Random Roadcuts #11: Geologist Investigates Utah Highway 7 near St George, Utah
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- Опубликовано: 2 фев 2025
- Learn to "READ" the rocks with this innovative video series designed to help you learn geology. Join geology professor Shawn Willsey and investigate a random roadcut, make observations, and formulate basic interpretations. Here in Episode #11, we visit a colorful and varied roadcut along Utah Highway 7 east of St George, Utah. GPS Location: 37.11478, -113.43131
Geologic Unit: Kayenta Formation (Jurassic)
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Looks like the Moenkopi Fm.
Not scripted, on-the-fly exploration, discovery, and explaination of the geology. We love it Professor, thank you for bringing us along!
Thank you Shawn, it nice to see this road cut at 3mph not 65! There is thrust faulting and parasitic syncline/ anticline folding in several places in the Virgin anticline. During construction of this cut a few years ago, there were quite a few dinosaur foot prints recovered from the second road cut (above from the rock layers you showed), now residing at the Dinosaur museum in St. George.
Legit one of my favorite RUclips series! I love 'em all. Yesterday I even added a new word to my vocabulary - diatreme.
Likewise.
I love this Random Readouts series for this vicarious travel it offers us viewers. How cool to look closely at an outcrop and ask what, why, and how and to hear your answers. As a result of watching you look closer, I've started to do the same when I've been out hiking and exploring. Learning is fun. Thanks Shawn!
I pull over at road cuts! Over the years I have found nice fossils & minerals at road cuts! Thank you professor for your time and efforts.
I think the episodes are particularly great where you have little prior knowledge of the terrain and go step by step. greetings from Germany
The rock hammer pinging always makes me happy!
Im a geologist at heart, Ive lived most of my life in London, no rocks no outcrops. Thanks to you I get to travel the world engaging my geological detective skills, I get to unravel what happened in the long distant past and when I can't you explain it. Of all the things you done Random Roadcuts are my favourites. You keep it interesting and really are a great teacher.
💚📗🖋Hi once a week a man! I love your coment in this vídeo; you and professor Shaml became a inspiration for anybody who live to study Geology. Best regard from Brazil.🙋💚🖍📗
Very interesting, thanks for posting Shawn. Great job as always!
Love random road cuts. We prefer driving and seeing this amazing country. Thanks
Never thought to stop and look at the roadcuts - who knew they could be so fascinating! Always a good show!
Excellent geo-ed adventure. Thx Prof ✌🏻
Another great learning day !
I always love these road cut episodes. I love seeing what a fault looks like in real life.
Thank you so much for highlighting southern Utah! This particular episode answered many of my questions I have had as I drive by these road cuts every day to and from work.
Thanks for your efforts, and keep up the good work!
You described the rockfaces beautifully... But what are those dark blue-grey rocks all along the bottom of the cuts? I couldn't think of a reason for humans to bring/put them there, but they don't seem to 'belong' there, either. Thanks for another interesting tour.
Basalt boulders for erosion control. They are much harder than these soft sedimentary rocks.
@@shawnwillsey Ha! I knew they weren't 'born' there... Thanks.
Wow cool road cut!
This road cut would've had me braking hard! Thanks for stopping and seeing the story. I couldn't've put it together as well as you did, though. The colors are so great! 👏🏻💕
My wife and I are overlanders who live in Hurricane. In fact, we live just a few miles from this road cut and travel it routinely. I had no idea. Watching your videos has changed the way we travel and the things we now look for. We are loving the education we get from you. Thank you so much. We're now looking at enrolling in geology classes at Utah Tech, and we're in our 60s! Proof one is never too old to learn things and fashion new interests. Thanks Professor Willsey!
That is awesome! Go for it. Glad I helped inspire you.
A lot to learn about the geology and climatology of the time, for the iron deposits near Cedar City to the red rock sandstones and mudstones of Santa Clara and St. George. And the pioneer history of that area is fascinating as well. Probably only the old-timers know that St. George was settled for the sake of growing cotton (not very successfully). Many trees from Pine Valley were used to build pipes for the first of the tabernacle organs in Salt Lake City. And farther east, Mountain Meadows and the Jacob Hamlin ranch. It’s a road well worth the extra time it takes to travel that way from St. George to Cedar City.
