long Valley Caldera and eastern Sierra Nevada. It's a project I've wanted to attempt for quite some time now and I just don't have the equipment or the production know-how to produce a program that will capture people's attention and help them _learn_ about the geology there. There are a multitude of videos by other folks about the LVC and eastern Sierra, but the processes taking place that shaped the landscape there are many and varied and so there really isn't a good video out there that incorporates ALL of the different processes that have happened to create the Sierra Nevada and continues to do so. That's what I'd love to do but producing these videos is no easy thing and takes quite a bit of time.
This also highlights another process, the exhumation of many of the mountains in the Southwest, including the Rocky Mountains. Much of the landscape we see was previously buried, either completely buried under post Laramide Uplift sediments, or partially buried under sediments. Over the last 40 millions - and in particular over the last 5 million years, for reasons that aren't understood - down cutting and removal of those sediments has been underway. There are many examples in the Western USA of rivers doing crazy things like this that stand as evidence of the deep burial that once existed.
A similar topography in Canada: Athabasca River alongside CA-16 between Edmonton, AB and Prince George, BC. Don't know about the subsurface geology, but the drive is unique😊
Thanks for the explanation. When I went to Dinosaur National Monument, it was to see the Dinosaur Quarry. (Which is pretty cool. It's a partially dug bluff enclosed in a building, exposing all the dino fossils still in the hillside.) But then I followed the drive down to Split Mountain. Couldn't figure it out, especially with the near vertical layers of rock. Didn't have a lot of time there, I had to be in SLC by the evening...
That was fascinating! Thank you so much! Geology was my favorite class in college. Pity I never followed it up, but I couldn't really think of a carrier I wanted to follow with such a degree. :/
Wouldn't a lot of the cutting have been caused by water erosion, and seasonal floods would have used the conglomerate as a cutting fluid to erode and cut out the harder rock? Could glaciation also have done some of the cutting? And thank you for your videos!
You always have such interesting videos. How this section of the Green River cut through hard rock reminds me of the Black Canyon of the Gunnison River. It sounds like similar processes were at work at both places.
Oh wow, what an impressive anticline! Thanks for explaining the geological conundrum that resulted in the creation of this magnificent landscape, Shawn :) The Google Earth view and your little drawing are very helpful. "Superposed": duly noted ;)
When I was there a few years ago, a ranger was telling me that the Green River has only been there for a few million years. After hiking to the rim of the canyon, I saw the easier path to the northwest. My theory was that the Yampa River is older and as the mountain was pushed up, the Yampa River was already there and it carved the canyon as the anticline formed. The theory you're explaining of the anticline being buried and the river carved it's was down makes sense, but what doesn't make sense to me is how was that sediment layer in the lower valley to the northwest disappeared so quickly. I'm not sure I'm explaining it well enough and hope it makes sense.
The Green flowed to the east until20 million years ago when crustal expansion lowered the eastern end of the Uinta Mountians and the Green was pirated by a small stream or river to assume its current course.
Thanks for the explanation. At first, I wondered whether there were small cracks in the hard rock and water just started flowing into those cracks. I thought that maybe erosion and freeze-thaw cycles expanded the cracks until the entire river went that way.
I'm Utah at the moment, I love it here (3rd visit). Just come down from Torrey through Escalante, to Bryce. Just absolutely stunning scenery. I recommended your videos to some people I met. 😊 I was wondering if the Sulphur Creek goosenecks at Capitol Reef were formed in a similar fashion?
I've watched videos of people driving one of roads that ends at the river. All the colors of the stones and mountains, the different types of rocks and mountain shapes. Very interesting.
I have the 3-D table top map that is going to the Gates of Lodore launch site right now... Such cool features. When we constructed the map that resides at the Dinosaur Visitor Center, the coolest, strangest feature we thought was the banked to the inside "race track" around the lower part of the anticline. We've done a lot of these maps, but we have never seen anything like it.
On the northern side of the Uintahs, in Brown's Park, is where the Green River cuts into Diamond Mountain at the Gates of Lodore, just a few miles upstream of here. It is a similar situation, but the river flows into the gorge, not out of it. I believe that John Wesley Powell was first led to the idea of superposition there, where the river makes an unexpected turn straight into the mountain, slicing through it instead of going around it.
