Geologist explains southern Utah's Navajo Sandstone and Moqui marbles at Snow Canyon State Park
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- čas přidán 12. 12. 2021
- Geology professor Shawn Willsey explains the geologic story of one of the Colorado Plateau's most famous formations, the Navajo Sandstone at Snow Canyon State Park near Saint George in southwestern Utah. Learn more about this Jurassic sedimentary rock, how it formed, and the interesting Moqui marbles that are sometimes found within it.
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Shawn Willsey
College of Southern Idaho
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im a geology professor at a community college in NC. I will show my classes some of your videos...thanks much
Awesome! Thank you!
I feel like I've stumbled upon a treasure chest of geologic knowledge and shared learning. Thank you.
You bet. I love doing these videos.
Thank you very much for the quality videos. It is nice to 'get back out into the field' again. I am a retired soil scientist who spent a career mapping soils in the Pacific Northwest. Geology was a major component of my work.
I am so glad the YT algorithms dropped your videos into my recommendations. I have always wondered about the “marbles.” Thanks for your informative videos. My family and I travel all over the western US, and we often see geological features that are fascinating.
Glad you enjoyed this and it was helpfully informative. Check out my other existing videos and look for more this summer.
Awesome description with lots of great detailed info. Thanks Shawn.
You bet. Thanks for watching!
Shawn, I just wanted to let you know how much I look forward to your videos. When I studied geology many moons ago, we were more oriented to the geology and orogenic history of the Ouachita Mts and Boston Mts of Northwest AR, so I find it really interesting to learn more of the western US. Look forward to seeing what you have for us in 2022.
John, thanks so much for the kind words. It's great to hear from folks who enjoy these. Haven't spent any time in Arkansas. So much geology to cover, so little time. Let me know if there is an area out west or a topic you would like to see showcased.
S glad I found our videos I’ll be watching them all. Geology fascinates this old great granny. Daily news does not especially the political rat race.
Glad you enjoy these. I'm sure you will find others you like. Thanks for watching.
In my mind, one of the most remarkable natural history events was the Great Oxidation Event.
Thank you for this great video. We just visited Snow Canyon and were discussing with the grandkids what the "marbles' were. You explained it perfectly.
Thanks for watching and I love that you were able to share with your family. Keep watching and if you have other locations or features you are interested in, let me know and I will try to do a video.
Thx, well done!
Thank you for this very informative video 👍
Looks like you've popped up on more than a few people's recommendation list. I know I'll be checking out a bunch of the 90ish videos you've posted. Thanks for the explanation.
Thanks for watching. It's fun to share these cool stories and places with folks.
Awesome video!
Thanks for watching and learning with me!
There are loads of 'Moqui Marbles' around Winslow, AZ, also on the Colorado Plateau.
Yep, its pretty common in the Navajo SS. I lived in Flagstaff for three years while at NAU so have been to Winslow, Clear Creek, and Jacks Canyon in that area.
Thanks!
the variety of sandstone formations in Utah is amazing! I was wondering about how the Muley Point East blocks were formed.
Always enjoy watching and learning from your videos, Shawn. Have you ever been to Mecca Hills Wilderness (Coachella area) just south of Joshua tree? Lots of cool geology there too.
Thanks Nick. I really appreciate your compliment. Yes, I lived in Blythe, CA for two years when I started my teaching career and regularly took students to the Mecca Hills and other amazing areas in the Salton Trough. Hope I can get back down there sometime soon and I will do some more videos.
Another excellent lesson Professor! I wonder how the Navajo sandstone relates to the Fountain formation along the front range that I scampered across climbing the Red Rocks Ampitheater in my childhood. Thank you Shawn!
Didn't know Hematite was part of the iron ore family. Interesting.
Must be amazing to live in that part of the country.
Love your videos. What are the hexagonal black or grey column rocks near the Oregon trail in Idaho?
My friends and I would run around Snow Canyon between classes at Dixie.
Good job. It might have been interesting to show what these rocks look like in closer view (simulating a hand lens) or to see an actual thin section. Then we could see the rounded grains and the dark cement. Jurassic sand dunes. Cool.
Valley of Fire and Red Rock Canyon also have exposures.
An interesting video would be the geography of "Two Buttes" mountain in southeastern Colorado. It is a lone, about 1000 ft(ground level) "mountain" (compared to anything else around it) sticking up out of an otherwise flat landscape. Apparently volcanic in origin, but the rock formations on top are sandstone.
Totally enjoyed this one with your nice descriptive explanation on hematite, and cross bedding. The marbles are an interesting plus. I once read/ heard that desert sand is not good for making concrete because the quartz grains are too perfectly round and therefore will not consolidate, do you believe that to be true ?
Hmm. I'm not sure. I don't see why the shape of grains would inhibit consolidation.
Fascinating! So, is the white Navajo Sandstone that color because of an absence of the hematite mineral?
Thanks for watching and learning with me. Yes, the white sandstone largely lacks the hematite that gives the sandstone its characteristic red color elsewhere.
