Petrified sequoias of Malm Gulch, Idaho (2 of 2): ancient huge trees encased in volcanic ash
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- เผยแพร่เมื่อ 4 ส.ค. 2024
- This is part two of a two video series on Malm Gulch, Idaho. In this video, geology professor Shawn Willsey showcases the fantastic fossilized sequoia stumps encased in solidified ash (tuff) of the Eocene Challis volcanics, a collection of volcanic and sedimentary rocks that were deposited in central Idaho about 45-51 million years ago. Learn how these stately giants yield important information about the ancient climate of central Idaho and how petrified or fossilized wood forms. If you missed it, also check out the first video which focuses on the angular unconformity and impressive conglomerate the forms the base of the Challis volcanics. This area is featured in my book, Geology Underfoot in Southern Idaho.
GPS coordinates: 44.33377, -114.22465
I love doing these videos and will continue to do so but if you want to provide support or much appreciated gas money, you can send support via Venmo @Shawn-Willsey (be sure to put two L's in last name)
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or a good ol' fashioned check to this address:
Shawn Willsey
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Twin Falls, ID 83303 - วิทยาศาสตร์และเทคโนโลยี
Thanks for setting up the PayPal Shawn. I have donated something to help cover your gas costs in appreciation of your videos which help the layman understand geology in the field. I think it really important to be able to read a landscape a little because it helps connect you to the environment in a thoughtful manner. Your videos help build up one's experience of reading landscapes and one can then apply it to one's own environment.
So, thanks again for your great videos, they are brilliant!
Brian, thanks for encouraging me to set up the PayPal account for folks. Yes, connecting and understanding one's backyard landscape is a basic human trait and one we should reconnect with. I appreciate your comments and support very much.
Omg stumps. Thanks for sharing
I’ve only ever had pyritised fossil wood degraded quickly .. amazing to see petrified wood.. huge
As always, loved it
Petrified wood is awesome. I’ve found a bunch in the greater Uwarrie region.
Wow, sequoia trees in Idaho 🤔
Yes. Once upon a time....
Outstanding video, Shawn. I had no idea about the sequoias.
Really interesting story, really well presented. Thanks for sharing it! I bought both your books (Roadside Geology and Geology Underfoot) to use as guides for my trip to Idaho in August.
Awesome and awesomer. I hope you enjoy the books while you travel around Idaho this summer. I've got several more Idaho videos I recently filmed that will launch soon.
awesome video, very informative thanks
Very cool. I never knew about the stumps. Thanks Shawn.
Back in the 1830s a fur trapper Moses Harris visited this area. He returned to Saint Louis and told a story of his adventures in the west. It was written down by Washington Irving. No use having a good story if you can’t make it better. He told how the grass had turned to stone, and even the birds setting in the trees. He didn’t realize he was in a petrified forest until he used his axe to try and cut firewood.
Man this was so awesome. Thanks for taking the time to make it and post. Very informative.
You bet. Be sure to check out existing videos and subscribe to see future ones.
This reminds me of all the petrified logs and Beachwood around the coal mine basin McBride Creek area at the Idaho Oregon border. Very similar geology except probably waterlogged wood that got buried in glacial floods or maybe lahars.
Those first stumps are actually one with it's heart wood gone.
Another really fascinating short video Shawn.
I will definitely look for part 1. Never saw petrified sequoias.
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What an incredible site!
It really is. I first came here in 2015 or so while checking out some possible sites for my first book, Geology Underfoot in Southern Idaho. I wasn't expecting much and almost drove past on an evening when I was tired and ready to be done with the day. So glad I made the effort to get here. The story of Malm Gulch turned into one of the vignettes for the book and it exceeded my expectations with the exposure and richness of its geologic history.
Love that the trees were buried either in ash or in a lahar flow. One batch was petrified then another forest grew and they did it again.
That's very cool I grew up in Rexburg and never heard nothing about anything like that around chalice I'll have to swing out and see it sometime thank you very much I really appreciate it
Yes, please check it out sometime. I really enjoyed this area.
Thanks for explaining the petrification process. Nice video. Cheers.
That's interesting. I wonder if that could be mapped with some sort of GPR. You might be looking at a trunk that goes 50, 100 , or 200 feet down
Shawn Willsey: Late Night Geologist
Ha! I just set the videos to launch at midnight on that day. I am much more a morning person. Most nights, I am out by 10pm.
