Older Lava Above Younger Lava? Geologist Explains Inverted Topography From Southwestern Utah 

Be sure to LIKE and SUBSCRIBE. You can support my educational videos by clicking on the "Thanks" button just above (right of Like button) or by going here: www.paypal.com/donate/?hosted_button_id=EWUSLG3GBS5W8 or here: buymeacoffee.com/shawnwillsey

This 10-minute video is a perfect microcosm of your channel's philosophy and style. Observation, differentiated events, geologic classification, hypotheses framed by geologic processes (pressure and time -- erosive here), clear explanations and pleasingly informative diagrams. You know your audience and have facilitated the growth of a welcoming and curious community. Thank you Shawn.

So much fun. I am going sound like a rock master when I explain it to the grandchildren 😊

Awesome. I'm from Montana but we used to have a place in St George. After seeing your video about the fault line to the east, I hoped you'd do Snow Canyon next! Any cyclists reading these comments need to visit this park. After a long climb up to the northern boundary you get to enjoy a fast, steep descent on a paved bike path along Hwy 18. St. George traffic is terrible but there are many bike paths that provide a safer way to enjoy long, scenic rides.

One more location added to my places to visit list. This is a more complex example of inverted topography than the long familiar Wright’s Point south of Burns, OR, a textbook example one crosses traveling from Burns to Frenchglen.

I tell you what man... I've learned a lot from watching your videos, and those from Nick, and Myron Cook... But I still feel like a clutz with this stuff when I walk out my door and see the redish shale that covers everything in my area and have no idea what I'm looking at. But I got this one... I figured it out right away, but only because you dated those lava flows, as I couldn't have figured it out otherwise... There's a learning curve. As with so many other things, there's just a lot to it. So... I thank you for being one of the small number of precious, prominent and professional voices in my geology studies. Peace.

Love that spot! You do such a wonderful job of interpretation. Really makes it easily digestible. Thank you, as always!

Thank you for these videos Mr. Willsey. I moved to St. George in 2017. The surrounding landscape is very dramatic and a far cry from the flat swamplands of Florida. Your videos have taught me so much and helped me understand the geological history of this region. The first video of yours that I watched was a random roadcut you did along I-15 explaining the lava flow cap on the Navaho Sandstone. That video sparked a learning adventure that I anticipate having no end. Thanks again. Many thanks!

Such raw beauty in this landscape! I want to grab my sketchbook and pens and capture some of this while I listen. Thank you for sharing and sneaking in your teaching while we are mesmerized by both the sight and the words. I'm hooked!

Hello Shawn and greetings from Kanab Utah ... It would be unfortunate if this region becomes volcanicaly active again! Thank you for all your efforts in bringing your knowledge of geology to soo many of us. Respectfully, Utah Mike. 🤩👍

I live 5 minutes away from Snow Canyon. I ride or hike this canyon multiple times weakly. I have seen Snow Canyon when the low clouds flow thru here and its absolutely beautiful. I’ve been here when it’s rained for days and there are waterfalls everywhere. My home is surrounded by lava flows.

Thanks! Wonderful class on interesting SW Utah topography!

It's amazing how much the Earth changes over time.

Great video Shawn. At the start I thought you were maybe going to describe some sort of magma dike being injected underneath an older layer, but I'd say the different lava flows still follow the superposition rule here. Each flow is still being extruded and layered over the older sandstone rocks, even if the elevations of the newer flows are lower in this landscape.

A magnificent example of inverted topography can be seen on Hwy 108 near the town of Jamestown in California. 10 million year old lava, which had flown down an ancient river valley, are now the highest point in the landscape. From the air, the curving path of the old river can clearly be seen.

Thanks again Shawn! I love rocks that tells us these stories.

Thank you for the informative history lesson. Earth sure is a mystery with many secrets waiting to be discovered!

I haven’t heard of, nor been to Snow Canyon SP. It looks like a place that I would like to visit. Thanks.

Thank you Shawn!! 🙏

Great video Shawn, clear, concise, visually pleasing and informative. I've been there many times. My old high school buddy lives maybe five to ten miles from that spot in a small community just north called Dammeron Valley.

Thanks Shawn! I always love your videos and educating information and love learning more and more about Geology and our planet all together. Thank You. I am supporter too. Peace.

This country is a thrill to see. Your sketches are perfect at explaining! It's definitely something new to consider and brings up more questions. I'll do some reading and get back to you. 😉 I love your teaching moments!

Love this lesson!

Nice 👍. A few of your vlogs and I’m really understanding what I’m looking at ! Fun !