Now I wonder if there are pines in pine valley {pinon?} as there is locally a "spruce mountain" covered in white firs but not a single spruce-
@@jackprier7727 Tree identification was not their strong suit.
@@jackprier7727 If my memory of Utah history is correct, I think there were large stands of pinion pine in Pine Valley in the 19th century. I have gone visited Pine Valley per se, so I can’t say what’s there now.
it was kewl watching and i could see the fault before you pointed it out..means i am learning whoohooo
Looking forward to seeing you on Nick Zentners RUclips geology. You both have great programs.
Yep....if I die in a fiery crash , on some lonesome desolate road it's because I was looking at the road cuts trying to recognize some of the things I learned from Professor Willsey's videos.
Wonderful, Shawn. At first I thought those vertical features were immature sandworm tunnels. Wrong planet :)
Beautiful landscape, with a story to tell! Thank You! 😊
There is a lot of blackish rock with some quart which could be what was left from the excavation blasting. Was that from a basalt layer on the very top of the land? thanks for this video.
Basalt boulders were brought in for erosion control. They are much harder than these soft sedimentary rocks.
very cool & informative...thank you
Thank you Professor.
My sister lives just up the road from this. I'm always in awe at the geology in that part of Utah. Thanks againfor doing these.
Another fun one to look at. Thanks.
Thanks!
Thank you for supporting geology education.
Love the Random Road Cut Videos! Thank you so much for the education!!!
Amazing what the rocks can tell us!
Perfect ending to a long week! Thank you!
Hey Mr Willsey,
What a great idea those "Road cut geol" as it seem roadcut is universal.
Either it's give us hypotheses for ours owns road cut,
or/& it's give virtual travel to your great geol country.
Thanks a lot from Maurienne France.
Marcel beaulaigue
Thanks, Dr Shawn!
Great stuff! Thanks for bringing us along. I was wondering about the road construction engineering that produces these roadcuts. They must have to determine the offset and slope based on the rock types or perhaps some type of testing, otherwise they could get a lot of landslides onto the roads if too narrow, or else waste a lot of land (and effort) if wider than necessary. It also appeared that they had deposited large rocks along the side of the road that came from elsewhere. Perhaps those were to break up and slow flows of potential flood water? Have you ever discussed the engineering with an expert?
I'll definitely buy your analysis and intrepretation of this roadcut seeing as I don't know much about geology...but I'm learning!!
Another very informative video, Thanks Shawn!
Question about the white layers; you said that they were where the iron oxide had been bleached out by ground water. What chemical would do this? Did this ground water have a basic pH? How long would it take for these layers to form?
Very interesting - I've never seen anything like this. At first I was thinking something like calcite intruding into a crack.
Very interesting layers and faults. To a physician these rocks look like striated muscle.
Cool fault description! A beautiful 90 fold in mid Pa on PA turnpike… might have to stop and photograph next time I drive past it
"Just another fun little roadcut...!"
Love the Road Cut episodes, some awesome video and pictures of how beautiful these are and so great we can all get an insight into something otherwise we migh not even get to see.
Keep up the great work!
Big thumbs up 👍👍👍👍👍👍👍 😉
Glad you like them!
I'm making an assumption that where you were standing was still on the NA craton and all that bedding was created by ocean tides on a passive margin -- given we're talking 100 million years ago. Please correct me if I'm incorrect in my assumption.
Definitely the NA continent. The San Andreas fault and my crust here is sitting on the Pacific plate. That’s 300 miles away.
You probably didn’t hear but we had 2 M 4.2 earthquakes on a side branch of the San Andreas called the San Jacinto fault. It was only 10 miles from me and so scared my cat and I dove for cover.
@@edwardlulofs444 I saw that; I have family living in Temecula, Menifee, etc. and they felt both. I lived down there for my formative years and was living in Long Beach during the Sylmar quake in 1971.