I was just down in st george and took tons of pictures of the moqui marbles wondering how they formed. Are they also referred as nodules? Or is that a different process?
Glad the video helped. Nodules form by a different process where rock or mineral material is replaced with other mineral material (usually carried by groundwater). A good example are chert nodules that are common in limestone.
Can you explain the discontinuities in the cross bedding? Where the angle of cross bedding suddenly changes from one layer to another.
This is a small erosional surface as the wind shift direction and/or the dune migrates over the older one.
Way cool
This was informative and very well explained, thank you! What's the difference between the Aztec sandstone in a place like Red Rock Canyon, NV, and Navajo sandstone?
They are the same and correlative. Different names due to occurring in different regions. Both were deposited in the large sand dune complex in the early Jurassic.
@@shawnwillsey Thank you. Also, it's wild that the shape of the sandstone was formed by wind. Was it a combination of wind and water, from rivers going through the lower parts of the canyons, and rain? Is there a way to tell which effects are from wind and which are from water?
Is the flat ground (the part we drive/walk on) in the valley of Snow canyon still Navajo Sandstone that hasn't been revealed by millions of years of wind and water? Also am I correct to assume the black lava flows in the park are the youngest rocks? Thanks for a great geology video!
Another great question. The floor of Snow Canyon is mostly covered with basalt (lava flow) that erupted from the Santa Clara cinder cone (on east side of Hwy 18, just north of park's north entrance) about 20,000 to 10,000 years ago. These are the youngest rocks in the park (and region) as you stated. There are two other ridges of lava to the east of the park. One forms the eastern rim of Snow Canyon and is about 1.1 million years old. These lava filled an ancestral "Snow Canyon". Because basalt is much harder than sandstone, the new canyon was cut to the west, the present Snow Canyon. There is another, older basalt ridge east of this one that is about 1.4 million years old. This landscape has changed a lot in the last million or so years and will continue to do so. Cool stuff!
I have a question. Knowing the sandstone has a thin iron coating which can be bleached off forming the various cream colors we have I bought muratic/hydrocloric acid and have tried everything possible including letting it sit and fizz half in half out to try to bleach part of it and the acid has zero effect as in none--why??
I've had one for like 20 years give or take (maybe more I can't remember at this point lol) it's a more metallic looking one that's a smaller one merged with a larger one so it looks like a little metal mushroom but isn't ferrous my stepfather found it when working in the oilfield near Vernal Utah I never knew what it was called till now I just always knew it was had to be some type of concretion or a coprolite lol he said they always called them blueberries when he was a kid guess I just never really thought about googling for it till now ☺
4:50 did I hear what I think I heard? 🤣
The elusive Piute Barking Spider, a VERY rare catch indeed!
😂😂😂
Hi! I saw a horizontal bed overlaid on the cross-bedded section. Is this some kind of angular unconformity on a shorter time scale? @5:04
Sort of. These are small erosional surfaces as the dune migrates over the older sand surfaces. Also, a change in wind direction and migration of dune can produce these as well.
@@shawnwillsey thank you! That a really in deep and concise explanation 👍
Great! I was wondering about the sand that looks like it goes under and up while another layer runs over top of it in the opposite direction. Did water flow do that or the wind?
Hi there. Happy to answer your question but I need more detail. Thanks for watching and learning with me.
@@shawnwillsey Right at 5:06 in your video. Rocks going under, some over top indifferent directions. Hope that helps. Thank you for answering.
@@deborahellenberger7153 Thanks for clarifying. This is all form wind deposition. The tilted lines you see are the cross beds, formed by wind depositing sand on the back side of the dune. Later, the dune migrates and cuts off or erodes the cross beds to form the horizontal lines.
@@shawnwillsey Thank you so much. I find this fascinating. And as I am reading your answer, it makes sense. Really enjoy your channel.
Are Apache tears formed in a similar way to the moqui marbles? They look kinda similar. Well, both are round. Lol. I really enjoy your videos. I grew up in UT and did a year at Colorado College, where I was planning on being a geo major, before life took me in a less traditional path. Your channel makes me feel like I’m 20 again. 😊
Apache tears are different. They are usually rounded particles of obsidian or vitrophyre.
Ps they are behind you near the end of the video. Thank you so much.
❤
Is that a sand dune or an underwater/subaqueous dune?
Is it possible tree branches and parts of trees could have formed the cast for some of these moki marbles? I ask because I have a section that looks for all like petrified wood, but is definitely confirmed by the kids out of the school there that it is a nice large and rather different specimen. That is from BLM land down close to the hole in the rock road near Escalante. Navajo sandstone, yes. It looks like a tree branch about 3 in wide and I have a section about 11 in long It is round with what looks like what was bark in the mold. About 5 lb, which definitely feels like iron is in there and is there for doing business.
Bro tooted
Looks like cedar. hangman1128 channel
Thanks!
Appreciated.