Man I just had that Ah-ha moment that tied all of everything you've been teaching the last 5 years, that tied it all together!! The Sierra linking up with the Idaho Batholith, the Baha BC stuff, the German chocolate cake the Yellowstone hotspot, literally everything you've taught us.... WOW what a moment!!! Thank you!!! Now I want to know more!!!
If the present total of 22 active/dormant Cascade volcanoes were set as the average population within the 900 mile arc (Silverthrone Mtn., BC to Mt. Lassen, CA.) and each was given a million year lifespan, the 42 arc generations would’ve produced @924 volcanoes. The 924 volcanoes in a 900 mile arc would require complete overlap where each volcano summit is just 1558 meters apart if they were all inline, which they’re not; the Three Sisters complex would be a good density model; this shows that every present Cascade volcano is born on the eroded basements of previous generations.
Hello Nick, My wife and I are noobies to geology but have been curious for decades, having purchased Roadside Geology Washington and Oregon in the early 2000's. Discovered you and this channel a couple of months ago. We find you engaging and informative. The very best of teaching. You make us want to learn more about this complex and fascinating topic.😢 Thanks for sharing your passion, knowledge, and drive to learn more. It's inspiring us. Thank you, Rick & Carla
5x5 Barbara Dick Fort Ransom, ND. Tuning in late, but I never passed up, you're welcome. My pup comes when he hears your voice thanks to your alphabet series last fall and winter when I found you during the Great Ice Age Floods. Amazing! How does it feel to be a world wide Teacher/Professor of Geology 101 in and out of the classroom? To know how you have grabbed the interest of so many, with the help of several who have helped you and all of us to understand a time that has been lost to most of the human race. Bless you ❤
I missed the stream but... Wow, what intriguing thoughts, especially, that 7 million year worth of Challis Magma activities, the articles make more sense now! I love it when you leave questions for us, thank you Nick!!😃💞💗✨
This Idaho Batholith/slab break off set of episodes, coupled with Nick’s upcoming Cascade volcano series, is shaping up to be a super interesting geologic exploration. 🗻🌎🗻 Thank you Professor Zentner for continuing to ask compelling questions and taking us along on your journey to find the answers!!
God Bless you Nick. Glad to see you getting back to Volcanos and Tectonics. Ive been following you since the preCovid days of December 2019 [?] Also been a ROADY for the POP-UP shows. {Miss them !!!] Please keep doing all that you do in your own way. You probably don't realize what an inspireing service you are to the world we live in. Sincerely, BRUCE the Twin Lakes guy.....
Back in my youth in the late 1950s & early 1960s, I lived in the Challis National Forest. The Geology there is very old volcanic as well as ancient subduction zones. The Stanley Basin sank over 2,000 feet below the Sawtooth Range to the South. I lived near where the Yankee Fork joins the Salmon River, as well as way up Slate Creek Canyon. My dad was mining galena until Pearl Harbor was bombed & he joined the US Army. He taught me a lot about the area's Geology.
I had to step away halfway through the live and came back to finish the stream - and all I can say is MIND BLOWN. Holy crepe... it's everything you've been covering for the past 5 years in one dang episode. I'm going to have to go have a think about this for a while.
I love your program notes, it's thought process at its finest. Please don't change a thing 😊. Your lessons are challenging for me, I need to revise my geology texts all the time but that's what makes it interesting. Thank you so much for all your work
36:56 The grin on your face at this moment and the follow up unveil. Fantastic! So nice to have the return of a regular to your past livestreams! I’m sure I am not alone in saying this, “We missed you Chalky! Welcome back!”
That was a roller-coaster today, Nick, and an exciting one at that. I will be sure to check the 351 challis magma episodes again. I remember that series fondly because of the amazing atmosphere between you and the class. It was a great series, so I am happy to take a peek at it again. Loving you back, Nick!
I live in British Columbia Canada and I have thought this very much. Just driving from the Rockies to the westcoast this idea reins strong with me. Every time I take the roads from east to west or west to east in our Province I can see this story you’re talking about. In Revelstoke there a Volcano called Mt Begbie and it is a Gabboric Plug. I find it all fascinating.
I confess to being a day late - But I enjoyed it just the same! Thanks so much for this episode. It was really helpful to start to understand this puzzle. Thanks for the great video and all your remarkable effort and enthusiasm!
I only caught the tail end of the live stream, and just re-watching now. As others have said, it's great to see you back live. Regarding last season's two and three hour marathons, I have to say I enjoyed them all, but they were pretty long and I can see why you might get them a bit more under control. Looking forward to this fall.