Cool video. I'd be interested in seeing something like this with the Delaware Water Gap. I've flown over it heading into NYC so many times and it still looks so surreal.
This isn't the only instance of a river seemingly choosing a harder path of flow. One that comes to mind is the Gunnison River going through the metamorphic rock of Black Canyon.
2:28 you assumed the sandstone was hard after millions of years from the assumptions made in radiodating, which forces you to assume the river flowed over the top of the mountain and erode downwards to its current level. Take out all your assumptions and the mystery disappears. Today's river is only following the course made by sheetflow draining into channels while the sand was lithifying from the minerals that washed through it by the draining floodwaters. PS Your preferred dating methods for continental erosion rates gives 30M years maximum for any continent before it's said to erode below sea level. That cancels any claim these sandstones are more than 40M yrs.
Big fan of the clipboard. Clear easy graphics. Old school. I do trials and I talk off a legal pad. Pen and paper or a whiteboard and marker. Hard to beat.
A point that was kind of passed over was that the river would have been already cutting into the rock establishing it's course before the top gravel layers had been eroded away. I knew the answer already from videos by Nick Zentner. It is interesting that while it seems an easy conclusion for me, it wasn't obvious to previous explorers. Another example of how we see farther because we stand on the shoulders of the people who made the earlier discoverries.
So was the ancestral river eroding into the landscape simultaneous as the uplift was occurring? How did the top layer of material get eroded away and where did it go?
That was my initial guess , but , no , the anticline had already formed , eroded to essentially a flat plain covered with thick residuum , and , the river eroded through the residuum and then encountered the anticline structure . Being already constrained to a defined channel , it simply continued down cutting through the anticline .
@@kaboom4679 that makes sense thanks. I guess I am just wondering what happened to the rest of the thick residuum? If the river was constrained to a defined channel then it wouldn't have been responsible for removing it right? This is likely a bigger geology question outside the scope of this video, I need to do some reading.
The Google overhead views remind me of the upper Columbia River Valley with it's faux prehistoric (Missoula floods) canyon. complete with waterfalls an spectacular cliff reliefs.
De Chelly canyon has the same puzzling features. I feel like these canyons were made near instantly with giant plasma strikes. The locals talk of a time of great lighting.
I can't explain fully why, but that spot is one of my favorite spots on earth. Nearby is Moonshine arch, and I noticed that there are "boulders" (rocks, really) on top of the rock layer the arch is cut from, but those rocks are a totally different color and material. But there's no where above them or rock layers that they have tumbled down from or eroded off of. Are they really just leftover straggler rocks that haven't just been washed away with the rest of the long-gone previous layers? There's not many of them, just a few random stragglers
It almost looke like the river may have had a few different courses crossing that ridge before settling into the bed running all the way around the end of the ridge. I wonder if the ridge was not just worn away, but subject to some uplift to keep the river moving its bed further downslope? Or maybe it was just greater erosion at the turning point finally breaking through to a lower area? Or none of the above? Nothing like a little geologic mystery.
I live just east of dinosaur and have explored that area quite a bit. Found a little piece of amethyst or something similar right there off the south bank
Sorta matches up with Washington's river gravels and cobbles on top of passes over small mountains..... Nick Z has ventured to a few of those. Would be interesting to see a good graphic that shows the evolution of even just the West Coast and Rockies. The movements of plates and stretching of land is mind boggling...... then you throw in hydrodynamics and precipitation, and BAM! It all gets weird.
Is there a stream piracy model for Split Mountain? There is a challenge to the superposition model for incised meanders as well. I think superposition to be most likely explanation for most of these seeming anomalies, but not always.
