Exotic E - Paleogeography

well hello everybody how's it going the local time is 1 44 p.m pacific time mid afternoon here in ellensburg washington usa and we will begin our program at the top of the hour at two o'clock local time thank you for joining us are we functional and hello and where are you viewing from this afternoon slash evening lars is in aloha oregon hello haley in tacoma geologically speaking todd hello five by five from phil jackie's in the dalles richmond virginia finland puealop eugene oregon austin texas calgary alberta canada skipping out of work to watch nice job jennifer i think carlisle pennsylvania chelan washington we are functional reaching the netherlands the netherlands she's in sweden these days have been enjoying her programs judith in leavenworth kansas ashley's in portland rainey seattle australia hello dallas texas bijou bijou is napping right in there you might hear my voice but he's inside for now boise idaho libby's in bainbridge uh we have plenty of pacific northwest people mid-afternoon seems like you're all doing fine you're not having trouble i mean audio and visual wise that's great to see blodgett oregon 5x5 thank you price uk hello brian boston mass the chihuahuan groban kelso washington you know what i'm barefoot but my feet are cold i need something on my feet i'll be right back uh today's program is session e e as in egg and the title is paleogeography oh we'll get into it and you're welcome to join us again sunday morning this is our schedule now two live streams a week fridays at two sundays at nine and we'll be talking about strike slip faults we're still setting the table but these are the last two table setting sessions session e uh yeah some thank yous i got three thank yous uh one i've already done but i want to do it again dareth sent a fruitcake and the fruitcake will be our main analogy for the exotic terrain basement here in the pacific northwest and so i have plans i have plans to use this fruitcake at least sunday maybe more i already showed you this but uh i can't wait to get into the fruitcake and i cut a couple tricks up my sleeve for sunday so dareth thank you for the fruitcake from collins street bakery in corsicana texas usa you gotta love it my second thank you is an audio daily double i teach geology 101 over at the university you know that and for about 10 years i've opened my classroom to the public and i've invited anybody in the area to come in and join us and it's usually retired folks who are with us in addition to the paying customers into the students now i can't do that this quarter because of the virus but i don't know how many times i've done it dozens of times and so i've had plenty of older people sit in sometimes just once but sometimes they sit in for the whole class and i call them townies the townies are here the people from town are coming in and sitting and it works particularly beautifully if there's an you know really elderly woman sitting in the third row and she's got some big offensive linemen on one side and some kind of goth person on the other and they get to know each other and they're studying for the exams together and i just love i love everything about that i tell you this because my thank you today verbally is to a townie winter just a few months ago seems like five years ago but just winter just winter quarter one of the townies was a guy named steve steve never missed he was in there the whole quarter and i get to know the townies just like i get to know the regular students and i haven't seen steve since everything kind of shut down in mid-march well i got done with you last time in the backyard here and i just turned off the camera and started walking to the house and there's steve out watching our live stream on his phone and steve is a wi-fi expert steve is on call with all the hotels in the region if there's wireless problems he's the guy to solve the problem so steve said i want to thank you for the class that you provided in winter i want to provide my wi-fi expertise so he's been over twice he's loaned me a new modem i was using a modem that was apparently more than five years old and he got me on a different channel now i don't even know what i'm talking about but steve got me on a different channel because he did his analysis and realized that i was competing with all the neighbors all the neighbors around the same two channels or something like that so he moved me over to some channel that nobody's using and so i suppose i'm jinxing it right now but i now know how to test my speed using an app and i'm like super strong and i think i'm perky enough here with steve's help steve the townies help thank you by the way steve i've already thanked you in person a million times but i'm thanking you publicly as well i think even out by the frogs i got a way stronger system streaming whatever megabytes per second again i don't know what i'm talking about i think i can stream from over there like i've been i've been i got my butt up against the house basically doing these live streams because i don't want to be too far away from the modem but steve i think has solved my problems to the point where i don't have to be right next to the house and i'm kind of in the shade right now i'd like to be out in the sun and um so i don't know i've just jinxed it we'll have major problems today i assume but just in case we don't and cave steve really has solved the problem or dramatically improved the problem i think i want to do the live q a out there i'm going to take you on larry the latter after the cozy fort we're going to use cozy fort today after the cozy ford i think i'm going to trial and see if we have if we're functional way over there and if we are then i know i can be kind of out in the sun away from the house that was a long-winded thank you but thank you steve steve the townie and cooper the dog thank you so much one more thank you oh boy oh boy this arrived in the mail today the marvelous mrs maisel box and this is from laurie laurie i don't know where you live but thank you for your generosity laurie sent uh something to me and something to beejou the cat this is what laurie sent to me can you guess what it is cyprus hello frederick this is a felt chalk blackboard duster eraser thank you lori for the erasure for the chalkboard and also actually addressed to bijoux zentner always cracks me up when i see that uh this is from lori's cat maggie so maggie the cat is sending gifts to bijou the cat these are fun to chew and kick on this is the magic ingredient okay so the fun to kick and chew on inside information from maggie the cat and of course they're filled with drugs catnip so maggie says this is the magic ingredient oh yeah this is the good stuff thank you lori and thank you maggie uh we're about to uh change bijou's world okay a couple more thank yous want to make sure we're doing okay of course i'm all cocky now about the quality of the technology judy says five by five frederick is in new mexico todd says five by five great to see that cat is lying in my chair that we have a cat update uh huh olympia hello hello patrick age seven patrick age seven oh breeze is picking up hang on patrick how's it going man excellent picture and and sound good elsie devin uk pete from the isle of wright oh great to see the brits here thank you or scots or what gracie age ten good to see you back again royal oak is from bavaria karen's from ontario oh we got the distant lands people chiming in it's friday night there they're half in the bag already sean can be oregon i got a beer waiting over there for our little uh q a uh ann from uh norway hello kathy from australia brisbane i have a good one thomas in germany um wonderful randy from north carolina exotics yes i offended some who i i said the east coast was boring of course i heard from many people how dare you i am offended uppercase i just oh i'm clutching my pearls right now surely get my pearls i need to clutch them why do you have pearls sir okay i got two minutes i'm very pleased that everything's working well robert from sweden hello uh we have a a mix of sun and clouds and so the the the amount of light in the sky changes every few minutes um it's one of those afternoons but uh we're dry and so i think we're ready to go give me two minutes would you please to collect my thoughts and we will begin talking about paleogeography session egg uh so what's up uh well a pleasant good afternoon to you from ellensburg washington usa my name is nick zettner i teach at the college here in town and we are doing another session on exotic terrains here in the pacific northwest exotic terrains a to z where are we we're in