Random Roadcuts, Episode #12: Geologist Explores Double Cut Near Kodachrome Basin State Park in Utah 

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I wish you had been my geology professor when I majored in geology in college in the 1990’s. You make it much easier to understand. Keep the road cut series going!

I love the Random Roadcuts series. Ty for doing it!

Thanks Shawn. Those dark brown mudstones with vertical and horizontal lighter bisecting elements are wild.

Great! I always learn something from these roadcuts. The layers are fascinating - but the intrusion made it extra special!

I really love this road cut series. As a young fellow I was enthralled by the rock exposed in road cuts, you've given me much knowledge to explain and identify the geological forces that created the exposed surfaces. I wish you were ( and the internet) were around when I was a young fella.

Love the Random Roadcuts! I learn so much more actually seeing rather than just reading. Keep on doing them, please.

Those mud layers look like a brick wall. I can imagine the mud dryed up and created little blocks then came the white mud morter to fill the cracks. Love it

The geometric lattice seems a mud bed that cracked into regular blocks and then flooded with the white sand mortar'. Awesome exposure! Thank you!

Every road cut lesson is fascinating. I will never look at a road the same way ever again. Thank you.

Thank you! My wife and I stayed in the Kodachrome Basin area several years ago. This road cut was one of the most interesting road cuts we've seen. The dark brown and white brick like layer was most intriguing. It almost looked man made on our first pass through but we stopped latter to inspect. We are not geologists but we do love the beauty of geology. You bring a lot of clarity to things we have seen. Southern Utah is spectacular. Thanks again.

Thank you, Shawn. That’s a great road cut to explore. There’s always something new to learn.

Yay! My favs! Random Road Cuts! I hope you enjoy your time exploring these as we do watching! Thanks!

Thank you, Shawn. I really appreciate you sharing your knowledge with us. My Geology degree was more years ago than I care to contemplate and you and Nick Z. have been filling in a lot of gaps. Things that I never learned or forgot and new understandings and interpretations that have come with more study.

Just have to add my appreciation for these Random Roadcuts, always fun, informative, and thought-provoking!

That road is Kodachrome Rd which becomes Cottonwood Canyon RD past the state park and that runs to the Grosvenor Arches, maybe 20 miles or so. The road continues all the way to the Old Paria ghost town/movie set and the highway on the south side. We were out there a few years ago and stopped at the Arches. Nice drive good road thru some hills.

Simply awesome, thanks for posting Shawn!

Thank you Shawn...always interesting to have you analyze and interpret the geology of an area...I'm still amazed the time periods involved in shaping all of our planet...

Roadcuts are how I learned about geology to begin with. They will always be special for me. If you can find a book about nearby roadcuts,buy it!

Love this road cut series! I so appreciate your easy-to-follow explanations, the use of terminology that accurately labels what we’re seeing, and the excellent camera work. Thank you!

I love the random roadcuts too… thanks for sharing knowledge 😊

A stop at a road cut in 1966 in the middle of the New Mexico desert for a nature call set me on the path to a lifetime of fossil and mineral collecting. At that road cut I found a seashell stuck on a rock. Not knowing how it got there I put it in my pocket and later in science class my teacher said it was a fossil. Now 58 years later I still stop at road cuts every chance I get.

Great episode! But I am afraid I am going to have to rewind and watch again. Was so excited to see you wearing your hat, I missed half of the details. LOL! Glad you are getting some use out of it. ❤

Amazing to hear the history of the activity that formed the rocks so long ago in an ancient world. Gives one an appreciation for the age of the earth and all of the various geologic events. Another great video.

I do wish that videos such as this had been available many years ago when I was more mobile than I am now. These random roadcut videos are both instructive and entertaining and I do enjoy your explanations of the visible strata. I have learnt so much from your videos and I hope that you will continue to produce such outstanding work for many more years.