Living in WA state in 90s thru 03 was fascinated with Cascades geology, your presentations have been tremendous in answering my rock and mountain questions! I hiked all over the Cascades and was blown away by the changes in rock types and compositions just going up the trail! Fascinating! Keep up my geology education, please.
Hypothesis: Siletzia was landmass sitting on both sides of a east-west-midocean ridge (like iceland). The Ridge was subducted under North America an initiated the Challis Magmas. The Siletzia landmass itself accreted to North america and ended the Idaho volcanic arc. On the new west coast a new volcanic arc (the Cascades) was created.
This is going to be a particularly interesting series, cant wait to learn more concepts and get a better idea how it ties into all the other topics that have been covered here!
I look forward to each and every one of your videos, livestream or not! This one was an unexpected trip mentally. Just as I had started to pry myself away from Btretz and into the Cascades, you throw a curve ball and take us to Idaho LOL. Thank you Nick for a stimulating presentation! I hope if you cover Challis magmas a bit more and that Crazy Eocene window that we can spend a little time exploring the volcanics around Wenatchee. Living right here at the convergence of so many geological processes I spend a lot of time looking and wondering if I am telling myself the right story about the rocks.
I am so proud of myself I finally got the nerve to ask a question in the Q&A .I was wondering if Western Subduction a possibility for volcanism That story is further back in time I have to be better disciplined It is easy to mix things up and there is a hell of a lot of geology to know and remember in the state of Washington.
Good evening Nick, Sorry I missed the class. I totally miss you and the classmates. Topic was excellent and it was nice to be learning again. Could you point me to the calendar if I missed it? Thank you, sir, see you next.
Okay Nick, you are driving me crazy. After all these episodes I find, as a scientist yet an admitted outsider (atmosphere, meteorology), that there is one outstand singular question which if answered will yield the connection between Baja BC, that crazy Eocene, Siletzia and the Yellowstone hot spot, not to mention the Idaho batholith and Cascade questions. And that question is,....(dramatic revelation), WHAT HAPPENED WHEN THE EAST PACIFIC RISE MET NORTH AMERICA? As I see the extension, the whole Rockies uplift, the tomography data (and much more) all point to there being something very active under the western margin of North America from some 270+ Ma including up until now. Ask this question of each professional Geologist and let's see if that can be the great unifying Q and A. SO,.. WHAT HAPPENS WHEN A CONTINENTAL PLATE COLLIDES WITH A MAJOR RIFT ZONE? Hey, and thanks for letting me brainstorm, Love ya', man!
I am not a geologist, but have watched most of the A-Z series, and I have thought about your question related to the East Pacific Rise being overrun by a westward rifting North America Plate. Anyway if you look at the longitudes of the East Pacific Rise in the Pacific Ocean today, they basically range from the Great Basin (say Elko, NV) to Denver if you extrapolate them straight north. So in my mind, right or wrong, I sort of figure the Great Basin expansion/extension, from Reno to SLC, represents where the rifting East Pacific rise is today, under North America. How that is related to North America's collision with Siletzia/Yellowstone HSP? I don't know. I just know that if you run North America over the East Pacific Rise, and if that were more or less straight north to south, then the East Pacific rise should be under Nevada and Utah today. I'm sure it is more complicated than that, and I hope to hear more from Nick and his guests on this--and hopefully one of these years Nick will do an A-Z series on the Great Basin. As far as I know though, other things you mention--such as the uplift of the Rockies (in the late Cretaceous--like 70 or 80 MA) and other events such as the accretion of various pre-Siletzia terranes to the Western Margin of North America---well these belong to much older stories--and in this lecture we're dealing with the Eocene (53 ma) forward. It blows my mind to think that these events in this lecture, such as the Challis magma arc, all begin 13 million years AFTER the extinction of the dinosaurs.
@@bingyoung3228 Thanks for the thoughtful reply. You must remember that rift zones are cut frequently by transverse segments, that is those which run at right angles to the rift trend. Examples are the theorized Columbia embayment and the observed Lewis-Clark Transverse zone in northern WA, ID, and MT with movement happening in both (east and west) directions. These segments can flex somewhat like a spine I suppose as pressures change in the internal driving force from the mantle and plate collisions/interactions. Very interesting to trace the history of the transverse zone motions. My deeper interest is in the mantle driving forces. I see the patterns produced in the lithosphere to resemble greatly the tops of thunderstorm complexes and the motions over time to resemble particular storms such as hurricane Hilary which just a year ago ran up the west coast like a Baja-BC archipelago. I am hoping insights from one branch of science can inform another branch. (Wagner, a meteorologist, proposed continental drift, i.e. plate tectonics.)
yes! would love to hear more about the seismic tomography and igneous geochem here! also: global story, thats where my thoughts end up and then i get overwhelmed and need to seek out more papers to tell me its even viable. such a huge project! super interesting nick!