I expect that the layer of gravels and softer rock would have acted like sandpaper in the river bed during the transition from the softer upper layer to the harder rock below. This sandpaper effect would have been in action while much of the softer gravelly layer still existed and that layer would have "discouraged"the river from seeking a more advantageous course, and by the time the gravels had completely gone, that initial sandpapered groove would keep the river in place. I therefore expect that the rate of river cutting downward would have been fastest during the earliest years of the formation of the canyon. Does that track with your observations, or were other factors playing a greater role? I can't help but notice that the canyon course is not a clean diagonal cut, but appears to have been influenced by the varying hardness of rock layers, and I can only mean that the current course is not identical to the original course, but there must have been some course modification sideways into relatively softer layers leading to the current zig-zag of the canyon.
Wonderful video. Another case of superposition that you may want to take a look at (even though it is far from your usual field) is where the Trinity River goes through Dallas, Texas. Also, the rock strata exposed from Dallas towards Ft, Worth is quite interesting. In a nutshell, the exposed strata dip to the east and in the Dallas Area are Cretaceous Age and age older to Pennsylvanian west of Ft. Worth. This area is the eastern edge of the East Texas Embayment and is also where the Ouchita mountains are buried underneath. Although there is not much to see on the surface, underfoot it is quite interesting. Another interesting fact is that many of the Texas main rivers (Brazos, Colorado, Trinity) actually drained from the Rockies until they were cut off by the Red River. Another interesting area is the Balcones Escarpment in the Austin area. There is several thousand feet of displacement between the west side of IH35 and the Edwards Plateau and the east side of IH35 where primarily Quaternary deposits exist.
Seems to me water cutting through soft soil is OK but as harder soil is encountered slowing down forward progress causing water to pool until softer soil is encountered and then continuing off in a new direction.
Not yet but I've visited there several times. I did do a video on a similar feature in southern Utah called the Comb Ridge monocline: ua-cam.com/video/ZQWw1sYjJ8w/v-deo.html
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Nick Zentner taught me that since a river never runs uphill, the river was always there first before the landscape uplifted and the present mountain eroded out of it, cutting down and preserving any meanders it originally came with, using the Yakima river as a particular example.
In the dry landscape of the western US, Myron Cook showed me crossbedding from prehistoric streams and taught me that floods are what predominantly move the course of rivers.
When you showed the picture at 1:55, I recognized both of those lessons and concluded that there was never a point in time where the river flooded in such a way to erode away a new, preferencial path around the narrow gorge. Lucky for us - because that canyoon is a beautiful sight!
Thank you and all the other geologists on youtube for making these lessons readily available - I get to learn about geologic principles as well as a good look at the particular geology on the literal other side of the Earth!
off topic but how do you think climate change might affect river systems and their erosion patterns in the future?
@@ChaosEarth-p8i There will be significant changes in the amount of water at locations - some drier, some wetter, and *when* rainfall happens may change too.
There should, however, be relatively minimal geological changes in the timescales we care about. Therefore, things like general drainage basins etc will not see any new potential major shifts (although some current potential shifts may be triggered)
Following the principles mentioned in OC, we can generally group into some (non-mutually-exclusive) categories:
Places that see more flooding, whether from changing precipitation patterns (more sudden rains, intense monsoons, etc) or just straight increased rainfall, may end up with more unstable river systems, as any major flood could cause rerouting of rivers.
Without additional flooding, we don't really expect to see changes/new river systems beyond what normally happens.
However, places that are drier and/or hotter, either seasonally or just in general, may see some parts of their system become seasonal or even completely insular as evaporation outpaces precipitation.
Notably here are systems fed by meltwater. Should these sources completely melt away, their flow could become much more seasonal, as dry, hot seasons will no longer have meltwater to sustain flow.
Rivers never run uphill. Exceptions to every rule apply. Subglacial tunnel channeled rivers are pressurized and do indeed run uphill sometimes. Re:Lesemann
Climate change is not a new thing if you ever learned about things like "snowball Earth" or the temperature of
the location seen here during the age of dinosaurs. That and the movement over long periods of time the continents have been moving which is also driving the climate of specific land masses. It is not just one thing like
CO2 increases made by man. I guarantee another ice age is coming in 2000 to 3000 years. It's like you building a sandcastle at the beach and the tide comes in and wipes it all away. What we are doing now is that insignificant
in spite all the doom and gloom climatologists are spreading via computer models and ancient ice core samples.