It's amazing that these rocks maintain their history for thousands of years. THX for your expertise & time. ⛏

This was fascinating! One tiny area has a LOT going on geologically. That stacked-brick looking formation is almost unbelievable. Super cool! Thanks for posting

Another great episode of Random Roadcuts! Each one is so different, but your careful observations help reinforce what I've learned from earlier roadcuts. I guessed correctly on both the regular fault and the dike formation (and learned new terms for it), so I'm actually retaining info, thanks to you. The sandstone here is so variable, ranging from massive, hard blocks at the top to easily crumbling dust toward the bottom...like a few good whacks with that hammer might cause a rockslide. And those white layers with vertical sections are wild...I've never seen anything like them. Thanks again!👍🏻👏

My favorite at this cut is the dark mudstone cut by the white. In the teaser bit in your previous video, it grabbed my eye right. To me, it almost looks like mason laid blocks. Complete with the vertical white bits offset from those below.

A clastic dike/breccia pipe, decorative layers as if intentionally designed, faults, lovely molded sandstone, beautiful! Thanks for showing us, Shawn! Starting to get the hang of this...😄👌🏼

Such a fascinating roadcut!

Thanks ! love ❤ Random Road Cuts

Great stuff. 15:40 the patterned features looks almost as regular as a brick wall - pretty neat.

I consider Nevada Arizona Colorado and Utah home. I can't begin to express my appreciation of these road cut explanations. There is no place as cool as Highway 89 both in Arizona and especially Utah. Now I know a little about what I've been looking at for over sixty years. I believe this is your home too. It shows. Be well.

Absolutely agree with the other comments. I just LOVE these Random Roadcuts videos!! It's quite fascinating and interesting to read the rocks. Keep bringing them on!!

Watching and learning from the UK here, I get a lot from this form of spontaneous observation Shaun. As a child I grew up 400 yards from Ludlows Ludford Corner, Silurian bone beds. I collected the fossil shells and remain hooked! More of this, please.

I'am surprised there isn't any snow on the ground, still very interesting .

Thanks Shawn for this double delight - both sides of the road! Loved the "bricks and mortar" layer on the south side and that butte on the north side looked like a Napoleon cake. Terrific stuff! Keep them coming - they're great fun and I learn so much!

This was a very interesting road cut.

These Random Roadcuts are the best! Thanks, Shawn!

Shawn that layer on the south side with the white segments looks as if they were made by a mason. I don't doubt it being a natural formation but very intriguing. Thanks for the video.

Keep up the good work! With every layer, I try to imagine the landscape with that layer on top, like the dark mudstone. The white intrusions almost look like garden sections against the dark mudstone. This area has long fascinated me, fortunately I survived all my hikes. Thanks for posting these.

This is my first "Random Roadcut" video (I'm normally catching your Iceland/Hawai'i updates) - I'm glad that I stopped by 🙂 With those two faults on the north side, it almost looks like the amount of displacement decreases with height, becoming almost zero once you get up to the rounded large sandstone layer. I would *assume* that this means that one could date the fault displacement by the amount of displacement (where "no displacement" = "no more slippage after this time") You students are lucky to have an instructor like who who (1) clearly knows his stuff, (2) is willing to share that knowledge, and (3) is a good communicator. Not to mention able to admit if he doesn't know some things. Keep up the great work.

Thx Prof for another excellent geo-ed adventure. ✌🏻

Beautiful roadcut, so much interesting stuff in such a wee space. Thanks Professor.

Thank you so much for your very interesting videos and for showing this gorgeous scenery to us. It truly is glorious country!

Hi Shawn, when you mentioned "breccia pipes" it really got my attention. I spent about 15 years as part of a team of geologists finding and mining millions of pounds of uranium and vanadium from breccia pipes across the Arizona Strip. Those pipes all appear to be collapsed features seated in the Red Wall limestone and in some cases crop out as far up section as the Chinle Formation.

Towards the southern end of Cottonwood Canyon Road is a formation known as Yellow Rock, not far from the abandoned townsite of Paria. I'd love to hear a Geologists take on Yellow Rock.

Goodness I learn so much! Wow that up going clastic dike was cool. Just beautiful scenery too!

For any student of geology this one road in Utah has the best overviews of all roadcuts in Utah. US 89 might be faster but this is the slower more scenic route along the Paria River to Utah 12 in Cannonville 45 mile to the north. You can deviate away from this road to see even more fantastic rock formations as you head north. My attention does go to that very thin white layer between the darker red sandstones below and the lighter above. This is mud (now a mudstone) that was set in between inland sea depositions? Rain, snow and wind is really wearing down all of this material and not just your hands. Great roadcut professor thank you for your observations!

