Supervolcanoes in the Pacific Northwest

so the topic tonight is super volcanoes in the Pacific Northwest that's true but I'd like to start with a story and it's a story that involves Ellensburg Washington USA right here and many of you in this auditorium have vivid memories of a Sunday morning almost 40 years ago may 18th 1980 yeah you're already reacting you remember you remember but for those that were not here let's go through the bullet points of what happened in Ellensburg Washington on May 18 1980 it was a bluebird day that's how the story begins it was a beautiful morning not a cloud in this guy and there was no rain in the forecast and those of you that were outdoors noticed the southwestern part of the sky there was this gray cloud that started to appear you're like oh that's weird I don't remember rain in the forecast is that like a thunderstorm coming from the Cascades and then that gray cloud got bigger and it got closer and bigger and closer and darker gray until by late morning the entire sky here at Ellensburg Washington was full of gray cloud and it started to snow at least it seemed like it was snow what is this stuff coming out of the sky I mean it's dim now I mean we can barely see the Sun is blocked out because there's so much gray cloud you remember this and this isn't snow this is volcanic ash and for many folks I think it took a while to connect what was happening on your forearm and that mountain they've been talking about in newspapers and radios for that all that spring that mount st. Helens a volcano and our state down by Portland was going to erupt Wow sure the so-called expert said that but by god I think it actually happened because here's volcanic ash falling out of the sky and landing in Ellensburg Washington landing on the roof of this auditorium and in the parking lot and on the sidewalk and on your windshield and on the golf course and in the haste all over and the rest of that Sunday May 18th was dark the streetlights kicked on and it wasn't just Ellensburg it was many towns in eastern Washington so the next day Monday the skies were starting to clear and we had a souvenir of the eruption of Mount st. Helens it was about a quarter-inch of ash a quarter-inch of fine talcum powder that was the consistency of the ash kind of a silvery gray color it's still around that was almost 40 years ago now if you go out and dig for that 1980 ash you're bound to run into some other volcanic ashes as well out here in the desert it looks a little different than this stuff that I brought in with me tonight this is st. Helens ash collected from the roof of Lynde hall by Jack Powell geologists it's in a whiner Gers wildcat choco mint ice cream container so feel free to come up and enjoy if you if you've never seen Mount st. Helens ash from 1980 we'll take a look you and I together will even open up and give you a little sample so there are other ashes that fell out of this guy so there are other layers that you can find out here in eastern Washington oh well here's an inch layer thick that must be a different volcanic eruption it is that's Glacier Peak that's Glacier Peak that sent some ash to the east here's Mount st. Helens that sent some ash to the east oh and here's another ash bed that's from st. Helens but it's more than 13,000 years ago and that glacier peak eruption was more than 10,000 years ago and it depends where you are with the circles these circles are cone volcanoes with an erupting column and the winds are blowing west to east and they're taking ash from the eruptive column above the erupting cone volcano in the Cascades sending it downwind and sure enough the ash is falling on to the ground we are downwind of the Cascades we receive the volcanic ash deposits from most of the Cascade volcanic eruptions you can erupt the lassen or Shasta and get ash blown downwind okay you supervolcanoes know we're not there yet hang on hang with me for a second I'm setting you up so by far the biggest of the ash beds from a Cascadia RUP ssin many of you know it's the Mazama ash that erupted seven thousand seven hundred years ago it was a cascade volcano a perfect cone that we call Mountain azama and that mountain almost totally blew itself up the only thing left of Mount Mazama is just the stump just the very base of that cone everything else is gone and it has not rebuilt itself by the way in the last seventy seven hundred years so it's the Mazama ash that dominates is the king of all of the ash fall deposits coming out of the Cascades the Mazama ash and here's Mount Mazama today you better you know what better has Crater Lake National Park that's Mazama that says this beautiful Blue Lake is sitting in the stump of that Mazama Mountain so the end member they did the extreme of what we think are possible cascade volcanic eruptions is the Mazama event and it's extreme I mean the Mazama ash here in our valley is a good six inches thick I exaggerate it's like a fish thing I exaggerate six inches thick it is two or three feet thick the Mazama ash that fell out of the sky over by Spokane exposed right along i-90 on Sunset Hill in their own aside so you can get feet of volcanic ash falling out of the sky from cascade volcano eruptions but within an hour drive of here south advantage near