@@briane173 I have heard some people claim that they are not afraid of earthquakes and actually enjoy them. That sounds boastful and inauthentic.
I had children during some of the larger events and they were terrified.
I’m not scared when outdoors where nothing can fall on me. And I tell people that they are hazardous mostly because things fall on people.
But quakes are disorienting at least and are fearful.
@@edwardlulofs444 Absolutely! The two worst earthquakes I'd experienced was the Borrego Mtn quake in '68 and then Sylmar in '71; I was 14 y/o for Sylmar and I was absolutely mortified; surprised I didn't soil myself. Even though I was some 35 miles from the epicenter the shaking was INTENSE; and we lived on a hill and it just felt like the house was gonna collapse at any moment. Luckily my dad (he was a developer) framed our house with steel I-beams on account of earthquakes and the fact that we'd built a 3-story house on the side of a hill; so OUR house at least withstood the terrible shaking during that quake. But your sense of security is destroyed when you never expect the ground beneath you to violently shake and roll and move, so when it does you're white with fear. It was not a pleasant experience and I never enjoy earthquakes as a consequence of having been in a particularly violent one.
Correct. This unit is the Jurassic Kayenta Formation, deposited mainly as fluvial systems and tidal flat along margin of continent.
Hi Shawn. Thanks for the education. I'm confused about the "faults" in the areas you videoed. Do these indicate they were a part of a parent fault. In other words, do faults have faults? I thought a fault is one massive layer. Sorry for my ignorance. You make things so interesting that my mind gets hooked and asks perhaps silly questions.
Yes, faults can occur at a variety of scales so you can have larger and smaller ones.
Thank you Shawn@@shawnwillsey
Thanks so much!
Maybe you could do a future series called something like “Random Road cuts Revisited”, where first you find some published geological maps that cover that road cut or nearby areas and use those to expand on the interpretations at these localities?
Thank you! I love Utah. I’m planning another trip there to combine my love of hiking and rocks! My favorite national park is Canyonlands. Thank you so much for this video.
A fun video of roadcut. I am looking forward to my upcoming Geological/ Botanical/ Herpetological expedition that will follow the Utah Nevada border down to Mesquite, not far from where your video was made. I know the spots I want to document as it's fairly familiar area for me.
Ah deep time the amount of sedimentary deposition out west during the Mesozoic is mind boggling is there a way to tell where these were mostly costal or riparian deposits? From the complex variability and the footprints someone mentioned recovering from there I would guess rivers were largely responsible as Utah was likely from the continental side of the various subduction complexes of the time leading up to and eventually resulting in the formation of the rocky mountains partly preserved in those thrust faults. Cool road cut as always.
I'm with you on the explanation of what you are showing us professor. Great analysis and unscripted observation.
Utah's geology is interesting, but not as much as other regions like the west coast or Canadian Shield. What makes Utah distinctive is, the geology is in-your-face.
What was the black rocks in the ditch? Did they come from the roadbed or on a layer on top?
I saw that. But random rocks often have less interest than the geological layering and structure.
There are many possibilities. Could be oil and dirt covered. Could be moved during road construction. Etc.
Perhaps someone might comment.
Looks like basalt blocks that were emplaced for erosion control.
Shawn, looking up and down the road at another cut just north of where you are, and I cannot reconcile how these layers intersected prior to the uplift. For example, where is the right side of the cut that slopes gently toward the north, but ends abruptly….?
I learned some more geology, and some more about the population growth in the area, from the traffic. Thanks!
Nice! Helps me see the landscape and have some idea of what happened soooo long ago. I know, very scientific terminology 🙂
Just fascinating! I’m ready for a road trip, now.
Another great episode in the series Shawn. Just one thing I'm not quite understanding; what do you mean by "bleaching" in the white segments? Is it chemical? The sun? Something else? Thanks for all you do.
Iron is reduced rather than oxidized so it is not red.
I feel I probably should note here that unlike oxidized iron which is insoluble reduced iron is water soluble so an anoxic groundwater flow can carry the iron away in essence bleaching the rocks through removal.