Hi guys from Sudney Australia. Great to be back on whale pod. QUESTION..WHAT HAPPENS IF YOU PUT OLD NORTH AMERICA IN REWIND? DOES IT NOT MOVE THE ARC AND THE TRENCH FURTHER EAST? SECOND,, WE COME BACK TO A QUESTION FROM PRIOR SERIES. WHAT HAPPENS WHEN THE CONTINENT RUNS OVER THE TOP OF A TRENCH. DOES INHERENT WEAKNESSES IN THE INTRACONTINENT BASEMENT CONTRIBUTE TO TIMING AND PLACEMENT OF THE ARC. Professor Tom Raimondo in studying old central Australia thinks maybe
Excellent episode! Looking forward to the next couple of weeks. Back in 2020 to 2021, watched the Exotic Terranes A-Z (2020-21) and the Spring 2021 351 class. Wrote out a timeline to try and keep events straight from about 90Ma to present. Some of my questions were about the Idaho Batholiths and related events. Be nice to see if there are any answers!
I've been binge watching the exotic terrane episodes. And this episode feels like it's just picking up right where I left off, even though that series was filmed 3 years ago
Professor Zentner thank you for your fine classes. Could you possibly bring in your office the green chalk boards? I. was always fascinated by your chalk board classes. I think the Idaho bath lithography would so interesting on the chalk board as only you can do.
"The evolution of the Eocene climate began with warming after the end of the Paleocene-Eocene Thermal Maximum (PETM) at 56 Ma to a maximum during the Eocene Optimum at around 49 Ma." That's curious. The climate changes and three million years later the Idaho volcanic arc shuts down. The climate changes again, and three million years later the Cascade volcanic arc starts up. The climate shifts are from CO2 and methane stirred up by plate tectonics, (maybe).
Nick, I'm working on a map of the Absaroka Volcanics province right now! Those stratovolcanoes in Wyoming have eruptive ages that follow a perfect north -> south chronology from 51.56 to 43.68 MYA, respectively. Seems to fill in the gap perfectly as part of the Challis, but seems to be clearly subduction-related, at least in that very local area? Let me know what you think - Feeley et al 2000 has a great overview.
How connected is Nick? I enjoyed the description of his chalk. I didn't know there was specific brand that was preferred. I am dumb to the subject. Yet here I am on my CZcams feed and am presented with a video entitled "Why is Hagoromo chalk so expensive?" Well connected. Looking forward to Cascades A-Z.
so, can you think of the extension as a relief and cause crust 'drip' and shut-off building of rockies; in association with siletzia docking. because by this time both Intermontane, batheolith complex and insular have docked.....wow, mind explodes.
Nick, looking at broader regional context. I just explored NE Wyoming and S Montana, using Google maps satellite. For example, Devil's Tower pluton is casually quoted to be 50 Ma (or 65 Ma? Conflicting). About right, or too old? Other: I am tempted to say I see lots of "calderas" looking like vanished cones with circular mountain rims around them. In no particular order looking at Google maps in "satellite mode": - Just east of Absaloka coal mine, 6 miles dia. - North Mocassin Mountains, 2.5 miles dia. - Green Mountain, Wy (near Devils Tower), 1 mile dia. - Also 3-5 mi south of Green Mountain, several more circular ridges. - Judith Mountain Lodge, 3 mi dia. - Thunder Mountain, 4 mi dia. Relevant? What are the ages of those? Are they in the Laramide/Eocene literature? And at 47.852734, -108.750054, what's that (no obvious name)?
Thanks for this video. QUESTION: In your 7mil window between the Cascadia and Idaho Arc lies, Crater Lake and to the south Mt. Lassen...were these two a result of the Pacific plate melt adding magma to the core forcing it upward resulting in the eruption of both these volcano's during that "loud time"?