the little town of Mattawa there's 30 feet of volcanic ash and it's eleven point eight million years old so it's far older than all these other ashes I've talking to but it clearly fell out of the sky but there's thirty feet of this stuff and it has been a puzzle for geologists throughout the 20th century it was clear was ash it was clear was asked that fell out of the sky 30 feet and in the geologic reports with question marks there was the message was some hell of an eruption in the Cascades someplace but everybody shrugged their shoulders I wonder where that was end of story well we now know the answer and that's the reason for this lecture that thirty feet of ash at Mattawa has been chemically analyzed now we have ways to get a chemical fingerprint for an ash and connect it to its source to connect it to its volcano like who made this mess who made this thirty feet of ash who's responsible for this the answer is a supervolcano the answer is not the Cascades the 30 feet of ash in Central Washington even though it's east of the Cascades and even though there's a bunch of other ash beds that fell out of the sky from the Cascades the Mattawa asked the saddle mountains ash came from a supervolcano in southern Idaho there I said it I feel better let's draw that let's draw that let's we're gonna we're getting rid of the Cascades the Cascades are done they're dead to us right now they're not going to help us at all this is a super volcanoes lecture and to stall why I erased the board let me tell you a pet peeve of mine have you seen a program on television or the internet about super volcanoes where's the place that they all mentioned four super volcanoes Yellowstone Park that's right if they've got words on the program fine but they need video they need to put video on the screen for their Yellowstone superval okay no story what do they show they show lavas from Hawaii they show Mount st. Helens they showed the wrong volcanoes to correspond to the discussion of super volcanoes and I don't blame them because humans have never seen a super volcano erupt humans have never seen a super volcano erupt we don't know exactly what the experience is like and if you're making a video program about a super volcano you can do your best but we don't have any footage to use and yet we have the 30 feet of ash in Mattawa suddenly put that X on again what is that that's the 30 feet of ash that fell out of the sky clearly what's the date for it 11 0.81 million years ago where's the source where's the volcano it's not a cone we're going to talk about different kind of volcanoes in a second it's not a Mount Rainier cone it's not a Mazama it's none of those cone guys it is a 30 mile wide crater are called Darryl called the Bruno Jarbidge caldera it's south of Boise it's west of Twin Falls it's near jackpot Nevada if you know that place I lived in southern Idaho for a while I know about jackpot Nevada the Bruno Jarbidge caldera a supervolcano a caldera and what I'm telling you is 11.8 1 million years ago stuff went down here this thing blew this thing exploded and sent ash through the sky 500 miles and landed here in Central Washington and I can't hold it because the energy is outstanding tonight you are a great group I'm going to keep rolling ash fell in Nebraska ash from the Bruno Jarbidge caldera that caldera right there made it to Nebraska as well as made it to us and there's almost a dozen different eventual eruptions of that source so we've got some work to do tonight don't we was the wind blowing what North or something like why is it coming up here I thought all the ash is getting blown down when to the east what does this look like why isn't it a Colin like all the rest of the volcanoes what do super volcanoes do when they do their thing what is a supervolcano let's start with that I did my master's thesis 30 years ago I was a grad student in Pocatello Idaho I did mapping of ash flow Tufts will talk about in a second there's not the word supervolcano in my thesis from 30 years ago so even the word is new super volcanoes so we got a lot of work to do and I want to make it quick because I've got a healthy accumulation of video clips and photos and maps and everything else okay crash course you ready not all volcanoes on planet earth are the same it depends on how much silica you have in a magma chamber these are underground rooms with molten material if you have low amounts of silica 40-point 45% when that lava gets to the surface it runs it's very fluid that's Hawaii and the kind of rock that is created is basalt were loaded in basalt we've had lectures on the flood basalts of Eastern Washington not the topic tonight if you go to a coastal setting around the world where you can actually mix oceanic crust with continental crust and increase the amount of silica present the magma is going to be stiffer it's going to build a different volcano it's going to be a cone volcano and you're like are they really cone-shaped you bet they are Rainier Adams glacier peak they're perfect aren't they don't you still get a thrill if you've lived your whole life don't you still get a thrill when seeing that mountain on the horizon that's an active volcano that's just perfectly formed and has erupted dozens of times and we have ash