Eocene Z - North Cascades w/ Bob Miller, Stacia Gordon, & Mike Eddy

good morning everybody how's it going today welcome to ellensburg washington usa on a saturday morning central washington university first floor of discovery hall the local time is 8 49 and we will begin session z north cascades in about 11 minutes from now top of the hour thank you for joining us today i hope that you enjoy the session i'm trying to calm myself down i just had a little incident uh which i'll share with you but let's uh first of all say hi with everybody look at that five by five already 430 people hey man it's the last show we'll have a few extras i suppose today folks that maybe have tuned out for the last couple of weeks and you're like oh yeah well at least i'll at least i'll show up on the last one and see what's going on so if that's you welcome back i got three people i have to invite by email but i'm going to say just i don't know a handful of hellos here dead crows in canada good morning don mom hi mom well it is a special morning even my mom rarely shows up in the live chat is here mary zettner good morning oscar in san diego steve miller kathy scrolling too fast cindy in wildport oregon william in natchez washington elaine is in new mexico denmark yeah too fast um okay so i'll tell you my little incident that i just had three minutes ago or so and then i'll uh i'll email the guest and then we'll go back to saying hi with others so yesterday at noon i gave a special presentation with nat nickel do you remember nat matt the guy who rode in on his white horse and saved my bacon involving hot keys and going to the ipad and switching cameras and doing all sorts of stuff do you remember i was really struggling and so it was before christmas that nat really experimented with me and gave me all sorts of options and much of the technology and the live guests and everything is all due to nat nickel so thanks to him however we did it through zoom yesterday and it was nat and i and we were broadcasting to people on campus basically people in his department his technology department and other professors who wanted to you know learn what was going on and he screwed up the thing nat thank you but i forgot to ask nat to get the ipad back to functioning with my normal thing so i can't get the ipad to work so that's nothing new right that's nothing new but i think i might actually hold the ipad up to the camera so what was the emergency i'm like oh god i don't have the ipad even before we start i can't get it to communicate and so i ran down the hall and i printed out a bunch of stuff and the photos looked crappy coming out of the printer so i think that's what i'm doing i think i'm going to hold the ipad up to the camera so that'll be a first so anyway what else is new there's always something at least i i'm less flustered than i was a couple years ago burping into the microphone excuse me mom okay uh i got i gotta email three people this is new all right so i gotta concentrate so thank you for thank you for being here i'll say hi to a few more in just a second bob miller email goes stacia gordon email goes michael patterson eddie iii all-american email goes receiving an email from who chris mattinson hey chris would you watch the show instead of emailing me other stuff please all right coming over here muting that screen which i always forget to do oh my god we got bob in the green room already hey man nice job didn't go to your junk folder excellent oh i didn't want to do that hang on hang on hang on maybe i am flustered 600 here that's a record 600 before we're even starting okay i'm going to scroll back now and say hi to as many folks as i can i have one very brief thank you i hope i don't forget before we start scrolling way back way back way back uh mr tony in camby oregon hello david in severe belt ray is in silverton oregon regine in france hello eagle river alaska the chugach that's wallace gordon is in glasgow scotland hello turvish in men belgium good afternoon good evening to you charles said i better watch my language that's true my mom's here although she's heard yeah okay uh now kind of scrolling our way a little bit trevor's in nanaimo british columbia jefferson eau claire wisconsin that's french hi jeff stefano is in italy hans talking to my mom okay she's regretting that she chimed in live i'm sure oh my god they're all talking to my mom okay sorry mom sorry that's it with the mom thing all right we're done with that i'm scrolling down to live i can't see you guys all talking to my mom embarrassing bob's in kamloops bc eric is in fort dodge iowa good morning santosh in india hello special shout out to you thank you for coming back uh patrick's here age eight good morning patrick i'm glad you're with us for the last show hoping to see you sometime this year ian in murumbina melbourne australia den is in dorset uk kirk in philomath larry in angola new york i'm talking like a computer now i don't know why hal cheryl's from aberdeen washington put some feeling into it boy talk to these people selfie's from fort bragg california good morning joe says good morning matt in napa oregon backcountry gary says hi to patrick i'm saying hi to you back country gary thank you i've got a special thank you to you patricia wong from portland hi patricia i remember that river trip we did a few years ago kirk in yet the boy sweden hi kirk good evening bevin in idaho falls idaho dawn in madras oregon and in san diego california richard in bellevue washington still just have bob in the green room up here stacia good all right and now we're waiting on the ever elusive michael eddie but we'll see we'll see how we do there can i double check we're five by five because i'm still feeling a little bit off kilter and while we do that let me get my little quick thank you thank you for the report this episode of nick from the classroom brought to you by indigo yoga in downtown ellensburg you've got to love it cherie down in indigo yoga says you've got to love it tell them ned sent you and by benmen's bakery in beautiful downtown ellensburg washington please you've got to love it vinman's bakery so i drop into vinman's on occasion on my way home you know get off my bicycle drop in say hi to jeff or whatever and uh now people are dropping off things at vinmons for me to pick up which is very kind it's like some sort of halfway house now so here's the card that was dropped off at vinman's bakery just south of camp the campus of central washington university and here's the gift so thank you i like your style simple direct and anonymous so thank you here's to you and here's to you all for joining us this morning by god we got michael eddie in the green room too so we're all set there a couple more quick hellos and then i got to get ready i got to get ready uh ed is in grand coulee dam washington i had geologically speaking hi todd from southern california san clemente if i remember mick is in eagle idaho bob and kathy from woodenville washington lord onion from northfield new hampshire leesburg florida belgium hello zazu honey greg in east texas uh east tennessee sorry geneva john is talking about something about venments everybody's talking about vinmen's depressed optimist from winona minnesota three more and i'm done les simply thanks for the series from the uk thank you les jennifer from boise idaho and cindy from austin texas okay thank you would you give me one minute i need to concentrate get ourselves ready for today's show thanks again for joining us hope you enjoy it hot mike okay okay you know what's going on today you have a plan it's not as wild as the basil show it's a little bit more structured you have your four questions get your four questions early frame it for yourself frame it for the guest frame it for the dream team they need to know what you're going to do go to talk about old greenie first go to your four questions then go to the ipad which you're literally holding up to the screen a camera then you got two other green boards to you're just lofting stuff out that's all you're doing you don't have to know it all you're just lofting stuff out you're lobbing i don't know are they grenades i don't know you're lobbing things out into the air and you're seeing what the what the experts want to talk about that's it and this isn't the last show with these guys so you don't have to nail everything down you're just our goals are just modest just make some progress that's it just make some progress move forward that's all we're doing you can do this i believe in you you can do it you can do it good morning everybody and welcome thank you for joining us for session z for our canadian viewers session zed we have 845 with us live and we'll have a couple of hundred other couple 100 i suppose uh joining us in a second we do have our three guests in the live green room right now and they are the experts i mean essentially i've been thinking about this north cascade stuff for about 45 minutes and bob miller's been thinking about it for 45 years so i mean come on i need to just make this quick and get to these guys this is a rare opportunity but these three folks in the green room who have deep knowledge don't really have any idea what i have planned so i have to do my usual thing mainly to frame our discussion and go to four basic questions that i would like to explore today let's go to it i mean this isn't our first show so we've already gone through some data we've already kind of like collated compare contrast between places hell we were we were as far east as montana we were as far south last time with basil tickoff we're down in what was it utah nevada looking at magmas and extension we were down in the lower mantle we're out in the pacific we're up in alaska so we've been around we're not starting from scratch but we're bringing it back to the north cascades it is true and i want to talk about these four things i wrote them out number one why are we getting all this crazy amount of extension during the eocene i mean i hit that hard last time session y i i was so adamant about that and we went to basil and i i just started going with basil we were all over the place and it was my fault i just kept following these things that he was saying and we never really did circle back and try to really come up with a very specific answer to why we flipped this switch 53 million years ago and start extending the cross what sort of plate tectonic answer do we have for that or at least ideas if we don't have the answer yet so i'm going to be seeing what our resident experts have to say basil got as far as saying there was a significant plate reorganization offshore 53 million years ago is it simply a dramatic change in oceanic plates offshore starting 53 million years ago to apparently instantaneously start this crustal extension in the north cascades or is there something else going on that maybe basil didn't appreciate because he's not a north cascades guy he's admitted that openly he did in the last show he says i you know i know idaho and other places farther inland i don't really know north cascade's kind of a blind spot for me and we kind of got there towards the end of the show with basil last time he's like why don't you ask the dream team he could have easily just said what are you asking me for why don't you ask the guys on saturday well we're going to do that we're also going to ask because these dykes these northeast trending dikes are not just in the north cascades but throughout the pacific northwest i'm wondering if we can learn a little bit more about what those dikes are telling us that's mostly bob miller that i'm going to go to first i think bob i'm going to bring bob in first talk to bob a little bit then we'll bring in stacia then we'll bring in mike there are two new papers waiting for you at nicksetner.com i'm not going to go there one is a brand new paper just published a few weeks ago miller and others 2022 focusing on the eocene dikes but then of course regionally talking as well i have two more questions though how do these magmatic flare-ups in the north cascades differ from each other we clearly know there's an age difference with some rather significant lulls in between these two these these three magmatic flare-ups but i'm wondering if anybody when they get on screen with me is willing to think about the bigger picture and i don't even know if you can read this but i'm wondering if our first magmatic flare-up which is