Clarno formation in Oregon - the internet says (and it's always right, right?) the age range is 54-39ma - so right in the same window (roughly) as the Challis. Is this maybe the "missing arc" not the Idaho batholith rocks? Not Washington but certainly seems like they need to 'fold' into the frosting on the fruitcake.
maybe theres some verticality involved, since the north american plate was moving north relatively fast and the earth is somewhat egg shaped this could result in the plates north being held lower by the plates rigidity then once the plates center got far enough north there would be a change in the speed of its adjustment and this combined with the subducted spread plate and the transtension maybe could explain why the volcanism during just that period is so strange its upplift poles hotter magna through the subducted plate maybe that iractically pulls water put of it where it otherwise wouldnt idk, i havent heard vertical adjustments of plates and effects discussed but itd have to happen since the earth isnt a perfect sphere and plates arent perfectly malleable
My question: The exotic terranes rode tectonic plates that rammed into the North America Cratons. There should have been arcs associated with each mashup. Is there volcanic activity associated with each accretion?
Back of a convergent plate boundary you will have doming and extension. The large pophryry copper deposits in Mongolia are hosted in a similar environment back of the collision between the Indian and Asian plates m
The Absaroka volcanics in Wyoming far to the east of the Idaho Batholith and in the same time span include andesites porphyries very rich in largish hornblende crystals. Perhaps related?
Can we tell the difference between chemistry of the NA plate and the offshore plate versus deep layers below the plates..if so..will this provide clues as to where the magma comes from?
At around 46:20. " 53 "...... Any chance " 53 " is around the time a real MMA match between 1) westward subduction ends . 2) eastward subduction starts 3) Siletzia joining in as the referee?
Did the asteroid hitting the yucatan 65mya cause the shift to the north and start the resettling of all the corresponding plate and magma movements? Would explain a lot of rapid movement during the Dinosaur die off during this time.🤔
Nick, Could the the clash of Siletzia caused the opening up of the fishers in Idaho, then fill the ocean basin in eastern Oregon and Washington and after the 7 million years of layer after layer have created a lava wall that forced the new cascade volcanic arc ?
And I am not sure I heard Nick the answer his question re: whether the granites of the Idaho Batholith, say near Stanley, Idaho, or up the Bitterroot Lobe near Hamilton, MT contain the hornblend signature of igneous rocks produced by subduction zones. I am guessing they do, just based on my recollection of what the rocks look like up there. I also had the idea that at least some of the granites of the Idaho Batholith are older than the Challis Volcanics of the Eocene, suggesting that there could have been a volcanic arc event prior to the explosive Eocene and the Challis magmas.
Man I just had that Ah-ha moment that tied all of everything you've been teaching the last 5 years, that tied it all together!! The Sierra linking up with the Idaho Batholith, the Baha BC stuff, the German chocolate cake the Yellowstone hotspot, literally everything you've taught us.... WOW what a moment!!! Thank you!!! Now I want to know more!!!
The Supreme 😮
If the present total of 22 active/dormant Cascade volcanoes were set as the average population within the 900 mile arc (Silverthrone Mtn., BC to Mt. Lassen, CA.) and each was given a million year lifespan, the 42 arc generations would’ve produced @924 volcanoes. The 924 volcanoes in a 900 mile arc would require complete overlap where each volcano summit is just 1558 meters apart if they were all inline, which they’re not; the Three Sisters complex would be a good density model; this shows that every present Cascade volcano is born on the eroded basements of previous generations.
Hello Nick,
My wife and I are noobies to geology but have been curious for decades, having purchased Roadside Geology Washington and Oregon in the early 2000's. Discovered you and this channel a couple of months ago.
We find you engaging and informative. The very best of teaching. You make us want to learn more about this complex and fascinating topic.😢
Thanks for sharing your passion, knowledge, and drive to learn more.
It's inspiring us.
Thank you,
Rick & Carla
Hi from Hong Kong! Good to see Nick back!
5x5 Barbara Dick Fort Ransom, ND.
Tuning in late, but I never passed up, you're welcome.
My pup comes when he hears your voice thanks to your alphabet series last fall and winter when I found you during the Great Ice Age Floods. Amazing!
How does it feel to be a world wide Teacher/Professor of Geology 101 in and out of the classroom?
To know how you have grabbed the interest of so many, with the help of several who have helped you and all of us to understand a time that has been lost to most of the human race. Bless you ❤
I have hiked the Idaho Batholic for several summers since our wonderful field trip to Riggins ID. Thank you for the more information for me to study
Always fun to watch!
I missed the stream but... Wow, what intriguing thoughts, especially, that 7 million year worth of Challis Magma activities, the articles make more sense now! I love it when you leave questions for us, thank you Nick!!😃💞💗✨
It just struck me. He’s the Mr. Rogers of geology.
