Knew nothing, just enjoyed rocks. Summers in Sequoia National Park, played my trombone the rest of the time. Didn't choose to have access until Miles Davis "Pangea" album. Enjoyed the music, certainly, and...became curious about the big blue marble. I've seen wicked landscape from the air, color me fascinated. I've driven through Oregon and Washington numerous times thinking "well, that looks interesting!" Thanks, Nick, for the access.
I have watched you for your roadside series. I'm not a geologist but I'm fascinated by rocks and educating myself. Your lecture was the first of paleo magnetism I've ever heard. Continental drift, place tectonics I have heard of. So at this time, I am a 2. I look forward to moving on this scale as I follow you on this journey.
Thank you, Darrel Cowan and Nick Zentner. I really enjoyed this lecture. I spent months hiking and rock climbing throughout West Texas, Nevada, California, Oregon, Washington, and western Colorado in the 90s. I was inspired to learn more about the geology of the West North American continent. It's a really special part of the world, and I hope people continue to better understand and take care of the land there. I would love for Darrel Cowan to come back to discuss his research in Death Valley.🙏
Merle and Randy.......seem to be very credible so far....to such a ultra complicated north america story.......just the proven facts.....as far as we know....no ego please.....good to be wrong....called learning me thinks.......bravo
This was super informative top to bottom. Thank you Nick and Darrel for taking the time to discuss these fascinating topics in the research. It is perplexing to me that someone could be a 1. How can you ignore the various evidence suggesting a much more interesting story than the fixist model? Looking forward to the next installment with Basil. Here's to you, Nick! We appreciate you.
Thank You Darrel ! Always a flurry of impactful information! So excited to see where we go and any clarification and solidification this series can provide.
Darrel is the best example of a scientist who keeps an open mind by continuing to challenge everyone’s conclusions, even his own. What a great episode and man.
Thanks to both of you. Nick, you have given us access to information and professors & their information, which normally is only available to professionals at very expensive conferences (I did that for my profession). And both of you present this so anyone can understand. Thanks
On the cusp of 50k subscribers Nick. Congrats. Should be triple that for sure. Fascinating subject. Thank you for your time you spend doing these streams.
I am an 8 looking at 9. I do not see anything compelling an alternate progression. Thanks Nick for another wonderful presentation and thanks to Darrel for his extraordinary knowledge.
Hearing this all again, and in a slightly different way from the Exotic Terranes series, it is making more sense to me already. I am learning far more now than I have in the past! Thank you Nick and Darrel!
Thank you, Dr Darrel Cowan. Your presentation was so clear, as were your answers to the live chat questions. Love from Liz and Ginger (pic left) in Australia.
Great idea to go back and cover the details of those insular units, especially for us stuck in the mid continent terrain of north America. I'm a New Madrid basin geologist. Thank you Nick.
Spectacular talk, as usual. Thank you. Science should always be an open-minded study, and beg the next question. I love seeing this being put into perspective. I hope this series might put into motion more interest and collaboration. Nick, you are doing wonderful work!
I have the sensation that Baja-to-BC has been handed the "J. Harlen Bretz treatment" from the wider geology community. Your interview with Robert Hildebrand comes to mind. Bretz was an outsider because the geology community did the same; dismissed it out of hand because it didn't agree with their beliefs. If one uses a belief rather than objectivity they aren't doing science.
It’s amazing that geologists can agree that Indian can break away from Africa and crash into Asia, and then doubt that Mt. Washington and environs could be moved from Baja to its present location.
Let's follow Nick Zentner's advice : in a truly scientific manner (in my views), keep an open and curious mind faced with what is now a longstanding controversy. His guest Darrel Cowan, a major actor of the Baja BC theory and a wonderful narrator/teacher/conversationalist, relates the difficult diffusion of those ideas to his fellow geologists. Important questions are exposed, but one thing I am absolutely sure : I, and you with me I bet, will watch with the greatest interest the next video, and the next...
LOVED THE BASEBALL ILLUSTRATION ALONG WITH THE IGNEOUS ROCK HAVING FROZEN TIME FOR LATITUDE MAPPING. WELL DONE AND I GUESS IF JESUS WAS A GEOLOGIST HE WOULD MAYBE SAY "IF YOU HAD FAITH THE SIZE OF A ZIRCON YOU COULD MOVE MOUNTAINS". KIND OF SEEM APROPOS FOR THIS SESSION. THANKS DARREL AND NICK FOR THE KNOWLEDGE.
5 by 5 comes from communication radio checks. The first 5 is the volume at the receiving station on a 1 to 5 scale. The second 5 is the readability of the reception again on a 1 to 5 scale. 5 by 5 indicates excellent reception in volume and readability.
I flew up the Californian coast this past week and looking down at the landscape I couldn’t stop thinking about Baja BC. You can really see the Franciscan Complex in stunning detail. Thanks Darrell for your work on that and contributing to this west coast story!
@47:00 Baja-BC Terrane transport is easier to visualize when the NA plate WSW drift is included, it would make the Terrane rafting sequences appear less extreme.
Yes: Bernie Housen at Western Wash U has accounted for the movement of North America during this period, so the displacements are with respect to where N Am was.
The geology of the Canary Islands is linked to a certain end of Ice Age controversy due to being partially submerged due to rising sea levels at the same time as slumping from rebound of the continental areas with the unloading due to melting of the Fenno Scandinavian Ice Sheet. The undersea alluvial fans are stunning in themselves.
I think of a tube of tooth paste. You point the opening N and then apply pressure from the E and W. The toothpaste flows N. The opening being a weak point and with E-W compression the toothpaste flows N, the direction of least resistance.
I feel like there is a similar scenario live in NZ at the moment with the Dun Mountain/Red Mountain units and their displacement along the Alpine Fault. Ophiolites involved, all sorts of whack stuff. Thanks Darrel, you're awesome as always.
Thank you Darrel for your awesome talk!😃 Especially, using your baseball in trying to explain Paleomagnetism of the earth, potentially in rocks, and in zircons!! , Nick, I love your accordion and cymbals analogy! So, did you say that the eastward subduction was shutdown for whatever reason around 85ma, then the northward migration of almost docked terranes may have started? Or, are we only talking about Strike Slip Faults moving rocks to the north, or both... I know I'm confusing myself with the question... Duh..., I answered my own question! Both and some!!🤣My mind maps moved around but not the time scale...🤪 😏I'm not a researcher or someone trying to prove or disprove a theory, I'm just trying to learn and enjoy something new that I haven't in geology, so I have no problem hopping around the scale in trying to understand Baja BC.. There should be a plenty of people defending one way or the other to entertain us!!😆💫
My live stream comment was: The Mendocino Triple Junction isn't a backstop preventing terrane migration from the South into Oregon @35:30; there is Franciscan blue schist that was quarried for the Bandon, OR. South Jetty 1/4 mile away, @185 miles North of the MTJ. This is solid evidence that the California Franciscan Terrane is in contact with Oregon's Siletz Terrane and the MTJ is a shear zone, like a bridge cutwater pier in a river.