Nice lesso, but I'm still baffled... something seems missing
Short, sweet, and to the point with no stupid music... great geology sluthing... thanks
There you go! Another greatly appreciated explanation. I've lived here all my life and now just learning so much from you. Kind regards from your 78 year old "freshman" student.
Thanks for all the hard work on these videos!
Thanks!
I'll just echo the praise of the other commenters here. A clean, clear, crisp video, simple but clear pen-and-paper diagrams and beautifully supported using Google Earth (enabled by your new-found ability to do voice-overs! 🎉). I can't wait to see what how the new camera will enhance things further!
I don't think that these videos are ever going to become slick videos such as National Geographic might make, but that's OK - that's not why we come here. We come here for some good old-fashioned learning! Thank you, Willsey. 👍
There's a similar formation on the San Juan River near Mexican Hat.
While I was camping in Gooseneck with a group of other people I had them try to figure out which formed first, the river or the mountain. It was fun teaching them how to solve a geologic puzzle like that.
I remember years ago when I signed up for a rafting trip in Dinosaur. I'm in the rafting company's van driving to the put in. We were driving across relatively flat terrain. As we approach the put in the driver points towards split mountain and says the river is over there. I was thinking what the hell? Why would the river cut through a mountain rather than flow in this flat terrain. It was a mystery to me and didn't make sense. Thanks for clearing it up.
The Green is a mighty river. So, superposed instead of superimposed. I learn something every time, Shawn. Thanks for your insight and best wishes.
Interesting!
One could see why there was such confusion.
Thank you Prof Willsey 🙏
Dr. you make learning fun. Thank you.
Perfect presentation of geology and a wonderful view.
Holy crap, your channel is amazing Shawn. Just came across this a few nights ago, but I can't stop watching. You've answered so many questions I've had for years about random stuff. Thanks!!!
Back in the late Pliocene, when I was a geology undergraduate, we called the Green River flowing through Split Mountain a classic example of an "antecedent river." The ancestral river superimposed its self on buried geologic structures as they were excavated by the river's downcutting and thereby preserving the ancient meanders of what was once a mature river system. The landscape would be described as "rejuvenated" as the lowering of the base level of erosion allowed erosional down-cutting while preserving the original course of the once mature river system. You want to see something "older than the hills?" Look at the river, it's much older than today's landscape.
Where I live on the Central California Coast, we have the Cuyama River that flows through the San Rafael mountains to the East of here. Highway 166 follows that river until it broadens out in a pull-apart valley (Cuyama Valley just West of the San Andres Fault). That valley is filled with sediments of temporary lakes that formed from time to time as the rising San Rafael Mts. temporarily dammed the ancient Cuyama River. The scenery along Hw. 166 is rather nice and the roadcuts West of the Mts. that reveal the lake sediments are interesting, but nowhere near as spectacular as Split Mountain and, truth be told, the Cuyama River is certainly no Green River. However, before the San Rafael's pushed up to create a severe Rain Shadow to the East, the huge drainage area the river today encompasses must have made it a erosional force to be reckoned with and the ancestral Cuyama River probably would have been fun to raft down. Even so, I really don't think the early Australopithecines were into rafting and they lived a long way off besides.
Is that similar for the San Rafael river and Muddy Creek cutting through the San Rafael Reef? I've floated both of those rivers and wondered how they ended up in their current paths.
Thanks. Yes I did enjoy this episode. I had looked at that exact location last spring when my wife and I did a short trail walk in the area. It is certainly an impressive cut through the rocks, even not knowing which are more or less resistant. Cool place to visit.
Great video! Thank you for what you are doing with this channel!
BEAUTIFUL landscape and very interesting to learn how it came about! Thx!
Thanks for taking a visit out there. That area of Utah is full of wonderful geology. Beautiful country.
I have privately rafted Ladore and the Yampa probably 15 times over the years. Always a great trip.
Split Mountain is a great ride at high water. Your thoughts on the geology makes sense because the river is a straight shot down Split Mountain. I once flipped a boat inside the cave near the bottom of the canyon on river right.........another story for another time........