Terrific episode ❣️ 🫶love the chalkboard back in🫶❣️ could not make it live but hey ho 😊 love and thanks a lot Nick❣️
This Idaho Batholith/slab break off set of episodes, coupled with Nick’s upcoming Cascade volcano series, is shaping up to be a super interesting geologic exploration. 🗻🌎🗻 Thank you Professor Zentner for continuing to ask compelling questions and taking us along on your journey to find the answers!!
I’m watching in retro, but there’s no way I’m scrolling forward lol the preamble is just too much fun 😀, hi Nick and all the other Zentnerds 👋
I like to see the blackboard back in action, make it more fun to watch and easier to understand
Please keep up the podcasts, we've only just started listening to them and they're great. Very much appreciated.
God Bless you Nick. Glad to see you getting back to Volcanos and Tectonics. Ive been following you since the preCovid days of December 2019 [?] Also been a ROADY for the POP-UP shows. {Miss them !!!] Please keep doing all that you do in your own way. You probably don't realize what an inspireing service you are to the world we live in.
Sincerely, BRUCE the Twin Lakes guy.....
On my way from Ontario to go look at some of this geology I’ve been learning for years. Currently in Montana. Thx Nick.
Back in my youth in the late 1950s & early 1960s, I lived in the Challis National Forest. The Geology there is very old volcanic as well as ancient subduction zones. The Stanley Basin sank over 2,000 feet below the Sawtooth Range to the South.
I lived near where the Yankee Fork joins the Salmon River, as well as way up Slate Creek Canyon. My dad was mining galena until Pearl Harbor was bombed & he joined the US Army. He taught me a lot about the area's Geology.
Can’t say how much I appreciate you sharing knowledge. I get a kick out of taking my kids hiking bombarding them with facts 😎
I had to step away halfway through the live and came back to finish the stream - and all I can say is MIND BLOWN. Holy crepe... it's everything you've been covering for the past 5 years in one dang episode. I'm going to have to go have a think about this for a while.
love love love
Keep going, your doing well.
Watched in replay. Sound is fine, video is fine. The chalkboard works fine. All seemed OK. Thanks.
I love your program notes, it's thought process at its finest. Please don't change a thing 😊. Your lessons are challenging for me, I need to revise my geology texts all the time but that's what makes it interesting. Thank you so much for all your work
Cheers Nick! And very happy for Vinman’s Bakery, one day I will visit!
I'm watching 351 right now. So this is extremely interesting. Ty for bringing us along for the learning journey.
36:56 The grin on your face at this moment and the follow up unveil. Fantastic! So nice to have the return of a regular to your past livestreams! I’m sure I am not alone in saying this, “We missed you Chalky! Welcome back!”
Hello Nick good to see you from Redding ca. better late than never for me. I’ve took 101 and 350 with you on line and got me started on geology
I love your videos so much 🥰 you are such a great presenter, thank you!
I pull night shift on my job, so I miss these live, but these are great at lunchtime!
That was a roller-coaster today, Nick, and an exciting one at that. I will be sure to check the 351 challis magma episodes again. I remember that series fondly because of the amazing atmosphere between you and the class. It was a great series, so I am happy to take a peek at it again.
Loving you back, Nick!
I live in British Columbia Canada and I have thought this very much. Just driving from the Rockies to the westcoast this idea reins strong with me. Every time I take the roads from east to west or west to east in our Province I can see this story you’re talking about. In Revelstoke there a Volcano called Mt Begbie and it is a Gabboric Plug. I find it all fascinating.
LOVE THIS! Like old times. I guessed the Chalkboard, BTW.
I confess to being a day late - But I enjoyed it just the same! Thanks so much for this episode. It was really helpful to start to understand this puzzle. Thanks for the great video and all your remarkable effort and enthusiasm!
Thank you Nick from Silver Lake Oregon .
glad your tallking about this stuff in Idaho and then there is the blue mountians which is a terane that slamed into Idaho too
Many thanks from Spokane
Hello from Tightwad, Missouri
I only caught the tail end of the live stream, and just re-watching now. As others have said, it's great to see you back live. Regarding last season's two and three hour marathons, I have to say I enjoyed them all, but they were pretty long and I can see why you might get them a bit more under control. Looking forward to this fall.
Living in WA state in 90s thru 03 was fascinated with Cascades geology, your presentations have been tremendous in answering my rock and mountain questions! I hiked all over the Cascades and was blown away by the changes in rock types and compositions just going up the trail! Fascinating! Keep up my geology education, please.
Hypothesis:
Siletzia was landmass sitting on both sides of a east-west-midocean ridge (like iceland). The Ridge was subducted under North America an initiated the Challis Magmas. The Siletzia landmass itself accreted to North america and ended the Idaho volcanic arc. On the new west coast a new volcanic arc (the Cascades) was created.