session e and session f is coming on sunday morning this is our weekly schedule now so session e is the egg session talking about paleogeography and let's say you're an impatient person let's say you're thinking like this is wasted effort i think this guy's stalling i don't think this guy's ever going to talk about terrains he keeps he keeps stalling and doing sessions that aren't talking directly about the terrains well this is a teaching choice i have plenty of weaknesses but i have some strengths and one of my strengths is knowing how to package complicated material in installments and this is e and f that are still setting the table for our exotic terrain discussion so if you are the impatient person waiting with baited breath to talk about the details of mount stewart and the blue mountains in oregon and the sierra nevada foothills and the north cascades national park and the cache creek terrain and the alexander terrain up in alaska it's coming but these six table setting sessions in my opinion are very important and i hope that you'll see why both today and sunday morning okay so two more table settings and then we're ready to go well wait a minute table settings what does that mean what have we done so far what are we trying to do today well let's start with what we're trying to do today it's a three act play again this afternoon act one is revisiting the passive margin i have some lingering thoughts i have a few new thoughts involving the dates that are here and i just want to make sure we're feeling comfortable about the passive margin discussion before we break new ground session two restoring the coastline of north america that makes no sense to you you say well we'll get into it and global position question mark so number two and number three are really the guts of what we want to do today and we're going to involve the chalkboard just a little bit we're going to involve christopher scottish's youtube channel in the cozy fort yes we're going full cozy fort today some jenna johnson animations and so i think that you'll see what we're doing once we go to the timeline he goes to the timeline if you're sick of me doing this tough i'm going to keep coming back to it this is our magic window and we've been avoiding the magic window these first sessions because i think it's important for us to get established what's going on before the magic window and today first main message today we're actually talking about younger than the magic window things that have happened up here in the last 50 million years of time that we need to undo actually that's both this and sunday morning sessions if you're looking for a theme this weekend it's what has happened since the terrains arrived which is where we'll be the rest of the fall i might add what's been going on since the terrain's arrived that has complicated the picture and so far you know that there's been lavas that have buried the exotic terrain bedrock otherwise known as the fruitcake bedrock but there's other things that have happened in the most recent 50 million years of time the tertiary and even the quaternary that we need to address today that's why we're restoring the coastline to what it used to be and then we're going to look back over here to where north america was before the trains arrived globally so it's a bit awkward possibly that we're kind of either up here or down here i'll do my best to keep have give you a heads up on whether we're younger or older than the magic window but this weekend the last of the two table setting sessions were we're still staying away but we will be diving in to the fruitcake the exotic terrain details starting next week okay so you can see this give you a little bit more view but i don't think you need a ton more here's washington oregon etc and here is a kind of a crazy swing like a railroad track here right these two white lines we're going to realize next week that there's good exotic terrain bedrock within this railroad track and what i want to address before talking about the details next week of what's within those two white lines is the fact that this is exotic terrain material this is the passive margin or the coastline of north america from last session and what's with the crazy swing was this coastline really a crazy swing like this during the magic window time when the terrains came in the answer is no so let's pause for a dramatic effect that coastline that passive margin needs to be restored needs to be returned to its original look and we're doing that in act two in fact this is an old map from i shared this with you before but this is a text that i had from grad school days 35 years ago the evolution of north america by philip king ucla geology professor beautiful hand-drawn diagrams i'll continue to use his but i took one of philip's sketches and i just colored it with my green colored pencil and let me pause and just give you a chance to look this is the crazy swing that i have on the chalkboard and so there's some correlations between these exotic terrains north cascades hells canyon blue mountains klamath mountains and then continuing south you've already heard one of the main messages this is not what the coastline looked like hundreds of millions of years ago and it took me a while to remember how i did this in the past so i literally watched this lecture which i gave a few years ago downtown ellensburg and i want needed to remind myself of what i wanted to do on the chalkboard so i'm duplicating that essentially today so we're going to restore the coastline in just a second okay i hope that you see the game plan for today so the the three act play passive margin restore the coastline global positioning before we get to this let's go back to last session session d as in dog and revisit a couple concepts and add a couple of new things i think it's important to do that plus i don't know about you i think we all have different ways of kind of making things work for our brains but for me it doesn't really stick until i draw it out and it really sticks if i even take my colored pencils out and i kind of you know make a little map for myself so here's something that we've used before but i've added a couple of things so the strontium 706 line we have discussed that's the edge of the basement rock the old older than 1.8 billion year old metamorphic material but draped on top of that is the passive margin that we discussed last time and starting a week from this afternoon we will be in the exotic terrain fruitcake bedrock and we won't leave we will not leave we'll be in there the rest of the fall but we're still kind of dancing and setting the stage just a little bit now notice i put a couple cities here boise is a nice location to get us at the edge of the passive margin to get at the at this old coastline and for me this is a brand new thought kettle falls washington i've only been through kettle falls a couple times but kettle falls washington is going to be a landmark for us to be at the edge of the past of margin and you're like okay i can't even remember what the hell a passive margin is sorry patrick so let's revisit that because i think it's important this was our established passive margin from last time do you recall the belt super group is not really the passive margin there's some fuzziness that still is fuzzy to me but i really want to focus on these dates these sedimentary layers that are draped casually and eventually get thicker and thicker off the edge of the old basement rock deposited between 750 and this is a new date for us 390 million years ago so we looked at the passive margin do you remember sharon from colville sending those rocks sharon sent the adi quartzite which is cambrian that's part of the passive margin she sent the stensgaard dolomite which is a marble which used to be a limestone from the passive margin sharon sends some metalline formation limestone and shale that actually had trilobites within them if you recall sharon sent the huckleberry greenstone which is actually originally basalt that shows when what when australia started to rift away from north america and begin our passive margin sequence so 750 was one of the big dates from last time which was the beginning of the rift the beginning of australia rifting away from the west coast of north america and creating open ocean at spokane washington and it's been a open ocean essentially during this entire span okay you're like okay i know all that you did this last time i'm leading towards something this was from last time it's not just washington or idaho even down between the grand canyon and arizona and the inyo range near death valley in owens valley california