beds to tell us that so the Cascades are these cone volcanoes but they are also not the topic tonight andesite is the kind of lava that's most common coming out of interrupting volcano sometimes called a strata volcano sometimes called a composite cone remember we erased the cat escapes there there we could do let we have done lectures on those we're not doing it tonight we are on this right panel and I'm gonna make this boundary we've got students here taking notes for their extra credit so get this alright we've got a major threshold of leaving the known to going to the unknown meaning that humans have never seen these super volcanoes do their thing the most recent supervolcano explosion was 70,000 years ago in Indonesia in India in volcano called Toba Toba supervolcano that's the most recent so these shield volcanoes erupt constantly Kilauea has been going since 1983 non-stop these cone volcanoes erupt every few centuries Rainier erupts every few hundred years will the deer up tomorrow afternoon or five years from now will they rearrange erupted a hundred years from now or two hundred years from now we cannot forecast that with what we know now but when we go to this last category the topic for tonight there are hundreds of thousands of years between explosions so that's good news if you are one to know if I should drive to Fred Meyer tomorrow because of the supervolcano I don't mean to belittle your anxiety but these are very rare events I'm on the pet peeve train I'm also give you one more have you have you seen the articles have you seen Yellowstone's to do Yellowstone's overdue Yellowstone why are you why are you going to Yellowstone why are you taking your children to Yellowstone it's overdue for a huge that is total BS there's no science behind that whatsoever so please flush all those headlines I don't know what they're doing but it's got nothing to do with the science that we know in Yellowstone Lord I'm angry tonight why is that you're you're here to enjoy learning some new material sorry for that sorry about that up in the balcony okay so let's do this quickly and then we'll go back and talk about these super volcanoes that we have discovered there's more than that one super volcano ours the one that made the cougar point tough the 11.81 million year old ash that fell in the sky here so the quick and dirty version is this if you have 75% silica magma you are clearly in the middle of a continent you have created magma that is so stiff that acts like toothpaste it barely gets to the surface and just sits there and doesn't budge and we build pressure as we trap gasses underneath that cork of rhyolite lava that's the kind of lava here I'm not even gonna write it out rile I should rhyolite so ironically the most lethal of volcanoes are the tiniest little Hills for hundreds of thousands of years but then something happens we finally get enough pressure built what we have something happen and we have a true super volcano explosion let's do it real quick we're going to do three things with a super volcano explosion remember we've never seen one happened but we have reason to know what it looked like based on the evidence that's laying all over the ground we've got our volcano we've got our magma chamber with our 75% silica magma we maybe have a little pimple of a hill maybe as tall as Minhaj Cass Ridge and no higher okay finally it's time for a super volcano explosion whatever that means and by the way do we have any warning for this are there other days weeks years are there centuries of buildup warning signs before one of these goes we struggle with the question because we've never seen what happened but yet when we finally do get the event the first thing to happen is a major collapse of the roof of the magma chamber we're sure of that that there is a collapse of the crust as we evacuate a bunch of magma from underground what we're forming topographically is a caldera what I've drawn for you here is a circular feature that is the bruno Jarbidge caldera each supervolcano was marked by a huge crater averaging 30 miles across much wider than crater lake secondly we actually I can do it here better than that we're gonna fill the sky with ash I don't care what direction the wind is going we're not gonna blow ash downwind from a super volcano a super volcano is going to make its own weather it's going to send ash in all directions regardless of the jet stream or anything else happening and the evidence for that is that we're finding ash from one particular super volcano explosion across this entire map all the way to Nebraska but also out into the Pacific and as far north as Central Washington this is an equal opportunity offender this is not just a few communities downwind when I let a field trip to this site last November everybody's talking about the wind oh my god listen we got it we got to totally change our view here if we can if it's possible well this this incredible ash you came to call it an ash cloud I mean it's everything within five hundred to a thousand miles in all direction of this supervolcano explosion eventually the energy goes away and all that material all that Ash and rock comes to rest and it comes to the rest in form of a very descriptive term called a welded tuff this is