Thanks Darrell and Nick! I am one who would like to be a a 9 or 10. But I want to stay open to learning what the data says to support or not support the concept. I want to maintain my life long doubting Thomas approach until the data convinces me one way or the other.
Hi Nick, Jerry from Jarratt (formerly Portsmouth) Virginia. Great start to the series. I'll be onboard for the rest of the live feeds this winter. Carry on!
A contingent of Canary Islanders settled in the area now known as San Antonio, Texas about 530 years ago. Every year their descendants still have a parade there.
In Karin Sigloch and Mitch Mihalynuk's 2017 paper, they discuss a prediction of a suture that runs along the coast of North America from Alaska to Mexico. They identify the Methow basin as a part of it. It was interesting in the patio interview with Ralph Hagerud that he pointed out the similarities between the Cache Creek and the Hozameen terranes. In a later video, you suggested that these terranes and some others were all "grello". If there was a suture zone that extended along the coast of North America, identified by more "grello" found further south, would that help the Baja BC story? (P.S. Really appreciate the exposure to science your videos provide and the idea that the work of science is a hugely collaborative effort. Here's to you, Nick!)
FYI. (I looked it up) The phrase "five by five" can be used informally to mean "good signal strength" or "loud and clear". An early example of this phrase was in 1946, recounting a wartime conversation. The phrase was used in 1954 in the novel The Blackboard Jungle.
I have that same battery powered alarm clock in my master bathroom for the past thirty years in case the world ends . Love your lecture series. MIT has some good ones too. Do you watch any of Randall Carlson's videos about the Scablands and the Moses Coulee Mega Floods? Thanks
Thanks again. While they may not be the same as the NW, you only have to look at the Indian subcontinent and the rift valley in Africa to see now the plates are always moving about. There must be alterative periods of fast and slow movement and types of change. But then I was an IT nerd and accountant, so what do I know. Love your work.
Thanks Nick & Darrel for an informative look at this topic. Interesting that Mahoney et al (2016 Geology 44) ... the final sentence reads; "At this point, the outstanding issue with the Baja B.C. hypothesis is how to explain the consistent paleomagnetic data that are interpreted to indicate large-scale latitudinal displacement." Almost saying, look i have this evidence that Nanaimo is clearly autochthonous so the large scale movement is nonsense ... BUT, we still need to explain the anomalous paleomagnetism!
@@toughenupfluffy7294 - The Nanaimo is (90-65 Ma) and we seem to be assigning 85-55 Ma for Baja BC (maybe if i remembered it right)??? Using Nick's number scale i think Mahoney is in the 1-3 maybe even 1-2 area but very much a non-mobilist from what i am getting. Will be interesting to see if Nick can get Basil on Weds to talk about Mahoney's work.
Hey Nick! I was thinking about this program, the series, and Baja BC in general. Part of what I find confusing is that we get an idea or a piece of information and it is not put into where it is in the story. There are two beginnings to this story and then they come together about the middle of the story. The other part is what I call the map problem. Anybody that is outside Washington has a problem connecting up the information and the area together. I understand the ideas but am having trouble connecting all the geology together. There are people watching that have never seen geology 101 and I think I am barely at a 201 geology level. I understand the types of rocks but just superficially. I hope this helps. I appreciate you doing this and look forward to the next show
I can only help re-direct you to, " BE ON THE LOOKOUT " for this [ map problem ] you mention here. While viewing past episodes, Nick tries to portray " DIFFERENT SCALES " of view on the MICRO & MACRO LEVELS. We are ALL just trying to fit the pieces of the < INFINITY PUZZLE > together , with Nick's help bringing this Awesome Cast of Characters | Major League Players , ;-) @NICKZENTNER , to the < 'GLASS TABLE' PLAYING FIELD > *ALSO NOTE ; Multiple "MAIN EVENTS", some occurring at the same time, some at various time markers of the GEOLOGIC TIMESCALE.
In the industry, the background items in view to "decorate" are included in the idea of "mise en scene" ("Maise on sohn") like the green blackboards. Green blackboards????
Apologies if this has been asked previously, and maybe I'm jumping ahead, but if one discounts the Baja BC thesis then what are the alternative theories that are used to explain the paleo-mag data? The paleo mag data seem pretty tight? Another fascinating session, Nick. Thank you and thank-you Darrel.
The standard reply is that you can obtain shallower than expected inclinations by tilt and/or rotation of the magnetized rocks. For bedded rocks-lavas and sandstones-this is an easy test. They pass. For the Mt Stuart pluton, Yale researchers were acle to find that the pluton has not been tilted. So: data stand.
Interesting discussion thank you to the both of you. I believe it is a combination of paleomagnetism, dynamic of deep rock viscosity and the restructuring of the crystalline mineral lattice and lastly the variation in Moho depth. In my opinion there are way too many variables and the situation cannot be narrowed down to one cause. There are many more examples of similar activities all over our planet and the diversity of the European Alps are probably the best documented one. By the way the latest edition of Earth Structure by B.A. Van der Pluijm and S.Marshak list many more good examples in the last chapters.
Hi Nick, I am just starting to watch the 2022 Baja to BC series after devouring the Bretz A-Z 2023-4 in replay. Thank you. A comment in your conversation with Darrel Cowan prompted an idea of the true value of your series. No, really all of your video work, the value is to make available to future geologists in thirty years or even seventy-five or a hundred years, is your collecting work in one place from Bretz, his predecessors and others, even Large poking Bretz to return to the scablands. Just think of the influence you will have on those people you have and will introduce to the subject. As one of my Scouts said on earning the Geology Merit Badge, "Geology rocks!"
Prof. Z. I only know about Baja-BC because of your lectures. I have only heard It is possible "Mt. Stewart" was once in Mexico due to Plate Tectonics and Zircons. And in the world of Tectonics the Plates and Cratons move north, south, east, west. In addition, I have never heard of a "Fixist" scientific paper being published or discussed. Because of the San Andreas Fault I would say I am a 8-8.5 positive Mt. Stewart moved 2,000 miles North by North-West some 50 myago
Amazing how you have kept this brilliant educational service going for us all for so long Nick. It's like being back at school--which, for me, was just when continental drift and polar wandering were being discovered, and the MOHO project had hopes of reaching the mantle. :) This fascinating talk leaves me rather baffled that paleomagnetisists and geologists are now two separate things. I thought palaeomag was a fundamental geologists' tool, and not much use for anything else. Anyhow: 2 questions arise: To work out the inclination of the magnetic field in the rocks, you have to know exactly where level was during deposition and fixing. How can you be sure of this? Are there minerals, or bubbles that always point up to give you a palaeoplumbline? Or what? Trees grow pretty straight up, but is there something smaller and more reliable? Also, I cannot get my head around how you can use magnetic alignment and dip angle to locate latitude when the magnetic poles are wandering at the same time as the continents, and sometimes the fields reverse entirely and may even have more maxima than simple 'bar magnet' N and S poles? 4 dimensional chess sounds easy by comparison! You may have explained this in you earlier talks. I have not been able to catch up with them all yet, but they really are a treat to be savoured more than once. Many thanks. Steve in chalky Bedfordshire, UK.
