Thanks Nick and Shawn for treating us to a campfire talk without the campfire! You are both excellent teachers and communicators. And thanks for all the previous programs and guest that laid the groundwork that got us to this point. This is going to be a fun series!
While at present this livestream is above my level of geologic knowledge, I learned a great deal. I have always been fascinated by geology though my education has mostly been botanical. Obviously botany and geology are inter related. Thanks to you and shawn for this livestream.
Wow, great episode! Shawn and Nick are the two leading geologists conducting outreach to the public in the U.S. (Kudos to Myron Cook as well!). Yet despite that incredible distinction, so much fun to hear you two “spit-balling” back and forth as you both try to understand the origin of the Idaho batholiths. Due to episodes like this one, Most of your audience does not feel so bad by being confused by these complex, 4 dimensional geologic changes. 😊😊. Thank you-keep up the collaboration!
I caught this on replay - Loved every minute. Nick Z. is everything a damned good lecturer and UA-camr should strive to emulate and great to have Shawn along - thanks both !
Thank you, Nick and Shawn for sharing with us a wonderful free-flowing conversation that we all know usually takes place behind "closed doors" and presented only after many of the details have been worked out. It was fun and exciting to be part of this discussion. It feels that we're all on this great journey of learning and seeking knowledge together. Sort of a mini-Penrose approach!
You guys are discussing the questions that have captured me since Lowell explored underthrusting in Idaho and Wyoming in 1977 and the early work on the WISZ in the 1980s. Really appreciate the wide angle lens.
Such a fun session to be a part of! It was great to see you both bounce ideas off each other! I always learn so much from each of you, and with you both together... well, the whole is even greater than the sum of the parts. I look forward to future collaborations! And thank you for answering my question towards the end. Thank you!!
Shawn is SO great! Every time I listen to him I hear someone who is interested in authentic discovery/authentic inquiry devoid of any ego. It makes the study of geology available to all of us - regardless of what we already KNOW we can inquire with and discover alongside someone like Shawn. What a great show this was!
Orogeny... The mess caused by Siletzia, Spreading Ridge, slab rollbacks, Baja BC,,, during Eocene period,,, Thank you, Nick, for streaming those fun conversations between you and Shawn in the search for your geological narratives for the upcoming Cascade Volcaoes A to Z! And, meantime, we gain understanding the geological history, what to not love it💞What a wonderful time we live in!!😃Thank you✨💗
this was great. i wish i had more time for geology things. i learn so much from both of you. i love how you brainstorm and theorize while not lecturing. so refreshing
I love honest attempts to learn. Bright people, when they get together in good faith and share questions and viewpoints, are among the best examples of what human potential can be.
Live for lunch at noon w Nick and Shaun, pretty nice for a Monday. Cool here too and the forcast looks great for the week in Northern Indiana. You and Shaun make a great brainstorming team and looking foward to the investigation of today's new questions and hypothesis. Best of luck to the expanding family....
Nick- Your boyish curiousity and true vulnerability toward the subject of Geology is brilliant. You sets the bar for academic accessibility for all with a curious mind. Thank you! and Willsey is cut from similiar cloth. All the best to both of you!
Missed the live stream, but glad to watch the replay! So kewl to see the Baja BC (BBC) connection ❤ It inspired me to dig into my Canadian Cordillera, and I am now working on an audiobook on the chosen rock of the Northern Canadian Cordillera 😅 thank you 🙏
@Nick Zentner Thanks for doing this live stream. It is a nice surprise on my birthday. Had to watch in replay as I was out for a birthday meal when this was live.
Well okay Nick, You set the hook pretty hard there! 👍 Got me big time when you started involving baja-bc 🎉. I remember the thinking about a much larger and even more complicated and further ranging implications of such a thing. Thanks Shaun and can't wait to see what you have up 👆.... see you then there's
There is a really cool fissure south of Bruneau that I have hiked on since you folks started showing all these shows. It has been such a blessing to stand on the very thing that is going on in your time slots talked about here and then to see Shawn's and others videos from Iceland has really brought this to reality for me. Thanks guys!
Great discussion, both of you! I agree, Nick, as you were looking at the uneven tear of the slab, then the Northward motion, it does make a compelling case and fits well with the evidence…. At least for a minute till my mind fogged up again!
Thanks Nick and Shawn! Great collab! (And I may have a road trip in my future.) Interesting discussion. ID batholith just is weird. One thing Baja-BC made clear to me is that different things are happening depending on location, eg, slab breaking under what is now WA/OR/ID while something else is happening in Calif. Plus things are moving around and you have to subtract basin-and-range stretching to understand it. Makes things confusing. And congrads in advance grandpa Nick!