there's this dramatically thickening package tens of thousands of feet thick by the way of passive margin sediments for 20 years i taught a field course out of bishop california with central students i never really had this in my mind we were working with the polita formation in the heartless formation i never really put that into a regional picture like i have with you guys so you remember this is for you for sure these live streams but just as much maybe more just for me there's just such relief to put some of these fragments of ideas together for myself for a bunch of reasons so the coastline is here i think we've got it now but it's problematic and this is going back to a lot to session two b as in boy we've got so much basaltic cover these are the flood basalts of just 15 15 16 million years old very very young but you can see that our important boundary between passive margin and exotic terrain is the exposures are few and far between and you're like well that doesn't that you can get all sorts of exotic well no no this is just the basalts there's cascade lavas and glacial till and all sorts of other things but i'm hoping to kind of combine last lesson with some of these other things we did earlier to help us make this all come together last passive margin message and this is my favorite again drawing maps for myself really just kind of looking at three or four favorite maps and then kind of making my own single map with my own little color scheme works i like brown for passive margin especially since rob thomas had so much brown in his brand new roadside geology of montana book for the belt so belt and the passive margin stuff let's make it nice and brown i never made this connection till last night and i'm excited by it maybe i'll be the only one excited by it but now we have the the broad picture of the passive margin boundary with the exotic terrains look at the scale of this first of all this is just washington idaho montana and british columbia the red line is the edge of the passive margin which essentially is our strontium-706 not quite but good enough the edge of old north america so what am i excited by in washington i certainly knew that the columbia river is coming out of canada and here's the columbia river then coming towards chelan working its way around the columbia river basalts that's not new but what is new to me and marley's roadside geology book of washington helped me see it i think it was more daryl than marley writing the section this stretch of the columbia river coming right through kettle falls is the passive margin is the edge is an important boundary exotic terrains to the west of the columbia passive margin to the east i never had that in my head until now is it true down here no it's just this stretch from just south of nelson bc to whatever this is i think it's lincoln washington a little dinky town where the columbia river starts to kick west but to me that's helpful and i'm dwelling on this because why not i'll tell you next week we're going to bring in our first terrains and our terrains are going to come in and add to this boundary so we're going to be right back to this area at least in washington maybe up in bc i'm not sure by the way did you know i think some of you know this maybe not everybody that the columbia actually flows north in bc for quite a few miles north up through radium hot springs and golden one of my favorite towns in bc and then loops around and then comes down and and heads to the uh the states that's so cool but the fact that this stretch of the river is actually following or is it a coincidence or not that that stretch of the columbia is actually straddling the boundary between this stuff which of course is coming in in the last 200 million years versus the old passive margin and maybe you can see why i didn't really have that in my head until recently a complicated map like this doesn't allow us easily to see the blues which is the passive margin sitting on top of old north america and then some of these colors not all but just some of these colors are going to be our exotic terrain material okay that's enough that's a slow build today is a slow build okay the rest of our session is scheduled we're to act two now and you know the the title of these talks are purposely bland they're bland because i want them to be short enough to fit on my cute little chalkboard did you notice i have my little chalkboard i use as a little template for these live streams so i want just to be one or two words so i can fit on the chalkboard and two i never really know exactly what i'm gonna do so they're bland because i i'm not really sure what i'm gonna end up teaching so paleogeography could mean about anything well here's actually paleogeography restoring the geography of the coastline to before the terrains arrived so trying to get that coastline restored to pre 200 million years ago and then where was north america exactly on the planet during passive margin time as we start bringing terrains in and by the way what is significant i'll give you a little teaser for next week next friday why 390 why doesn't the passive margin go all the way to 200 million years ago well this is new for me i was reading a little bit i was reading ahead just a little bit and apparently there's some volcanic rocks that indicate from this age that indicate that our passive margin is no longer passive starting 390 million years ago i don't know why i'll see if i can figure out in the next week but our passive story is here and we're going to try to restore the coastline so for the next little bit first for act two of i got letters i got numbers i got eggs i got a lot of stuff to keep track of we're leaving the passive margin for a bit we're bringing all the terrains in and we're adding all the terrain material all the fruit fruit cake bedrock on this chalkboard and so now we're going to what has happened in the last 50 million years that we need to undo if we're going to really say something meaningful about where and when these terrains are coming in can we explain this crazy swing we can there's two main reasons that this band of exotic terrain material does not head straight ah heck let's just do it starting next week we're going to see some connections we're going to see some exotic terrain material that seems to be the same kind of stuff all the way through this white zone and all i'm saying today is that this white zone was not squirrely like this we want to visualize more of a straight exotic terrain belt why here are the two reasons do you know the answer why is it squirrely like this and why did the coastline 200 million years ago or even 50 million years ago look more like this i'll give it to you verbally basin and range extension and clockwise rotation of the pacific northwest those are the two reasons they kind of work together it's actually one reason but we'll we'll break it into two have you heard of the basin and range it's here in nevada and the western half of utah and just a tiny amount of northern california and a tiny amount of oregon what's going on in the basin and range crustal extension is the answer the crust is actively stretching how do we know another diagram from king's wonderful book i actually hinted at this last time we see that there's a lot of belt super group sitting on top of the craton and of course these black blotches are where the craton has actually come to the surface in the rockies but then there's all these black blotches that are just so scattered like why why don't we have a more coherent look of the outcrop why is it so scattered like that and i'll add to it when we look at a map from king's book and again i use my colored pencils what is brown i'll wait what's brown what's brown going to be the rest of the fall the brown colored pencil what's it going to indicate delay in the comments oh god no brown is not exotic terrain am i losing us passive margin lorraine correct belt correct yes oh i thought that was going to be easier let's go back you're like who cares about the colors well i think i care about the colors because one of one of the many challenges with our exotic terrains is that every map has a different color scheme and you're like oh canelia okay green oh no canelli is pink canelli is like why can't these maps all look the same so one thing i'm going to try to do i don't know if i'm going to be successful is to build our little color scheme and stick with those colors i think i'm going to just keep making maps for us and for myself with the right color fro i let it be let it be said let it be announced i'll shout from the mountain tops we're going to use brown we're