It is probably better to use the term Apparent Polar Wandering curve as it is actually the continents that are wandering. The magnetic pole reflects 3 primary conditions: 1 the p core is comprised of liquid metal (iron). 2 heat from the earth’s center causes convection currents in this liquid 3 the earth’s rotation generates the magnetic field. If all the continents were fixed, same age rocks on different continents would point to the same magnetic pole. They don’t so relative movement has occurred. The direction of the magnetic pole gets recorded in the rock when magnetite in a basalt or igneous rock cools below the Curie temp of 650 deg.
For latitude, consider how magnetic the magnetic field is perpendicular to the ground at the poles and parallel at the equator. So the inclination/dip steepens from the equator to the pole. Inclinations for My Stuart were shallower than those of N America Cretaceous poles. Either the rock was rotated up from a steeper inclination or formed where the inclination in situ was more shallow. Then you have to look to geologic data. Did the entire batholith as a unit rotate north side up about 30 deg or did it raft up from a lower latitude. .
Regarding the Plutonic Magnetization dates: Isn't it reasonable to assume that during active subduction there would sufficient heat to encourage convection currents within the magma chamber? These currents would likely have more physical influence over the magnetic elements than Earth's magnetic field. However, after the subduction stops there is likely a period where the temperature has dropped enough to halt convection but where the rock is still liquid, which is when the magnetic elements are locally still enough to align with the Earth's magnetic field prior to solidification. That mechanism suggests that the paleomag dates should be AFTER the cease of subduction but prior to solidification, no?
[ IN MY MIND ] *not exactly sure how to incorporate the " convection currents " variable in your statement. BUT what is troubling me is , the < METAMORPHIC STAGES > that Nick presents. M1 M2 M3 ; referring to the kBar = deg. C. matchups. Buried to a certain depth , then PARTIAL SOLIDIFICATION < 550 deg. C. \ as Darrel states >, then REMELTS ( being 'churned up' like butter at that Currie Point { ZONE } ) , to then be SOLIDIFIED INTO ITS FINAL STATE ( Like the Flour not being sifted fine enough before making dough ; hence , Recording multiple Magnetic Orientations ). Could this be our source for PALEOMAG ( UN-stable ) READINGS ? @NICKZENTNER @darrelscowan1537
Important to recall that the grains of magnetite and ilmenite do not orient themselves parallel to the magnetic field. They record it in their crystal lattice. So convection in the magma shouldn't be an issue.
1 - 10? The pacific plate is grinding northward still and the north american plate is still turning counterclockwise> I think you are correct. Keep digging.
I think the question about how the basin and range extension altered the shape of California's coast is part of the reason there is difficulty in people visualizing Baja BC. The basin and range extension has pushed California outwards compared to the motion of North America as a whole after the Sierra Nevada batholiths shut off. The illustration at 46:45 really does not show how far east the California coast (the franciscian subduction zone) was accurately IMHO.
Although Dr Cowan mentions at 54:44 the absence of Shuksan north of the 49th, are there indications that the Baja BC movement continues north into Canada, i.e. there are Washington and Oregon terranes hundreds of kilometres north into the west coast of British Columbia?
The only rock unit I know on the west coast of Vancouver Island, near Tofino and Ucluelet, is the pacific Rim complex. It bears some similarities with rocks in the San Juan Islands, but it is in fault contact with VI bedrock. It was probably moved there in the Cenozoic by dextral slip on a fault like the Queen Charlotte.
My sticking point with paleolatitudes from paleomagnetic data: what sorts of observations can we use to tell if a given rock unit has rotated over time. It seems more likely that a given plutonic rock unit would rotate between emplacement and exhumation than that it would not, and it seems unlikely that as a general principle plutons and stocks remain at the same attitude over their entire existence. But then it comes down to this or that specific unit, and the evidence that we have for the persistence of its attitude to the horizon over time.
Pardon me for getting ideas above my station here, but rather than eastern subduction of the Pacific plate, isn't it a case of the Americas being pushed westward by an ever expanding mid-Atlantic ocean ridge? Rather than the ocean floor subducting, surely the land mass is over-riding? I mean, there is no spreading force in the middle of the Pacific forcing the ocean floor to slide under the surrounding continental mass. Kind of pedantry but when trying to build a mental picture... With thanks and gratitude for all that you do Sir.
Sorry Bob, but I would have to disagree with the statement, " no spreading force in the middle of the Pacific forcing the ocean floor to slide under the surrounding continental mass. " Please review the topic item that Nick presents in various shows : " Subduction of a ( Spreading Ridge* ) ". *This here would be ( in itself ) your Pacific force on the ocean floor. Stay tuned for the rest of the SERIES please ! note: multiple moving parts , all working together at the same time , nothing is actually stationary in nature, just like you will never find a straight line. [ IN MY MIND ]
@@VIBCTrevorInscho I have been around since the 2nd episode of the lockdown series, sat through them all. The ring of fire isn't a so much a consequence of ocean floor slipping under land, more a case of the land around the Pacific closing in and devouring the ocean floor. Obviously nothing is static or fixed.
@@bobgnarley1 Please forgive me for my initial interpretation of your original statement. Totally agree with this secondary one. In similarity, COLD FRONTS ( assimilated Continental Plates ) Vs WARM FRONTS ( assimilated Ocean Fronts ). The COLD with always win over the WARM ; Stronger and more dense. Enjoy the rest of our journey with Nick , I know I will.
It was interesting to listen to Nick talking about 'Fixism vs Mobilism'. This isn't the first time paleomagnetism has stirred up a hornet's nest- when the 'Snowball Earth ' theory was first proposed, part of the evidence presented was the magnetism of ancient drop-stone deposits which indicated they were dropped by ice-sheets at the equator. Mid you, the acrimony that theory caused was driven as much by the personalities of the scientists involved as the theory itself. However, I wonder just how 'Fixists' explain the anomalous paleomagnetics of the rocks. Repeated testing should have eliminated obvious sources of error, such as malfunctioning equipment, and human error. Ignoring the evidence isn't going to make it go away. What then? To paraphrase a quote from a famous fictional character, once you've eliminated all the other possible reasons for the data, what is left, no matter how fantastical it seems, has to be right. I guess then we come down to the fundamentals of science. A truly objective scientist should follow their data no matter where it leads. However, how many of us are actually, truly objective?
I'm a '5' - I want to smash the accordion with the cymbal! The Mt Stuart Batholith came from the south (eg, fault reconstruction, 650 to 900 km movement). But from Baja? Not sure but I'm open to the idea and would like to hear the evidence. Another great video. Thanks Darrel and Nick!