different than ash fall this is ground hugging clouds of ash flow that are traveling over the surface of the ground as well as a bunch of other material that has momentum finally losing energy and is still white hi so when it finally comes to rest it's so hot that it welds itself it's a great descriptive term for a change in geology welded tuff it takes a hard effort it takes hard work with a hammer with a sledge even to get welded tuff open it was originally all this ash material but it is dense rock sometimes welded tuff is called ash flow tough sometimes welded tuff is called ignimbrite doesn't matter we've got the concept don't we that's surrounding this caldera we're going to have about a hundred miles of death I guess if you want to say let's that's that sounds like I'm on TV it's a lethal area I don't see anybody surviving within a hundred miles radius of a supervolcano because this is our area where we have welded tuff that most dramatically is flowing over an ash flow is hugging the ground more than freeway speeds and killing everything plants animals anything else in its path finally we're gonna have some ash fall some air falls a material coming out of that huge sky dwarfing cloud innocently falling on the surface so my point is we know that dates for these supervolcano explosions not because of the hole in the ground that's not going to help us we're going to get dates from these welded Tufts we can get accurate dates from the actual welded tuff material that surrounds the caldera and then again I don't have the time or the energy but ironically but we can have ash falling out of the sky over this entire map all the way to Nebraska do you see how this is different than a cone that we can't really talk about st. Helens or Rainier and these guys in the same breath I hope so now I want to do one more thing on the chalkboard before we move on and that is to plot our discoveries where have we found super volcanoes in the Pacific Northwest I don't know maybe you had this cut this guy was somebody before you came what's the title tonight of this talk were going to super volcanoes in the Pacific Northwest what super volcano that's Yellowstone he's calling Yellowstone in the net in the Pacific Northwest that's kind of a stretch Yellowstone's in Wyoming Yellowstone's in the Rockies that's not the Pacific Northwest I take your point you're right there is one of these 30 mile wide calderas in Yellowstone Park that's why Yellowstone is such a freak show hot water is shooting out of the ground with Faithful geysers mud is boiling like pea soup it stinks like rotten eggs it's a volcano there's a heat source beneath there and the only other supervolcano we know about so far in this lecture is what I had for you just a few minutes ago the Bruno Jarbidge caldera eleven point eight million well let's get right to it where are the other super volcanoes that have been discovered in the Pacific Northwest some of you know this there's a bunch of them murmur the crowd is murmuring right now let's move to Chicago this does not look good well I've got good news for you first of all I've drawn these calderas in an overlapping sense and we don't know the exact size and location of each of these older calderas because they're now buried if you get real pumped by this lecture and start driving south of Boise and looking for this big caldera you're not going to find it because it's been buried by younger stuff and partially eroded as well we have evidence at these spots but we have to be kind of clever in how we find the evidence but if you're totally confused why these calderas are lined up like this and I'm feeling spunky so I'm going to continue this has been known for 50 years that we have super volcanoes number one and that they're all lined up in this huge line what's the relationship well they're lined up aren't you glad you came tonight but they get older as you go down the line this youngest caldera is visible is topographically a rim in the Yellowstone Park area that caldera went six hundred and forty thousand years ago as we go down the line the calderas get older they're about five million years old by Pocatello Idaho where I met my wife and lived for three years ten million years ago Twin Falls 15 million years ago south of Boise 17 million years ago in northern Nevada let's keep going 29 million years ago in Northern California and by the time we get above 50 million years ago we have a heat source out in the Pacific Ocean what in the world is going on it looks like there's a heat source burning a hole in the continent making a supervolcano explosion and then it looks like the heat source is marching to the Northeast that's what it looks like it's not what's happening this is a geologic hotspot most of us view that hotspots are stationary they do not move but what is moving North America North America is moving to the southwest North America is slowly drifting over a stationary hotspot can you do that in your mind so the hotspot is not marching this way North America is drifting over a stationary hotspot the hotspot happens to be today here but 11.81 million years ago it was here what am I saying I'm saying that the ash at Mattawa is a Yellowstone story not a cascade story even our flood basalts not the