For most of my guiding life, i was a whitewater snob, Westwater, Cataract and the Grand Canyon. Then i was asked to take a Green River trip to the confluence of the Green and Colorado. One trip and i couldn't get enough of the Green .
Great video Shawn.
Cool! What an interesting geology lesson! And some vicarious travels too. Thanks for your time and energy to share these lessons.
And a few local river features I've always wondered about just made sense.
Thanks for another awesome video.
Dinosaur is such an underrated national monument. The vault is amazing, of course, but the Colorado portion of the monument (upriver from this video) is just gorgeous and definitely worth the effort to visit.
I was at Echo Park campground this summer at the Yampa and Green rivers. We accidentally came upon the trail when exploring Dinosaur. An interesting and fun ride down, and you could clearly see the different rivers water well after they combined.
Thanks for explaining this. A nearly identical situation exists in the Smokehole Canyon in West Virginia, where the South Branch of the Potomac River takes a seemingly impossible jag through the most unlikely mountain path, while by passing the immediately adjacent stream valley. A superposed stream would explain Smokehole Canyon, but this is the first time I've seen it explained in any other geologic context.
This is excellent. I was born and raised in Craig, CO and so when I have flown over the area I look for familiar landmarks. On one flight back to Reno, I crossed over this feature and took an image of it. I wondered how it could have formed and now I have my answer. Thank you!
Thank you. I've always heard "superimposed" and "superposed" synonymously, it's nice to hear that we're all agreeing on one term. Such superposed drainages are wonderfully common on the Colorado Plateau, including being the cause of Paradox Valley, which has got to be about the best named landform on the plateau.
Video subject idea: A related topic that I know just enough about to be curious and confused is the geomorphic history of the Green River. I understand that at one point the Green River was part of the Mississippi River drainage basin; I take it that it was a tributary to either the Sweetwater River or North Platte River, I don't know which. I understand that eastward movement of the Yellowstone hotspot has caused all sorts of drainage reorganizations, this being one. I also don't know the timing of the river's capture into the Colorado River drainage basin, but it would obviously be before the river become entrenched in the Unita Mountains. I'm also curious about the evidence for the river's earlier course, can there really be river terrace remnants still around?
Thanks!
Myron Cook has a video exploring this idea: "Yellowstone to Hudson Bay connection: What Happened?"
Very cool to see a depiction of this. I know of another stream that cuts across an anticline. Now I know why!
Many years ago, traveling west on Highway 20 across Wyoming with my nine-year-old son, we came to the Boysen Reservoir and to this day he remembers how I pulled over on the side of the road, and sat on the hood of the truck, staring at the impossible and moaning that I didn't understand. The Wind River runs north, up into the mountains. It was getting dark when Alex finally convinced me that we'd never get a good campsite near Thermopolis if we stayed there longer. On our return home to Iowa City, Holmes Semken, professor of geology at the University of Iowa, lent me John McPhee's book Rising from the Plains, which is, decades later, still one of my favorite rereads every couple of years. Same phenomenon, of course. I highly recommend the entire Annals of the Former World series by McPhee, as well as all his other books on science. Rising From The Plains is his best, I think. Thanks for this fun video.
Great lesson! Extra production and editing is noted and well done! Thx Professor!!
That's the stuff I gotta learn how to do on YT so I can make coherent videos describing and studying the Long Valley Caldera and eastern Sierra Nevada. It's a project I've wanted to attempt for quite some time now and I just don't have the equipment or the production know-how to produce a program that will capture people's attention and help them _learn_ about the geology there.
There are a multitude of videos by other folks about the LVC and eastern Sierra, but the processes taking place that shaped the landscape there are many and varied and so there really isn't a good video out there that incorporates ALL of the different processes that have happened to create the Sierra Nevada and continues to do so. That's what I'd love to do but producing these videos is no easy thing and takes quite a bit of time.
This also highlights another process, the exhumation of many of the mountains in the Southwest, including the Rocky Mountains. Much of the landscape we see was previously buried, either completely buried under post Laramide Uplift sediments, or partially buried under sediments. Over the last 40 millions - and in particular over the last 5 million years, for reasons that aren't understood - down cutting and removal of those sediments has been underway. There are many examples in the Western USA of rivers doing crazy things like this that stand as evidence of the deep burial that once existed.