I don't think of Mt. Stuart as a piece of Baja Californina, which sports its own Cretaceous magmatic are called the Peninsular Ranges. The Insular superterrane-part of Baja BC-has its own arc represented by Mt Stuart and the younger plutons in the core of the Cascades. Therefore, we view INS as an integral element that had its own convergent plate boundayy.
@@markearnest3570 Basil may comment. The entire Sierran block has moved and is moving with North America, but there might have been a couple of hundred kilometers of dextral displacement with respect to NA.
@@markearnest3570 One of Basil's focuses right now is the abundant evidence for late Cretaceous dextral faults within not only the Sierran batholith but also others in the western Cordillera. However, these do indicate some displacement but much less than INS. As for Yakutat, it has a fascinating history that is still being investigated. John Garver and Cam Davidson have written a paper ready to submit and I keep provoking him to do it. There is a question about the basalt in Yakutat. Most of the element is sandstone and melange, not a plateau. Basalt was dredged offshore decades ago, I I heard a comment by Donaghy and Eddy that the putative basalt exposed on land in the Samovar Hills isn't basalt! As Garver has written, i favor the Yakutat as having started life way down south, then about 49° 50-60 Ma, then like a cymbal north to Alaska.
I'm just now realizing (based on Karins work) that Insular also would have subducted the Mescalera spreading ridge, which could / might mean the N Cascades may have subducted two spreading ridges (pre Insular accretion & associated with Siletzia). 😲🤯 🤤 Also, at 46:16, there is a good illustration for my other question about how much of the Cascade slab might be associated with Insular.. This may sound more lunatic fringe than Basil ever could, but based on the illustration, Insular is south of the California triad at 90 MA; which makes me wonder if the Cascade slab (extending to GA) is associated with Insular and the slab associated with the California subduction would be north of the Cascade slab.(?) 😼💖💞
In response to the answer to Thomas’ question (1:24:05), could not the movement of detritus zircons east to west have occurred during the glacial lake outburst floods known to have occurred around the Younger Dryas times?
Thanks Darrel and Nick. Sorry if this question is nutty, but could there have been a counter-clockwise rotation happening with these terranes sort of cartwheeling in on a plate towards N America? I’m sure I’ve oversimplified but imagining the point at the bottom of the cartwheel spinning up helps move it both N and E. Thanks again!
Fixist - mobilist - non-geologist here. over the last 100ish million years how far as the north American plate moved during this time? How does that compare to the movement of the west cost northern migration? 150years ago, everyone was 'fixist' is my understanding, until a weatherman/climatologist thought differently :)
I am having trouble believing the mag thing now after hearing it. I always think of it as East West. That is what I can see with a compass. Obviously if I were at N or S pole, would see it going not parallel to the ground. But any distance from that, I visualize it as being parallel to the surface. I would be more accepting of this if I could see measurements of it. Sure someone can do that. Don't have anything for that.
Build a compass such that the needle can point freely with the magnetic field. Take it with you in your travels through the world and record what you measure. Profit.
@MrRmeadows Please read the < REPLIES > made by @lindanoson6014 , to the INITIAL made by @spamletspamley672. This may help. |*| it would be any degree < 0 to 90 > = latitude dependent. < zero = vertical = poles | * | 90 deg. equator = totally parallel >
Isn’t your scale really all about hypothesis testing in science? As new evidence comes in, the hypothesis may or may not need to be adjusted (or refuted) based on what the new evidence is suggesting. Baja BC is an hypothesis, with the two extremes on the scale being, in essence, non-scientific (proponents assume their respective hypotheses are now fully proven theories). Everything else on the scale (2-9) shows one degree or another of scientific open-mindedness, willing to at least reconsider reevaluating one’s opinion as new evidence comes in.
I am not a fan of the use of the word "cartoon." I prefer to think of them as illustrations. Cartoon brings to mind things that are not serious but silly. On the other hand "illustrations" bring to.mind more serious ideas.
Darryl was great! Yes, the material is complex but he explained it well. Since it was complex, it required concentration and what he was saying. Unfortunately, Nick, you were a distraction. Even nodding your head can be a distraction. Do you want us looking at you or listening to him? Do we need to see all the papers that he mentions? Just a suggestion to let your presenters present without distraction. Second suggestion: don't beat the dead horse about why people may not be interested in the Baja BC. We are interested. Otherwise we wouldn't be tuning in. The scale was unnecessary and irrelevant.
54:35: nappe: a sheet of rock that has moved sideways over neighbouring strata as a result of an overthrust or folding. It oftentimes is an isolated portion of an overthrust sheet, eroded away from the main portion. Heart Mountain in Wyoming is an incredible example, the Earth's largest known rockslide: en.wikipedia.org/wiki/Heart_Mountain_%28Wyoming%29. From the German, 'knappe,' meaning short, or shortened.
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Knew nothing, just enjoyed rocks. Summers in Sequoia National Park, played my trombone the rest of the time. Didn't choose to have access until Miles Davis "Pangea" album. Enjoyed the music, certainly, and...became curious about the big blue marble. I've seen wicked landscape from the air, color me fascinated. I've driven through Oregon and Washington numerous times thinking "well, that looks interesting!" Thanks, Nick, for the access.
Darrel is very good at explaining concepts, ideas, and data.
I have watched you for your roadside series. I'm not a geologist but I'm fascinated by rocks and educating myself. Your lecture was the first of paleo magnetism I've ever heard. Continental drift, place tectonics I have heard of. So at this time, I am a 2. I look forward to moving on this scale as I follow you on this journey.
Thank you, Darrel Cowan and Nick Zentner. I really enjoyed this lecture. I spent months hiking and rock climbing throughout West Texas, Nevada, California, Oregon, Washington, and western Colorado in the 90s. I was inspired to learn more about the geology of the West North American continent. It's a really special part of the world, and I hope people continue to better understand and take care of the land there. I would love for Darrel Cowan to come back to discuss his research in Death Valley.🙏
yes Victoria a state in SE Australia, Melbourne is there
I have to say that Darrel had an extremely impressive ability to recall things from the past 25 years. Another exceptional lesson and wonderful guest.
Merle and Randy.......seem to be very credible so far....to such a ultra complicated north america story.......just the proven facts.....as far as we know....no ego please.....good to be wrong....called learning me thinks.......bravo
This was super informative top to bottom. Thank you Nick and Darrel for taking the time to discuss these fascinating topics in the research. It is perplexing to me that someone could be a 1. How can you ignore the various evidence suggesting a much more interesting story than the fixist model?
Looking forward to the next installment with Basil. Here's to you, Nick! We appreciate you.
The clickety-clack of the chalkboard... Chalk on! I've so missed it!
Thank You Darrel ! Always a flurry of impactful information!
So excited to see where we go and any clarification and solidification this series can provide.
Darrel is the best example of a scientist who keeps an open mind by continuing to challenge everyone’s conclusions, even his own. What a great episode and man.