On a side note: the southern half of Oregon is covered by the Tyee Formation which is sediments several thousand feet thick in places. It is thought to have formed in the fore arc basin created by Siletzia. The sediments are predominantly from the Idaho Batholith with a sprinkling of Klamath Mountains. Roadside Geology of Oregon 2nd edition Miller. Page 35. The cliffs at Mapleton, Oregon are Tyee Formation.
We have interesting volcanism on the eastern edge of the Pintler range. Andesite tufts that are exposed north/east at the foothills of the Pintlers on the southern edge of Anaconda. Cinder cones and massive rhyolite tufts on the east side of clear creek with basalt flows scattered up that basin where they logged/smelted all the copper from Butte. It’s a geological mess that is absolutely fascinating and it just gets crazier east and south of the Pintler’s. The thrust and fault of the Pintler locking up and deforming rocks to the east. Petrified forest just beneath the surface-even fossilized bones of god knows what but I’ve found vertebrae and a bone eroded by glaciation or exposed by a terminal moraine. Mind blown!
In addition to the subduction zone, don't we have segments of crust wandering let's say north, the way those did in California? There are blocks of say Belt surrounded with granodiorites and possibly that magma coming to the surface as extrusives in places.
Excellent discussion! First, I am a professional geomorphologist and haven't studied the rocks you are discussing, but most major structural and topographic features of the western US are oriented N-S. For example the san andreas fault and the contemporary subduction zone, the Sierra's and Cascades, the horsts of NV and UT, the Wasatch front, and the "front range" of CO. But there are exceptions that are oriented E-W, all located near a (wide) line between Laramie and Portland. Those include the Columbia River gorge and the southern boundary of the Columbia plateau, the western Snake river plain (which was pulled apart in the N-S direction, the Uninta block and the anticline in Dinosaur National Park among others. In addition the highest points in the Rocky mountains (starting in NM and CO) shift West on the North side of that line, including the high peaks in ID and MT and British Columbia. That line, or zone, has got to be explained with your upcoming "grand theory" of the Idaho batholith. Regards, Kirk Vincent, USGS (ret)
Thank you Prof Nick and Prof Shawn. I’m not a professional or an expert geologist, but a wannabe. When I took geology 101, my professor taught us that the Idaho Batholith was due to the subduction of the oceanic plate under the North American plate, and at that time the coast was at the modern border of Idaho. The Atlanta lobe of the batholith is much older than the Bitterroot lobe. Please correct me if I’m wrong. I had an outstanding professor for my Geology 101 class and installed a love for geology. I had an art major. When I graduated I received my BFA.
Shawn, they are called knowledge silos and, Nick is correct, we are lightyears ahead of days of old when those silos prevented idea development for a variety of reasons. Thanks to both of you for your work in communication arena. Question: Do we know anything about how the movement of the Siletzia plate east of the break? Did it flip up and possibly push what was above upward?
I'm binge-watching to catch-up. Great so far❣ 🤯 I like and agree with the possibility that the Idaho batholith might not be from subduction, but potentially related to Insular / Wrangellia since there doesn't seem to be any indication of subducted slabs to the east-ish / northeast-ish of the Yellowstone hotspot (where Idaho would seem to have been at that time) and transform compression &/or extension seems a reasonable potential cause / explanation. It seems that the Challis magmas would more likely be associated with a spreading ridge (and perhaps the Yellowstone hotspot) if the Yellowstone hotspot is in approximately the same place and the west coast of North America was east of the current Yellowstone location during the Challis magmas time. If the Yellowstone hotspot was west of the current location of Idaho and has moved along the strike-slip fault (as Basil has mentioned movement in past years) while North America has moved west, the slab breaks and rollback causing the Challis magmas seems reasonable. If the spreading ridge, the Yellowstone hotspot & Siletzia were in approximately the same location as Yellowstone is now, and Idaho was east-ish / northeast-ish of the current Yellowstone hotspot location, plus Insular / Wrangellia sliding along the west coast just before the accretion of Siletzia; could that have jammed up Siletzia enough to start subduction to the west of Siletzia and then cause the slab breaks to the west of Siletzia? I look forward to more❣❣🤯
Friction has to add tremendous amounts of energy to the system and then with supposed ccw motion of the NA plate. Reminds me of friction welding in metallurgy. Your pizza boxes make me think bulldozers on a frozen feedlot. Keep it up.
Look into the Anatectic belt Nick. It also coincides with the block uplift to the East. Basil referenced a paper from Chapman et al, in 2021, for the belt.
Where did the eroded evidence end up. My guess is up north. As two large sheets are coming together, previous ribbon or wedge shaped slices that were moving north were sent north with a lot of evidence of the new volcanism. Blends in with the ' Terrane Wreck' or 'Big Whale" story a bit.