OK, so that makes it more clear what I am seeing. Thank you for this explanation. I'm just a geology hobbyist with no training. So let me ask you another question. Why would iron be reduced? From the limited understanding I have, iron wants to give up electrons (oxidize) not receive electrons (reduced). Can this be explained to a non-scientist type? @@Dragrath1
@@michaelsanfilippo7433 It is more complicated than that, reactions generally don't go all in one direction except at a statistical basis depends on the environmental conditions in environment as the reactions don't go one way but really are determined by the chemical abundances of reactants and the flow of energy in a system. For example if molecular hydrogen is much more abundant than molecular oxygen reactions will tend to be driven in the reverse such as might be found in the hydrogen rich environments of the early solar system or the giant planets such as Neptune Uranus Saturn or Jupiter
Notably on Earth anaerobic photoferrotrophs and chemotrophs biologically drive reductive reactions using iron as a an electron donor for carbon fixation. The conversion from Fe 2+ to Fe 3+ in order to convert dissolved hydrogen ions into is an ancient biological reaction which appears to be around 4 billion years old. Sulfur reduction is another big anaerobic means of primary production for example. If one direction of the reaction stores chemical energy the reverse reaction will release that energy an most of these processes are generally reducing the main exception being atmospheric/dissolved molecular oxygen.
How close is that fantastic roadcut to the Hurricane fault? That one is a massive normal fault, down to the West, but might there be some associated structural dynamics that created the compressional thrust faulting?
About 7 miles (11 km) west of Hurricane fault. These are two different faulting episodes.
I really liked your commentary on the thrust structures. I'll be looking for them now.
An image of a road cut in the under construction Toquerville Parkway (a new section of Utah Highway 17 that bypasses the town) showed up on my Facebook feed. It showed vividly colored laminations that were fairly thin. Some looked to my eye like ashfall. Next time you are in Washington County you might check it out... would be interested in your interpretation.
Saw that when I was there in December and wanted to do a video there but there were construction crews there and signage to stay away.
Thank you for spelling the awkward names. I was wondering about the severe (Sevier) orogeny that you'd mentioned before.
That is a really beautiful spot. I'll try to make a trip to the area.
Hello, just wondering about the black rocks at the base of the roadcut. I didn't notice a source above the red sequence. Thanks.
Basalt boulders for erosion control. They are much harder than these soft sedimentary rocks.
That was awesome. Thank you!
Classic textbook-perfect roadcut, slanted strata allow millions of years of time in short lateral passage- Is it real to think that most of these eroded alluvia were deposited from wild levels of erosion because there was little or no vegetation way so long ago?
These days when I drive by a road cut, I accidentally slow down to see what is visible. I’m going to get into an accident one of these days. BTW, would there be fossils in those depositions?
The Kayenta Formation does have fossils, including dino tracks.
Those bright blue rocks in the roadside ditch look foreign.
Basalt boulders, brought in for erosion control along gully.
We seem to pay the most attention to the large scale, dramatic, high displacement structures, but I wonder if you were to add up all the subtle and often overlooked small displacement faults like the ones you pointed out, if those would actually account for a significant portion of the total crustal extension or compression in a region. If you ever make it back to the Las Vegas area, check out the Las Vegas Valley shear zone, which cuts across the landscape north of the city. It's most visible in parts of the Lake Mead National Recreation Area, northeast of Las Vegas itself. It's a wonderland up there, although in many ways similar to southwestern Utah.
Just looking at where the cut was located it looks to be part of the Virgin Anticline. Zooming out in Google maps you can see the anticline as it heads towards Quail Creek State park.
Yep. It’s well exposed there.
Nice ! Thanks
A bit too blue on the rocks and plants, but thank you for being so informative!!
One question? How do you determine the direction of the thrust faults. To the left or the right?
Thrusting was to the east, to the left in these videos.