Thanks to both of you. Nick, you have given us access to information and professors & their information, which normally is only available to professionals at very expensive conferences (I did that for my profession). And both of you present this so anyone can understand. Thanks
Keep your eye on Patrick. Someday he may be teaching you.
As always I learned a lot. Thanks Darrel, and thanks Nick.
Nick I just love your A to Z series and thank you Darrell you are definitely one of my favorite Geologists
heck yeah, thanks
I’m from exotic terranes Lake Chelan! Didn’t make it live but I’m glad I’m here!
On the cusp of 50k subscribers Nick. Congrats. Should be triple that for sure. Fascinating subject. Thank you for your time you spend doing these streams.
I am an 8 looking at 9. I do not see anything compelling an alternate progression.
Thanks Nick for another wonderful presentation and thanks to Darrel for his extraordinary knowledge.
Hearing this all again, and in a slightly different way from the Exotic Terranes series, it is making more sense to me already. I am learning far more now than I have in the past! Thank you Nick and Darrel!
Thank you, Dr Darrel Cowan. Your presentation was so clear, as were your answers to the live chat questions. Love from Liz and Ginger (pic left) in Australia.
As an instructional tech and geography nerd I like the pre-show check-ins as much as the actual geology
I love it. Thank you for the discussions and sharing of your knowledge.
Great idea to go back and cover the details of those insular units, especially for us stuck in the mid continent terrain of north America. I'm a New Madrid basin geologist. Thank you Nick.
Thanks so much! What a pleasure hearing from Darrel Cowan. This is my third A to Z series. Loving it!
Using the baseball as a teaching aid was actually very helpful for me. Thanks!
I watch you on TH-cam in Chiang Mai, Thailand.
Spectacular talk, as usual. Thank you. Science should always be an open-minded study, and beg the next question. I love seeing this being put into perspective. I hope this series might put into motion more interest and collaboration. Nick, you are doing wonderful work!
I have the sensation that Baja-to-BC has been handed the "J. Harlen Bretz treatment" from the wider geology community. Your interview with Robert Hildebrand comes to mind. Bretz was an outsider because the geology community did the same; dismissed it out of hand because it didn't agree with their beliefs. If one uses a belief rather than objectivity they aren't doing science.
Thanks Nick and Darryl! Good session!
It’s amazing that geologists can agree that Indian can break away from Africa and crash into Asia, and then doubt that Mt. Washington and environs could be moved from Baja to its present location.
Let's follow Nick Zentner's advice : in a truly scientific manner (in my views), keep an open and curious mind faced with what is now a longstanding controversy. His guest Darrel Cowan, a major actor of the Baja BC theory and a wonderful narrator/teacher/conversationalist, relates the difficult diffusion of those ideas to his fellow geologists. Important questions are exposed, but one thing I am absolutely sure : I, and you with me I bet, will watch with the greatest interest the next video, and the next...
Well said , Love your word used ; diffusion.
How wonderful to think that Patrick could very well walk into Nick's classroom a decade from now! ♥️
Luv'it
He could be teaching in Nick's classroom in a decade and a half!
@@joekilbourne2242 absolutely!!
Shamin' them ones!
LOVED THE BASEBALL ILLUSTRATION ALONG WITH THE IGNEOUS ROCK HAVING FROZEN TIME FOR LATITUDE MAPPING. WELL DONE AND I GUESS IF JESUS WAS A GEOLOGIST HE WOULD MAYBE SAY "IF YOU HAD FAITH THE SIZE OF A ZIRCON YOU COULD MOVE MOUNTAINS". KIND OF SEEM APROPOS FOR THIS SESSION. THANKS DARREL AND NICK FOR THE KNOWLEDGE.
Hi from 16 miles southwest of Mojave, CA! Some of my ancestors came from Europe, too - but they first arrived in 1640. (LTB, age 78)
5 by 5 comes from communication radio checks. The first 5 is the volume at the receiving station on a 1 to 5 scale. The second 5 is the readability of the reception again on a 1 to 5 scale. 5 by 5 indicates excellent reception in volume and readability.
Nick and Darrel, great episode!
Thank you, Darrel & Nick. Good stuff!
I flew up the Californian coast this past week and looking down at the landscape I couldn’t stop thinking about Baja BC. You can really see the Franciscan Complex in stunning detail. Thanks Darrell for your work on that and contributing to this west coast story!
I did the same kind of thing on a flight from : Vancouver, B.C Las Vegas , NV. *Amazing BIRDS EYE VIEW lol
@47:00 Baja-BC Terrane transport is easier to visualize when the NA plate WSW drift is included, it would make the Terrane rafting sequences appear less extreme.
Yes: Bernie Housen at Western Wash U has accounted for the movement of North America during this period, so the displacements are with respect to where N Am was.
Thank you, Darrel
The geology of the Canary Islands is linked to a certain end of Ice Age controversy due to being partially submerged due to rising sea levels at the same time as slumping from rebound of the continental areas with the unloading due to melting of the Fenno Scandinavian Ice Sheet. The undersea alluvial fans are stunning in themselves.
You are the best!!
Phenomenal! Thank you.
I think I’m at a 7 right now. I want to believe so that makes me more cautious with how much I can let myself believe.
I think of a tube of tooth paste. You point the opening N and then apply pressure from the E and W. The toothpaste flows N. The opening being a weak point and with E-W compression the toothpaste flows N, the direction of least resistance.
😄Thank you Darrel! @1:30:30 How many times have I said, to understand the mechanism of Baja-BC, look no further than?… Baja!
I feel like there is a similar scenario live in NZ at the moment with the Dun Mountain/Red Mountain units and their displacement along the Alpine Fault. Ophiolites involved, all sorts of whack stuff. Thanks Darrel, you're awesome as always.
Thank you Darrel for your awesome talk!😃 Especially, using your baseball in trying to explain Paleomagnetism of the earth, potentially in rocks, and in zircons!! ,
Nick, I love your accordion and cymbals analogy! So, did you say that the eastward subduction was shutdown for whatever reason around 85ma, then the northward migration of almost docked terranes may have started? Or, are we only talking about Strike Slip Faults moving rocks to the north, or both... I know I'm confusing myself with the question... Duh..., I answered my own question! Both and some!!🤣My mind maps moved around but not the time scale...🤪
😏I'm not a researcher or someone trying to prove or disprove a theory, I'm just trying to learn and enjoy something new that I haven't in geology, so I have no problem hopping around the scale in trying to understand Baja BC.. There should be a plenty of people defending one way or the other to entertain us!!😆💫
3 types of rock: Ingenious, Sedentary, and Metaphoric.
Creative, lazy, and symbolic.