really not the flare-up that's being studied by this current grant but i'm wondering if we could talk about it anyway because we've been talking about the accretion of rengelia rather significantly throughout the winter is this a slab failure story to create these major plutons yes or no what would we look for if we cared about documenting that as we get to the late cretaceous or the tweener magmas which mike mentioned before christmas was not quite as voluminous here are the names these are the names of the plutons in the north cascades which i will continue to learn about with the help from our experts is that a subduction story i think at least statia and bob clearly see evidence for subduction during this time down here too subduction down here too they're both a congressional regime or transpressional regime but then of course this has been the main focus this entire winter not just the magmas not just the plutons but of course all this other stuff that we've been hammering [Applause] is this a subduction story that's kind of how we ended it with basil do you remember i'm confident but we'll double check with our experts is there really a subduction story for our eocene magmas in the north cascades yes or no and if not is it a slab window and a rollback story okay those are the four questions i simply want to do a few more things visually and a couple other quick things on the chalkboard and then we go to our guests again it's a rare treat if you join us late there's a story here but whatever let's not bother 45 degrees cold front coming through we're going to be back to winter like conditions next week it sounds like you know how to get to these papers not secure nicksetner.com click in the upper right the brand new paper by miller and others on the eocene dykes just came out mike eddy did a nice sweet short paper on the golden horn that's also available to you what i really want to show you is two things first of all just to remind you you've seen many of these before this is gary can i go full back country gary i just want to rapid fire go through these photos one more time this is almost like cozy fort days where i have a reflection thank you back country gary for all of your amazing photos gary was a long time back country ranger in the north cascades both crystal and core wenatchee block as well as chelan block and he has annotated these for us i've been using them for more than a year and he's probably got a four a few more in his back pocket as we go to baja bc next winter so i continue to come back to these photos gary because of their beauty but also as i continue to learn from the experts i see more and more in these photos here's aaron donaghy country with the chum stick basin so i'm also just showing this to remind you how amazing this landscape is and i'm super pumped to get back out there with or without members of the dream team straight creek fault will come into our discussion today a little bit back country gary wonders if those dykes are laid cretaceous do we have multiple generations of dykes i don't know are they all eocene okay you're getting seasick because i'm holding this thing up to the camera but things just do not stop from back country gary and we've made progress i can see these plutons but i know they're not the same age and now our simple one of our simple goals today is to try to tie some of these huge batholiths to a specific tectonic story thank you gary paul thank you gary paul who studied geology university of washington by the way but wait there's more some of you have seen the photos that are the video that i shot last summer when i really spent time with the dream team for the first time foggy do campground that was last summer 2021 well guess who was at foggy due campground in 1985 probably the same picnic table so this photo was emailed to me last night by frank who was a student of bob and frank has been a regular he's probably in the live chat right now frank thank you you gave me the names of the other cats as well i didn't have time to punch those in but i mean bob has been doing this for a long time man and we want to take advantage of this opportunity uh these are all from not only the brand new paper that you can look at after the show's done maybe you've already been there but there's another brand new paper that's not ready to be shared but a few of these figures i've gotten permission from bob to share so i just want to give you a sense yeah here's i assume this is bob maybe paul talking about how do we draft up this uh series of crazy eocene events and then i think this is a brand new diagram again sorry it's so shaky but some of this is available to you to study very carefully now some of these are from a paper that's about to come out hopefully later this year but the point is there's a lot of this stuff kind of coming out or has just come out in published form that will advance this discussion so i'm just trying to wet your appetite this is this is all the stuff we've been talking about and it's just so satisfying and real thrilling i think is the word to see it all put together these guys have been at it for a long time recently and i'm just this group here has just been slowly trying to ramp up to see it all being put together so i guess by i don't know christmas time hopefully you'll have all of these details for you as well and you're like slow downs like i don't think so just trying to just trying to get this out so this is all great bob miller as i understand it is kind of the the motor behind a lot of this i may have that wrong but even the fact that we have the roche lake fault zone active with the golden horn and the cooper mountain batholith active and then we kill that and we decide to move abruptly to the south it's all new so i think it's okay to share this this is maybe the tentative title maybe it's the formal title that will come out later on so you're not going to find it now anywhere but hopefully by christmas you'll have this on in your hot little hands finally jeff tepper sent this to me last night and oh god how am i going to do this i'm just going to give you a chance to look at it quickly and then i'm going to read you the email from jeff tepper sent yesterday jeff tepper the guy from tacoma mr eocene plutons hi nick i'm pasting below a new plot i created a few days ago based on uranium lead ages and geochemical data for eastern washington granites that i think ties nicely into the crazy eocene story the y-axis is an element ratio lanthium no lanthanum to euterbium oh god that is a proxy for depth of melting think pressure it's an indicator that garnet is present and the higher this ratio is the thicker the crust is interpreted to be the plot shows the crust thickening beginning after 100 million years ago and peaking around 55 million years ago after that around 53 million years ago we see a lower lanthanum guterbium ratio as the crust collapsed and thinned the colors on the plot distinguish cretaceous versus eocene plutons but the real change is at 53 million years ago these data extend across washington to idaho and the timing would appear to to not the timing would appear to tie in nicely with core complex unroofing your interviews with caleb and dave are part of what led me to try to make this plot i'm flying to florida tonight and spend a week with my parents and brother but we'll try to log in to watch episode z while waiting for them to arrive at the key west airport pepper are you at the key west airport right now if that fails i'll catch the replay it's been a great series and i hope now you can enjoy a break and maybe just read a novel for fun cheers jeff two more things and then we go to our guests i have to show you this so i've i've entered indicated my questions trying to frame our discussion the lulls to me are interesting i don't know if i should be preoccupied with the lulls and me in other words these spooky quiet times in the north cascades what does that mean station particular has been documenting sediment addition to magma systems and perhaps flaring up the magmatic activity is that only here statia or do we have sediment introduction at other times as well i guess i did kind of cover this okay two other quick things and then we go to our guest how many times has he said that so the crystalline core we know is here between the roche lake fault zone and the straight creek fault zone and we lose it when we get into the flood basalts the german chocolate cake we have the chelan block that came rapidly up rocketed to the surface in the eocene as well as the wenatchee block these two separated by the antiot fault each of these are strike slip faults these two guys have been offset by the straight creek so we know that the continuation of these two faults are up here in british columbia my question and this is more probably a teaser for next winter when we do baja bc but my question is and i tried this with bob before christmas and i think i want to come back is this crystalline core in the insular super terrain or in the intermontane and trying to think about that does that help us or hurt us try to think about why these magmas are being generated so i'll just try this it might be a total disaster i think you can see yeah so old north america then we bring in a super terrain known as inter montane that's been thrown around quite a bit we haven't focused on it much because the accretion happened roughly 170 million years ago then we bring in rengeli and friends otherwise known as insular super terrain that accreted 100 million years ago then finally we bring in celestia to build the pacific northwest if i use blue chalk and i just use x seif not for cross country but for crystal and core if the crystalline core is really in the intermontane in other words if the the high country the beautiful country in north cascades national park where the dream team is working if it's tied to the inter montane then are we making plutons intermontane insular we had crete insular 100 million years ago and we have this fireworks right we have our first round of magmatic flare up post insular accretion here if we like the cross the cross country team here in the inter montane is that a slab failure that's what i'm asking so if we bring insular in and the subducting plate is therefore failed this is bob hildebrand's idea among others are we generating our first magmatic flare-up in the north cascades inland of this suture and if we don't have the chemistry for that or we have all sorts of other details in the geology of that first magmatic flare-up between 96 and 87 if it's really a subduction volcanic arc then what kind of geometry do we need with our plates what am i missing second magmatic flare-up is between accreting insular and accreting celesius i don't know what to do with that but it must be just an eastward subducting oceanic plate but then when we finally bring in celestia i don't see how we can have a subduction story is it a slab failure again and to me the key is not looking just cross-section wise but then turning our perspective and looking down and now suddenly we're in baja bc because if you were a baja bc person as daryl cowan is and that was one of the moments this winter that i still recall vividly daryl said more than once i think the crystalline core is insular daryl cowan and you're like okay big deal why is that a big deal well if you're a baja bc person you want the insular super terrain in southern california at least or maybe mexico and then you move it north so you know when we're looking at this stuff here this is how we'll finish teasing you for next winter baja bc is a concept of moving the insular super terrain from baja mexico up to british columbia and when does that happen when does that northern transport happen it happens between 85 and 55 million years ago a crete rengelia accrete celezia but between those two major events if you're baja bc you're moving north during the time that you're creating these things can you see how crazy crazy this can get we'll see if we get to a triple junction migration which is my fourth question but i'm starting to realize that bit off too much for me to chew this morning we'll see we'll see we'll see how it goes it's 9 23 and i think it's time to get to our first guest bob i'm coming to you and i'd like to talk about these dikes stations on standby and uh mike's in the hall good morning bob hi nick how are you today oh i'm doing fine nice that was a nice photo