When you think of the Yellowstone Super Volcano video that Nick did, how the many numerous ancient caldera’s now flattened, reached deep into the land mass. They moved in from the ocean with a few ancient ones to the north of the main trajectory, to where the active caldera lays now, against the granite of the craton …… yeah, could be …..Baja BC. The chocolate cake is still churning
Shawn’s idea that there was a magmatic arc that didn’t express as a volcanic arc feels correct to me. Heat moving up could be subduction related. Or, a slab break off melting rock and mixing below the surface creating the Idaho batholith could present as an arc as well. The source of the heat is just different.
This for both Nick and Shawn. Shawn, a while back you did a roadside video near Puerto Vallarta and I believe you were looking at stuff a bit north of PV along the coast in Nayarit state, if my memory is right--which if you go north of PV you wind up in the Mexican transvolcanic belt. I wish you had had time to go south of PV as well, as you are along the rugged coastline of the Sierra Madre del Sur, and it appears to be all granite, or mostly granite and gneiss--and though I am not a professional geologist, the whole mountain block south of PV appears to me to be mostly a large pluton or batholith--all intrusive rock. It is dramatic landscape, and when I have hiked up some of the ridges, it reminds me so much of being in the central Idaho mountains--but for the plants and trees. Very steep, deep canyons, and granite everywhere. So as long as Nick is casting a wide net for a while (bringing up Baja BC), my question is whether this large plutonic body, i.e. SM del S,--located near an active subduction zone (the southern twin to the Juan de Fuca plate)--relates at all in time to the other plutonic areas further north, say in Baja, the Sierras, or Nevada. I can't find any information on it, easily anyway. (Seems like there is lots of interchange of ideas between American and Canadian geologists on this big picture stuff, but once you get south of the border--maybe because of language, or other factors--it's very hard to find much information or interchange dialogue between professors, or maybe I just don't know where to look.) I very much enjoyed this show today (and the prior ones) because I grew up near the Idaho Batholith and our family had a summer home in an area of the Challis volcanics (Williams Lake, near Salmon, where I found my first geode), and the geology of this area, well all of central Idaho, has puzzled me my entire life. It is exciting for me, after so many years, to see folks in the know homing in on these questions.
Just missed this live from Fayetteville, NC where we also experienced lightning/Thunder w rain last night too! This whole area is on very notable sandy soil. Wonder if that may mean ocean at one time
Q: How can “Baja-BC” convey Northward if an active oceanic plate is in subduction mode with NA North of it at the same dad-gum time? My A: The Holocene version of it is happening in Northwestern California and Southwestern Oregon right this minute. It’s the mechanism that’s conveying the Franciscan Assemblage North, around the East side of the Mendocino Triple Junction, up the NoCal coast skirting the West side of the Klamath Mtn. Terranes and continuing up the Oregon South Coast to the Southern margin of the Siletz Terrane @Coos Bay, OR.! The mechanism is older, tectonically inactive and uplifted/exhumed oceanic crust conveyed by a tectonically active conveying oceanic plate under it from the South. The tectonically active plate shears away-left at the Triple Junction and the older inactive plate continues on its original trajectory. The South Gorda plate isn’t subducting under North America per se, it’s subducting under the Northern end of the Franciscan Assemblage. The Franciscan Assemblage is on the same track as the Siletz Terrane, causing the NW rotation as it pushes from the South to the North-Northwest. That is how a Strike-Slip fault system can coexist with a Subduction System. Stuart rode the continental slope North. Transduction?
Amazing stuff ... as seen from the UK Could the different magma compositions (and times) have resulted from 1) the release of mantle-derived magma from the underside of the torn slab; followed by 2) composite magma derived from mantle-derived magmas melting and picking up material form the upper and/or lower surfaces of the slab curtain to give a strange composite magma??
We are still the blind men (, albeit experts) examining the elephant. For instance, how can we consider the role of Siletzia without consideration of the Yakitat terrane? It goes rift, subduction , rift, subduction,... on and on, you don't get a rift pushing on a rift or a subduction sucking down another subduction do you? I can see the possibility of the East Pacific rise producing as its eastward stream, the tomography we see underlying the Eastern US .
When you two were talking I had an idea of perhaps using supercomputer models to try to recreate present day conditions. Similar to how they do things for galaxy evolution models. Bear with me. With galaxies, we know their present conditions and they can make models that trace backwards plausible earlier conditions. Or even use monte carlo runs to see most likely scenarios leading to present conditions. We know current plate movements and current rock types and conditions needed to get said rock types. They could place these parameters into models and run back the clock. Of course, many guesses need to be placed hance thr need for many simulations. But i mean, they do it for galaxy evolution spanning as many or more parameters and run the model over longer time frames…. Just a thought
Would a smaller plate between the North American and Farallon plates earlier in the Mesozoic being subducted from both sides (with Siletzia being on the Farallon side away from the smaller plate being subducted under it) act as a slowing force/cushion, and when it is subsumed (especially if it was spreading in the middle at one point before being overtaken), the speed would seem to increase for the Farallon in the late Cretaceous? Such a plate being pushed ahead of the Farallon when it too was subducted could also be mistaken for a slab break. After all, it's really hard to guess just how many plates the ancient Panthalassa may have had.