This is a crack up Nick. Love it. Talkin to yourself. Ha. I do that all the time. Then get very self conscious. Ugg
Catching up via playback. Thanks Nick and Darrel. Always fun and interesting! 👏👏👏
My live stream comment was: The Mendocino Triple Junction isn't a backstop preventing terrane migration from the South into Oregon @35:30; there is Franciscan blue schist that was quarried for the Bandon, OR. South Jetty 1/4 mile away, @185 miles North of the MTJ. This is solid evidence that the California Franciscan Terrane is in contact with Oregon's Siletz Terrane and the MTJ is a shear zone, like a bridge cutwater pier in a river.
Thanks Darrell and Nick! I am one who would like to be a a 9 or 10. But I want to stay open to learning what the data says to support or not support the concept. I want to maintain my life long doubting Thomas approach until the data convinces me one way or the other.
Hi Nick, Jerry from Jarratt (formerly Portsmouth) Virginia. Great start to the series. I'll be onboard for the rest of the live feeds this winter. Carry on!
A contingent of Canary Islanders settled in the area now known as San Antonio, Texas about 530 years ago. Every year their descendants still have a parade there.
In Karin Sigloch and Mitch Mihalynuk's 2017 paper, they discuss a prediction of a suture that runs along the coast of North America from Alaska to Mexico. They identify the Methow basin as a part of it. It was interesting in the patio interview with Ralph Hagerud that he pointed out the similarities between the Cache Creek and the Hozameen terranes.
In a later video, you suggested that these terranes and some others were all "grello". If there was a suture zone that extended along the coast of North America, identified by more "grello" found further south, would that help the Baja BC story?
(P.S. Really appreciate the exposure to science your videos provide and the idea that the work of science is a hugely collaborative effort. Here's to you, Nick!)
Could the proposed suture zone be what defines the location of spine of the Cascade Range through Southern WA., OR. and Northern CA?
@@johnnash5118 are you suggesting that the suture was a weak point in the crust that let the magma flows start?
Just ended, warming up outside, starting with the replay. Victoria is the smallest state in Australia.
FYI. (I looked it up) The phrase "five by five" can be used informally to mean "good signal strength" or "loud and clear". An early example of this phrase was in 1946, recounting a wartime conversation. The phrase was used in 1954 in the novel The Blackboard Jungle.
I have that same battery powered alarm clock in my master bathroom for the past thirty years in case the world ends . Love your lecture series. MIT has some good ones too. Do you watch any of Randall Carlson's videos about the Scablands and the Moses Coulee Mega Floods? Thanks
You look great in blue.
Just stay away from Green < 'a little inside baseball' > @NICKZENTNER
Thanks again. While they may not be the same as the NW, you only have to look at the Indian subcontinent and the rift valley in Africa to see now the plates are always moving about.
There must be alterative periods of fast and slow movement and types of change.
But then I was an IT nerd and accountant, so what do I know.
Love your work.
Thanks Nick & Darrel for an informative look at this topic.
Interesting that Mahoney et al (2016 Geology 44) ... the final sentence reads; "At this point, the outstanding issue with the Baja B.C. hypothesis is how to explain the consistent paleomagnetic data that are interpreted to indicate large-scale latitudinal displacement."
Almost saying, look i have this evidence that Nanaimo is clearly autochthonous so the large scale movement is nonsense ... BUT, we still need to explain the anomalous paleomagnetism!
Why couldn't the Nanaimo have formed within the large scale movement? Besides, the Nanaimo is older than the Baja BC movements (I think).
@@toughenupfluffy7294 - The Nanaimo is (90-65 Ma) and we seem to be assigning 85-55 Ma for Baja BC (maybe if i remembered it right)???
Using Nick's number scale i think Mahoney is in the 1-3 maybe even 1-2 area but very much a non-mobilist from what i am getting.
Will be interesting to see if Nick can get Basil on Weds to talk about Mahoney's work.
Hey Nick!
I was thinking about this program, the series, and Baja BC in general.
Part of what I find confusing is that we get an idea or a piece of information and it is not put into where it is in the story.
There are two beginnings to this story and then they come together about the middle of the story.
The other part is what I call the map problem.
Anybody that is outside Washington has a problem connecting up the information and the area together.
I understand the ideas but am having trouble connecting all the geology together.
There are people watching that have never seen geology 101 and I think I am barely at a 201 geology level.
I understand the types of rocks but just superficially.
I hope this helps.
I appreciate you doing this and look forward to the next show
I can only help re-direct you to, " BE ON THE LOOKOUT " for this [ map problem ] you mention here. While viewing past episodes, Nick tries to portray " DIFFERENT SCALES " of view on the MICRO & MACRO LEVELS. We are ALL just trying to fit the pieces of the < INFINITY PUZZLE > together , with Nick's help bringing this Awesome Cast of Characters | Major League Players , ;-) @NICKZENTNER , to the < 'GLASS TABLE' PLAYING FIELD > *ALSO NOTE ; Multiple "MAIN EVENTS", some occurring at the same time, some at various time markers of the GEOLOGIC TIMESCALE.
How far South was North America 90 M years ago?
@@macking104 Basil Tikoff may discuss Bernie Housen's thorough re-exam of the position of NAm at 90 and younger.
In the industry, the background items in view to "decorate" are included in the idea of "mise en scene" ("Maise on sohn") like the green blackboards.
Green blackboards????
How Green was My Valley...Blackboards?
In aviation, radio loudness and clarity are rated 1 to 5.
Apologies if this has been asked previously, and maybe I'm jumping ahead, but if one discounts the Baja BC thesis then what are the alternative theories that are used to explain the paleo-mag data? The paleo mag data seem pretty tight? Another fascinating session, Nick. Thank you and thank-you Darrel.
The standard reply is that you can obtain shallower than expected inclinations by tilt and/or rotation of the magnetized rocks. For bedded rocks-lavas and sandstones-this is an easy test. They pass. For the Mt Stuart pluton, Yale researchers were acle to find that the pluton has not been tilted. So: data stand.
Interesting discussion thank you to the both of you. I believe it is a combination of paleomagnetism, dynamic of deep rock viscosity and the restructuring of the crystalline mineral lattice and lastly the variation in Moho depth. In my opinion there are way too many variables and the situation cannot be narrowed down to one cause. There are many more examples of similar activities all over our planet and the diversity of the European Alps are probably the best documented one. By the way the latest edition of Earth Structure by B.A. Van der Pluijm and S.Marshak list many more good examples in the last chapters.
❤❤
Thanks Nick. Time for you to go home and have a beer.
Hi Nick,
I am just starting to watch the 2022 Baja to BC series after devouring the Bretz A-Z 2023-4 in replay. Thank you.
A comment in your conversation with Darrel Cowan prompted an idea of the true value of your series. No, really all of your video work, the value is to make available to future geologists in thirty years or even seventy-five or a hundred years, is your collecting work in one place from Bretz, his predecessors and others, even Large poking Bretz to return to the scablands. Just think of the influence you will have on those people you have and will introduce to the subject. As one of my Scouts said on earning the Geology Merit Badge, "Geology rocks!"