nice photo of you in 1985. had you seen that one before oh yeah yeah that uh i had that in my office that was my uh first summer of uh having at san jose state so um those uh had a bunch of students working up in that area around foggy do did you recreate yeah did you recruit those guys to uh to to work on the north cascades or you inherited those students when you first showed up well they were uh i think they were orphans when i showed up i think they might tell you otherwise but they didn't have a thesis advisor at the start and you probably you may maybe old enough nick to remember those days when uh after uh gas rationing and that sort of thing there were so many geology students it was probably the heyday of geology programs and we had a lot of masters students and i got really lucky that there were some excellent students had those students and one student to work down on the blue scissors and green shish that hicks butte not not too far from where you you are right now so yeah it was a great it was a very stimulating time very cool well you're still at it for sure i mean that i have to say that i'm just so impressed with you you're you're not exactly 35 anymore and you're still cranking out these papers and doing all this stuff so i mean and you're not talking about the old days either i mean you're using the the latest stuff so major props to you thank you i got a question about the dykes and i know you had much more in that paper besides the dykes but i think what i learned from that paper and this is the paper that everybody can enjoy after the show and we we've been thinking about these dikes for a while now in the pacific northwest uh caleb had them in montana dave rogers had them in idaho and then of course we have them here as well i guess the main thing i learned from that paper bob is that you have slight differences in orientation of dikes in the north cascades and you're tying them to strike slip motion as opposed to the accretion of celestia am i getting that correct yeah well yes but it may be the accretion of celestia in in the change in the plate vectors that's driving that but yes okay and then uh so i i don't know that they're chicken and egg type things that they're or may be that sort of thing that they're they're closely linked uh would be my interpretation okay uh as far east as montana we're still well that's that's i don't you know that that's one thing we didn't really address i looked into it but there aren't one of the things that came out of just putting all the data together and you know those dikes that many of us had ignored for so many years or at least i had because i was interested in the older rocks and the dikes got in the way um that finally gone done dawned on me that maybe it would be worth putting this together and getting more data is you know we've always sort of said oh they're northeast striking but that's mostly based on the tiana way and i wonder if you went in montana and idaho and looked as carefully at dike orientations so for instance the republic robin which you've talked about in northeastern washington and the rocks uh in the crystalline rocks next to it in the uh in the domes there are uh the dykes tend uh it's the little data that i've seen at least uh published or mentioned the dykes strike more like almost north south they're slightly northeast but they do have a different orientation i just wonder if people went to uh did a quantitative study like what you tried to do if they would see the see the same thing but yes variability no question about it well let's talk about the variability and what you've done with that so i i don't have the ipad but i've got these two i think from the paper this look familiar so you've got a set of these dikes there's a lot going on here but am i understanding that there's a generation of this particular orientation that's tied specifically to these faults as opposed to a slightly different orientation of another set of dikes that are a little bit younger that you're tying specifically to straight creek well uh yes and no i think that that diagram is really uh to show expected orientations that that's sort of a textbook diagram on secondary structures related to strike slip faults but what we're trying to show is uh if it's parallel if you look at those structures relative to the ross lake and any at since they strike northwest whereas the straight creek tends north south then you would expect different orientations so that was a figure really mostly designed to set up the set up the reader to have an idea of context of okay what orientation is what he might we expect and then in transtension uh that would rotate dikes uh to or rotate the stress field not necessarily the dikes but rotate the stress field as um you know you've talked about several people have talked about so it's pretty pretty messy in fact uh the straight creek trend or if you want to relate that to strike foot faulting as we do uh this this is a really old idea uh that the tianway dikes fit nicely for a model of strike slip uh with the straight creek fog they're right next to where the straight creek um projects southwards and goes and those are the most spectacular dikes and they're easy to get to from ellensburg since that's the center of the geologic world i'm sure that's why [Laughter] that's right well um so one more thing and then we're coming we're going to bring stacia in and we'll keep you on screen bob um when i read mike eddie's paper five years ago i got all excited i saw somebody young was working north of town and i'm sure you were involved as well but i didn't lock on you i was just blocked on mike and i i gave this public talk downtown and i've been giving this little talk ever since involving a coin purse where i use this little prop and i say look we're going to open these extension or these tensional dikes by squeezing in these two directions and we're going to open perpendicular to that and here comes this chianti basalt coming out of these cracks basically it's like a health class now but you get the idea and so i was trying to say look this is not strike slip at all i wasn't thinking about strike slip motion at all instead i was saying we're going to bring celezia in and that's our squeezing of the coin purse and you're saying i can still run with that or as i teach this in the future i could somehow get the strike slip faults going at the same time how would you do it if you're teaching a 101 class well that's uh i mean i i don't think i disagree with the overall i think what we would add uh is that the strike slip faulting is playing a role so and that that's important i think uh for those who saw tecla harm's presentation tecla emphasized uh that her collapse or her forget what analogy she used for the for the collapse and so if you have purely collapse with the orientation of those core complexes you would expect dikes to be striking north south right because if you're pulling apart yes and uh if you can see my fingers on the screen yeah my hands are supposedly going to be moving east-west so or uh yeah so the dikes as i said i think at least from the available data the dikes a little farther east are more north-south whereas we have more at least in washington i'm only talking about the republic robin area which as far as i know i think it'd be great for a senior thesis or a master's for someone to go and really take that apart but um the uh that would give you what you'd expect nor south dikes so the fact that they're more northeasterly in the cascades that can fit with having a component of strike slip and since we're near the plate margin that makes perfect sense and and if you go back to the eddy at all paper to mike's uh paper that's his one of mike's big conclusions was that strike slip faulting may have accelerated or even initiated i would argue didn't initiate but maybe in the local area and that's why the chump stick basin starts to form right at the same time as the uh strike slip faulting uh the annie at fault and leavenworth fought kind of in that interval as well and arguably the straight creek fog so all of that sort of happens very close in time at least we know they're all close and fine then how we tie that together is another matter i got one i got one more and then and then we'll move on um a two-parter so can you think of some core complexes with the dikes coming right through like is that can we can we call uh i'll hold off on that forget i said that how much rotation have these dikes done now ray wells down here in southern oregon has got these things rotating more than 45 degrees whatever right so are we too far inland and too far north to have dramatic rotation in the last 50 million years well i think that's a that's a good question that's still a it's a great question which hasn't been totally resolved but there are paleomagnetic data that merle beck uh obtained uh back in his students way back i think in the 1970s right around he was doing mount stewart which started baja bc and they found at least in the uh ladies seen igneous bodies that there was no no within statistical uncertainties no significant uh rotation and that was based on i think the granite falls stock which is kind of in that area that's northeast of seattle with too many trees uh to see the geology well but that they had some stud data there and and forget what other volcanics i think they had so from that perspective the thought was well the rotation increases to the west and to the south so no but there was one other study another really old study done in northeastern washington by a fellow named fox usgs fellow and he they did i think merle was part of that too they also found some rotation uh in in northeast washington so it is a little confusing how would the north cascades not rotate significantly okay it always comes back to murrell somehow we need to do merle beck a to z i think i mean well if you ever go look at the tiana way you'll just see there's lots and road cuts we've probably been there are lots and lots of holes in the rocks and they did do paleo mag on the tanaway dikes which are the most voluminous but unfortunately they didn't they didn't yield interpretable results at least maybe now with better technology yeah they would but no one's done it as far as i'm here time is right the time is right for some of that um thank you bob let's keep you on let's bring in the other two what the heck station and mike we're bringing you in we'll see if we can get this to work brady bunch style here so let's go uh stacia from reno nevada hi stacia good morning thank you for joining us thank you for giving up your field trip i don't know what happened with that but it's a holiday weekend here did that just fall apart or did you opt out postpone until spring break perfect perfect thank you and now uh mike from indiana hey mike how's it going today pretty good good uh oh this actually is snapped into four rectangles love it um so let's just let's just make this happen the best we can i think the goal i don't know the goal is like we're sitting around uh the picnic table at the campsite and we're just talking and there's no formality here and people are finishing each other's sentences or whatever so that's our goal that we can just kind of have a discussion like we would anyway and i don't you know i'll start by saying this like so so bob just just emailed this this unpublished paper to me which i am not sharing with anybody but are is there any part of this that you're kind of reluctant to talk about like you're like i haven't published this yet i don't want to i don't want to say out loud what we're working on like somebody's going to steal our whatever is that a thing or are you kind of an open book anybody want to reply to that let mike i've done enough talking okay no i don't i don't think there's anything that we wouldn't be willing to talk about good good i mean it's i i sometimes do feel like i'm this is kind of unusual this really hasn't been done before and i i don't want to you know screw up basically by having us talk there's a decent audience for this but you let me know if you want to keep anything well like i'll add that uh yeah the version i sent you you might have noticed there were in track changes mike and jeff arguing with each other jeff pepper and not so cool yeah it's not something we necessarily want to put out there and [Applause] there are no there's no comments like what an idiotic thing to say but