Near the end of the talk, were you suggesting perhaps, that as the farallon/kula/resurrection are subducting, that the subducting edge is moving northward as well, but once a subsucted plate piece detaches it gets “stuck” with local resultant magmatism. ??
In that illustration, did i see a swap from westward to eastern subduction. Also, looking at the Pacific plate 60 million years ago, do we see rotation of the plate whilst moving east, moving the trench and the Farallon plate
Proponents of major northward transport in the PNW (i.e. Baja-BC) need to explain why there is no evidence for northward transport in the Great Basin and pre-San Andreas Cali. How do you get your terranes around this major westward bulge in the continental margin? I don't know much about the ID Batholith, but I do recall a particularly brutal claim-staking session in insanely steep terrain near Sun Valley. Not the greatest exposures but it sure seemed like the granitic rocks intruded into the pC-Paleozoic shelf sedimentary rocks, rather than a fault contact.. There are also Jurassic plutons in the Newfoundland and Deep Creek mountains around the Salt Flats in UT.
my math was off -its 1515 mi offset for 160 million years at .6 inches a year horse heaven hills in 15 mil years has raised 2500 ft above the pre glacial melt sea level..jump off joe peak sits at 2200 ft presently the columbia is at bedrock in walulla gap-1000 ft deep approx -thats 3k ft
Professor Willsey’s brief mention of the nearly contemporaneous India-EurAsia collision, and the possibility of that collision’s producing a magma upwelling similar to the Idaho Batholith triggered some thought and speculation on the matter. India, having separated from Gondwanaland, is usually depicted as moving fairly rapidly in a generally northerly direction, gradually closing the Neo-Tethys, until it collided with EurAsia. EurAsia, which had been moving gradually southward from the slow spreading Gakkel ridge in what is now called the Arctic Ocean, could have been a very large exotic terrane which India accreted. From India’s point of view, the EurAsian accretion was analogous to the relationship of Siletzia and the North American Craton. To further speculate regarding the similarities in the effects of the EurAsia-India collision and the North American Craton’s over-riding of much of the ancient northern Pacific portion of what is today called the East Pacific Rise, a subducted ‘Neo-Tethys Rise’ spreading zone moving beneath the Indian Craton(s) could well be the source of the late Cretacious-early Cenozoic magma upwelling that is known as the Deccan Traps.
Thanks Nick and Shawn for treating us to a campfire talk without the campfire! You are both excellent teachers and communicators. And thanks for all the previous programs and guest that laid the groundwork that got us to this point. This is going to be a fun series!
And to your good health sir.
While at present this livestream is above my level of geologic knowledge, I learned a great deal. I have always been fascinated by geology though my education has mostly been botanical. Obviously botany and geology are inter related. Thanks to you and shawn for this livestream.
My two favorite geology educators getting together! Thanks! Listening to you guys brainstorming was awesome. Looking forward to more!
Wow, great episode! Shawn and Nick are the two leading geologists conducting outreach to the public in the U.S. (Kudos to Myron Cook as well!). Yet despite that incredible distinction, so much fun to hear you two “spit-balling” back and forth as you both try to understand the origin of the Idaho batholiths. Due to episodes like this one, Most of your audience does not feel so bad by being confused by these complex, 4 dimensional geologic changes.
😊😊. Thank you-keep up the collaboration!
I caught this on replay - Loved every minute. Nick Z. is everything a damned good lecturer and UA-camr should strive to emulate and great to have Shawn along - thanks both !
Thank you, Nick and Shawn for sharing with us a wonderful free-flowing conversation that we all know usually takes place behind "closed doors" and presented only after many of the details have been worked out. It was fun and exciting to be part of this discussion. It feels that we're all on this great journey of learning and seeking knowledge together. Sort of a mini-Penrose approach!
Awwww! A new first grandchild. ❤❤❤ How wonderful!
the beauty of learning...thank u ..Nick and Shawn ..out at the Canadian shield
Catching this in replay - great chat. Excited to see where this goes. You're both such great educators, it's a pleasure to watch both your videos!
Hello, Nick.
Continuing to watch from Russia...
Thank you, You (and the team)....
You guys are discussing the questions that have captured me since Lowell explored underthrusting in Idaho and Wyoming in 1977 and the early work on the WISZ in the 1980s. Really appreciate the wide angle lens.