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Interesting how similar these fossilized red woods are to todays trees after million of years of evolution.
Looks like a mini Devils Tower. Hmm...
Devils Tower is made of Phonolite, a kind of lava. Petrified wood is made of silica (cryptocrystalline quartz). If there were a tree with the diameter of Devil’s Tower (~800’), with the proportions of a sequoia (~36’ diameter, ~300’ height), if approximated by the volume of a cone, which is an absolute minimum, because it disregards the volume of any hypothetical branches in its would-be-more-than-mile-high crown, at the density of phonolite (~2.5 g/cubic cm), such a tree would, at minimum, weigh 8.72 BILLION TONS. Ice is ~2.5 times less dense than phonolite, and the continental glaciers that covered northern North America during the Last Glacial Maximum were between 2 and 3km thick, or about as thick as this hypothetical devil’s tower tree would have been tall. And yet, with 2.5 times less weight per unit area, the continental glaciers of North America were heavy enough to depress the surface of the earth, such that thousands of years later, the surface is still rebounding (glacial isostatic rebound), and the total vertical displacement from the ~2.5 times less dense ice of the LGM was about 400m. There is zero evidence that more-than-mile-high trees existed at any point in the history of the earth, and if they did, they would cause extreme isostatic depression if the surface of the earth due to their weight, which would be recorded in deformation and ongoing isostatic rebound, just like today’s post glacial landscapes.
Devil’s Tower is the base (neck) of a former laccolith or maar-diatreme volcano that was filled with phonolite. The age of the phonolite lavas is about 40 million years old, and during that time, hundreds of feet of sediments that once surrounded it were eroded away and transported into lowland and marine basins far away by 40 million years of alluvial networks and aeolian action. The Devil’s Tower phonolite, being harder and more resistant than those eroded sediments, has differentially eroded and remains as a kind of inselberg or modadnock, towering over the landscape. But it isn’t alone-there are many such alkaline igneous remnants all over the western and central United States of similar age and composition, mainly in Wyoming and South Dakota.
1:42 now you have me wondering the age of the charcoal.
Shawn, what is the difference between extension and rifting? Is rifting a continuation of extension that if it progresses far enough causes the break up of the land mass? What causes extension to stop and in the case of the Challises Volcanics be a depositional period that covers the thinned crust. Why do we consider the Rio Grande Valley or the Salton Sea to be rift zones and not extension?
Good questions and some of this is semantics and sticky definitions. Extension is the fundamental stress or force acting on rocks where they are pulled apart in opposing directions. At a plate boundary level, we call this divergence. But extension can also occur in regions within a plate (not on a plate boundary), such as the Basin and Range region of the western US. Rifting is usually applied to continental areas (not in ocean, like many mid-ocean ridges) such as eastern Africa. You could also argue that the Basin and Range is also an area of rifting. Complicating things a bit is rifting is sometimes also a term applied to volcanism such as the Great Rift of southern Idaho, a 50+ mile long zone of fissures (some eruptive, some non eruptive) extending across the Snake River Plain and parallel to many faults north and south of the plain. Even though it is considered a volcanic feature, its orientation is perpendicular to the regional extension direction so it is influenced by it. I would consider both the RIo Grande Rift (an inland rift, not on a current plate boundary) and the Salton Trough (an oblique divergent plate boundary) as areas of extension since that is the fundamental force that is creating the volcanism, earthquakes, heat flow, and landforms.
Thank for your consistency on making great videos, I hope can donate, but i dont have paypal yet,
(Greetings from local geologist at the nearest region from Krakatau volcano)
I should add that I've been told about remnants of a petrified forest along Highway 95 between Marsing , Idaho and Jordan Valley, Oregon North of the State line.
Any chance you know more about places in south west Idaho ?
Anywhere specific? I do know the area pretty well.
@@shawnwillsey bruneau and Nampa. We are heading to succor creek after visiting rock shop today
@@magapickle01 I've got an older video of Bruneau Sand Dunes. th-cam.com/video/6BayX2ccGQo/w-d-xo.html
What is the position of this area to the Northamerica plate?
It is very much on the North American plate. About 500-600 miles east of subduction zone along Oregon coast.
