Geology of the Bizarre White Stripes in the Jurassic Summerville Formation of Southern Utah 

That really is a bizarre formation. The gypsum veins give the cliff face an almost biological appearance. Thanks again, Shawn, for another super interesting video!

That cliff looks like a rather "dry-wall"😊

Wow, Utah has some seriously cool geology, thanks Shawn

Utah is such a fascinating place from a geologic standpoint. Thanks again for helping those of us who aren’t so sophisticated to learn something about it.

You have taken us to some interesting places professor and this one really needed the explanation about the gypsum. Never seen anything just like that before.

If I would have come across that on my own, I would have been so confused on how the stripes could cross layers like that. Thanks for the explanation and the video. I found it very interesting.

Fascinating location, thank you. Still looking forward to a possible video on the Heart Mountain Detachment. Thanks again.

Wild stuff, really..amazing it was deposited millions of years ago..

Great story Shawn, brought to life with your context map which really helps me to understand this better. All makes absolute sense.

Great content as always Shawn thank you.

Road cuts must provide a wealth of information to geologists. Since watching your videos, I keep my eye out for everything I pass by while driving.

thank you shawn willsey...for keeping it simple & to the point....it takes work & dedication to just talk about what is simply here for the viewing...awesome

Excellent explanation! Thank you.

More than 50 years after a Geo 100 course I wondered if the veins might be gypsum and whether you might do a Mohs hardness test with a fingernail. Amazing how one Geo course stays with you long after you've forgotten your Shakespeare.

Thank you for the fine video. I’ve watched many of you videos and I really appreciate your positive tone. I just bought Roadside Geology of Idaho. Thanks!

When I first saw the gypsum veins I thought it was some form of strapping to keep the cliff from collapsing, it looked man-made. Fascinating how a mineral rich water infiltration could deposit those bands so uniformly.

Mr Willsey thank you for your videos. In 2007 I took a bicycle ride from California to Kansas. A bit of interest in Geology grew into a great interest in Geology. Especially the Geology of Nevada and Utah. I biked right by the formation in this video. Your videos have been so informative. Almost more than I can process. I have since traveled from Virginia to the West coast and back. I have been to Craters of the Moon andI find your Snake River Plain videos very interesting. I visited the obsidian cliffs in Yellowstone. I grew up on the fall line in Virginia and have been trying to put it's Geology together. Thank you again, keep it coming.

Always answering questions that have puzzled me over the years! Thank you again.

Thanks,,, your explanations of geological deep time are fascinating. Much to ponder on in the interpretation of our individual surroundings wherever we are in the world.

@Shawn Willsey Oh my gosh, outside of Hanksville, Utah!! My gosh it's been too long. I was raised here. You have an awesome channel. Growing up where I did & the Amazing geology of Southeastern Wayne County. It's unparalleled

Awesome, informative video! Beautiful formation!

I saw those criss-crossing veins and got really excited, but turns out different. I once spotted a few car-sized boulders here: 44°48'55.67"N 89°51'58.51" eleven miles SW of Rib Mountain. Rib itself is a quartzite monadnock, but the boulders are a fine-grained uniform dark grey hard stone. And criss-crossing them are thin veins of pure quartz, often at right angles to one another.

A very interesting hypothesis

Another amazing educational video ................... Thanks Shawn ................

Great presentation, the paleo geographic map really helped put this information into perspective! Thank you!

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Thank you Shawn, that was really interesting. Looking forward to your next video😊

Mind blowing!

The Ancestral Rockies had been uplifted at about 300 MYA, but had largely eroded away, as can be seen on the map at the right. The Sevier Orogeny was largely complete at 160 MYA - the mountain range on the left - and this inland sea may have been a large foreland basin resulting from a down-warping of the crust adjacent to the mountains. It's fascinating the way the gypsum crystallizes as vertical columns. I assume that since the seam was filled with gypsum solution that was all crystallizing at the same time, it was easier to grow upwards and push away the soft sediment, than sideways, against the other crystals. They took the path of least resistance.

Very interesting. In Utah, I have not been south of I70. These videos are introducing me to an area I have never been to. I am seeing that I need to learn more about those ancient inland seas. Thank you.

Thank you for a clear and informative explanation of this interesting cliff face.