I was curious about where that lava came from. I just went to Google Earth of the area and found up the canyon is the Santa Clara Volcano. And looking at the topography of the canyon you can see how those layers formed and see how the erosion of the red Navajo Sandstone that led to the next layer of lava's path down that canyon as you pointed out. Fascinating! I got to do some geology and didn't have to leave my house! Although, I admit, being there would be more fun.

I really appreciate your efforts

Thx Shawn for breaking down the processes that formed this landscape...

I've learned a lot from watching your videos, especially videos like this one, they're short and clear. Keep up the good work & thank you Shawn !!

Thank-you once again, DrShawn. Your succinct & informative presentations have taught me &, no doubt, so many others so much about geology. What a gift you give. Thanks again.

Beautiful location. Thanks Professor, i was scratching my head till you produced one of your great drawings. 👍👍👍

Great to watch. Thanks Shawn.

Thanks, Shawn. Happy Sunday to you.

Absolutely fantastic information’ great easy explanation.

Great video Shawn. Thank you for posting it.

Thank you 😀

Great info! Thanks

Thanks!

Fascinating! Thanks so much. Made me smile.

Thank you Shawn 😊 very interesting 👍 😊

Very scenic valley there, esp to the south! I believe Table Mtn on the west edge of the Sierra not far from Sacramento is another example of this inverted landscape type, with a lava flow from the east of the Sierra crest (the range was lower) flowing to the west dozens of miles. So in present day we now have this mesa mountain with a cap of basalt, and erosion has lowered the land to the sides.

What a beautiful location! Here I was trying to guess something complex. This is a good reminder to me that it can be and often is a basic erosion story. Basics are so important and must not be forgotten. During your sabbatical you have greatly expanded my geology experience beyond places I have traveled. I'm very glad because I'm discovering so many new to me beautiful and fascinating places. You are creating wonderful tools for use with your future in person classes. Plus so many people not taking in person classes are gaining wonderful learning from fun videos.

This was very interesting, I feel like I learned something today.

Well done!

wow. pretty kewl. makes so much sense. geology is so not boring at all :)

Well done, I learned something.

In addition the south end seems to be pushed up (as evidenced in the layers of sandstone) also adding elevation to the older flow.

Another interesting video!

Thx Prof. ✌🏻 fascinating geo-ed adventure.

I think a similar dynamic played out on the South Fork of the Boise River canyon.

I'll keep a better eye at my next hike on the Canary islands volcanoes, ie Teide volcano on Tenerife island, thanks for the simple explanation!

Thanks again Shawn, I was able to figure it out, kind of similar to what it looks like at Table Mtn by Oroville Calif. I like your videos, good editing, tidy job!! :-)

Thanks

You rock!

Cool!

Love your videos, I sort of guessed it had something to do with erosion. Very interesting

That was a neat little mystery. I was thinking some kind of subsidence so no, I didn't guess the real reason. That was fun though trying to figure it out.

Great explanation! Thanks. Q: what happened to the huge amount of sandstone mass that was eroded away?

With repeated lava flows I was thinking active region and my mind went to a graben. But erosion works as well, of course.

The theory of superpositioning works great when the rocks are stacked on top of each other. A perfect example of this is the Snake River plain basalts there are thousands of feet thick stacked on top of one another

Thanks-I had thought maybe massive intrusions from beneath but of course Geology is really about deep time so my thought did not include enough patience-

I see the older lava is higher than the younger but I they're not actually on top of each other physically. They're indifferent areas areas so to me it makes😊 sense

Thoroughly enjoying learning geology with you! If the source of the eruptions is the same, shouldn't there be a location nearer to the source that has lava flows in the normal order because they'd be on top of one another?

The GPS location seems to point to Zhengguo China on Google Earth, just saying. Thanks for all the great videos.

Interesting. I would have guessed either this or upthrust. While this was clear, I find myself still curious about the following: - How old is the Navajo Sandstone? - I'm guessing the Navajo Sandstone was the old sea bed? - When did the sandstone get raised from the sea bed to the current elevation? Clearly longer than 1.4Myo

Would love to have you do this type of video in the volcanic areas of Northern Arizona. There's a lava tube you can walk in, sunset crater, and of course the peaks (volcanoes) around Flagstaff. There should be some good hiking & rock climbing around for you, too. :-)

Shawn, this is fascinating. How quickly--or slowly--does erosion occur in sandstone? Is it measureable? If so, can you give us details?

Watching Nick Zentner’s videos clued me into that being the likely solution.