Love the lessons! 2 questions: can you comment on the dark gray/black rocks at the base of the mountains, are they from road building scraps?? And at 17:30 or so, what are all those vertical cracks down the mountain, are they also core drills or another kind of fracturing? Thank you
The description states that SR 7 is west of St George. That description is not correct. Using the provided GPS coordinates in Google Earth puts us at a location slightly East Northeast of St. George and East Southeast of Washington.
Typo. Thanks for spotting this. Fixed now.
It’s okay. I do frequently substitute the opposite compass direction when I speak. Don’t know why. It carries into writing.
This I also a great drive both directions.
I haven't paid attention to the roadcuts before; now, I probably will.
what are the blue-black rocks along the bottom of the first cut? did some road crew put decorative stones, or are they from something in the area?
Basalt boulders for erosion control. They are much harder than these soft sedimentary rocks.
Have you done a video on the road cut on I70 at Morrison, Colorado? It’s amazing!
Some plants look like they are blue instead of green. Wonder what they are called.
Professor Shawn, the blueish rocks at the bottom of the road cut just doesn’t seem to be fitting in properly. What are they and why are they there. Is it something the road department scattered in what could be a road drainage to possibly slow the flow of water to prevent erosion.
Basalt boulders for erosion control. They are much harder than these soft sedimentary rocks.
Thanks for sharing your vision of the rocks! But what were those black rocks at the bottom? I didn't see any such rocks anywhere else, except at the very end of the cut it looked like a steep fault section where they were tumbling down. A manganese stained layer? Basalt from an eruption? These roadcut videos are cool!
That's like a mile from my house.
What are the blue rock on the bottom, in the dirt? Also have you ever been to Canyonlands National Park? Must be a scientists utopia. LOL All the colors, shapes, rocks,and layers. One of the most incredible places that I've seen. Not in person though. Would ne awesome to see in person.
basalt brought in for erosion control.
I don't understand the white 'Bleaching' but will take your word for it. Very nice view of horizontal faulting. I like the Google Earth view at beginning, it really shows that something interesting is going on here. Thx!
Could the white bedding possibly be Calcium-Carbonate deposits, evaporates?
Very nice! What are the darker rocks lying around on ground?
Basalt brought in for erosion control.
what about the dark stone that appears to be hauled in during road construction (at the base of the outcrop)... graywacke?
Basalt.
Love these! Have you ever done anything on the great crack in Oregon?
Not yet!
I m waching every episode i can find. This one i think is Triasic moencopey are the white lines a different maybe evaporate layer? Or can you explain the bleaching? I think i see both in several cuts in Saint George. Some times i have found gypsum layers and other times definitely bleaching. I just don't understand the bleaching . Thanks i wach lot's of your lectures also love the mineral explanation video's. You are great the eruption video updates are awesome
So what were all those blue rocks on the ground below the cut?
Basalt. Brought in by highway dept.
Shawn, are there any spots left for Iceland?
The 2024 trip is full. But I’m planning another for 2025.
@@shawnwillsey excellent. My wife was all over me for not taking advantage of the first one. I will keep an eye out. Looking forward to you being on Nick’s class Feb 3rd. I play in a bluegrass band and we play that morning in church, so I will probably catch the replay. Thanks for everything, especially the Iceland updates.
Geologists leave all sorts of traces of their activities in the rocks for the far future archaeologists to ponder.
Are those dark stones green?
Where would they have come from in all that red mud?
Basalt.
Brought in for erosion. Harder than sandstones and mudstones.
👍
What are those black rocks strewn at the bottom?
basalt brought in for erosion control
❤❤❤❤❤
What are the black rocks at the foot of that feature? They seam out of place.
Good eye.
They are indeed out of place. Basalt.
You didn't mention the blue-black rocks at the base of the road cut. Maybe put there at the end of the road construction? Not seen in the face of the road cut sandstones..
basalt brought in for erosion control. much harder than sed rocks.
Thanks - that's what I thought. Just trying to use all the info you bring in your vids to figure out what the rocks tell us.@@shawnwillsey
Are the dark rocks, in the ditch, basalt?
Yes.
Thank you@@shawnwillsey