Loving the road cuts, well all your videos honestly. I’ve learned so much!

Thanks Shawn the pattern of the mudstone is really interesting all kinds of features.👍

I grew up in western Pennsylvania and have traveled a lot in Utah, Colorado, Idaho and Arizona. I have been impressed with how different the geology is between the east and the west. In Pennsylvania we have lots of sandstone and shale. Based on the fossils found there in road cuts and strip mine walls the age is about 250 million years. I would really like to see you do some traveling in western PA and comment on the local geology.

Stunning! Thank you. Those white layers against the dark were mindboggling.

15:41 Ancient Aliens brick wall... That's my ultra-scientific guess. Great roadcut Shawn! The South-side is amazing to look at. Your commentary is great to listen and learn.

Thank you, The windowpane layer was strange and wonderful!

Yep -- my first thought was clastic dike. I nice wide one. Here's what I can imagine, and you can tell me whether I'm too far afield with this idea: I notice first of all that the clastic dike not only lines up on either side of the road, but it is also situated _between_ those two little faults. Additionally, the fault angles allow me to envision a little "graben" dropping that chunk of sand layering between the fault surfaces. Were that the case, I could then envision that "graben" dropping during an earthquake, pressing down on groundwater below it as it's sloshing back & forth during the earthquake, and creating a _sand blow_ (or sand _boil)_ -- an element of liquefaction that can send groundwater squirting out from the ground -- which in this case would be the genesis of this clastic dike. How's THAT for a nutty story?

It would be interesting to excavate some of those regular white intrusions to see what they look like horizontally. I wonder if there was a mud layer that dried out leaving hexagonal cracks which then subsequently got filled in by the white material and we are just looking at slices through the hexagonal sections from the side.

Good find Shawn! Thanks for the look and impromptu classroom!

O thank you stay safe ALL.

Thank you Shawn for sharing! 😁 I really enjoy all your videos!

Thanks Shawn for these and all of your videos.

Beautiful. Utah's geology is so varied. The sedimentary layers can be so dramatic. It's odd that this road is called Cottonwood Canyon Road. The Cottonwood Canyons I'm familiar with are cut from glaciers in the Wasatch range. Little Cottonwood Canyon had a glacier that descended right to the shoreline of Lake Bonneville where it left a huge mass of till. These canyons have their own amazing roadcuts. I was admiring the quartzite blocks in Big Cottonwood Canyon the other day. I never have enough time to do this. Thanks again, Shawn.

Thanks Shawn! That was very interesting and beautiful!

Have you ever studied the Utah Uintah Basin (Asteroid) Impact ? It fits into the same time as the Chicxulub asteroid, K-T boundary, dinosaur killer at the Yucatan. 12 mile diameter asteroid, buried 12 miles deep, with impact basin 110 mile x 119 mile zone. Same Uintah Basin asteroid size and impact zone - but buried 4-6 miles deep ... under/near Skinwalker Ranch Utah.

Did you say Kodachrome 📷 Edit::; This was a very interesting road cuts thank you.

Fascinating!

Very awesome.

So Cool! Thanks for posting!

It's funny you stopped to talk there... I specifically stopped there a year ago to investigate the brick-like mudstone I spotted along the drive. When I was driving by, it struck me that it looked similar to chert deposits I'd seen before (but larger), but alas, just mudstone and clay or sandstone...

I learned to love geology from a great professor at Weber Stete early 70s Dr Richard Moyle

Thanks!

Any idea why the soft sand layer is not cemented while it seems the layers and formations above it are cemented? Perfect example of a clastic dike, good video thanks!

Great content!

Next time you’re around Escalante and have the time, check out the Inselberg cyclonic sand pit aka the Cosmic Ashtray. It’s a bit of a hike and dirt road drive to get there but a great and unique feature.

Just watched a show on mountain forming in Sicily. Some totally wow formations over there. Maybe a real road trip time.