going to use brown for the passive margin sediments we're going to use brown including the belt all of those sedimentary rocks that are sitting on and on the edge of north america's craton is going to be brown from this point forward now i'm going to have many different colors for exotic terrains because we'll have lots of different stuff so don't memorize the green yet please but brown was meant to be sediments deposited on top and on the margin in a passive margin remember the wheelbarrows dumping a bunch of stuff offshore so when we look back at a map of nevada utah there's three colors i've chosen what's the brown passive margin the edge of old north america is here fine up until 390 million years ago fine that's the edge coming right down through a portion of nevada what's the green green so far is just exotic terrain again we'll cut we'll come up with different stories but what's the main purpose of this map is to show you how chopped up nevada and western utah are yellow is dirt yellow is very young sediment that's covering up the brown or the green and you're like what i don't get it why why does the basin in range that's what we're looking at why does the basin and range have all these yellow patches and that's where king can help us out and stan chernikov can help us out what's the question again why isn't this just all brown here and all green here like we had on other maps why do we have all this yellow [Applause] the yellow is very young sediment and so you can see that each brown some people have described the basin range as a bunch of brown caterpillars marching north each of the brown is a mountain range each of the yellow is a valley called the basin and range when you cross nevada you go have you done have you driven across nevada it's very lonely whether you're on i-80 or you're on some of those other u.s highways where you're going north south through one basin for like a day and a half there's nobody out there man it's a unique part of north america but the point is the valleys are yellow the basins are yellow the ranges are brown but it's brown passive margin bedrock all through much of nevada and western utah it's just been chopped up more recently you're like are we on a tangent what are you doing i thought we were doing this well we are because if you go like this or like this these are normal faults and normal faults indicate crustal extension the rain has begun it can all handle a few raindrops he says to himself let's not lose our train of thought this is from stan chernikoff's book this is the textbook i used for many many years in my geology 101 class written by stan chernikoff who was a long time geology instructor at the university of washington i've shared this this spring and my favorite part of stan's book are things that were not done by stan but by his artist's collaborator and you know what i don't think i shared that guy's name before and i heard from a few of you saying you know ramesh but i'd like to get in contact with this guy his work is amazing and i don't know if he has a collection of geology illustrations that continues but this is one of ramish i'm sorry if i'm mispronouncing your name this one of ramish's uh you know there's hundreds of these kinds of like watercolor type sketches uh in the book but it shows beautifully the basin and range province and the main thing i'm going to is that we are stretching the crust and you see why i'm taking the time to discuss this today this is crustal stretching that's happened in the last 30 million years 30. the basin and range extension began 30 million years ago and continues to today and it's not just a little bit of stretching this amount of basin and range extension has doubled the width has doubled the distance between the sierra nevadas and california and the wasatch mountains let's say in salt lake city this is a part of north america in the last 30 million years that has doubled in width the distance the driving distance between reno and salt lake has doubled because of this crustal extension look at how thin the crust is there and yes if this continues at the rate it has been this will eventually become an ocean basin but let's not get let's get not let's not get sidetracked this is the concept we want for the last 30 million years and what's the payoff the payoff is that if we undo that extension if we close the accordion and go back even 30 just 30 million years this exact terrain material is further east so i'll say it a different way in case you don't see it passive margin coastline used to look like this and in the last 30 million years this portion of that coastline has been sent west because of the basin and range extension and if you want to talk about why the basin and range extension happened that's really off the track of what we're trying to do here we might talk about a little bit over there if we're still functional but that's an important message okay if this was a real classroom and you were all sitting here with me i'd pause and say who's got questions and we go back and forth can't do that here but we do have normal faults if we go back to philip king's sketch each of these basins has one major normal fault one normal fault per basin and what you're looking at here then if you've got good eyes you can see some of these black lines are heavy they're heavier and each of those fat black lines is a normal fault so i've got wooden blocks the first of our fault basics discussion we'll do more fault basics sunday and this will help us get ready for our exotic terrain feast beginning a week from today i some of you have seen me do this before these are two blocks of crust this is the hanging wall this is the foot wall these are mining terms usually we have miners drilling tunnels on a fault zone because there's a lot of goodies to extract out of the earth so they hang their lantern in the hanging wall they are standing on the foot wall hanging wall is the block of crust above the fault foot wall is the block of cross below the fault well we're talking about normal faults today we're talking about every valley has one normal fault on one side of the basin and not a major normal fault on the other side of the basin well what do the normal faults tell us well normal faults exist because of crustal extension and if we extend the crust or pull the crust apart like i'm doing with my hands gravity is going to pull this hanging wall down and to be honest i'll be more accurate now there's kind of a rotation these normal faults are listrick they have a bit of an angle to them at their base so what we're looking at my nose is now patrick evelyn gracie my nose is now sitting in the bottom of the basin okay nose in the basin and these blocks are pulling apart we're rotating the blocks pretty much like big old dominoes that are tipping over three at a time you'll see some animations from agenda johnson in just a second but that's one of our main messages for today to restore our old coastline we need to get rid we need to get rid of the basin and range extension it's too young i'll say it finally one more way and then we'll move on none of these basins and ranges existed during the time that we were receiving terrains none of the basins and ranges existed the crust was thick in nevada during this time it's only here in the last 30 million years that the crust has begun thinning and continues to thin okay i've hit that pretty hard now related to that idea is clockwise rotation so in addition to arrows like this there's also arrows like this which is a concept that audiences love they love the clockwise rotation now let me slow down even though i got a few raindrops on this and this is one of my favorite diagrams from marley miller's roadside of oregon book roadside geology of oregon i didn't bring it out but you've seen it i love this page in the roadside geology of oregon book by marley miller second edition came out 2014 maybe i'll just pause and give you a second here so we're leading to the other major point of restoring the coastline here's the mesozoic that's in our magic window time here's only 20 million years ago and here's today look at what she's doing she's showing us oregon this is oregon that we know today this is oregon with the blue mountains in the upper right and the calamus in the lower left blue mountains klamath mountains they have similar exotic terrain material within them and today's arrangement of oregon it's like okay i guess but what she's doing is removing the basin and range and she's removing the clockwise rotation and look at the arrangement of the blues and the calamus if we go back to the mesozoic time and this is ultimately what