I love you guys, always so interesting to listen to your enthusiasm for your subject.
I love it, when you and Shawn put your heads together to figure things out. It's always a joy to think together in chat too.
Congradulations on your grandchild children and grandkids certainly make life worth living
Such a fun session to be a part of! It was great to see you both bounce ideas off each other! I always learn so much from each of you, and with you both together... well, the whole is even greater than the sum of the parts. I look forward to future collaborations! And thank you for answering my question towards the end. Thank you!!
More cool thought’s and questions for mulling over Farallon events and so much more! THNX
Congratulations Nick on the impending grandchild! You are going to love it!
"You gotta love it!"
Happiness is being a grandparent!!!
Love watching and listening to the dynamic duo of the Pacific Northwest geology wise.
Shawn is SO great! Every time I listen to him I hear someone who is interested in authentic discovery/authentic inquiry devoid of any ego. It makes the study of geology available to all of us - regardless of what we already KNOW we can inquire with and discover alongside someone like Shawn. What a great show this was!
Shawn and Nick - The Superfriends!
Orogeny... The mess caused by Siletzia, Spreading Ridge, slab rollbacks, Baja BC,,, during Eocene period,,, Thank you, Nick, for streaming those fun conversations between you and Shawn in the search for your geological narratives for the upcoming Cascade Volcaoes A to Z! And, meantime, we gain understanding the geological history, what to not love it💞What a wonderful time we live in!!😃Thank you✨💗
Great video! Love watching you both. The cretaceous interior seaway could be a fun future series idea.
this was great. i wish i had more time for geology things. i learn so much from both of you. i love how you brainstorm and theorize while not lecturing. so refreshing
I love honest attempts to learn. Bright people, when they get together in good faith and share questions and viewpoints, are among the best examples of what human potential can be.
Thanks, ❤guys.
Live for lunch at noon w Nick and Shaun, pretty nice for a Monday. Cool here too and the forcast looks great for the week in Northern Indiana. You and Shaun make a great brainstorming team and looking foward to the investigation of today's new questions and hypothesis. Best of luck to the expanding family....
Huge Link Up!!
Excellent interesting video. Thanks Shawn & Nick.
DOE’S EXTENSION & COMPRESSION HAVE ANYTHING TO DO WITH SUBDUCTING THE 3 HEADED SPREADING RIDGE?
Great program. I love watching you both. I'm subscribed to both of you. In another life, I would have been a geologist.
Wow my two favorite geology guys together! Thank you!
Thank you both, such an interesting discussion!
Watched most of this live but had to miss the last q & a part so I'm re-watching it all. I love it!!!!!!
Nick- Your boyish curiousity and true vulnerability toward the subject of Geology is brilliant. You sets the bar for academic accessibility for all with a curious mind. Thank you! and Willsey is cut from similiar cloth. All the best to both of you!
Missed the live stream, but glad to watch the replay! So kewl to see the Baja BC (BBC) connection ❤ It inspired me to dig into my Canadian Cordillera, and I am now working on an audiobook on the chosen rock of the Northern Canadian Cordillera 😅 thank you 🙏
Two of the strongest presenters I know.
Thx, Nick & Shawn. Appreciate it!
Thank you for a great session
@Nick Zentner Thanks for doing this live stream. It is a nice surprise on my birthday. Had to watch in replay as I was out for a birthday meal when this was live.
Happy Birthday!
@@LilA-zl6tf Thank you.
Nick and Shawn you guys rock!
I would like to think I am a little wiser, but I am not sure I am(?) But I am hooked!!! Thank you.
Well okay Nick,
You set the hook pretty hard there! 👍 Got me big time when you started involving baja-bc 🎉.
I remember the thinking about a much larger and even more complicated and further ranging implications of such a thing.
Thanks Shaun and can't wait to see what you have up 👆.... see you then there's
Excellent presentations! Thank you! Sláinte!
There is a really cool fissure south of Bruneau that I have hiked on since you folks started showing all these shows. It has been such a blessing to stand on the very thing that is going on in your time slots talked about here and then to see Shawn's and others videos from Iceland has really brought this to reality for me. Thanks guys!
Great discussion, both of you! I agree, Nick, as you were looking at the uneven tear of the slab, then the Northward motion, it does make a compelling case and fits well with the evidence…. At least for a minute till my mind fogged up again!
Thanks, Nick and Shawn, for some great insights, and yet another reference to COTM! 😂
Thanks Nick and Shawn! Great collab! (And I may have a road trip in my future.)
Interesting discussion. ID batholith just is weird. One thing Baja-BC made clear to me is that different things are happening depending on location, eg, slab breaking under what is now WA/OR/ID while something else is happening in Calif. Plus things are moving around and you have to subtract basin-and-range stretching to understand it. Makes things confusing.