Thanks!

Thanks for this Shawn. Wondered what those stripes were.

Positively gorgeous formation wow, for one sedimentary rock is always pretty, but the veins of gypsum are wild. I thought they were layers of decade old fraying tape or something that was meant to prevent rockslides, it doesn’t even look like part of the rock. Also looks almost like tree roots

Great gypsum explanation

It's fascinating

"You miss 100% of the fossils you never look for." -- Wayne Gretzky.

Really nice presentation. We have a similar formation in England along the southern edge of the Bristol Channel up to around Miehead. Here, You can see the exact same Gypsum incursions in to sedimentary beds with vertical bands. At Kilve beach, you can also see it in the oil shale layers.

Wow. I love how geology is used to work out the history of an area. I live on the northern slopes of the Sierra de Mijas in Andalucia in S. Spain. I would love to walk the area with someone like you. Walking up a dry arroyo near where I live is fascinating. Mostly it looks like a giant digger has scraped up a huge lagoon floor dumping water worn stones and clay. Then there are odd intrusions. Then you hit the remains if a sandy beach white sand and sea shells a couple of hundred feet up. By a worked out silver mine. Of course the uplift is caused by Africa slowly moving northward. So I have been told or read. The valley floor is also littered with the remains of the ancient lagoon. Fields full of the stones from the the lagoon floor. Some are used to edge terraces on the slopes as well as to build the older houses. I suspect they used the clay as mortar.😉

The White Stripes rock

Fascinating video. This amateur Oregon geology fan is subscribing to your RU-vid!!

Pretty rocks!

The earth is a recycling machine, so to have this formation to look at from 100's of millions of yrs ago is remarkable, I'm fascinated to think about that land where creatures from that long ago walked the earth. Thank you

The different geological beds are conceptually similar to tree growth rings. Excellent presentation.

Thankyou for your time.I am in Australia looking at my local area in a different way.

This formation is intriguing and definitely needed your explanation, fascinating to find gypsum in those layers. I really like that map, is it available to order? And this area is now also on my list of places to scout out. Thank you so much again Shawn.

Cool. Been by that area a few times, I even have a photo of the bluff you're standing next to. (Right close to Prairie Dog rock, right? 😁) Just came across your channel. Always been fascinated by the geology of the area and the West. Will have to look over your channel before I start coming up with questions, lol...

Another great video. Shawn do you think you will have any field trips with IMMG or others that guests would be invited to attend. Keep up the great work for an old, retired geologist.

I don't know if you'll make it to the Hanksville area but I would be interested in the geology of the Long Dong Silver formation. Great video.

Hay Shawn you should come up to northern Minnesota and do a video in the iron range abandoned ore pits I've come across some very weird layer stacking in the hard rock. Tower Sudan mine shafts give you great access to deeper layers including diamond ladin columns

i did mapping in the Ephraim area for my geology degree. I did find much gypsum, ripple marks, and a fossil that I thought to be a turtle bone. The thing was that a person could see almost all of the geology because of the climate, unlike OhiO or Virginia where everything is covered with soil or vegetation.

Thanks Shawn, great video. I used to drive to Boulder Utah to measure a ponderosa pine test plot. Went swimming in the Fremont on hotter days. For some reason I got the sense, looking at the outcrop that the horizontal thicker gypsum layers would have been deposited on the surface, ie salt water drying, then another deposition of muds, sands et al. Would that be somewhat close? As t the non-horizontal smaller gypsum layers, they almost appear as trackways, As usual I have no clue and need your great guidance. Cheers, Jim

7:19 .. . . being assembled . . . . A shout out to John McPhee?

Could we be looking at seasonal layering, with the light and dark sediments?

Fun fact: the Tidwell Member of the Morrison Formation used to be considered part of the Summerville Formation!

Now I can figure out what my counter tops are “formed” by Muahahahah..... Lovin it!

...... Land o' Lakes,wi.........here for class ...no way,veins of quartz???..holy cats,,,what layers....tnx,pat&family.

Omg mate don't pull at it too much.waiting for it to fall on you.great job in showing us here in Australia.we have bungles bungles up north of western Australia.