Prof. Z. I only know about Baja-BC because of your lectures. I have only heard It is possible "Mt. Stewart" was once in Mexico due to Plate Tectonics and Zircons. And in the world of Tectonics the Plates and Cratons move north, south, east, west. In addition, I have never heard of a "Fixist" scientific paper being published or discussed. Because of the San Andreas Fault I would say I am a 8-8.5 positive Mt. Stewart moved 2,000 miles North by North-West some 50 myago
Amazing how you have kept this brilliant educational service going for us all for so long Nick. It's like being back at school--which, for me, was just when continental drift and polar wandering were being discovered, and the MOHO project had hopes of reaching the mantle. :)
This fascinating talk leaves me rather baffled that paleomagnetisists and geologists are now two separate things. I thought palaeomag was a fundamental geologists' tool, and not much use for anything else. Anyhow: 2 questions arise: To work out the inclination of the magnetic field in the rocks, you have to know exactly where level was during deposition and fixing. How can you be sure of this? Are there minerals, or bubbles that always point up to give you a palaeoplumbline? Or what? Trees grow pretty straight up, but is there something smaller and more reliable? Also, I cannot get my head around how you can use magnetic alignment and dip angle to locate latitude when the magnetic poles are wandering at the same time as the continents, and sometimes the fields reverse entirely and may even have more maxima than simple 'bar magnet' N and S poles? 4 dimensional chess sounds easy by comparison!
You may have explained this in you earlier talks. I have not been able to catch up with them all yet, but they really are a treat to be savoured more than once.
Many thanks. Steve in chalky Bedfordshire, UK.
It is probably better to use the term Apparent Polar Wandering curve as it is actually the continents that are wandering. The magnetic pole reflects 3 primary conditions: 1 the p core is comprised of liquid metal (iron). 2 heat from the earth’s center causes convection currents in this liquid 3 the earth’s rotation generates the magnetic field. If all the continents were fixed, same age rocks on different continents would point to the same magnetic pole. They don’t so relative movement has occurred. The direction of the magnetic pole gets recorded in the rock when magnetite in a basalt or igneous rock cools below the Curie temp of 650 deg.
For latitude, consider how magnetic the magnetic field is perpendicular to the ground at the poles and parallel at the equator. So the inclination/dip steepens from the equator to the pole. Inclinations for My Stuart were shallower than those of N America Cretaceous poles. Either the rock was rotated up from a steeper inclination or formed where the inclination in situ was more shallow. Then you have to look to geologic data. Did the entire batholith as a unit rotate north side up about 30 deg or did it raft up from a lower latitude. .
That should say outer core is liquid
Regarding the Plutonic Magnetization dates: Isn't it reasonable to assume that during active subduction there would sufficient heat to encourage convection currents within the magma chamber? These currents would likely have more physical influence over the magnetic elements than Earth's magnetic field. However, after the subduction stops there is likely a period where the temperature has dropped enough to halt convection but where the rock is still liquid, which is when the magnetic elements are locally still enough to align with the Earth's magnetic field prior to solidification. That mechanism suggests that the paleomag dates should be AFTER the cease of subduction but prior to solidification, no?
[ IN MY MIND ] *not exactly sure how to incorporate the " convection currents " variable in your statement. BUT what is troubling me is , the < METAMORPHIC STAGES > that Nick presents. M1 M2 M3 ; referring to the kBar = deg. C. matchups. Buried to a certain depth , then PARTIAL SOLIDIFICATION < 550 deg. C. \ as Darrel states >, then REMELTS ( being 'churned up' like butter at that Currie Point { ZONE } ) , to then be SOLIDIFIED INTO ITS FINAL STATE ( Like the Flour not being sifted fine enough before making dough ; hence , Recording multiple Magnetic Orientations ). Could this be our source for PALEOMAG ( UN-stable ) READINGS ? @NICKZENTNER @darrelscowan1537
Important to recall that the grains of magnetite and ilmenite do not orient themselves parallel to the magnetic field. They record it in their crystal lattice. So convection in the magma shouldn't be an issue.
See Ya'll Wed.
1 - 10? The pacific plate is grinding northward still and the north american plate is still turning counterclockwise>
I think you are correct. Keep digging.
I think you mean clockwise?
I think the question about how the basin and range extension altered the shape of California's coast is part of the reason there is difficulty in people visualizing Baja BC. The basin and range extension has pushed California outwards compared to the motion of North America as a whole after the Sierra Nevada batholiths shut off. The illustration at 46:45 really does not show how far east the California coast (the franciscian subduction zone) was accurately IMHO.
Although Dr Cowan mentions at 54:44 the absence of Shuksan north of the 49th, are there indications that the Baja BC movement continues north into Canada, i.e. there are Washington and Oregon terranes hundreds of kilometres north into the west coast of British Columbia?
The only rock unit I know on the west coast of Vancouver Island, near Tofino and Ucluelet, is the pacific Rim complex. It bears some similarities with rocks in the San Juan Islands, but it is in fault contact with VI bedrock. It was probably moved there in the Cenozoic by dextral slip on a fault like the Queen Charlotte.
I don't think of myself as a mobilist or a cymbalist. I'm a dedicated purple-hatter.
Classic clock.
My sticking point with paleolatitudes from paleomagnetic data: what sorts of observations can we use to tell if a given rock unit has rotated over time. It seems more likely that a given plutonic rock unit would rotate between emplacement and exhumation than that it would not, and it seems unlikely that as a general principle plutons and stocks remain at the same attitude over their entire existence. But then it comes down to this or that specific unit, and the evidence that we have for the persistence of its attitude to the horizon over time.
Pardon me for getting ideas above my station here, but rather than eastern subduction of the Pacific plate, isn't it a case of the Americas being pushed westward by an ever expanding mid-Atlantic ocean ridge? Rather than the ocean floor subducting, surely the land mass is over-riding? I mean, there is no spreading force in the middle of the Pacific forcing the ocean floor to slide under the surrounding continental mass. Kind of pedantry but when trying to build a mental picture... With thanks and gratitude for all that you do Sir.
Sorry Bob, but I would have to disagree with the statement, " no spreading force in the middle of the Pacific forcing the ocean floor to slide under the surrounding continental mass. " Please review the topic item that Nick presents in various shows : " Subduction of a ( Spreading Ridge* ) ". *This here would be ( in itself ) your Pacific force on the ocean floor. Stay tuned for the rest of the SERIES please ! note: multiple moving parts , all working together at the same time , nothing is actually stationary in nature, just like you will never find a straight line. [ IN MY MIND ]
@@VIBCTrevorInscho I have been around since the 2nd episode of the lockdown series, sat through them all. The ring of fire isn't a so much a consequence of ocean floor slipping under land, more a case of the land around the Pacific closing in and devouring the ocean floor. Obviously nothing is static or fixed.
@@bobgnarley1 Please forgive me for my initial interpretation of your original statement. Totally agree with this secondary one. In similarity, COLD FRONTS ( assimilated Continental Plates ) Vs WARM FRONTS ( assimilated Ocean Fronts ). The COLD with always win over the WARM ; Stronger and more dense. Enjoy the rest of our journey with Nick , I know I will.