but nothing like that but uh there are some well of course sorry for jeff if he's down in key west yeah that's right that's good yeah right well you should he's huddled in the corner of an airport with wi-fi trying to get this thing not to buffer on him okay um stacia i learned so much not only from you but from tecla and basil about these metamorphic core complexes and i was in those shows starting to not starting i was saying is the crystalline core essentially a metamorphic core complex and i brought this up just casually with mike and last summer i think where are we with that should i just not think about what we know about the basics of core complexes at all when we're talking about your turf in the crystalline core uh i mean it's not too far off i think the main difference is just that we do have this major strike slip component compared to the core complexes to the east but it's still the same idea of the upper crust extending um with the trans tension um and then the deeper crust being more buoyant and ductily flowing and and all that good stuff that you see in both the core complexes as well as the crystalline core so similar processes but just adding a major strike slip component to it okay that works for me except like right next door we got this massive shoe swap complex of course the valhalla that you worked on etc and don't we have an i don't know do we have an upper plate that's sliding westward off of this major turtle shell and if that's true isn't it sliding right into your field area trying to think i guess the whole thing i guess you can think of it as an integrated system um i'm trying to think in terms of the directions of how it's sliding it seems like it's just an east-west thing but maybe it's all sliding east i mean i i it just feels like there might be a connection between these two stories since they're just so close to each other but i don't see anybody doing that and i i don't know what i'm missing with it do i because we have such significant offset on these faults at the same time that is the reason i shouldn't be connecting dots between the openings [Music] there's some of that i think there's also a lot of intrusives in the middle that are younger and kind of hiding some of the story that's going on um trying to think of another i don't know yeah uh do you have anything else to add well i would just say that if you project the the okanagan valley or whatever if you use the canadian term the normal fault zone that would go well into the subsurface and the satan fault shouldn't be a problem that's the big one farther east that bounds the metal basin because it would be inactive i you would start potentially getting interaction with the ross lake fault zone if you tried to do it in three dimensions we really don't know there were the geophysics unfortunately uh there was a big seismic line called cocorp back in the days where we learned a lot of crustal structure and it did all right in northeastern washington but because of the highways they weren't able to go east across strike in the north cascades and for some reason was dot or whatever you call that department of transportation didn't want this giant machine going up over north cascades national park and sending off seismic waves so we infer a lot from uh from british columbia there's a lithoprobe line something that was the name of the canadian equivalent where they went across the country and they imaged some of these faults and you can see even even questions like what happens to the ross lake fault zone or its equivalent potentially on the other side of the straight creek fraser they actually show some of those faults flattening out at depth uh now august uh tecla harms kind of went into that a fair amount so you know but it gets pretty hard to interpret that lower crustal structure so you can speculate all you want but it would be in a hanging wall position so that that oh right north cascades would yeah uh mike let's involve you a little bit more and again i'm just throwing stuff out we'll just see where it goes it might be dead end i don't know so of course i have to go into what you and tepper were discussing in the margins of this working document mike you seem like a reasonable person but you are against the grain with this particular triple junction migration story and you're on record saying you're happy to discuss anything so let's do it so the idea is for our our visits our viewers is here's a sim i just took something an hour ago spreading ridge two ocean plates yes we don't have offsets okay fine and please remember that if we have an ocean plate and another ocean plate with a spreading ridge in between out in the water and then north america we have a triple junction my discarded coffee mug is the triple junction okay so i put my finger that's dumb i can put my finger on a map where three tectonic plates are together now again it's like i'm advertising for next winter when we do baja bc but the baja bc people say this triple junction is real and it has slowly been migrating through time north up the coast and generally the baja baja bc people say this is the cooler plate on the north side of the spreading ridge and this triple junction migrates north through time mike you don't like that why not you want it going south well i i'll give it a caveat i mean that's all fine with me but i i just want it up at like where juno is today by the early daily june and so i guess i'll push back a little bit on the baja like that yeah is good like it's easier to work backwards from today right you're out tectonic settings than to see that things were moving in the cretaceous and then invoke that this is where a plate had to be in the cretaceous yeah and so if we just kind of forget that we need to move a lot of western north america and the cretaceous which i'm willing to do maybe everyone else isn't but uh yeah we'll put it off the next winter we start our our world in the paley gene what we know is that there had to be a triple junction somewhere in the north american margin what what i'm sorry what time frame are we paleogene but could you give us a a number please oh yeah so 66 until the end of the legacy and i guess which i actually don't know 30 or something okay so we're we're thinking hard about where that triple junction is between 66 and 35 sure yeah yeah okay so um we know that there's good evidence that it was interacting with this chugach terrain which you talked about with daryl cowan yeah okay and that that evidence shows that that interaction was moving to the east and south across the oracle line in alaska up yeah way up here yeah but yeah yeah but the chugach has moved right maybe you know and so if you slide back down uh next to british columbia okay true gacha is here yep then all you need is that single triple junction which we know had to exist uh moving down towards the south along the coast and everything to the north of that is exposed to the cooler plate which is really obliquely moving relative to north america and so it can drive strike-slip motion and translate things like the chugach terrain to the north um and everything to the south has a bit more head-on subduction and so there's a little bit less of an impetus for strike-slip motion so our argument in washington was we see selecting a creek and then we see a lot of straight dextral strike slip motion yep exactly and so it looks like that triple junction has popped down to the southern end of celestia following that accretion event how far south you want to go mike yeah somewhere in somewhere in oregon oregon yeah sure and so just to pause you i want to keep going with this this is great i think what i'm hearing you say and when i did this in my geology 351 class last spring we were trying to really think hard about this idea of a southward migrating triple junction which is what mike is saying and not many people not many others are saying i think what i'm hearing again from you right now is you have documented dextral right lateral motion on these strike slip faults and you need an oceanic plate offshore that's that's doing that like the timing here has to you have to have the cooler offshore but if you take the model everybody else is saying they they have the cool off the map by the time that you're doing this is is that the timing that is the problem sure or they'd have it like there so they just have it in the same place but moving in the other direction at that time okay so the one big complication which basil talked about is that like the entire pacific basin goes nuts uh at this time yeah uh in and even the indian ocean basically goes not so india collides with kawastan izu bonin arc starts the aleutian arc starts like everything changes so all the pleat vectors change at this time because you're opening up new subduction zones you have new plates pulling in new directions as they subduct down into the earth's mantle and so the way i you know he's absolutely right that we have to think about whether we're looking at a um a local or like a global story here right um but the thing that i would say is that so we pop down that triple junction into oregon if you'll allow me and then in order to get to the current plate configuration we have to get it back up north into bc because that's where its successor triple junction is today and so this change in direction probably happened around when the pacific basin was reorganizing all the vectors were reorganized at 55 no younger younger yeah i'd say that happens at 50. so to summarize you almost your your time window that you're uh you've been thinking about the most 65 to 35 let's say are you you kind of have a yo-yo you want this triple junction coming south and then you want it coming back north a long-standing regime that allows that triple junction to move south so you get okay and all right so you got a north east striking ridge and you get north america thank you north america is moving to the west and yeah that triple junction point just moves south so that's totally fine and then as everything reorganizes in the eocene as you open up all these new subduction zones it allows it to move back north and that's something that surprisingly i think is going to pop out of aaron's phd is that we're seeing sort of evidence for the late eocene early legacy passage of that triple junction back to the north um which coincides with when we think the street creek fault shut down which yeah i think i think we'll be able to make a nice story but that's this is like a few years out now okay okay well that's and one last thing there and then we're going to go to stacia it's so you're pinning down the triple junction multiple ways activity and timing on strike slip faults inland but are you using near trench magmas like we were trying to do back in january is that part of this as well yeah i mean that's most of the story for the chugach terrain and then as daryl pointed out there's some in washington and vancouver island as well are there some down here that you like as near trench magmas i don't think i see that from other people well you're not gonna so the geology is different is so after you accrete celestia your your triple junction is now intersecting uh your ocean across your oceanic plateau so there's no no sediment to melt there to get weird uh oh s-type granites like you would in the bugatti or like you would up in washington so the near-trench magmas look different you can interpret them as near-trench magmas but they don't have the same chemistry as burning holes yeah so the problem is i feel like i'm drowning on here but the problem with good stuff is uh okay so the stuff in the chugach and washington they're really weird because you're in the four arc which is normally a super cold place and yet the intrusions look like melted sediment so they're like garnet and muscovite bearing full of aluminum not your typical kinetic magmas and so really i mean like the only way we know to do that is to pump a bunch of basalt into your normally cold forearc and melt some of that sedimentary material that's in say the accretionary prism so if you accrete celezia and now your triple junction is intersecting with that accreted silencia block you don't have sediment right where the triple junction is anymore right now you've got an oceanic plateau or this wad of basalt and so there you might have a triple junction you might have a little bit of basalt coming through but it's just going to be the salt