Smarty pants. I'll just keep listening. Eventually I'll get it. I think this stuff is very relevant to know as volcanism and earthquakes start to increase.

Thanks for teaching me something new today! I think that Utah is a beautiful state. So many beautiful places to see! Question, Have you ever been to The Valley of Fire in Nevada? It has some incredible geology. If you haven't been there, you definitely need to see this place!

Again, more than a touch of envy that you can just drive up there, park up and walk about in this fabulous landscape - here in the U.K. someone would have put a fence around it, some KEEP OUT signs or a little booth to pay entrance fees.

Nice info, thanks. Question, where did the Lavas/Basalt come from in that area? And possibly why?

I love your intro by the way, especially the knocks with the hammer. 😊

It seems so obvious once you explained it, but my first guess was a major flood. Shows you why I'm not a geologist.

Shawn I think you need a Quadcopter for aerial photos that you can edit into your commentary.

I would love to see a lesson on the Owens Valley in California

❤❤❤❤❤

😁 Thx for the great video, Shawn! I have a question... Does this area share/overlap space between the Colorado plateau and the Basin & Range? It seems that way on satellite Google maps view... 🤔

👍

To me I would look at Grindavik Iceland, If the land is sinking, It is sinking, where the land is rising due to a temporary rift!!!

QUESTION - Thank you for all your videos - we watch all the time - here is my question - the different lava flows makes total sense. Where was the volcano located that erupted? North? Thanks.

The word I’m looking at is Graben

How was the basalt dated? How old are the layers of sandstone? Where was the source of the lava?

This is very informative and interesting! But would you please keep your camera steady, mount it on some kind of tripod? The constant moving of it is not comfortable to watch.

Where was the volcanic vent located that created these basalt cliffs?

Maybe I lived in Nevada too long - was there not any kind of pulling apart? I mean to the right I do see what looks like the markers of erosion, but to the left where the two layers of sandstone are visible, it looks more like the valley floor dropped down than was eroded out. I was thinking it was more separation than erosion (and I'm not a geologist or a geology student, I just want to know the stories the rocks are telling.)

Where did the basalt flow originate from?

it looks like there’s erosion of the sandstones along the edge of the youngest lava flow way in the west of the view you showed us. But why is it called Snow canyon?

It has to do with Graben Horst terrain doesn't it? At least the uplift component boosting erosion and providing the lava via extension. I knew about inverted topography but I'm ashamed to say that slipped my mind at the time, though in my defense you hadn't gotten to the part of the video where you explain there are no faults in this general area between these flows and the canyon. Faulting is my default guess in a mountainous area to get inverted terrain layers at least barring something absolutely crazy like the Heart mountain slide which Myron Cook brought to my attention. Off way in the distance on the other side of the canyon is that yet another ancient lava flow?

As a geological layman, how could I find out the ages of rock I was looking at without digging (pun intended) into the geological literature? Is there a website that provides the ages of exposed rock for different areas of the country or would I have to get geology books on that area or ask a friendly local geologist? Great video and thanks!

Guessing before you declare solution… I’m guessing erosion between lava flows / eruptions.

How are you in so many places all the time? I want to do that.

The word "superposition" has been hijacked by the quantum mechanics crowd and now means something else (which I,admittedly, don't get). The time scale involved suggests ice age floods may have carved the valley. Were the two older flows at their terminus or were they originally more expansive and partially eroded away.

Is there a river running through there now?

might be a simple erosion (river make canyon then lava flows into that canyon)

Are all of the elevation changes due to erosion, or is this valley a graben?

I mean aside from the anomalous deposition of said lava, it does reinforce the fact that states outside of the larger volcanic zones (cascades arc etc) are still, and should be considered, volcanically active. 20,000 years isn't enough time to consider a volcanic field extinct..

My (totally uneducated) first guess would have been Basin & Range extension causing a series of grabens, the lava flowing into what was the lowest at the time. When you look at the landscape, what are you seeing that rules this out? Thanks.

what erosion and not alien engineering :) Having grown up in UT/AZ absolutely love the landscape and miss the rockhounding that was possible, where I am currently in stationed in Germany in the Rhein Graben, kind of boring homogenous Geology, Luckily not too far away get into some rhyolite and other igneous rocks with a few agates and a bit of an ancient 25 M year old coastline with a few interesting fossils.

Superposition includes adjacent rock? My understanding is that it applies to layers. And probably shouldn't be used for rocks at different locations. Are there 10000 year old lava flows directly under the 1.4 million year old flows?

it is a pity that in Holland the volcanoes are in the Wadden Sea and are 160 million years old and covered withe sand and water