This is going to be a particularly interesting series, cant wait to learn more concepts and get a better idea how it ties into all the other topics that have been covered here!
It’s like Nicki’s putting together a doctorate understanding of the formation of the Western United States.
I look forward to each and every one of your videos, livestream or not! This one was an unexpected trip mentally. Just as I had started to pry myself away from Btretz and into the Cascades, you throw a curve ball and take us to Idaho LOL. Thank you Nick for a stimulating presentation! I hope if you cover Challis magmas a bit more and that Crazy Eocene window that we can spend a little time exploring the volcanics around Wenatchee. Living right here at the convergence of so many geological processes I spend a lot of time looking and wondering if I am telling myself the right story about the rocks.
I am so proud of myself I finally got the nerve to ask a question in the Q&A .I was wondering if Western Subduction a possibility for volcanism That story is further back in time I have to be better disciplined It is easy to mix things up and there is a hell of a lot of geology to know and remember in the state of Washington.
Yes! Love the use of Chalkey!
Good evening Nick, Sorry I missed the class. I totally miss you and the classmates. Topic was excellent and it was nice to be learning again. Could you point me to the calendar if I missed it? Thank you, sir, see you next.
Hey nick, just fell in to ur channel....I'm also a zentner, and love this kinda of stuff
Okay Nick, you are driving me crazy. After all these episodes I find, as a scientist yet an admitted outsider (atmosphere, meteorology), that there is one outstand singular question which if answered will yield the connection between Baja BC, that crazy Eocene, Siletzia and the Yellowstone hot spot, not to mention the Idaho batholith and Cascade questions. And that question is,....(dramatic revelation), WHAT HAPPENED WHEN THE EAST PACIFIC RISE MET NORTH AMERICA? As I see the extension, the whole Rockies uplift, the tomography data (and much more) all point to there being something very active under the western margin of North America from some 270+ Ma including up until now. Ask this question of each professional Geologist and let's see if that can be the great unifying Q and A. SO,.. WHAT HAPPENS WHEN A CONTINENTAL PLATE COLLIDES WITH A MAJOR RIFT ZONE?
Hey, and thanks for letting me brainstorm, Love ya', man!
I am not a geologist, but have watched most of the A-Z series, and I have thought about your question related to the East Pacific Rise being overrun by a westward rifting North America Plate. Anyway if you look at the longitudes of the East Pacific Rise in the Pacific Ocean today, they basically range from the Great Basin (say Elko, NV) to Denver if you extrapolate them straight north. So in my mind, right or wrong, I sort of figure the Great Basin expansion/extension, from Reno to SLC, represents where the rifting East Pacific rise is today, under North America. How that is related to North America's collision with Siletzia/Yellowstone HSP? I don't know. I just know that if you run North America over the East Pacific Rise, and if that were more or less straight north to south, then the East Pacific rise should be under Nevada and Utah today. I'm sure it is more complicated than that, and I hope to hear more from Nick and his guests on this--and hopefully one of these years Nick will do an A-Z series on the Great Basin.
As far as I know though, other things you mention--such as the uplift of the Rockies (in the late Cretaceous--like 70 or 80 MA) and other events such as the accretion of various pre-Siletzia terranes to the Western Margin of North America---well these belong to much older stories--and in this lecture we're dealing with the Eocene (53 ma) forward. It blows my mind to think that these events in this lecture, such as the Challis magma arc, all begin 13 million years AFTER the extinction of the dinosaurs.
@@bingyoung3228 Thanks for the thoughtful reply. You must remember that rift zones are cut frequently by transverse segments, that is those which run at right angles to the rift trend. Examples are the theorized Columbia embayment and the observed Lewis-Clark Transverse zone in northern WA, ID, and MT with movement happening in both (east and west) directions. These segments can flex somewhat like a spine I suppose as pressures change in the internal driving force from the mantle and plate collisions/interactions. Very interesting to trace the history of the transverse zone motions.
My deeper interest is in the mantle driving forces. I see the patterns produced in the lithosphere to resemble greatly the tops of thunderstorm complexes and the motions over time to resemble particular storms such as hurricane Hilary which just a year ago ran up the west coast like a Baja-BC archipelago. I am hoping insights from one branch of science can inform another branch. (Wagner, a meteorologist, proposed continental drift, i.e. plate tectonics.)
yes! would love to hear more about the seismic tomography and igneous geochem here! also: global story, thats where my thoughts end up and then i get overwhelmed and need to seek out more papers to tell me its even viable. such a huge project! super interesting nick!