Could it be possible that the very thin layers of sediment within the larger dark layers represents one days worth of tidal action? I have noticed similar thin layers within the upper Morrison Formation at the Dinosaur Ridge road cut near Red Rocks park, just a couple miles north of Morrison, Colorado.

Gypsum has a very interesting history

9:24 Let’s talk about that beautiful stone sticking out! Look at that! How many millions of years ago, As it landed where it still lays, It had already been worn smooth… I’m reminded of a cartoon video I saw about the lifecycle of stones/rocks. I’m fascinated by them. A snapshot of a moment in time. I’ve also noticed, Every stone has a base shape, and every one of them spirals. Triangles, flower petals/tear drops, pentacles and squares, all spiraling through space, and frozen in place For us to contemplate. Thank you for explaining the veins so well, they amaze me. Sometimes, the “Flaws” of the stone are what makes the stone so wonderful. Here in #Vermont, We have #GreenMountainJade. They stick to magnets, It’s cool. They often have veins of #Quartz, and other things. They are beautifully mixed from deep dark green/black, to a light almost white, with some yellows and oranges. A lot of our sedentary stones sparkle with pyrite and other minerals. Anyway, I’m rOcKiN nuts, Just really wanted to say Great video And you would LOVE our stones!

Does tectonic uplift then cause the formation of the green river in Wyoming? Was there a massive flood afterwards that created the formations of plunge pools, and flood etching over moab, as well as castle valley, San Rafael? My question is basically: was there a massive drainage event?

What explains the vertical travel of the gypsum beds? Was that uplift after sedimentary action? Or was it veins that they seeped into and evaporated as you described?

I don't know what specific environment was necessary for the evaporation of sea water to leave salt deposit and gypsum, mutually exclusive... Any help?

I have seen this outcrop many times, and others like it. But how can these obvious layers of gypsum be post-depositional? Aren’t they simply evaporite layers put down in brackish water? Thanks for an informative video. What do such outcrops tell us about the regional picture of the depositional environment?

I'm interested in getting any copies of those maps if possible for teaching geology?

Just a thought, if these stratification layers were laid down so many millions of years ago would not the layers become more solid as you dig into them instead of the crumbly Parts that are eroded and visible on the "surface" of the formation?

Seconding the earlier comment, where can we order those maps that the NAU Professor created? I want to wallpaper my house with them. ❤

Is this map you are using on your website for download? Or a link to the map?

Correlative with the Wanakah Formation in Western Colorado. Interpreted to be hypersaline marine facies, likely estuarine or tidal mudflats. Gypsum CaSO4 +2OH (hydrated calcium sulphate) is interpreted to have precipitated from shallow high-saline arid marine environments: think the Dead Sea. It was carried in groundwater which was injected between the strata due to pore pressure causing Griffith cracks that subsequently propagated across the weakest lines of resistance, if you must know, and IMHO. JK Nice Vid, I approve from my armchair!

Sorry Shawn Some geologists include tidal flats in marine facies, as they are transitional between marine and terrestrial. My bad.

❤

Is that water area the western interior seaway?

Thank you from a home-biased Utahn

❤❤ what precipitates calcium sulfates....

I was wondering what that was.

What event broke that ? Leaving It open sideways!

When I was young we drove through an area of gypsum mines in Arizona. I believe it was call Gypsum City. There was nothing much out there. Sand and rocks and for me the only interesting part of the desert. Thx

Mudflats, baby!

I just ordered Geology Underfoot in Southern Idaho! I couldn't find where to send you a message so, could you sign it to Gary B? (I comment here frequently) Thanks!!

Looks like you put tape on the wall

How does the gypsum transverse vertically through millions of years of mud and sand deposits? Hmm?

Could it be possible that those veins were created by insects?

And all that in only 6000 years 😁

This is what I do not understand...if a meteor is responsible for wiping out the dinos, then how come we don't find a lot of bones at the demarcation that separates the end of the dinos, and period after. If a rock slide takes you out, we would find the slide directly on top of your bones. So how come that thin white line that folks point to that can be found around the world as the fall out from the meteor...who come dino bones are not found in contact with that line.

Professor Nick Zentner sent me. Most excellent videos and information. I want to pack up and out of the Rock River Valley Illinois and head west.

God Utah is such a cool place