And congrads in advance grandpa Nick!
On a side note: the southern half of Oregon is covered by the Tyee Formation which is sediments several thousand feet thick in places. It is thought to have formed in the fore arc basin created by Siletzia. The sediments are predominantly from the Idaho Batholith with a sprinkling of Klamath Mountains. Roadside Geology of Oregon 2nd edition Miller. Page 35. The cliffs at Mapleton, Oregon are Tyee Formation.
Nick you make rough diagrams like I do. Keep the discussion going.
I would like to see Myron Cook with you two working on the Batholite puzzle. Maybe?
Great topic. There is a lot to learn about the Idaho Batholith. You are the perfect person to put a better more complete story on the creation of it.
We have interesting volcanism on the eastern edge of the Pintler range. Andesite tufts that are exposed north/east at the foothills of the Pintlers on the southern edge of Anaconda. Cinder cones and massive rhyolite tufts on the east side of clear creek with basalt flows scattered up that basin where they logged/smelted all the copper from Butte. It’s a geological mess that is absolutely fascinating and it just gets crazier east and south of the Pintler’s. The thrust and fault of the Pintler locking up and deforming rocks to the east. Petrified forest just beneath the surface-even fossilized bones of god knows what but I’ve found vertebrae and a bone eroded by glaciation or exposed by a terminal moraine. Mind blown!
In addition to the subduction zone, don't we have segments of crust wandering let's say north, the way those did in California? There are blocks of say Belt surrounded with granodiorites and possibly that magma coming to the surface as extrusives in places.
Thanks for this - a Lot!
You get that view and you get paid to see it, what a gig! 👍😁👍
Perhaps if one were to unearth a fossized lighthouse in the Idaho batholith, one could conclude the theory of a breakaway. 😂
Excellent discussion! First, I am a professional geomorphologist and haven't studied the rocks you are discussing, but most major structural and topographic features of the western US are oriented N-S. For example the san andreas fault and the contemporary subduction zone, the Sierra's and Cascades, the horsts of NV and UT, the Wasatch front, and the "front range" of CO. But there are exceptions that are oriented E-W, all located near a (wide) line between Laramie and Portland. Those include the Columbia River gorge and the southern boundary of the Columbia plateau, the western Snake river plain (which was pulled apart in the N-S direction, the Uninta block and the anticline in Dinosaur National Park among others. In addition the highest points in the Rocky mountains (starting in NM and CO) shift West on the North side of that line, including the high peaks in ID and MT and British Columbia. That line, or zone, has got to be explained with your upcoming "grand theory" of the Idaho batholith.
Regards, Kirk Vincent, USGS (ret)
Thank you Prof Nick and Prof Shawn. I’m not a professional or an expert geologist, but a wannabe. When I took geology 101, my professor taught us that the Idaho Batholith was due to the subduction of the oceanic plate under the North American plate, and at that time the coast was at the modern border of Idaho. The Atlanta lobe of the batholith is much older than the Bitterroot lobe. Please correct me if I’m wrong. I had an outstanding professor for my Geology 101 class and installed a love for geology. I had an art major. When I graduated I received my BFA.
Exciting times on Geo-Earth; putting the pieces together~!
had to catch this in replay but wanted to ask, are there any tonalites around?
When does Clockwise Rotation start?
Shawn, they are called knowledge silos and, Nick is correct, we are lightyears ahead of days of old when those silos prevented idea development for a variety of reasons. Thanks to both of you for your work in communication arena. Question: Do we know anything about how the movement of the Siletzia plate east of the break? Did it flip up and possibly push what was above upward?
Will absolutely keep the Stanley meeting on my calendar. Wouldn't be that long of a drive from Cache Valley.
I'm binge-watching to catch-up. Great so far❣ 🤯
I like and agree with the possibility that the Idaho batholith might not be from subduction, but potentially related to Insular / Wrangellia since there doesn't seem to be any indication of subducted slabs to the east-ish / northeast-ish of the Yellowstone hotspot (where Idaho would seem to have been at that time) and transform compression &/or extension seems a reasonable potential cause / explanation.
It seems that the Challis magmas would more likely be associated with a spreading ridge (and perhaps the Yellowstone hotspot) if the Yellowstone hotspot is in approximately the same place and the west coast of North America was east of the current Yellowstone location during the Challis magmas time.
If the Yellowstone hotspot was west of the current location of Idaho and has moved along the strike-slip fault (as Basil has mentioned movement in past years) while North America has moved west, the slab breaks and rollback causing the Challis magmas seems reasonable.
If the spreading ridge, the Yellowstone hotspot & Siletzia were in approximately the same location as Yellowstone is now, and Idaho was east-ish / northeast-ish of the current Yellowstone hotspot location, plus Insular / Wrangellia sliding along the west coast just before the accretion of Siletzia; could that have jammed up Siletzia enough to start subduction to the west of Siletzia and then cause the slab breaks to the west of Siletzia?