I have long wondered about the course of the Green River and it's route south of flaming gorge. Thanks for clearing that up.
A million, 10's of million, 100's of millions of year of geological history in 6 and a half minutes.
And delivered thousands of miles by satellite to your hands in seconds.
Utah feels like that in every mile travelled. 😊
Sounds of silence trail (West of Split Mountain!) gives a great view of the strata that once overlay the Weber.
A similar topography in Canada:
Athabasca River alongside CA-16 between Edmonton, AB and Prince George, BC.
Don't know about the subsurface geology, but the drive is unique😊
Excellent explanation
Always learning, thank you for great teaching.
Thank you Professor
Thanks for the explanation. When I went to Dinosaur National Monument, it was to see the Dinosaur Quarry. (Which is pretty cool. It's a partially dug bluff enclosed in a building, exposing all the dino fossils still in the hillside.)
But then I followed the drive down to Split Mountain. Couldn't figure it out, especially with the near vertical layers of rock. Didn't have a lot of time there, I had to be in SLC by the evening...
Thank you for making this
That was fascinating! Thank you so much!
Geology was my favorite class in college. Pity I never followed it up, but I couldn't really think of a carrier I wanted to follow with such a degree. :/
Wouldn't a lot of the cutting have been caused by water erosion, and seasonal floods would have used the conglomerate as a cutting fluid to erode and cut out the harder rock? Could glaciation also have done some of the cutting? And thank you for your videos!
You always have such interesting videos. How this section of the Green River cut through hard rock reminds me of the Black Canyon of the Gunnison River. It sounds like similar processes were at work at both places.
Geologists date the Black Canyon at just over a million years, a short time to carve out a 2600 foot deep river canyon.
Thanks, that was good to know
Oh wow, what an impressive anticline! Thanks for explaining the geological conundrum that resulted in the creation of this magnificent landscape, Shawn :) The Google Earth view and your little drawing are very helpful. "Superposed": duly noted ;)
When I was there a few years ago, a ranger was telling me that the Green River has only been there for a few million years. After hiking to the rim of the canyon, I saw the easier path to the northwest. My theory was that the Yampa River is older and as the mountain was pushed up, the Yampa River was already there and it carved the canyon as the anticline formed. The theory you're explaining of the anticline being buried and the river carved it's was down makes sense, but what doesn't make sense to me is how was that sediment layer in the lower valley to the northwest disappeared so quickly. I'm not sure I'm explaining it well enough and hope it makes sense.
The Green flowed to the east until20 million years ago when crustal expansion lowered the eastern end of the Uinta Mountians and the Green was pirated by a small stream or river to assume its current course.
Great video, thank you.
I live in vernal and have always wondered how blue mountain and split mountain formed. Thank you!
I was on the edge of my seat like a real cliff hanger. Because my internet connection stopped just before the reveal.......
I see what you did there.
"a real cliff hanger"
@@geefreck well done! 😁😁😁
thank you very much for your content. It's like i am back in college. i really enjoy your content. Please keep ut up good sir.
Does this explanation also apply for the Yampa River through Cross Canyon? Thanks for the video!
Didn't know you could street view kayaking down the river, thanks!!
Thanks for the explanation.
At first, I wondered whether there were small cracks in the hard rock and water just started flowing into those cracks. I thought that maybe erosion and freeze-thaw cycles expanded the cracks until the entire river went that way.
Is this the same process that formed the Black Canyon of the Gunnison?
I like the river’s individualism.
I love that area, Echo Park is fantastic.
I'm Utah at the moment, I love it here (3rd visit). Just come down from Torrey through Escalante, to Bryce. Just absolutely stunning scenery. I recommended your videos to some people I met. 😊
I was wondering if the Sulphur Creek goosenecks at Capitol Reef were formed in a similar fashion?
I love Google Earth Street View!!!!!
What I am interested in is the origin of the conglomerate that over capped the more resistant limestone? Was it local glaciers?
The Green is actually the main stem of the Colorado River; the Upper Colorado is just a tributary.