@@VIBCTrevorInscho Not a problem Sir, nothing wrong with healthy discussion. Have a great day!
It was interesting to listen to Nick talking about 'Fixism vs Mobilism'. This isn't the first time paleomagnetism has stirred up a hornet's nest- when the 'Snowball Earth ' theory was first proposed, part of the evidence presented was the magnetism of ancient drop-stone deposits which indicated they were dropped by ice-sheets at the equator. Mid you, the acrimony that theory caused was driven as much by the personalities of the scientists involved as the theory itself.
However, I wonder just how 'Fixists' explain the anomalous paleomagnetics of the rocks. Repeated testing should have eliminated obvious sources of error, such as malfunctioning equipment, and human error. Ignoring the evidence isn't going to make it go away. What then? To paraphrase a quote from a famous fictional character, once you've eliminated all the other possible reasons for the data, what is left, no matter how fantastical it seems, has to be right. I guess then we come down to the fundamentals of science. A truly objective scientist should follow their data no matter where it leads. However, how many of us are actually, truly objective?
9.5
I'm a '5' - I want to smash the accordion with the cymbal!
The Mt Stuart Batholith came from the south (eg, fault reconstruction, 650 to 900 km movement). But from Baja? Not sure but I'm open to the idea and would like to hear the evidence.
Another great video. Thanks Darrel and Nick!
I don't think of Mt. Stuart as a piece of Baja Californina, which sports its own Cretaceous magmatic are called the Peninsular Ranges. The Insular superterrane-part of Baja BC-has its own arc represented by Mt Stuart and the younger plutons in the core of the Cascades. Therefore, we view INS as an integral element that had its own convergent plate boundayy.
@@darrelscowan1537 wow, another whole nother class from one answer. thxs sir
Ok, I really want to see core samples taken from Half Dome now. If Mt Stuart came from way South, how South was Half Dome when it was magma?
@@markearnest3570 Basil may comment. The entire Sierran block has moved and is moving with North America, but there might have been a couple of hundred kilometers of dextral displacement with respect to NA.
@@markearnest3570 One of Basil's focuses right now is the abundant evidence for late Cretaceous dextral faults within not only the Sierran batholith but also others in the western Cordillera. However, these do indicate some displacement but much less than INS. As for Yakutat, it has a fascinating history that is still being investigated. John Garver and Cam Davidson have written a paper ready to submit and I keep provoking him to do it. There is a question about the basalt in Yakutat. Most of the element is sandstone and melange, not a plateau. Basalt was dredged offshore decades ago, I I heard a comment by Donaghy and Eddy that the putative basalt exposed on land in the Samovar Hills isn't basalt! As Garver has written, i favor the Yakutat as having started life way down south, then about 49° 50-60 Ma, then like a cymbal north to Alaska.
I'm just now realizing (based on Karins work) that Insular also would have subducted the Mescalera spreading ridge, which could / might mean the N Cascades may have subducted two spreading ridges (pre Insular accretion & associated with Siletzia). 😲🤯
🤤
Also, at 46:16, there is a good illustration for my other question about how much of the Cascade slab might be associated with Insular..
This may sound more lunatic fringe than Basil ever could, but based on the illustration, Insular is south of the California triad at 90 MA; which makes me wonder if the Cascade slab (extending to GA) is associated with Insular and the slab associated with the California subduction would be north of the Cascade slab.(?)
😼💖💞
In response to the answer to Thomas’ question (1:24:05), could not the movement of detritus zircons east to west have occurred during the glacial lake outburst floods known to have occurred around the Younger Dryas times?
From the leech river fault: Yorath is a fixist?
Hi fellow Islander ! Nanaimo here.
Thanks Darrel and Nick. Sorry if this question is nutty, but could there have been a counter-clockwise rotation happening with these terranes sort of cartwheeling in on a plate towards N America? I’m sure I’ve oversimplified but imagining the point at the bottom of the cartwheel spinning up helps move it both N and E. Thanks again!
Bathymetric studies that could show such a large amount of movement for Baja BC?
The ocean floor from that time has all been subducted.
Isn’t the movement similar to how the San Andreas’s moving?
Oh forgot to ask him about the magnetization age of 95-82 ma… also how many purple hats he has )
Fixist - mobilist - non-geologist here. over the last 100ish million years how far as the north American plate moved during this time? How does that compare to the movement of the west cost northern migration? 150years ago, everyone was 'fixist' is my understanding, until a weatherman/climatologist thought differently :)
I am having trouble believing the mag thing now after hearing it. I always think of it as East West. That is what I can see with a compass. Obviously if I were at N or S pole, would see it going not parallel to the ground. But any distance from that, I visualize it as being parallel to the surface. I would be more accepting of this if I could see measurements of it. Sure someone can do that. Don't have anything for that.
Build a compass such that the needle can point freely with the magnetic field.
Take it with you in your travels through the world and record what you measure.
Profit.
@MrRmeadows Please read the < REPLIES > made by @lindanoson6014 , to the INITIAL made by @spamletspamley672. This may help. |*| it would be any degree < 0 to 90 > = latitude dependent. < zero = vertical = poles | * | 90 deg. equator = totally parallel >
set your compass with the needle point north. Then rotate the case 90 %. Think of the case as the earth.
Isn’t your scale really all about hypothesis testing in science? As new evidence comes in, the hypothesis may or may not need to be adjusted (or refuted) based on what the new evidence is suggesting. Baja BC is an hypothesis, with the two extremes on the scale being, in essence, non-scientific (proponents assume their respective hypotheses are now fully proven theories). Everything else on the scale (2-9) shows one degree or another of scientific open-mindedness, willing to at least reconsider reevaluating one’s opinion as new evidence comes in.
I am not a fan of the use of the word "cartoon." I prefer to think of them as illustrations. Cartoon brings to mind things that are not serious but silly. On the other hand "illustrations" bring to.mind more serious ideas.
Darryl was great! Yes, the material is complex but he explained it well. Since it was complex, it required concentration and what he was saying. Unfortunately, Nick, you were a distraction. Even nodding your head can be a distraction. Do you want us looking at you or listening to him? Do we need to see all the papers that he mentions? Just a suggestion to let your presenters present without distraction. Second suggestion: don't beat the dead horse about why people may not be interested in the Baja BC. We are interested. Otherwise we wouldn't be tuning in. The scale was unnecessary and irrelevant.
close your eyes, problem solved.
54:35: nappe: a sheet of rock that has moved sideways over neighbouring strata as a result of an overthrust or folding. It oftentimes is an isolated portion of an overthrust sheet, eroded away from the main portion. Heart Mountain in Wyoming is an incredible example, the Earth's largest known rockslide: en.wikipedia.org/wiki/Heart_Mountain_%28Wyoming%29.
From the German, 'knappe,' meaning short, or shortened.