I look forward to more❣❣🤯
Basil's Hit and Run explains....
Your styles are very different, but quite compatible.
Friction has to add tremendous amounts of energy to the system and then with supposed ccw motion of the NA plate. Reminds me of friction welding in metallurgy. Your pizza boxes make me think bulldozers on a frozen feedlot. Keep it up.
Look into the Anatectic belt Nick.
It also coincides with the block uplift to the East. Basil referenced a paper from Chapman et al, in 2021, for the belt.
Where did the eroded evidence end up. My guess is up north. As two large sheets are coming together, previous ribbon or wedge shaped slices that were moving north were sent north with a lot
of evidence of the new volcanism. Blends in with the ' Terrane Wreck' or 'Big Whale" story a bit.
When you think of the Yellowstone Super Volcano video that Nick did, how the many numerous ancient caldera’s now flattened, reached deep into the land mass. They moved in from the ocean with a few ancient ones to the north of the main trajectory, to where the active caldera lays now, against the granite of the craton …… yeah, could be …..Baja BC. The chocolate cake is still churning
The Farallon plate is my favorite followed but the Kula.
Shawn’s idea that there was a magmatic arc that didn’t express as a volcanic arc feels correct to me. Heat moving up could be subduction related. Or, a slab break off melting rock and mixing below the surface creating the Idaho batholith could present as an arc as well. The source of the heat is just different.
I can't wait to see the Seattle video. I bet you two were a couple of pilgrims in a unholy land. 🤭😆
This for both Nick and Shawn. Shawn, a while back you did a roadside video near Puerto Vallarta and I believe you were looking at stuff a bit north of PV along the coast in Nayarit state, if my memory is right--which if you go north of PV you wind up in the Mexican transvolcanic belt. I wish you had had time to go south of PV as well, as you are along the rugged coastline of the Sierra Madre del Sur, and it appears to be all granite, or mostly granite and gneiss--and though I am not a professional geologist, the whole mountain block south of PV appears to me to be mostly a large pluton or batholith--all intrusive rock. It is dramatic landscape, and when I have hiked up some of the ridges, it reminds me so much of being in the central Idaho mountains--but for the plants and trees. Very steep, deep canyons, and granite everywhere.
So as long as Nick is casting a wide net for a while (bringing up Baja BC), my question is whether this large plutonic body, i.e. SM del S,--located near an active subduction zone (the southern twin to the Juan de Fuca plate)--relates at all in time to the other plutonic areas further north, say in Baja, the Sierras, or Nevada. I can't find any information on it, easily anyway. (Seems like there is lots of interchange of ideas between American and Canadian geologists on this big picture stuff, but once you get south of the border--maybe because of language, or other factors--it's very hard to find much information or interchange dialogue between professors, or maybe I just don't know where to look.)
I very much enjoyed this show today (and the prior ones) because I grew up near the Idaho Batholith and our family had a summer home in an area of the Challis volcanics (Williams Lake, near Salmon, where I found my first geode), and the geology of this area, well all of central Idaho, has puzzled me my entire life. It is exciting for me, after so many years, to see folks in the know homing in on these questions.
Joan Denoo, eager to learn more about the geology of the Idaho batholith.
Just missed this live from Fayetteville, NC where we also experienced lightning/Thunder w rain last night too! This whole area is on very notable sandy soil. Wonder if that may mean ocean at one time
Hello from kitsap county
that was really fun. wondering if the floating bobber of the farrilon plate and the curtain is at the same level below the craton.?
rotation and time frame fit with Mexico moving up
Q: How can “Baja-BC” convey Northward if an active oceanic plate is in subduction mode with NA North of it at the same dad-gum time?
My A: The Holocene version of it is happening in Northwestern California and Southwestern Oregon right this minute.
It’s the mechanism that’s conveying the Franciscan Assemblage North, around the East side of the Mendocino Triple Junction, up the NoCal coast skirting the West side of the Klamath Mtn. Terranes and continuing up the Oregon South Coast to the Southern margin of the Siletz Terrane @Coos Bay, OR.!
The mechanism is older, tectonically inactive and uplifted/exhumed oceanic crust conveyed by a tectonically active conveying oceanic plate under it from the South. The tectonically active plate shears away-left at the Triple Junction and the older inactive plate continues on its original trajectory.
The South Gorda plate isn’t subducting under North America per se, it’s subducting under the Northern end of the Franciscan Assemblage.
The Franciscan Assemblage is on the same track as the Siletz Terrane, causing the NW rotation as it pushes from the South to the North-Northwest.