i'm trying to do can i do this here's the blue mountains i'll do it this way and here's the klamas now where are the blues and the klamaths going to be in our diagram today here are the blues here are the clamis we're restoring the coastline we're undoing the basin and range extension and we are also removing substantial clockwise rotation which is really part of the basin and range extension plus some influence by the two ocean plates that have been doing their thing offshore let's assume you've never heard of the clockwise rotation i guess i gotta go get the the magic board hang on just a sec i guess i can still talk so this is a board that has been deeply satisfying to use it was created by robert butler at the university of portland jenna johnson made an animation that we'll see in a second and we can see the basin and range and these blocks the northern california block the western oregon block and the western washington block veterans of the live streams are sick of this they've seen this i don't know how many times but it's important and so the concept of clockwise rotation which has also been happening in the last 50 million years it's not happening during terrain time it's happening after the terrains are here is this it was proven geologically a generation and two generations ago this business of clockwise rotation of the western portions of these states and confirmed in the last 10 years by gps measurements instruments anchored into the bedrock that show us with precise measurements that this really is a thing and the basin and range is opening behind that what are we doing today we're getting rid of it we're restoring we're getting rid of the clockwise rotation and we're closing up the accordion to get our coastline back to the way that it was when the terrains were coming in okay it's 240 i have one more act with me this will go quickly i think and then we'll go in the cozy fort hope we're doing okay one bit of housekeeping uh the base now the craton session session c uh many of you really liked uh these maps remember these showing the earliest days of the craton and then the craton that had younger material added on uh i saw a lot of comments a lot of discussion about these two so this is from i think i correctly identified keith during that session but he's got a number of geology books that are framed around some kind of human history and he's a wonderful author if you don't know keith meldahl's books again this is kind of the textbook for the class by marley miller and daryl cowan and we'll start going deeply into this book starting next week but to get to the final act of our little performance before we go on the cozy fort a quick shout out to robert dot uh who passed away a few years ago and bob was my historical geology professor at the university of wisconsin back in the early 1980s a very big name and this book was used probably worldwide but definitely in north america in most historical geology class is dot and batten very very famous book and bob was a very gentle person and took special time to work with some of us new geology students in the mid-80s we went out on saturdays we'd get the van and go pick him up at his house and away we'd go he'd have his little cheese sandwiches and i still remember one trip it's weird what you remember i remember bob dot stopping at the last stop we were looking at the saint peter sandstone and we stopped in at this farm it was october beautiful bluebird day golden colors of leaves and everything and he stopped and bought a fresh apple for each of us and we all sat there in this corn field eating these beautiful crisp juicy red apples makes me emotional just thinking about it so this guy was very very well known and yet he had a human touch and uh so i just wanted to give you a sense of why his book was so famous each chapter was a different period within the paleozoic and the mesozoic here are the trilobites we saw in sharon's uh metamorph in his in sharon's shale that turned to slate and then what we're leading to is this is back in the mid 80s now even the early 70s when he first put this book out he had paleogeography maps of north america at each period at each time and occasionally he he'd even say something like this which is possible equator so this is before youtube this is before christopher scotis but i remember seeing these this is the book that i had i remember seeing these and kind of going wow north america is at the equator weird and here's his passive margin discussion that we discussed last time so thank you bob dot i'm not the only one saying thank you bob so shortly we're going to be bringing in terrains and adding them on to the edge of north america and this last little paleo geography session is really asking the question was it a north-south coastline like all the maps show this but were we really at 47 degrees north latitude and was this coastline perfectly north-south 500 million years ago and the answer is no we already got a taste of that last time but we're going to do a little bit more of it right now so i showed you this one global now this is not an idea now this is confirmed i mean dot was doing it 50 years ago 60 years ago and and there's been a lot of work done since to come up with very accurate paleogeographic maps of the globe we know exactly where each continent was at different intervals in time there's no guesses to this there's fossil content there's paleomag content there's a bunch of evidence i can't even describe right now i don't know all of it but this is no longer an idea this is a for sure so these maps you can hang your hat on this is accurate as far as where these continents are and where the equator was and here's our coastline where we start pulling australia away from north america now on our map we have it like this of course but this is almost too much for us to visualize i almost hesitate doing this section with you because there's going to be so much mental gymnastic stuff about the terrains coming in and what kind of rock it is and what's the age and what's the age of accretion and it's almost like we have to do this to give ourselves a break but i think it's worth addressing that the latitude the longitude and even the orientation of the continent was different so a taste of that is here blakely ronald blakely i think ron blakely has beautiful maps like this former dot student i might add deeptime or something dot com i should have looked that up so here's north america 550 million years ago during our passive margin time when the trilobites are crawling up onto sharon's backyard here's the equator here's all of north america in the southern hemisphere but this is the only way we can make sense of it right montana alberta and of course there is no washington in oregon and denise is saying no great lakes that's right the great lakes are less than 20 000 years old and i forget yeah so these maps by blakely not only show us the position of the continents here's that 485 million years ago north america again but notice that we have more of north america submerged under a shallow sea so some of you are parts of the continent where your main geology is from this time when most of north america was submerged sea level was higher topography was modest and of course there's times later in the paleozoic where most of north america is underwater there's just a little bit of shallow water how do we know that well you can follow limestone layer scent that was bob dot's specialty so i'm just trying to give us the sense although i don't think i'll keep following up on this because again it's too much for our too much for my brain probably yours too too that this is the actual arrangement of the planet latitude-wise but north america is going to make more sense to us if we turn it like this now this is going to be more effective with the cozy fort coming in less than five minutes but i can't hold it a little bit younger than 400 million years ago again we have north america oh man we got terrains that far back in time i don't know anything about the arctic terrains and i don't know how if we'll emphasize them much because you know that our focal point will be the north cascades of northern washington and then we'll branch out from there to help us understand washington's terrains but this is a story for sure if we go back far enough in time so those of you who have already kind of reached me and said i disagree you're going to talk about exotic terrains uh sir i respectfully disagree with the way you've set it up there are exotic terrains that are older than 200 and there's even some exotic terrain material that's been translated on strike slip faults