Thanks for another fascinating roadcut report. What. a gorgeous area and a stop with very little road traffic -- just one car. The clastic pipe is an interesting feature-- wow-- quite the mud intrusion. Appreciate you describing the grain size and texture of the sandstones. Any idea of the source of all the sediments? What eroded? where was that? I love the learning I get watching your talks.

I have all Paleozoic marine sediments , mostly limestones , in my area . If you see features similar to those clastic dikes , they are actually solutionally enlarged joints with clay fill . Yeah , lots of karst and caves hereabouts . One cool feature of these clay filled enlarged joint is that the more resistant materials get weathered out in relief and fall down into the enlarging joint . This is typically chert nodules , concretions , and , marine fossils . At the base of a road cut they can form a debris fan / talus slope , and , are great places to find very nicely detailed fossils weathered free of the limestone that once surrounded them . I have noticed a depressing trend where new cuts are pulled back and sloped , then covered with soil and grass , as if the general public must somehow never know that rocks and geology exist .

At 07:06 it looked like some of the material from the cross-bedded unit had filled in a “V” shaped channel in the more flat lying unit underneath.

Come to the Arbuckle Mountains in Oklahoma, there's some very neat Road Cuts there

Exposed formations (other than Quaternary alluvium) in nearby Kodachrome Basin range from the Jurassic (~180 Ma) to the Middle Cretaceous. (~95 Ma). From younger to older they include: the Tropic Shale, the Dakota Formation (which perhaps should be called the Naturita Formation here); the Henrieville Sandstone; the Entrada Formation, and the Carmel Formation. The Topic shale and the Dakota are Cretaceous, the Carmel and Entrada are Jurassic, and the Henrieville Sandstone is Late Jurassic.

Nice hat too.

Roadcut on San Andreas Fault Hwy. 14 just before Lancaster, Ca..

Regarding those mudstone layers with the sandstone horizontal and vertical divisions - is it possible that this area was dry, with lots of wind-deposited sand layers, then went through a wet period where a thick layer of mud was deposited, then that dried out, forming deep cracks which filled with the light-coloured sand that covered the mud, then the process repeated for another cycle before the local climate switched back to wind-blown sand deposition?

I love this series! What do you think formed the rectangle white features in the sandstone?

Awesome cut...so much Geology opened up by roads...would this sand have been under water at some time? Would there be fossils?

Could the dark with white be filled mud cracks? Imagine viewed from top.

I think I might actually be learning, because I identified the faults before you pointed them out, and I also thought that was some kind of dike when you showed it. I'm still very green, but at least improving!

Just a heads up. A Nevada town called steam boat springs seems to have 208f water coming up in new places in a news story. As the back ground showed the geothermal plant. Seems confusing and explained at the same time.

Brilliant, Shawn, thanks. One question. With the faults, how do you know which side moved up and which moved down? I think you referred to these in these video as 'normal' faults? Cheers! Jeremy.

The mudstone patterns on the south side look like bricks and mortar. I've never seen rocks do that before

Are their geologists assigned to the road cut crews? It seems like they purposely left that South side dike just for us to examine ⛏️ Or did it just weather out since the road went through? Another great video!

What kind of modern features would those clastic dikes represent? Maybe a spring or hot spring? The contact between it and the sandstone layers on the south side looked like they might be altered not unlike the baked rock in a magma dike contact

They say those white markings every 1/2 to one meter were how the calvary spaced their horse parking.

Are we going to see more from Cottonwood Creek Rd, farther south in the Coxcomb Monocline?

I was afraid you weren't going to mention that weird layer at the bottom that looks like brickwork with the white 'mortar' and dark 'brick'. It even has the 'brick' segments fairly regular in size and shape with the vertical edges with white 'mortar' being offset in the same way you would lay bricks. Very strange. I wonder how this formed.

Could that “breccia pipe” be a slot canyon that filled at least partially by mud and debris from like a hundred year flood?

Could the dark mudstone with white fill be cracked dried mud that's had sand fill in the cracks?

You have some nice faults

Is it obvious what direction the "classic dike" was moving? Are the faults from the dike's formation, or did the dikes form due to the faulting.