That is how a Strike-Slip fault system can coexist with a Subduction System. Stuart rode the continental slope North. Transduction?
September in Stanley Bring your snow shoes!
Amazing stuff ... as seen from the UK
Could the different magma compositions (and times) have resulted from 1) the release of mantle-derived magma from the underside of the torn slab; followed by 2) composite magma derived from mantle-derived magmas melting and picking up material form the upper and/or lower surfaces of the slab curtain to give a strange composite magma??
Be careful picking a spot around Stanley. Some campgrounds were closed due to fire.
Did you both pick up on the Yellowstone manager's comments on Baja? Michael Poland's comments.
We are still the blind men (, albeit experts) examining the elephant. For instance, how can we consider the role of Siletzia without consideration of the Yakitat terrane? It goes rift, subduction , rift, subduction,... on and on, you don't get a rift pushing on a rift or a subduction sucking down another subduction do you? I can see the possibility of the East Pacific rise producing as its eastward stream, the tomography we see underlying the Eastern US .
Laser Show 🤘
When you two were talking I had an idea of perhaps using supercomputer models to try to recreate present day conditions. Similar to how they do things for galaxy evolution models. Bear with me. With galaxies, we know their present conditions and they can make models that trace backwards plausible earlier conditions. Or even use monte carlo runs to see most likely scenarios leading to present conditions. We know current plate movements and current rock types and conditions needed to get said rock types. They could place these parameters into models and run back the clock. Of course, many guesses need to be placed hance thr need for many simulations. But i mean, they do it for galaxy evolution spanning as many or more parameters and run the model over longer time frames…. Just a thought
Would a smaller plate between the North American and Farallon plates earlier in the Mesozoic being subducted from both sides (with Siletzia being on the Farallon side away from the smaller plate being subducted under it) act as a slowing force/cushion, and when it is subsumed (especially if it was spreading in the middle at one point before being overtaken), the speed would seem to increase for the Farallon in the late Cretaceous?
Such a plate being pushed ahead of the Farallon when it too was subducted could also be mistaken for a slab break.
After all, it's really hard to guess just how many plates the ancient Panthalassa may have had.
Near the end of the talk, were you suggesting perhaps, that as the farallon/kula/resurrection are subducting, that the subducting edge is moving northward as well, but once a subsucted plate piece detaches it gets “stuck” with local resultant magmatism. ??
The columnar basalt canyon just East of Boise is supposed to be Challis Magma.
So are the mantle currents acting like a river and that hanging slab a boat bobbing along in them like a boat at anchor
In that illustration, did i see a swap from westward to eastern subduction. Also, looking at the Pacific plate 60 million years ago, do we see rotation of the plate whilst moving east, moving the trench and the Farallon plate
Proponents of major northward transport in the PNW (i.e. Baja-BC) need to explain why there is no evidence for northward transport in the Great Basin and pre-San Andreas Cali. How do you get your terranes around this major westward bulge in the continental margin?
I don't know much about the ID Batholith, but I do recall a particularly brutal claim-staking session in insanely steep terrain near Sun Valley. Not the greatest exposures but it sure seemed like the granitic rocks intruded into the pC-Paleozoic shelf sedimentary rocks, rather than a fault contact..
There are also Jurassic plutons in the Newfoundland and Deep Creek mountains around the Salt Flats in UT.
That was fun - almost wish that I were fifty-five years younger so that I could become a real geologist.
Making sausage! A fun hour.
😎
my math was off -its 1515 mi offset for 160 million years at .6 inches a year horse heaven hills in 15 mil years has raised 2500 ft above the pre glacial melt sea level..jump off joe peak sits at 2200 ft presently
the columbia is at bedrock in walulla gap-1000 ft deep approx -thats 3k ft
Professor Willsey’s brief mention of the nearly contemporaneous India-EurAsia collision, and the possibility of that collision’s producing a magma upwelling similar to the Idaho Batholith triggered some thought and speculation on the matter. India, having separated from Gondwanaland, is usually depicted as moving fairly rapidly in a generally northerly direction, gradually closing the Neo-Tethys, until it collided with EurAsia. EurAsia, which had been moving gradually southward from the slow spreading Gakkel ridge in what is now called the Arctic Ocean, could have been a very large exotic terrane which India accreted. From India’s point of view, the EurAsian accretion was analogous to the relationship of Siletzia and the North American Craton.
To further speculate regarding the similarities in the effects of the EurAsia-India collision and the North American Craton’s over-riding of much of the ancient northern Pacific portion of what is today called the East Pacific Rise, a subducted ‘Neo-Tethys Rise’ spreading zone moving beneath the Indian Craton(s) could well be the source of the late Cretacious-early Cenozoic magma upwelling that is known as the Deccan Traps.
That complicates my NE Washington geology even further.