erupted on the salt and that's that gets people going a little less well well i love this stuff and and it ties so much together with some of the themes we've been working on and so part of this is going to be in black and white in this paper that's about to go into the pipeline it sounds like i think i kind of scanned it last night so that's the paper that's going to be published but hopefully by the end of the year maybe actually yeah money up and get it in color so oh see you took me literally and aaron's gonna have potentially in her phd thesis and then a couple papers in the next three years gonna be kind of nailing this down as well it sounds like so that's something really to look forward to wow we got the inside scoop there that's wonderful thank you for sharing uh stacia i want to involve you and then i don't know then we'll just kind of talk about this summer and what the what the team is hoping to do i guess stacia i'm um i've avoided the sediment being introduced into the magma to to complicate things because i don't think i still have it straight where the sediment is coming from on the back arc or the four arc or whatever and i don't know if we want to go there a lot but why do you have that sediment signature or what do you have in these magmas that tell us that sediment is just being shoveled into that magma system and do you have any hint of that sediment introduction in these other two flare-up events as well uh well we actually don't see that much evidence for sediment being introduced into the magmas in that 78 to 60 ma you don't you don't yeah so we from jenny matzell and um some of my former student kirsten's work where both of them collected a lot of whole rock neodymium isotope data it doesn't seem to show a big sediment input um for either kind of the first or the second flare-up event it's not until kind of the eoc magmas that you start to see kind of the chemistry changing and mike can kind of answer more about those magmas but yeah that middle flare-up we don't see it well i'm sorry i missed that i thought that was the second flare-up that had that signature wow okay well i'm steering us towards the current grant and um so stacia you're well let's talk about your roles one more time let's take a step back and live viewers what do we have uh 1100 watching and we are coming to your live questions for all these guys in in a bit but i feel like i want to do a little bit more here so to revisit the basics of this team as i understand it bob is mostly strike slip faulting mike is plutons and geochem and stacia is metamorphic uh rocks in in in the crystalline core but it's not appropriate to say that because you guys are collaborating on all sorts of things so stacia how much of the strike slip story or the pluton story is clearly part of your work you're not just metamorphic rocks right yeah i would say i focus more on kind of studying those rocks in the field and and collecting the analytical data from those particular rocks but yeah we need the kind of what mike's finding out from those plutons and bob's kind of overall mapping and structural kind of collection of data from across the whole crystalline core to kind of understand the entire system because they all parts of it are so interconnected um and so i think what we're seeing for that middle flareup time is yeah the sediment isn't necessarily [Music] driving a huge amount of magnetism at least from what plutons and things are exposed to but there's all that magnetism that's happening and it's actually probably really weakening the crust and it's weakening it enough that that's what allows kind of the under thrusting of some of the sediment from the west side of the ark from the forearch side to be kind of dumped into that mid crust of the arc system well let's go there so in the grant which i tried to reread last night and there's a lot in there you guys you guys speak a very specific language can you still hear me you guys i can okay something's happened on my end okay well we'll let you play a little bit um okay the real the reality you're good the rheology of the crust seems to be a huge deal for you guys i don't understand why or can you instead of saying that um how are we viewing the crust at these three different times right now is this this is the thickening chapter and it's strong and then it's weaker here and then it's disintegrates in the eocene or why is the rheology important in your study anybody well so reality is largely that just means like the strength of rocks so how they're going to behave when you're trying to form them and it's largely temperature dependent okay and so the idea is right like pump a bunch of magma and it's going to get really hot so does that drive ductile flow like at the most basic level like do you do you end up with a bunch of ductal deformation because you're putting you know heating the stuff up and then you can add to that that you know the deformation is really going to partition into those weaker areas and so part of it is kind of tracking how that deformation is changing through time which is as mike was just saying kind of very strongly linked to where the magnetism is focused and then if you add in the meta-sedimentary rocks they're also going to be really weak compared to the crystallized magmas the plutons and so then it's important to understand kind of where the sediments are and where they're kind of introduced relative to those plutons and magnetism and all that too and i guess i would add one of the points you raised in your introductory remarks nick is that flare-ups uh what causes flare-ups is still a big question they're observed through uh through a lot of a lot of arcs and people the comments we've made and the general idea of well sure it makes sense you put a bunch of heat in and you weaken it but and deformation should be localized but do we really have very many examples where that's been documented that we can say in an art bam we had this magma come in and then these rocks deformed or did they start deforming a little before or after and i don't think uh i think that's one of the great things that for me at least working with station mike is combining our field observations with these quote-unquote cutting-edge techniques we can really we're our goal whether we succeed or not is always a question is to really pin this down the timing events down to a pretty local scale maybe even um you know down to the kilometer scale or 10 kilometers so can we show deformation within the skagit nice varying in time but very precisely so that's interesting so if this was a huge magmatic flare-up the first one why wouldn't there be a bunch of evidence of core complexes at that time or you're just talking about deformation being totally different from ductal flow and core complex stuff it's just folding of of units what am i visualizing for deformation after we have a big heating up event well i think i think in the where i i spent a lot of a lot of my the first half of my career working in the wenatchee block uh i'm sure there's a lot of relations we've scott patterson and i worked on the chawakham schist and various units near the mount stewart and and in the ingles but trying to pin down there we didn't have we with the available data we can make some statements but uh no one's done that kind of work that we're proposing and this was a compressional in the mid cretaceous this would have been compressional people can debate about what caused it so uh you know we we don't have we don't have the core complex development perhaps if it's right of course like crustal thickening so that's that would be uh you know we that would be another area that would be another part of the crust that would be really interesting to look at but we think with the the skagit area that we that from the geochronology that's available from multiple people including stacia that uh there's uh a fairly protracted or may not protract it but uh there are things that are going from 75 to 50 million years within the skagit night so we can look at all of those all of those and with the kinds of precision mike can get in geochronology and and we can really nail that down perhaps better than in the mount stewart to wacom chest area uh in the 96 to 87 million player i'm loving this by the way i don't know how our live viewers are feeling but this is exactly what i was hoping for let's do a little bit more and then we're going to come to the live viewers anybody maybe mike since he hasn't spoken in the last 10 minutes are you willing to say mike this is all subduction generated magmas and we just have some quiet times but it's ongoing subduction during this whole chalkboard yes or no um uh i would say probably not in the eocene let's start there yeah there i think there's a lot of good geophysical evidence and that you can see celestia attached to a subducted kind of like dangling slab that's still underneath north america that we we really we accreted something and then ripped up the plate that was subducting that it was attaching attached to um and those uh you get really weird um magmas in that eocene bunch like things that don't normally form in subduction zones uh like part of the part of the golden horn is per alkaline which is not um it's got like big blue amphiboles in it which is very odd let me pause you right there so the golden horn keeps coming up obviously it's unique for many reasons the paper is waiting for our viewers for your work on the golden horn five six years ago do you have evidence that the golden horn fed a volcano and what kind of volcanic system was it and is there any chance the tufts in the chum stick are tied to that well thank you very much for asking that question nick um i think so and if you look at our map the like the southern part of the golden horn looks like there's a down dropped block which is kind of circular which kind of looks like it could be part of a caldera system and then one of the toughs down in the chum stick does match up like the biggest intrusive body and the golden horn their ages match up pretty well so i you know i think there's a story there uh definitely but it would have at least part of it would have fed very large eruptions um very cool yellowstone size but okay yeah um so you guys have been working with jeff tepper obviously and he has this rollback thing uh his model bob or anybody before you started dealing with jeff tepper and that data were you thinking subduction and station go ahead bob i'm sorry go ahead oh no certainly the standard view that i had many people had was that it was just arc magnetism we called it the we called it the arc uh and then uh you know going back but going back to the 1960s at least peter mish when he first i think saw the golden horn and then with the work people did in the duncan hill and cooper mountain it was recognized that there was a change in the chemistry of the plutons or at least the just photography that uh as mike said it's not just the golden horn uh tonalite dominated the uh which is which has which is more typical of the coast bathood as a whole and then in the scene there was this change but it wasn't really until we had the geochronology i think in part where where the uh where we recognize this gap through uh basically through sam bowering's students work yes including mike's and and and others aaron shea that we realized between 60 and 50 there really were no plutons of any size and that got us thinking more about low angle subduction and then somewhere around there where ridge subduction rich people started proposing on vancouver island uh the rich subduction then that uh event that got us thinking at least in my mind then that was sort of our hypothesis and i think in the in the grant that uh funded mike's phd work i haven't read that in a long time but uh you know around 2008 or something like that we started thinking daryl wrote that important paper in 2003 on the chew gach and the rich trench so that that that i think is when i got started and jeff's drafts uh jeff's really been the one to that wasn't trying to make a pun but to roll with the rollback story and come up with that and what it might mean so you know i think it was kind of the way science often works where we're all sort of honing in on the same general idea well so it feels like at least two of you are are seeing are backing away from subduction as an active mechanism here but stacia i thought the sediment introduction was tied to a