sir younger i got it i got it but our focus is north cascades and this time window makes most sense none of the exotic terrains of the north cascades in washington were here 200 million years ago and none of them are coming in anymore by 50. so let's use the youngest of the terrains that's why we have our magic window a little taste and why not another little taste 400 million years ago that thing's gonna end up in washington just a little taste i don't know much of the story yet but if you've heard of the yellow aster complex up by bellingham and mount baker there you go all right i got to give you a little taste don't i maybe you'll stop joining us if i if i keep uh setting the table like have they texted are they coming yet are the terrains here yet okay cozy fort many of you were not with us in the spring you didn't get the whole story on why it's called the cozy fort or what am i doing with this stuff i don't think i'll give you the whole story but the basic messages i like sharing things on my laptop it took probably a month worth of trial and error before a viewer named steve from cedro woolley came up with this contraption that is anchored onto larry the ladder and experiment with different kinds of cloth and i usually sweat when we're inside of the cozy actually i've never been in kind outside the cozy fort with a microphone before that'll be interesting never thought of that till right now uh i like the cozy fort so of course there's many that say this is ridiculous you need obs or whatever it's called and something else and some split screen i know i know i like to do things my way i also think there's a certain charm to be in here with you bob's buffering are you all buffering all right hitting the turning the volume off of our program and i would like to start with some short animations to show basin and range extension by jenda johnson good most of you are fine i think this one's silent it's just putting the concept of normal faults and i mentioned the concept of domino's tipping over maybe you can see what i mean now the animations are worth a million words but we're in nevada and western utah and we are stretching the crust making the basin and range pattern short and sweet i got a bunch of short and sweet ones here all queued up i think this is gender the basement narrating province is a broad region of parallel north-south oriented valleys known as basins and surrounding mountain ranges can i get that loud as this area of the north american plate was stretched fractured and broken into hundreds of mountain blocks i can't get but i i got my microphone here so maybe that'll help the wind's picking up some stuff's blowing out there i don't care the basic range province is a broad region of parallel north-south oriented valleys known as basins and surrounding mountain ranges the province was created as this area of the north american plate was stretched fractured and broken into hundreds of mountain blocks let's watch a hypothetical block undergo early rifting both sides of the area under tension pull apart evenly hot material from the asthenosphere migrates upward causing the land surface to rise and break along platinum basins and ranges heat from the asthenosphere warms the upper mantle and lower crust facilitating ductal deformation thus allowing this lower part of the plate to stretch and pull thinner like coffee the buoyancy of a warm material in concert with the fitting of the plate contribute to continued upward movement creating fault-bound valleys and up faulted mountain ranges this is considered by some to represent early onset of rifting okay i'm getting some comments from you you can't hear that was that was low audio wise but i'll i'll improve thank you for your feedback i i think i'll just turn the sound off of these for now i'll practice getting audio better let's not get preoccupied with that this is uh jenda's masterpiece and i only want to show a couple parts of it the first part i turn the volume off i'll just narrate the first part is she in animation form restores the coat she gets rid of the basin and range in the clockwise rotation it's beautifully done and then i'll skip ahead to the last part i can't remember why but we're going to skip ahead to the last part so the purpose of this video is nothing to do with today it's talking about young vulcanism but what she's going to do here after setting it up is restore keep your eye on nevada and western utah again she's focused on volcanoes we don't care but she's gonna bring a timeline in in just a second and she's gonna there's the basin in range here we go present day let's go back oh look at that look at that she's doing animation-wise what i was trying to do on the chalkboard and she's always she's only going back 55 million years ago god that was exciting i want to do that again just for me i want to do it again i got to give you a little heads up we'll eventually talk about baja bc you can't really do baja bc with california sticking out in the ocean that far but you can do baja bc if you get california back to where it was further east hope that makes sense to some of you now why did i think we should oh yeah so she's got a creative way to show the clockwise rotation in the last 15 million years she's got these sprockets ignore all the colors and all the lavas but i just want you to see her here's our clockwise rotation which i hope you can see is needs to be undone if we need to go back to exotic terrain time she is a master agenda johnson what's the uh and you're and you you're late to the party you've never heard of her before you want to go to youtube channel iris earthquake science do yourself a favor and subscribe to that iris earthquake science youtube channel okay i do need audio for this and maybe the audio is a little stronger than the gender stuff if not i don't know how to help you but we're switching we're going to look at three christopher scotis uh animations paleogeographic animations and again this is his youtube channel can you see it right here that's his name that's how to spell his last name you'll not regret subscribing to scotis's web his youtube channel now this is on one of the videos on his youtube channel and it's an interview with him in 1993 i had just moved to ellensburg at that time this is before the internet he's doing this back then this isn't the guy who just started making paleo geographic global animations last year he's spent most of his career doing this uh he taught for a long time university of texas arlington yes and retired a few years ago i think he's now based out of northwestern i just sent him an email but i haven't heard back here's a four minute video christopher scottish describing his process actually some of you said why don't i put the can i pull this out of my pants can i pull this out of my pants interesting okay so let me crank the volume max there and then i'll try to hold this next to i don't even know where the sound's coming out in many respects geologists are our time travelers uh because what we try to do is imagine what the world looked like back then and uh by reconstructing environments and understanding the rock record so all i've really done is used computer technology to to build a virtual time machine to allow us to travel back in time and see what imagine a little bit better what it was like ah old school like a television program for god's sake dr christopher scottis discusses paleo map reconstructions with regional examples dr scottis is associate professor of geology at the university of texas at arlington he is chairman of both the paleo map and the pangaea project all right get to it previous positions include senior research geologist at shell development company and research associate at the institute for geophysics university of texas at austin this is so good has published numerous papers on paleogeography and plate tectonic reconstructions and has developed plate tectonic modeling software welcome to the research lab the paleo map project at the department of geology university of texas at arlington in this video journal we will be discussing some of the results of the paleo map project describing the interactive computer graphic techniques we use and reviewing some of the digital data sets we have assembled as part of our research an example of the results of this project is a wall chart published by aapg illustrating the changing distribution of continents and ocean basins during the past 600 million years on each map land areas are illustrated in green mountain areas are shown in red and the changing width of shell seas are shown in light blue though maps are a good way to show changing