I've watched videos of people driving one of roads that ends at the river. All the colors of the stones and mountains, the different types of rocks and mountain shapes. Very interesting.
I have the 3-D table top map that is going to the Gates of Lodore launch site right now... Such cool features. When we constructed the map that resides at the Dinosaur Visitor Center, the coolest, strangest feature we thought was the banked to the inside "race track" around the lower part of the anticline. We've done a lot of these maps, but we have never seen anything like it.
On the northern side of the Uintahs, in Brown's Park, is where the Green River cuts into Diamond Mountain at the Gates of Lodore, just a few miles upstream of here. It is a similar situation, but the river flows into the gorge, not out of it. I believe that John Wesley Powell was first led to the idea of superposition there, where the river makes an unexpected turn straight into the mountain, slicing through it instead of going around it.
Babe look, a Shawn Willsey video just dropped!
Answer starts at 3:50. Cool!
Cool video. I'd be interested in seeing something like this with the Delaware Water Gap. I've flown over it heading into NYC so many times and it still looks so surreal.
How does it compair to the new river in west virgina?
This isn't the only instance of a river seemingly choosing a harder path of flow. One that comes to mind is the Gunnison River going through the metamorphic rock of Black Canyon.
I need to learn more about the Laramide Orogeny.
I’ve been wanting to see a video on the green river - good stuff. I was curious about this cut.
Great explanation of the superposed drainage! Are there remnants of the younger gravel sedimentary layer visible nearby?
Water travels the path of least resistance. Usually considered downhill.
2:28 you assumed the sandstone was hard after millions of years from the assumptions made in radiodating, which forces you to assume the river flowed over the top of the mountain and erode downwards to its current level.
Take out all your assumptions and the mystery disappears. Today's river is only following the course made by sheetflow draining into channels while the sand was lithifying from the minerals that washed through it by the draining floodwaters.
PS Your preferred dating methods for continental erosion rates gives 30M years maximum for any continent before it's said to erode below sea level. That cancels any claim these sandstones are more than 40M yrs.
Big fan of the clipboard. Clear easy graphics. Old school. I do trials and I talk off a legal pad. Pen and paper or a whiteboard and marker. Hard to beat.
CCR sang about it a fairly long time ago!
Not really... according to Fogerty, “Green River is really about this place where I used to go as a kid on Putah Creek, near Winters, California,”
Walking along the river road at night, Barefoot girls dancing in the moonlight. 🤩
A point that was kind of passed over was that the river would have been already cutting into the rock establishing it's course before the top gravel layers had been eroded away. I knew the answer already from videos by Nick Zentner. It is interesting that while it seems an easy conclusion for me, it wasn't obvious to previous explorers. Another example of how we see farther because we stand on the shoulders of the people who made the earlier discoverries.
So was the ancestral river eroding into the landscape simultaneous as the uplift was occurring? How did the top layer of material get eroded away and where did it go?
That was my initial guess , but , no , the anticline had already formed , eroded to essentially a flat plain covered with thick residuum , and , the river eroded through the residuum and then encountered the anticline structure .
Being already constrained to a defined channel , it simply continued down cutting through the anticline .
@@kaboom4679 that makes sense thanks. I guess I am just wondering what happened to the rest of the thick residuum? If the river was constrained to a defined channel then it wouldn't have been responsible for removing it right? This is likely a bigger geology question outside the scope of this video, I need to do some reading.
The Google overhead views remind me of the upper Columbia River Valley with it's faux prehistoric (Missoula floods) canyon. complete with waterfalls an spectacular cliff reliefs.
most interesting since I live here. and did not know the details.
De Chelly canyon has the same puzzling features. I feel like these canyons were made near instantly with giant plasma strikes. The locals talk of a time of great lighting.
I assume the process is very similar in the San Rafael Swell with the San Rafael River and Muddy Creek.
I can't explain fully why, but that spot is one of my favorite spots on earth.