topic of tonight is tied more to the Yellowstone story than it is the Cascades so this is a major shift in how we view geology of the Pacific Northwest just in the last 20 years this chemical fingerprinting was done by Barbara Nash at the University of Utah and she has run a micro probe lab for 50 years and she gets people sending in ash beds from around the world and she runs them through her instruments and gets a specific age and a specific chemical fingerprint and ties it to a particular volcano that's how we know this ain't BS here's the last thing we're doing on the chalkboard oh oh oh good lord you heard of Smith rock it's a climbing place it's a state park it's near Redmond Oregon if you drive 97 from Ellensburg across the river it bigs Madras Redmond and then bend the Crooked River caldera is right next door nobody knew about The Crooked River caldera until 10 years ago everybody knew about Smith Rock everybody knew those were rhyolite severy buddy knew they were welded toughs that were twenty nine point five million years old nobody had the imagination to map a caldera which we now know as The Crooked River caldera so our last topic for the chalkboards is why is this guy out here and by himself or herself what's the story well it's not as isolated as it appears have you heard of something called the clockwise rotation of the Pacific Northwest crust a topic we've talked about in this lecture series over and over and over again the rotation of the clockwise crust of the Pacific Northwest Northern California Western Oregon and western Washington are rotating against northern Washington and BC which are not rotating the results are the folds and faults of Central Washington but what else can we do with a rotating crust we can take a twenty nine million year old caldera in California and move it into Central Oregon The Crooked River caldera when it blew was in Northern California it's now in Central Oregon because of the rotation of the crust that's happened since that time and in the works right now with the geologists were going to meet by video our other discovered calderas supervolcano calderas in Oregon that appear to be originally down here in this line and have been moved by this clockwise rotation so if you given me guff about this title super con su / volcanoes in the Pacific Northwest they're in the northwest they maybe weren't originally but they're here now and they're creeping closer to you every day put that in your pipe and smoke it okay take a moment if you would talk to your neighbor talk about how worried you are now about a supervolcano and we'll get the projector going thank you that's not a supervolcano right that's not Rainier it's a composite cone volcano it will erupt in the future it's not our topic tonight not our topic tonight but this is how we started the lecture with our story and this is Mount Saint Helens what it looked like prior to 1980 and this is Mount st. Helens on the morning of its eruption belching ash into the sky for the rest of that Sunday May 18th 1980 and the winds were blowing the ash from that eruption column eastward heading towards the Morgan auditorium so here's our cone here's our erupt of column it is not a super volcano scene we are not sending ash in all directions here's Ellensburg a few blocks from here at high noon too much ash in the sky to see the Sun and I realize if you're from Yakima or Moses Lake or Spokane you had a different experience it was darker your ash was thicker we get it you're better than us screw you all right that was uncalled for I'm sorry so this is in the yakima canyon and these are the ash beds we're talking about this one that many of you know we're still not totally sure which volcano produced it this is 2/3 of the way down the yakima canyon if you've heard Mazama we have some chemistry and some ages that don't totally work with the Mazama story so it's still up in the air this one we do know down by Benton City near tri-cities for sure at st. Helens for sure it's ash that fell out of the sky during the Ice Age flooding story and the date is 16300 calendar years before present these convoke Ainos don't blow themselves up completely they're still mountains they still have elevation they will rebuild themselves but can we get a handle on volumes that's one of the hopes for this early part of the slide show a rather meaningless number is to say that all the ash quote-unquote and when I say ash tonight I really mean with these volcanoes on this chart all the lava and lahars and ash flows and ash fall ok I'll just say ash for short so all that ass that came out of st. Helens in 1980 equals one cubic kilometer so I can't picture that can you well I tried we can fill 1766 Rose bowls of ash and that will be the amount for one cubic kilometer that came out of st. Helens that's a lot of ash I have to enunciate tonight that's I got to make sure the ash a the H is there ash that's a lot of ash vesuvius Italy that's 4 cubic kilometers 4 times the stuff that came out of st. Helens Krakatoa you know if you mentioned supervolcano these are the names that people bring up right off the vent well how about Krakatoa how about Vesuvius that was huge well let's keep track of the numbers here the Silvius was in the 19th century 18 