subduction slab story and if you're if you're saying the sediment story is eocene then are you wanting some subduction in the eocene then no no it's just in the isotopes you see them becoming a bit more evolved which is just um some more crustal component but i would assume that's more i mean is that correct mike that seems like that's what you see but i'm assuming that's more that you're just getting this really voluminous magnetism due to that slab window and everything of celestia and that that's actually melting some of the crust just as it's going and passing through it so it's not actually new sediment being introduced it's just that existing crust that we have there from all these prior events that you have on the chalkboard there and that some of that is just melting when you have this super voluminous magnetism of the eocene oh i'm with those two not through arc magnetism and let you seem and going down just to finish the thought then so this can be quick everybody's agreeing it's it's a true arc and it's a subducting plate for our late cretaceous magmas all right as we know okay mike yeah yeah i'm happy with it okay i mean that's stacia can tell remind us on the timing but i mean that's like when we're shoving sediments under the yard wait a minute so so that is the sediment story here but it's not going into the magmas it's going underneath the ark or into the middle of it oh okay yeah okay no that's me that's me and and and finally down here in the early days i do realize it's not your focal point now but you know bob was in the wenatchee block it was nothing but this right bob for your first 15 years or something uh so i don't know should we get into it a little bit like is this subduction is it eastward subduction is it westward subduction is its lab failure i know we can't do this in three minutes and the live viewers are wanting to ask questions but i'm just i think it's eastward i think it's i think it's eastward subduction but i definitely think it's i think it's subduction i have trouble with that being purely break off in part because we see plutons of that age going from the peninsula ranges up to southeast alaska and they intrude you know they intrude different different terrains so uh and again it really depends how much where you put the strike slip faults it comes back to baja bc yeah yeah and all of this discussion even about the okanagan you know and i if the okanagan was because it would be part of the inner montane and mount steward is you know that's that that's whether for better or worse it's the original baja bc body right so uh if it was a 1500 kilometers to the southeast relative to the okanagan you you really got to think differently about alcohol yeah so hopefully you'll resolve all this in the winter so oh god what's really going on but anyway i i don't i don't have i don't see the evidence for some localized slab break off just because we're not even localized just because of the length of that that's a huge pulse of magmatism along the length of the courtyard even in patagonia so well it should be obvious now why we've saved i've been so regimented like keeping the baja bc thing out i think chris madden's in the middle of a sentence i'm like stop next winter stop so i just can't handle it i don't think anybody here can handle it and yeah it'll be fun to to try to get some of that going live viewers you've been patient thank you it's quarter after 10. do you guys all have another 10 15 minutes to answer some questions okay it's afternoon there mike i'm sorry i'm cutting into your saturday uh uppercase i'm just going to ask and if any of you guys can see the questions feel free to jump on anything that looks good to you chris asks mike have you or others compared any of the goal of the geochem in this area to what is seen in the colorado utah volcanics 38 to 25 million years ago are there any similarities have you have you done any work in nevada i guess or or utah or colorado mike uh well yeah we started working on some plutons down in nevada um that are oligocene through myosin extensional as as the basin range was forming uh i haven't really thought about comparing the magma compositions no i can't really speak to that but um yeah i would point out that things go nuts in the southern part of north america at a different time yeah um but it could be reflecting some of the similar processes that we've been talking about right like what's happening at the margin that crazy maya scene in the in southern nevada or whatever yeah it's like okay so why are you down yeah if you if you were at unr right you might be talking about the crazy oligocene as if you were doing this video series right so similar things happen at different times along though okay okay well why are you down there right now do you have a grad student down in nevada why are you talking about basin range stuff oh i just i got really interested in um magmatic systems where you can see the volcanics and the uh and the guts as well and so that is great for that because there are all these normal faults and detachment faults that just like slice things and lay them out horizontally so it's a good place for that nice very cool um [Music] yeah viewers if you want to ask a particular person please include their name like like that person did that helps me um okay mike says so mike and rick two different people why eoc extension is it celestia accreting is it global reorganization is it both or is it none of the above anybody did we already kind of just addressed that do we want to say it again stacia you worked on a core complex it was a long time ago well yeah but i think it all ties into what's happening on those plate margins and um and just the impact of celestia and the slab window forming that kind of drives extension into the upper crust and so i think that's kind of the main thing that we're seeing of that history but a lot of it is yeah just the plate reorganization and changing how that stress is on the plate boundary well i'll add just one thing that i have no idea what the player plate reorganization looks like offshore but it sounds like we all agreed that this is not a subduction story which means we don't have transpression or head-on convergence so the era is done and apparently it's a it's a pretty quick abrupt switch 53 million years ago across the pacific northwest so this slab window is we we don't we don't have a big ocean plate subducting anymore i think that's what we're all saying so that could be good enough i guess and then some of these over thickened people just say it's unsatisfying to me but they go well you got thick crust and eventually it's just going to start to extend like that doesn't sound sexy enough to me but is is this the timing right to just extend it because the crust is too thick and it's just waiting to it's waiting to go well well the simple-minded idea i guess probably i had but i think that the tecla alluded to is you're you're kind of holding the thick crust up right and then when the plate vectors change which all you know which they should just mention then it's much easier for it to collapse and that's why i would see you know starting with those dikes why i would say well we know there's more east west extension say in in the shoe swap or uh priest river kettle whatever your favorite core complex there is in northeastern washington and that we again the effects of strike slip become much more important to the west as stacia said answered that early question about core complexes so what the north cascades was a core complex so i think the thick crust probably had played a role i'm not sure what station might think but uh but more inboard and that gets it the whole question that basil raised how how far inboard did the collision of celezia drive deformation and i would say you know at least as far as the scat the skagit and ice uh complex but probably not too much farther east i got to keep coming to the viewers this is great i'm scrolling back looking for uppercase bluesky720 asks would mantle flow from the subducted spreading ridge would mantle flow from the subducted spreading ridge be driving rifting and extension mantle flow from the subducted spreading ridge is the spreading ridge still active beneath us or was it at that time sort of um okay so all right so when you have a spreading ridge your plates are moving apart right mantle decompresses trigger some melting but when you're at the sea floor that magma that basalt erupts and solidifies into the salt and you get your oceanic crust so after you've subducted two plates they're still getting pulled in different directions right so they're still diverging they're still moving out of the way and there's still an impetus to have mantle flow into the space that they were previously occupied so that mantle will decompress and melt the difference is it's not erupting and solidifying as basalt anymore so instead you have the salt that can then go up into the overlying crust so that basaltic melt so yes the same sort of thing is happening below the continent at this time but you're not making the oceanic crust and you're just making the salt good answer you're good with your hands mike that mike eddie he's good with his hands uh patrick h hey patrick age eight are there any old theories that were abandoned as false that you've picked up again in our finding to be true now thank you for today love patrick well bob any ideas that were hip 50 years ago that everybody thought was ridiculous and now we're using them again well in uh in specifically to the pacific northwest see 50 years ago i was i was i didn't live here then so i wasn't okay i was lowly in pennsylvania but now that was that was right when plate tectonics came out so certainly uh as a naive grad student i thought well gee what's going to be left to figure out people or you know it's just a convergent margin and it drives this or it's extension and if you ever went to a gsa talk uh geological society america talk in the 1970s you know it was all these rocks represent an ark and this is uh and it all seemed like we it was it was simple now but of course we knew that wasn't the case but i'm trying to think of a specific one for the pacific northwest uh you know i can't think of anything right off the bat well let's spin it slightly differently um to anybody here most of you all three of you are extremely well read you know all the work that's been done in your area for the last 30 40 years i'm guessing was somebody ahead of the curve like somebody was doing some like unusual work using a different unusual technique or in an area that didn't make any sense and now two decades later let's say everybody's like oh okay that person was way ahead of of where we are now well certainly merle back i'm sorry mike you want to go ahead all right i just throw merle beck uh doing paleomag on the mount stewart bathless someone might have said why just yeah it's a bat well and still probably would say why because right you know why it's horizontal why assume it hasn't been tilted but that's certainly certainly whether he solved it or not he certainly created a lot of a lot of uh subsequent research and money to go to people to work in the pacific northwest from the national science foundation so that was really good mike uh just gonna say in general every time i read a master's thesis from up there like i don't know master's theses at the end right you're like trying to tie it all together and so you write your three or four different ways it could all work some of them are kind of crazy ideas but you know you're just speculating at the end so you can get away with it and i would say probably about 20 of those that i read from in like old theses turned out like the crazy idea turned out to be something that like people are thinking about now and they just you know they they recognize that like maybe that was how it worked but didn't have the the data to conclusively show it so it kind of just like a speculative paragraph at the end of the thesis can you think of an example um from a thesis no uh so something that i'm realizing now out on the olympic peninsula is so the crescent formation a big pile of basalts is split into lower and upper and one of the original papers in the 70s about it said that they were in fault contact in different ages and then really gained no traction and then now we go out there and we try and date it and it looks like yeah they're very different