Nearby is Moonshine arch, and I noticed that there are "boulders" (rocks, really) on top of the rock layer the arch is cut from, but those rocks are a totally different color and material. But there's no where above them or rock layers that they have tumbled down from or eroded off of. Are they really just leftover straggler rocks that haven't just been washed away with the rest of the long-gone previous layers? There's not many of them, just a few random stragglers
Thank you.
learned something 30 yrs later after a kayaking there , awesome area
I like how easy it is to tell who's from the same state as me, Mr. "Mou-N"
It almost looke like the river may have had a few different courses crossing that ridge before settling into the bed running all the way around the end of the ridge. I wonder if the ridge was not just worn away, but subject to some uplift to keep the river moving its bed further downslope? Or maybe it was just greater erosion at the turning point finally breaking through to a lower area? Or none of the above? Nothing like a little geologic mystery.
Just out of curiosity when did it change from" super-imposed "to superposed could it have been in the 1950s??
I live just east of dinosaur and have explored that area quite a bit. Found a little piece of amethyst or something similar right there off the south bank
Sorta matches up with Washington's river gravels and cobbles on top of passes over small mountains..... Nick Z has ventured to a few of those. Would be interesting to see a good graphic that shows the evolution of even just the West Coast and Rockies. The movements of plates and stretching of land is mind boggling...... then you throw in hydrodynamics and precipitation, and BAM! It all gets weird.
Is there a stream piracy model for Split Mountain? There is a challenge to the superposition model for incised meanders as well.
I think superposition to be most likely explanation for most of these seeming anomalies, but not always.
How about doing a video on the Sweetwater/Moonstone Mountain granite in Wyoming while climbing it? Thanks.
Check out the Nolichucky River between Erwin and Limestone TN. It separates Buffalo mountain from the rest of the chain.
I expect that the layer of gravels and softer rock would have acted like sandpaper in the river bed during the transition from the softer upper layer to the harder rock below. This sandpaper effect would have been in action while much of the softer gravelly layer still existed and that layer would have "discouraged"the river from seeking a more advantageous course, and by the time the gravels had completely gone, that initial sandpapered groove would keep the river in place. I therefore expect that the rate of river cutting downward would have been fastest during the earliest years of the formation of the canyon.
Does that track with your observations, or were other factors playing a greater role?
I can't help but notice that the canyon course is not a clean diagonal cut, but appears to have been influenced by the varying hardness of rock layers, and I can only mean that the current course is not identical to the original course, but there must have been some course modification sideways into relatively softer layers leading to the current zig-zag of the canyon.
Wonderful video. Another case of superposition that you may want to take a look at (even though it is far from your usual field) is where the Trinity River goes through Dallas, Texas. Also, the rock strata exposed from Dallas towards Ft, Worth is quite interesting. In a nutshell, the exposed strata dip to the east and in the Dallas Area are Cretaceous Age and age older to Pennsylvanian west of Ft. Worth. This area is the eastern edge of the East Texas Embayment and is also where the Ouchita mountains are buried underneath. Although there is not much to see on the surface, underfoot it is quite interesting.
Another interesting fact is that many of the Texas main rivers (Brazos, Colorado, Trinity) actually drained from the Rockies until they were cut off by the Red River.
Another interesting area is the Balcones Escarpment in the Austin area. There is several thousand feet of displacement between the west side of IH35 and the Edwards Plateau and the east side of IH35 where primarily Quaternary deposits exist.
Pick up the book Roadside Geology of Texas. It is awesome and talks about all of that and more.
@@garyb6219 I have a copy and other references.
The river was there first......
ding ding ding!
Wow you must not believe in God! /s
@@parkergailey9625 cultist...
@@ajearthdude8467 look up /s
No. The mountain was there first. It was underground, so technically not a mountain, but it was there.
Similarly to the Black Canyon in Gunnison by the Gunnison river then?
Seems to me water cutting through soft soil is OK but as harder soil is encountered slowing down forward progress causing water to pool until softer soil is encountered and then continuing off in a new direction.
Have you ever done the water pocket fold
Not yet but I've visited there several times. I did do a video on a similar feature in southern Utah called the Comb Ridge monocline: ua-cam.com/video/ZQWw1sYjJ8w/v-deo.html
How does this relate to the Green River cutting through the Uinta Anticline? Is it a similar story?