Hi guys from Sudney Australia. Great to be back on whale pod. QUESTION..WHAT HAPPENS IF YOU PUT OLD NORTH AMERICA IN REWIND? DOES IT NOT MOVE THE ARC AND THE TRENCH FURTHER EAST? SECOND,, WE COME BACK TO A QUESTION FROM PRIOR SERIES. WHAT HAPPENS WHEN THE CONTINENT RUNS OVER THE TOP OF A TRENCH. DOES INHERENT WEAKNESSES IN THE INTRACONTINENT BASEMENT CONTRIBUTE TO TIMING AND PLACEMENT OF THE ARC. Professor Tom Raimondo in studying old central Australia thinks maybe
Dang it. I missed the livestream.
Excellent episode! Looking forward to the next couple of weeks.
Back in 2020 to 2021, watched the Exotic Terranes A-Z (2020-21) and the Spring 2021 351 class. Wrote out a timeline to try and keep events straight from about 90Ma to present. Some of my questions were about the Idaho Batholiths and related events. Be nice to see if there are any answers!
Dang it #2, I missed the livestream.
I've been binge watching the exotic terrane episodes. And this episode feels like it's just picking up right where I left off, even though that series was filmed 3 years ago
This is a really good synthesis of NW geology, keep going!
Hi from Sturgis SD 😮
Professor Zentner thank you for your fine classes. Could you possibly bring in your office the green chalk boards? I. was always fascinated by your chalk board classes. I think the Idaho bath lithography would so interesting on the chalk board as only you can do.
Nick seduced me into being excited about the upcoming Cascades series. I hadn’t thought about the complicated history there in exposed rock 🤤
Good show Nick! I appreciate the new format. How do I find out about weekend outings?
Don't forget the WISZ and the timing around the Columbia River impound..
"The evolution of the Eocene climate began with warming after the end of the Paleocene-Eocene Thermal Maximum (PETM) at 56 Ma to a maximum during the Eocene Optimum at around 49 Ma."
That's curious. The climate changes and three million years later the Idaho volcanic arc shuts down. The climate changes again, and three million years later the Cascade volcanic arc starts up. The climate shifts are from CO2 and methane stirred up by plate tectonics, (maybe).
Nick, I'm working on a map of the Absaroka Volcanics province right now! Those stratovolcanoes in Wyoming have eruptive ages that follow a perfect north -> south chronology from 51.56 to 43.68 MYA, respectively. Seems to fill in the gap perfectly as part of the Challis, but seems to be clearly subduction-related, at least in that very local area? Let me know what you think - Feeley et al 2000 has a great overview.
Four Lakes, WA
I regret to leave, as I must cook dinner. Back later!
How connected is Nick? I enjoyed the description of his chalk. I didn't know there was specific brand that was preferred. I am dumb to the subject. Yet here I am on my CZcams feed and am presented with a video entitled "Why is Hagoromo chalk so expensive?" Well connected. Looking forward to Cascades A-Z.
5 by 5 from the Canadian Shield, Ontario, Canada
Looks like you tidied up your bookcase and moved books and displayed more of the gifts.
so, can you think of the extension as a relief and cause crust 'drip' and shut-off building of rockies; in association with siletzia docking. because by this time both Intermontane, batheolith complex and insular have docked.....wow, mind explodes.
The chalk board works great.
I like the podcast, you speak much slower and thoughtfully, works better for me. Might also work as getting to sleep ;)
Why wouldn’t Siletzia be riding on a spreading center with the Yellowstone hotspot? This would be similar to Iceland.
Nick, looking at broader regional context. I just explored NE Wyoming and S Montana, using Google maps satellite. For example, Devil's Tower pluton is casually quoted to be 50 Ma (or 65 Ma? Conflicting). About right, or too old?
Other:
I am tempted to say I see lots of "calderas" looking like vanished cones with circular mountain rims around them. In no particular order looking at Google maps in "satellite mode":
- Just east of Absaloka coal mine, 6 miles dia.
- North Mocassin Mountains, 2.5 miles dia.
- Green Mountain, Wy (near Devils Tower), 1 mile dia.
- Also 3-5 mi south of Green Mountain, several more circular ridges.
- Judith Mountain Lodge, 3 mi dia.
- Thunder Mountain, 4 mi dia.
Relevant? What are the ages of those? Are they in the Laramide/Eocene literature?
And at 47.852734, -108.750054, what's that (no obvious name)?