paleogeography the earth is a dynamic planet the best way to show these dynamics is through computer animation in the latter part of this video journal we review a new computer animation that illustrates the changing distribution of the earth's continents in ocean basins let's start off by looking at a brief part of this animation a couple more minutes brief segment of the paleo map reconstruction we start with the earth's plates in their present locations as we view the video backwards in time we observe the changing positions of the continents and plates over millions of years here we see the closing of the atlantic ocean and the union of the american and african plates i love the music [Music] now play technotonix has been around for 30 years and it's taken about 20 years for the sorts of data to accumulate for us to be able to make maps of the past everyone is familiar with the present-day plate boundaries let me just bring some of those up what's shown on the globe is present-day coastlines in green the edge of the continent in light blue and certain tectonic boundaries in this case modern plate boundaries are shown in yellow major strikes with faults in red and throughout much of asia purple lines which represent zones of closure between continents where ancient oceans were consumed uh resulting in sutures all right you can watch the rest of that an interesting analogy can be made what we do is in many respects like there's one more minute but i want to move on so that was what almost 30 years ago right so this one came out from christopher's lab six months ago no may of 2019 and he's come a long way i'll put my i don't think i need sound for this i think he's got some classical music but not that important it's nice but not that important so what i want to show you this is less than two minutes long he's going to start us 540 million years ago the cambrian when the trilobites are in sharon's backyard in colville and i'll try to is this the one he has chicago on it i'll try to help you find north america and we're just going to track the western margin of north america through the magic window time let's just try it all right north america western edge of north america dates are up here in the upper left this can go fast now he's going to go from the beginning of the paleozoic still passive margin for us 390 was the end of our passive margin right now now we're in the northern hemisphere early straddling the equator pangaea begins pangaea begins now ice age come and gone [Music] still pangaea pangaea about to end start splitting north america away from europe and africa and begin the days of terrain accretion we're in the magic window for exotic terrains right now [Music] we're still in the magic window for our class but we're approaching 50 million years ago we're done with exotic terrains and in the last 30 million years we're going to do basin and range extension clockwise rotation and the san andreas fault bad news bears exactly all right one more this is the newest uh of scotis's animations whoa whoa whoa whoa whoa whoa what's going on uh this is six minutes long i don't think we'll look at the whole thing but it's dual hemisphere he's got both sides of the planet viewable at all times and he's got a time scale along the bottom and i think we'll does this start also 500 yeah so this is the same time frame but um we'll just play it i don't know we'll just play it for a little while this came out in uh winter months ago not nine months ago november last thanksgiving here we go oh uh hang on hang on hang on [Music] i gotta figure out who we are where we are [Music] that's us that's us that's us that's us got it north america right here margin on our north coast so the west coast like idaho shoreline sharon's backyard over here obviously a lot to soak in here so i'll let you play with these on your own soothing music makes me think of ordinary people timothy hutton mary tyler moore donald sutherland filmed when i was in high school okay [Music] did i want to sure let's let's let's go to our magic window so i've skipped ahead to our magic window for this fall which is 250 right 200 to 50 million years ago we'll obviously come back to this but here's the western edge western edge of north america magic window begins now terrains [Music] haven't really split yet from africa now we begin active margin passive margin [Music] we're in the cretaceous dinosaurs [Music] okay we'll use that a lot thank you to christopher scottis for his excellent work over the years that's the end of the cozy four no it isn't one more what's been going on since 50 million years ago mostly this coast frame is which pushes on the washington coast range block british columbia doesn't go anywhere seattle gets crunched that's bob butler narrating let's see it again it's an animation of the clockwise rotation also the basin and range extension pushes on the southern part of the oregon coast block which pushes on the washington coast range block british comey doesn't go anywhere seattle gets crunched okay so it's a good time i think to not only answer a few questions about today but maybe get people up to speed if you're feeling like this is starting to slip away from you and you don't have some of the basics yet and remember i am also feeling like i want to experiment we got more than 850 people i'm going to see if i have a signal way over there and i got a beer waiting for me as well nick i gotta say i just i do not approve of you drinking alcoholic beverages on a live stream nick there are children watching i am deeply offended by your behavior [Music] cell phone live streaming on a ladder moving the ladder are we functional i'm going to be pretty pumped if i can be this far away from the house and we're functional next time if we are next time i see towny steve i'm gonna kiss him on the cheek what give me a second 10 minutes after the hour all right not that bad i guess let's pop out i'm glad you're still with us um popping out the live chat like a boss right between the eyes we're gonna do some between the eyes sunday if you're not sure where that came from we're still good oh no am i not good wait what am i oh i got hang on hang on hang on i gotta get on this power channel with my wireless because we're still good oh we're buffering no it is ah all right i got greedy i got greedy all right we'll try it again in a second but i don't i don't want to waste your time um i'm right here by the house and my laptop's back over there but let me just answer a few questions here and then we'll try it again by going back over there it's just an experiment so would you mind typing in an uppercase your question and i'll just try to grab it here in real time i'm getting mixed results now or mixed reports on the on the buffering what questions do you have about today or anything we've done so far steve so are the terrains in our magic window a result of the proto-pacific ocean spreading steve thanks for the question generally yes but i'll tell you what steve i'm pretty sure that for the next few weeks i'm going to only be visiting terrains and collecting data and i'm going to try not to do a bunch of tectonic modeling because that's where the confusion is there's lots of different ideas for how these terrains got to us and so we'll eventually talk about changing situations in the pacific but i'm going to ask you to be patient on that why is pendleton in the middle of the center of the rotation fluffy basically you're far enough inland as i understand it the clockwise rotation is a direct result of the two ocean plates doing their thing the juan de fuca plate in the pacific plate and by the time you get away from the ocean to pendleton you've lost that influence of major clockwise rotation tooligan doesn't see baja bc on the animations you're right baja bc is still a minority opinion among many we'll get into it when did australia split from north america 750 million years ago that was the lesson from last time why not use magnetic surveys of orientations to find the old edge of north america donna magnetic surveys there's been a lot of different ways to find the old edge of north america including seismic profiles tomology strontium chemistry we had that discussion a couple sessions ago that's the best i've got for you functional though blurry probably do the weather on my end that beer you're drinking do i dare go back over there and see if this is still working i think i'm going to try it we'll do a few more i'll try to walk slowly because i know i know if i move quickly there's a problem so you're part of an experiment i hope you're not annoyed by that so you're back to larry you're