in age and it ends up resolving a lot of issues because like one we think is telling a rifting extensional story which is what everyone was so keen on for a long time and then the other is more the celestia story but that yeah i mean that's an idea that kind of got shelved for like 40 i guess 50 years now there you go patrick there you go uh three more questions i'll find out i've gotta i've got to ask real fast i've gotta tease mike good probably never read my master's thesis huh i have not bob you put me on the spot oh god he doesn't like ugly i've been trying to talk station mike into going to the ingalls complex for as long as i've known them with with no success so i just had to tease mike okay uh i've got two for station this is dealer's choice stacia one from joe stacia how did your garnet search help verify age of spreading ridge or this other one from robert station do all the core complexes form at the same time and were they linked together somehow either one okay i can start with the garnet one um it doesn't really tell us that much about the spreading ridge but we're hoping that some of the information we can get from those garnets will tell us when those rocks and the crystalline core are starting to decompress and starting to be moving towards the surface and so ultimately that probably is intimately connected to celestia and the spreading ridge interacting with the margins so you know in a way you can kind of tie those together hopefully depending on how things go um and then the core complexes they're actually pretty interesting because they do run anywhere from or all the way from southeastern british columbia down into the southern us and northern mexico and there is kind of belts that people kind of categorize them into into a northern a central and a southern and overall the history gets younger as you go south and you're also exhuming more shallow rocks as you go south so the ones in the north in bc and washington and even down into nevada you are seeing kind of rocks that were coming from the mid crust up to the surface whereas that's not the case in in arizona um and then the yeah extension ages get younger as you go so i think i got one more maybe for stacia from papa gino could the side pressure from squeezing cause metamorphic changes mimicking depth pressure changes could the side pressure from squeezing cause metamorphic changes mimicking depth pressure changes i suppose it could change kind of how your crust is ductily flowing um and you know we kind of think of it as potentially flowing both horizontally at times as well as later vertically and so in that sense you know that i'm not sure exactly what squeezing they're referring to but that could cause the flow to change more towards a vertical flow which would then definitely affect the mineral reactions occurring in the rock thank you a bunch of people asking did we get the answer to the insular intermontane question for the crystalline core that's probably going to be revisited next winter with our series but bob you did kind of lead us towards thinking intermontane for many of the rocks in the crystalline core are you still leaning that way for now well i guess for at least the triassic rocks that um what's called the marble mount dumbbell belt with cascade river shift although kirsten uh sauer with stacia has shown that some of that's actually cretaceous which has made it even more interesting but the margie russ moore and people like that have argued that that's what we think is equivalent one of daryl's former phd students have argued that to be equivalent on the other side of the fraser fog in british columbia that that's tied to the kenya which would put it on inner montane uh jim monger the canadian tectonist uh jim called those he has these what he calls small terrain sort of captured between the inner montane and the insular and i kind of like that because there are things like the bridge river which we would call in the pequot we think is the metamorphosed bridge river uh which are in between what's pretty clearly part of the intermontane and what's clearly insular and they would argue or he proposed that these were sort of flotsam and jetsam caught in between those two super terrains and so those are the rocks that come down into washington i i guess i've thought that maybe rengelia uh the insular is is probably underneath uh mount stewart that those rocks were under thrust beneath the uh ingalls and and uh joachim schiff but that's that's pretty speculative so that would mean both potentially yeah okay well that's a perfect springboard to next winter and i'm hoping to not only keep talking about this stuff with you guys this summer but also be nice to have you back next winter and week and speculate more on this before we sign off with you guys what is the plan this summer which students will you have with you will we be getting together all four of us uh at some point in the summer so stacia who have you got working with you this summer when do you plan on being in the north cascades uh the same graduate student that was there last summer alex wingville will be uh back up and doing some mapping um and she'll probably head up or together we'll head up late july probably time period and she's been doing a lot of work and kind of the central skagit um so in between the northern lake chelan and and kind of south of colonial creek campground for those that know that area um and that's an area where we don't have a lot of data on kind of the metamorphic history and how the pressures and temperatures evolved through time so she's going to work on that and collecting fabric data and that sort of thing and that's what you'll be doing as well kind of working with her or do you have another objective for yourself personally this summer uh well we've been emailing a bit the three of us and and one thing is potentially trying to go up into canada to see um the skagit equivalent across the border because i've never seen those rocks and bob always talks about how interesting they are so that's one part of kind of the summer objective too on the west side of the fraser fault on uh let's see it'd be on the east side of the freezer on the east side no so why is there skagit in canada that's also on the east side of the fraser where well think about the straight creek fault going up i can't do it backwards we're looking at that little bit the tippy top of the triangle there oh oh oh i got it i got it oh cute all right one one foot in the states and do your work in in canada that's great uh mike uh you're gonna be up in alaska with aaron donaghy our old friend uh for a while but you're going to be in the north cascades as well with a different grad student yeah i'll come uh earlier in the summer we haven't nailed down dates but probably the end of june first week of july okay and his name is sora karmikar so he's brand new graduate student and i think we're going to focus on sampling the plutons from that middle uh flareup so we're going to go around the range and sort of figure out what he's um what sort of hiking and camping he's comfortable with and and then use that as a way to design his his project and then yeah the second half of july we're going to go up to alaska to the yakita terrain which is supposed to be the other half of celestia and see if we can make a story about it sliding up cool to alaska then i'll try and swing back through on my way back i'll try and stop in seattle and pop over and meet out the three of you guys you promise you promise you'll swing back i'm gonna yeah i think i think that'll work okay i hope so it's not that far you know no that's right like juno down to seattle that's right no that's right how about you bob uh well i i have a master's student who started this year jeff wagner uh he was a western washington undergrad and he grew up in bellingham as well so so he he knows the country or at least knows what he's getting into and he'll be working on the skagit uh south of where uh stacia was talking about with her in the central skagit this would be more between lake chelan and uh the divide between the twist river and lake chelan for those who know the geography so he would be working in an area to the south a master's student aaron shea of mine who then went on to do her phd at mit over lap mike she she worked right up to the cooper mountain bathless and then there's another uh master student zac michaels who worked up around speaking and ironically ended up getting a phd with basil so they're all all kind of working different things but between those two areas there's there's quite a gap and one of the issues in the skagit is it's really hard to map out individual bodies for well you saw gary paul's pictures you can imagine why it's not like walking around in low-lying desert but that is one area where we have some map units and there's enough high circs and if the countryside's easier to get around in and so that's that's the hope and he'd be doing structural and trying to map out how big units are and then doing this the kinds of things that uh mike and stacia and alex uh did last summer where we really looked for places where we could say see a strongly deformed body intruded by a less deformed body and then maybe cross cut by a dike where we could then tie tie that well one try and get the timing of the of the structures so anyway that and then i uh i probably tag along with mike and sorev in the beginning for a few days at least and uh definitely uh going up to to bc and uh just there the problem and this this is why like your question about the scandit is the chilliwack baffleth which jeff tepper did his phd on that that batholith cuts off almost cuts off the skagit so we don't see it right up at the border but just across the border there is there is skagit this goes up to right around the town of hope british columbia cool it's easy to see that if you know where hope is so yeah totally right on the trans-canada highway sure and so that's my those are my plans nice well speaking of tagging along i don't want to be desperate or anything but i'm hoping i can hang out with any of these little excursions i'll bring my iphone and we'll just record a little bit i don't know if all four of us will get together or not but it'd just be fun to much of the audience now is kind of invested in what's going on so i hope i can tag along at least a little bit this summer with with a combination you guys yeah well i think that's enough and i can't thank thank you guys enough for being part of this this morning it was a wild idea i had a few weeks ago and i'm happy with it i hope i hope you felt okay and uh please enjoy the rest of your weekend and we'll check in with you this summer thank you thanks nick okay we'll see you bye bye-bye okay one at a time i'm getting rid of you guys mike you're going first goodbye mike and still yeah look at that so stacia thank you again and we'll see you soon goodbye bye and bob miller thank you bye bob i uh really it's always a thrill to talk to you you know so much and you're able to be patient with folks like us who are just starting to think about this so special thanks to you thank you nick did a great job thank you we'll see you bye bye the dream team north cascades geology thank you for all your questions i'm sorry we got to just a few of them that's the way things go we got about a thousand watching and instead of answering more of your questions although i see them right here okay that that's what i was going to finish with a bunch of you right now are saying what happens next what's happening this spring and so on so i do want to talk about what's next but before i do that let me grab one folder that says end of show so i would like to thank all of the geologists who joined us this winter it was an experiment and i'm very pleased with it and i hope that you enjoyed getting a chance to meet all of them and get a sense of how they operate and how they think and in many cases taking a little peek behind the curtain and see where we are with some of these thoughts before the ideas are written in stone so would you allow me thank you in order of appearance to jerome lessman nanaimo british columbia basil tickoff madison wisconsin bob miller san jose california rob thomas dillon montana daryl cowan seattle washington aaron donaghy west lafayette indiana ray wells portland oregon mike eddy west lafayette indiana matt mcclency portland oregon jeff tepper tacoma washington