I am back Nick
Gotta get caught up!
Thanks for this video. QUESTION: In your 7mil window between the Cascadia and Idaho Arc lies, Crater Lake and to the south Mt. Lassen...were these two a result of the Pacific plate melt adding magma to the core forcing it upward resulting in the eruption of both these volcano's during that "loud time"?
Best chalk in the world!
Clarno formation in Oregon - the internet says (and it's always right, right?) the age range is 54-39ma - so right in the same window (roughly) as the Challis. Is this maybe the "missing arc" not the Idaho batholith rocks? Not Washington but certainly seems like they need to 'fold' into the frosting on the fruitcake.
maybe theres some verticality involved, since the north american plate was moving north relatively fast and the earth is somewhat egg shaped this could result in the plates north being held lower by the plates rigidity then once the plates center got far enough north there would be a change in the speed of its adjustment and this combined with the subducted spread plate and the transtension maybe could explain why the volcanism during just that period is so strange
its upplift poles hotter magna through the subducted plate maybe that iractically pulls water put of it where it otherwise wouldnt
idk, i havent heard vertical adjustments of plates and effects discussed but itd have to happen since the earth isnt a perfect sphere and plates arent perfectly malleable
Here’s a crazy idea: someone should drill down below the volcanic flows in eastern WA & take rock samples. A lot could be learned from those data.
They have tried. The pockets and voids and layers eat drilling equipment.
FYI, your audio is still pretty good when you face the chalkboard.
My question: The exotic terranes rode tectonic plates that rammed into the North America Cratons. There should have been arcs associated with each mashup. Is there volcanic activity associated with each accretion?
Watching from Walla Walla
You have to combine the exotic terrains story with your new story. The coastline 45 MY ago was way east of today’s coastline.
When you said, "Back in the Forties--" I hear Big Band music. But what does Basil have to say about this? Idaho is his turf, after all.
Also about the same time: many basaltic cinder cones were popping up through Paleozoic sediments in Virginia/West Virginia. Weird.
Back of a convergent plate boundary you will have doming and extension. The large pophryry copper deposits in Mongolia are hosted in a similar environment back of the collision between the Indian and Asian plates
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The Absaroka volcanics in Wyoming far to the east of the Idaho Batholith and in the same time span include andesites porphyries very rich in largish hornblende crystals. Perhaps related?
More likely Challis type relationship. 53 ma - 46 Ma
Hi from Rich in Murray, Idaho. So, did the mountains along the Idaho Montana border form before 43 million years ago and 56 my?
What is the geology of the "Ditch" under the Columbia River Basalts?
Can we tell the difference between chemistry of the NA plate and the offshore plate versus deep layers below the plates..if so..will this provide clues as to where the magma comes from?
At around 46:20. " 53 "...... Any chance " 53 " is around the time a real MMA match between 1) westward subduction ends . 2) eastward subduction starts 3) Siletzia joining in as the referee?
Northern Idaho!
Did the asteroid hitting the yucatan 65mya cause the shift to the north and start the resettling of all the corresponding plate and magma movements? Would explain a lot of rapid movement during the Dinosaur die off during this time.🤔
Catching up - the Ochaco and Clarno volcanics are involved here somewhere. They are further west than Idaho. Arc(s)?
Would the "Imnaha River Jade", (probably a green stone) be associated with subduction of the IMS?
There has to be a Squeeze Box allusion in this somewhere.
My comments are made prior to your conclusions, which is interesting.
Did the Purcell Trench occur during that 7 million year extension?
Nick, Could the the clash of Siletzia caused the opening up of the fishers in Idaho, then fill the ocean basin in eastern Oregon and Washington and after the 7 million years of layer after layer have created a lava wall that forced the new cascade volcanic arc ?
Also WHAT EFFECT DOES THE TRANSFER OF STRESS FROM THE CONTINENTAL MARGIN TO INTRA CONTINENTAL REGIONS HAVE?
The hornblend question was the same I had about the Montana rocks Kaleb showed us....would this correlate to the same trench just farther inboard?
And I am not sure I heard Nick the answer his question re: whether the granites of the Idaho Batholith, say near Stanley, Idaho, or up the Bitterroot Lobe near Hamilton, MT contain the hornblend signature of igneous rocks produced by subduction zones. I am guessing they do, just based on my recollection of what the rocks look like up there. I also had the idea that at least some of the granites of the Idaho Batholith are older than the Challis Volcanics of the Eocene, suggesting that there could have been a volcanic arc event prior to the explosive Eocene and the Challis magmas.