Where would we find a graph or chart of the climate conditions of the time the Sequoias were living. CO2 levels, rainfall, estimated temperature ect. I've just found your channel and subscribed. I will acquiring your book. Thanks for your efforts and ability to communicate the geological story for the layman.
How radioactive?
I am not sure nor have I seen any published info on this.
@@shawnwillsey What I've seen is something about the "Petrified Tree Uranium Occurrence" at Gateway, CO.
Think how long 50 million yr old forests have to be buried, fossilze, then get uplifted to be the side of a mountain peak we see today. Do we know about when it started to rise to form mountains?
Well, the Lone Pine Peak Fault as well as the Challis-Warm Springs segments of the Lost River Fault System, which are just north of Malm Gulch, are still active. Parts of the latter were involved in the 1983 Mw 6.9 Lost River Fault EQ. The former runs right through the Malm Gulch area. And there is an unnamed (number 16) fault which is south of Malm Gulch that is somewhat older (active in the last 16 Ma). These faults collectively all started during the mid-Miocene, with the beginning of Basin and Range extension throughout the Great Basin, though these faults represent the very northern tip of that deformation, but not all of them are that old. It is generally much more difficult to tell when movement on a fault started, compared to when it last moved.
An interesting fact about the intermontane west is that much of its topography is very recent in age. When a lot of these Eocene basin sediments and volcanics were deposited, there was an extensional regime active generally in the northwest, and relatively low elevation. In fact, the intermontane west was by and large buried during oligocene time by sediments that had been collecting and filling its basins since the Laramide uplifts, and only in Neogene time has the terrain really become rejuvenated, and even more so with the advent of Icehouse conditions in the northern hemisphere. There is a plantation surface known as the “Rocky Mountain Sub-summit Surface” located at about 10-11,000 ft that records this…you can drive over it on the Beartooth Highway from the Chief Joseph Scenic Byway Junction towards Red Lodge, MT. In southern and central Idaho, the Neogene rejuvenation of the terrain is associated specifically with Basin and Range-related Faults, as well as the passage of the Yellowstone Hotspot under the Snake River Plain, which has the effect of dynamically uplifting topography over the active plume (currently represented by the high plateau terrain around Yellowstone), then subsiding in its wake as thermal uplift fades and thick volcanic deposits fill and depress the basin left behind.
Did Purgatorius cut that down? Just kidding.
Cool are world has been going through and will go through many more changes in Climate this will happen with or without the paranoia and taxes imposed by poor Government managment
Why isn't the tree still buried in the same strata that petrified it?
If you knew you could tell the age of the earth. Counting the tree rings and the amount of time it takes to petrify the tree with what petrified it.
That would only tell you how old the tree was and when the volcanic eruption produced the lahar deposits that entombed the tree stump. These particular rocks are ~50 Ma (millions of years old), and the Challis Volcanics in general were erupted during the Eocene period, between 52 and 39 Ma. And as Shawn explained in the video, the stumps ARE in situ, and there are at least 6-7 levels of them at different stratigraphic levels, the result of multiple eruptions and ecological succession resulting in reestablished sequoia forests hundred of years following the deposition of each new thick layer of silicic volcaniclastics that buried the previous one. The age of the earth is known, and it is 4.54±0 .05 Ga (billions of years). This age has been determined by radiometrically dating the material from which the earth accreted during the Hadean Era, and it is consistent with the oldest known rocks and detrital minerals (4.404 Ga zircons of the Jack Hills in NW Australia) that have also been radiometrically dated.
@@AvanaVana Carbon dating is not accurate. Carbon-14 is in everything. Soft cell tissue determines the age of fossils indicating thousands not millions of years.
@@chrisminblkdiamond "Radiometric dating is a method of measuring the age of geologic materials like rocks and minerals. Radiocarbon dating, a type of radiometric dating can be used to measure the age of materials that were once living, like wood, cloth, fossils, or human remains"
@@wrathmachine7609 Maybe you're not aware that type of "dating" is not accurate. There is no distinction between live samples and fossilized samples of flesh or strata.
@@chrisminblkdiamond Accurate as in what up to the seconds of life of matter? We get the ball park and that's good enough if the dating shows ~50 million years that is good enough especially when we can use other geological indicators around the area. What exactly are you trying to imply besides the idea that this dating isn't accurate enough to your liking?
Idaho is a really nice state I drive through Idaho once a week I actually wish I could move there the best part is their a Red State too 🇺🇸