wireless you're not i mean you're on a wireless you're not on data and i'm just gonna look at your comments here can you give me a five by five or not paper's all over the place now hang on hang on so perfect five by five cured cured curd five by five okay great well let's just assume we're good uh am i the same thing here yeah i'm live here too okay good well let's let's try it more questions we'll go another five ten minutes because i've kind of wasted your time on this i do have pants on what kind of beer um this is the last of the icicle brewing company's german chocolate cake ale geology questions uh patrick age seven is horst and grabbing the same as basin and range more or less patrick but the horsham groban model is no longer as accurate as we think it was once upon a time and i talked about that a while back in spring if you remember instead of it's a half grabbing model where the blocks are rotating as opposed to just blocks going up and down thank you for being being with us patrick what do i find most fascinating about these exotic terrains martian that's coming um there's lots of things to really be excited by and i appreciate everyone's patience before we get there i hope you can see the value in these pre-sessions to get our mind ready for the timing and also today trying to get some of that coastline restored to the right position how do we know the passive margin is the coastline says price interesting question in addition to the limestones and the shales and the sandstones there are fossils of things that are only found at the beach or in a tidal lagoon or immediately offshore things like stromatolites things like ripple marks things like um basically beach systems that are preserved in the rock so you're right there are limestones and shales and sandstones that are not at the beach but we have enough evidence from the paleontology community and the sedimentology community to know that we were at the margin of the continent back at that time reading more questions before we quit uh is that nevada spreading breaking up the craton interesting question i guess it is successful in breaking up the craton in eastern nevada and western utah i've never really thought about that before yeah i think it is that's a short answer but i think it is okay did the passive money ever become an active margin if so when yeah that's where we pick up our story a week from today 390 million years ago our western margin now you know when i say western margin right it wasn't really the western margin it was the northern margin through much of christopher's animations but again i can't do that in my head every time so we're just gonna view north america quote unquote the right way up and down you know what i mean but yes 390 million years ago which was on our whiteboard as the end of the passive margin it becomes active it becomes a convergent boundary and we'll start looking at that evidence from today why a week from today why not next time well next time we're going to do some basics on strike slip faulting and we'll see how much the terrain fruitcake has been offset by younger than 50 million year old strike slip faults there i just gave you the plan for sunday morning kathy in brisbane is basing range extension due to cessation of subduction story or clockwise rotation or both there's still some different opinions kathy on why that extension is happening everybody agrees there's hot mantle coming to the surface underneath nevada some think it's tied to the east pacific rise slipping beneath north america and others think it's more tied to the clockwise rotation as you basically actively rotate california away from the rocky mountains and the basin and range extension is happening kind of in the wake of that rotation a couple more is the basin range complex the place where you can find craters of the moon got me yes i wish we could view the continents correctly always using north-south confusing well corey sue i take your point but aren't we so used to reading maps north and south i can speak for myself i can't do that i can't i can't spend all of our time uh talking about our coastline being north east southwest and then having stuff come in because we'll keep comparing to these places which we are most conveniently viewing in our north south orientation so i think you're better than i am in that respect three more and we're done it's 20 minutes after the hour already fruitcake in relation to the german chocolate cake okay well those are my two cake analogies that i've used so far the fruitcake as you'll see on sunday is the main analogy we'll use for exotic terrain basement and you'll see why on sunday and then a majority of the fruitcake is covered in german chocolate cake which erupted 16 million years ago so we only have a few precious places to see the fruitcake directly to see those those little nuts and the dates and the other stuff that's in there and i will be cutting into the fruitcake in derrick's fruitcake on sunday is the nevada basin range connected in any way to the failed northern mid-continent rift i don't think so the mid-continent rift all i know about it is it's back in duluth minnesota stretching down through the upper midwest and it was active 1.1 billion years ago that's a lot a lot older than the initiation of the basin and range extension 30 million years ago but you might know about the more about the mid continent riff than i do two more am i down to present day is the basin and range a failed rift no it's still active some of the earthquakes we had this spring during the live streams were from nevada and western utah and even central idaho that's all tied to normal faults of the basin range so it's still rifting it may fail at some point but it's not a failed rift now for sure two more yeah are we still okay one last check with you i'm this far away i'm getting excited where i might actually live stream from here right next to the frogs and i i like it because i i have more direct sunlight even though it's tough to squint in so yeah we're five by five ah tony steve you son of a gun looking for one to end on here we'll end with jl cop is the old north american coast visible anywhere near boise no and that's the heck of it at boise we have young snake river plain western snake river plain graben patrick sediments lavas that are younger than the columbia river basalts there's so much of this old north america story that just is unavailable to us and that's one of the main reasons i was spending so much time setting the table quote unquote so with our sketches that we had it looks like our coastline is plain as day all the way through and the passive margin sediments are all just as flat and well-behaved as you'd like well it turns out most of that is either buried or invaded from below and new information most of the passive margin isn't flat anymore think of how much action there's been in the last 500 million years think of how much faulting how much folding and we'll get into that as time goes on a toast to you and let me grab the clipboard thank you for joining us today in our discussion called paleogeography trying to restore the old coastline of north america restoring the passive margin by taking out the basin and range extension and the clockwise rotation there's one more thing to take out by the way and that is the amazing amount of strike slip faulting and offsetting of major chunks of real estate here in the american west and we will learn about strike slip faulting we will remove the strike slip faulting on sunday morning and i think if the weather's cooperative we'll take a little bike ride on sunday morning as well to celebrate the end of our table setting and to rejoice in the fact that our visitors are almost here the exotic terrains are almost here when's the next live stream sunday morning 9 a.m pacific here's to you for continuing to show up with an open mind with an inquisitive mind and ready to learn a few new things each time we get together here's to the health of your family and friends near and far and here's to all the workers around the world in various capacities in various lines of employment trying to keep us all going on a large scale and on a small scale thanks for joining us today thanks to towny steve for allowing me to live stream what 20 yards away from the router i'm thrilled and i'm hoping that we'll be able to do this again sunday morning at 9 00 a.m goodbye be well enjoy the weekend we'll see you sunday morning 9 a.m i love you goodbye you

Channel: Nick Zentner

Views: 18,521

Keywords: Nick Zentner, Paleogeography

Id: 9bHaGCrPaqw

Length: 104min 53sec (6293 seconds)

Published: Fri Sep 25 2020