spencer fuston from houston texas karen siglock nice france dave rogers pocatello idaho robinson cecil los angeles california caleb scarberry butte montana stacia gordon reno nevada chris mattinson ellensburg washington and tecla harms amherst massachusetts they could easily say no they could easily say i'm too busy they could easily say who are you i've never heard of you but they all said yes i was only denied once when i asked somebody i think it was more nerves than anything else um okay so that's the end of the crazy e scene a to z this has been a live stream series two live streams per week with a live audience and a couple of science papers every show i love the format it helps me get through the winter and it seems to be working so if you like this live stream approach and you like the level of detail i know for some it's too much i know for some you're like i can't this is too much i can't deal with it i can't keep it straight i'm going to stop well i'll talk about you guys in a second but for those that like this level of detail you're up to the challenge of learning these kind of hardcore geology things i love this format and i'm going to continue next winter i've already made that announcement but i guess i'm formally announcing it now so mount stewart pluton north of ellensburg washington is the centerpiece of a concept called baja bc somebody sent me this a while back there's mount stewart with a mexican flag on it and so nine months from now mid-november of 2022 we will start the next live stream series baja bc a to z similar in timing similar in frequency i don't know if it'll be wednesdays and saturdays but and i don't know if i'll be doing melon and i don't know if i'll have live guests i don't know i don't know much but i want the baja bc thing to be similar to this series and i want it not to be a cheerleading session i don't want everybody in the series to be pro baja bc i want i want everybody i want the most staunch anti-baja bc people as well as the people who are deeply in love with baja bc and everybody in between i think i think all three of our guests were in between to be honest with you so if you're a fan only of the live stream series and the content baja bc is coming to you in november if you missed some of these earlier live streams there's i don't know 25 shows that i did in spring talking about the eocene so i was learning some of the eocene stuff with my students in spring of 2021 you can find that at nick sutner.com not secure if you really feel like you're in over your head and you just want some 101 stuff there's 25 of these live streams that you can watch in replay and yeah i did a live stream series that i've referred to pretty regularly more than a year ago and those are also available on my youtube channel for you to watch so i don't know if you've seen all these or just some of them or just today first time you're with us i don't know but there's plenty in that live stream format that's there for you and yes what i'm saying is i'm not doing another live stream series until november which is nine months from now so am i really saying that i'm not doing anything here on this youtube channel for nine months of course not i'm not saying that i'm addicted to you i'm addicted to this i cannot stop i need a break for sure but uh there's too much good stuff here there's just too much positive here for me to just be dead for nine months and not do anything but it's not going to be a schedule and it's not going to be a live stream series so let me share just verbally before i sign off my thoughts i guess what you need to do if you haven't already is make sure you've hit the subscribe button on this youtube channel it's free you don't have to pay anything it's free and notify or turn on your bells and whistles turn on your notification notifications if you want to kind of keep up with what is going on this spring this summer and this fall there's no schedule and i like that that sounds appealing about right now like there might be a week or two weeks where there's nothing and there might be a week in april where there's a video every day there might be two videos in one day i don't know like it's based on weather it's based on who i'm visiting with it's based on what i'm interested in and how excited i am about a certain topic so that's going to have to be our agreement between now and november that there is no schedule and many of those videos will be pre-recorded they won't be live we won't have this live chat some of you have seen some of those before in past summers for instance i'll take a hike with liz bring the iphone along record it barely edit it and post it without fanfare um conversations with people record it interview people like in their backyards or out driving somewhere randy lewis haven't seen him in nine months other native americans hopefully that's an interest of mine ice age floods great lavas out at the coast new tsunami stuff i mean it's time for me to take a break from thinking about the north cascades as much as i've been enjoyed it you know there's lots of other kinds of geology out there i've got them flagged in my little emails you know by topic by color i use the flags in mac mail so i got you know all sorts of stuff that i've just put off because i've been busy with you guys with this north cascades thing so i'm saying there's going to be no schedule there's going to be no theme or any organization whatsoever i'm just going to kind of roll with that whatever i'm thinking about and share it with you as often as i can but there's no obligation for me to do things at a certain time which i like especially at the moment i think i'm also going to be focusing on what's going on in this building i really haven't talked about this collection of geologists that i work with or the grad students that are here at central washington university's geology department or the undergrads here as i've already told some of the professors who are i think we'll be back to normal i hope in spring and we'll go out in field trips and use the vans and everything i think i'm just going to tag along with lisa ely's geomorphology class or hannah sham lew's volcanology field trip or or whoever or visit with chris mattinson do some lab work and film that so i for a number of reasons i think the timing is right to put a big old spotlight on this department which i really haven't done to this point and finally i have lots of interest in doing more of these pop-up geology things now some of you attended or at least watched what i was doing last fall i was experimenting with this idea called pop-up geology where on my youtube channel i announce a location the gps location the day the time like 48 hours in advance and i say whoever's interested i'm going to be out at this coulee floor at this time on this day and bring a camp chair and we'll just kind of set up a little flash mob thing we'll have a little party i'll give a lecture and i will live stream it so if you like if you don't care about the content here you just like being in a in a community of of live viewers then there won't be a schedule but there will be some live events some pop-up geology events and i will post the announcements and couple days later because the weather's good or whatever we'll do it and you'll be able to be included in those even if you're watching from a long way away i like that format i'm just starting to kind of play with options with that and so that'll be another thing that i'm that i'm up to so there'll be plenty last thing i want to yeah yeah last thing i want to say before we quit you've heard it a million times for me i i get way too many emails for me to reply to each one so that will continue thank you for all the feedback thank you for all the emails thank you for all the phone messages thank you for all the direct messages on instagram and everything else you know you just don't have time to reply to everything you've heard that but you haven't heard this and i'm going to try it i might regret it but i'm going to try saying it anyway i continue to hear from a lot of people saying basically this thank you for doing this i really appreciate learning all this stuff it's exciting but there's always a third thing and they say i hope you get what you're trying to get i hope you you meet your goal and and what they're saying is i don't understand why you're doing all this and you must be trying to get some sort of promotion or some sort of big contract or tv program or book deal or some plaque or some award or you must be motivated by that is it's not just one or two people it's a lot of people and again i want to thank you for contacting me and and and i'm glad that you're enjoying this and i've said it a number of times haven't i here i do it because i enjoy this and i enjoy that there's no money involved in this and yet people can they just don't believe me some of you i don't think you just believe me it's it there's got to be some other motivation for this so here's what i want to say there have been awards there have been book deals offered there has been all sorts of recognition but it's a hollow experience that's the only word i have for you it's a hollow experience and you're like to be given an award it's a hollow experience yes you know why the organization or the person who's up on the podium uh saying all these wonderful things about you they don't they don't they're not they're not here they don't know what this is you're recognized for excellence and nobody in the room knows what the excellence is it's all just a rumor oh i heard that guy's doing some really amazing stuff that's nice but nobody has a sense of what this is so what i'm trying to say is and maybe this is the way that will finally kind of satisfy some of you the emmy awards or whatever it is national whatever that's the hollow thing this is the opposite of hollow this is why i keep coming back am i looking for recognition i don't have to look for recognition it's here it's here scrolling right now that's why i keep coming back it's selfish it feels good that you're here and you're positive and you're warm and welcoming to anybody who stumbles into this place i don't go around town talking about all this this thing here because nobody gets it they're just confused so it's like why bother i'm not gonna so does that does that give you a different take on this i what am i going to do with a bunch more money anyway i got i want to go buy another pair of shoes or buy a boat or i i wouldn't know what to do we lead a simple life so that other stuff has happened and it doesn't mean much to me compared to what this is this is the meaningful thing this is the good stuff whatever the opposite of hollow is that's what this is a toast to you here's to you here's to your enthusiasm and your commitment to all of this it's not just the learning it's just being in a place where we don't have to think about all the other stuff going on in the world here's to you here's to our guests today three of them dr bob miller from san jose state university dr stacia gordon from university of nevada reno whoa from university of nevada reno or maybe it's just called university of nevada now here's to eustacia here's to mike eddy dr michael eddy from purdue university in west lafayette indiana and here's to all those guests that i just read off the sheet what a thrill that's also recognition that these folks are willing to come on here they see what's going on that means way more to me than some golden statue so this is it if you're a calendar person this will be happening again in mid-november of 2022. but until then i say thank you i love you and goodbye from ellensburg washington usa it's very clear our love is here to stay not for a year forever and a day outside the rockies may crumble gibraltar may tumble they're only made of clay but our love is here tuesday in time the rockies may crumble baltimore tumble thanks kate they're only made of clay on [Music] our love is here tuesday ah [Music] [Music] um [Music] oh oh [Music] i cleaned out the closet obviously [Music] oh boom boom boom boom boom boom boom boom boom boom it's very clear our love is here to stay forever [Music] our love is here to stay

Channel: Nick Zentner

Views: 30,824

Keywords: Nick Zentner, North Cascades, North Cascades geology, Dream Team, Bob Miller, Stacia Gordon, Mike Eddy, Micheal Eddy

Id: x6ksmB6NuPs

Length: 137min 58sec (8278 seconds)

Published: Sat Feb 19 2022