times the volume of st. Helens so that's more than 30,000 Rose Bowl from Krakatoa in Indonesia a cone volcano crater lake Mount Mazama up to 75 cubic kilometers depending on who you listen to but certainly dwarfing the amount of ash that came out of Mount st. Helens Mount st. Helens was a an impressive event we all remember it but we know that it's kids stuff compared to what we're talking about with these here's Mazama Southern Oregon near Medford blow up most of the mountain were left with this huge hole in the ground an impossibly blue lake called Crater Lake is a destination point for us today and here's a map of the ash fall downwind of the Cascades Mazama versus st. Helens in 1980 okay great the Mazama here is right along i-90 here's an exposure in Johnson Canyon east of Kittitas about six inches thick here's the Mazama ash along i-90 this is Andy buddington from Spokane community college a couple of feet worth of ash Mazama we have a tectonic reason for the cascade volcanoes it's a subduction story it's an ocean crust diving story and as long as we subducting you to erupt volcanoes in the Cascades not the topic of tonight our topic is super volcanoes nothing to do with subduction now we're going Orange because we're crossing the threshold to supervolcano category we're already up to 400 cubic kilometers 400 times the ash that came out of st. Helens the vias caldera in northern New Mexico so I'm doing this for you but you already know this from the chalkboard hopefully we are now over here to stay on the right panel with high silica high viscosity lavas and caldera formations caldera ash flow tuff and air fall professional diagrams showing that here are professional diagrams trying their best to talk about the collapse during the super volcanic event and then something I didn't talk about in the chalkboards there's commonly some resurgence of some of the lava so we get these after the fact little domes that are common inside of these calderas resurgent domes we call them made out of very stiff toothpaste like rhyolite lava so let's get up in the air and look at some of these things here is the vias called they're only 13 miles across it's small compared to others but look at how amazingly circular it is on a map as well we're in northern New Mexico and outside of the net the caldera there's a state park some of you have been to probably northern New Mexico bandolier park and there's 1.2 million year old ash flow and ash fall Tufts that have an archaeological story where people were living in the supervolcano deposits related to the vias caldera now take a good meth can you memorize this photograph by the look it's a very thick cliff it's pinkish it's kind of modeled in appearance there's no obvious layering that's what a welded tuff looks like that's what one of these deposits looks like after the supervolcano calamity and the ash comes together and welds to form this very dense rock we're gonna see this at a bunch of spots you got it that says supervolcano to many of us quickly Long Valley caldera another supervolcano this time in eastern California if you're a skier Mammoth Mountain is on the western margin of the Long Valley caldera it's north of bishop the bishop tuff is a very famous welded tuff and of course yellowstone yellowstone a plateau it's a plateau for a reason there's heat that's heating up that portion of North American creating a higher elevation than some of the surrounding areas and in Yellowstone Park have you ever noticed that the roads form a circle in Yellowstone the road is following the rim of the Yellowstone Caldera from the last super volcanic event 640 thousand years ago now here's what we did on the chalkboard showing the march of older calderas across southern Idaho which happens to be the Snake River plain and this particular figure which is the conservative way to do this stop the trail of calderas in northern nevada I'm a fan of continuing them to the Pacific Ocean because of the clockwise rotation oregon caldera story that is emerging in the literature in the last few years let's finish our list here's Toba the most recent of the super volcanic explosion what are we up to now how many rolls we'll be talking now good lord we got 3,000 cubic kilometers these are estimates these things are so big and newly-discovered calderas in the Rockies the la garita caldera 27 point eight million we got 5,000 cubic kilometers the Wawa Springs is the biggest known supervolcano caldera yet found in western Utah 30 million years old more than so I mean at this point they're just big numbers we can't picture anything anymore oh but maybe we can can't we take all the ash from that biggest known supervolcano and put it in the Grand Canyon it would all fill one Grand Canyon there you go bigger than the Rose Bowl so one of our main objectives tonight is to not mix volcanoes to keep those volcanic style it's apples and oranges and what at grapes I don't know something else and so our our Rainier is dinky compared to these systems that produce these super volcanic events and the ash plume the physicists have been involved now to try to to crunch the numbers and figure out how you get an umbrella cloud sending ash in all directions we got to go to some places don't we forget the diagrams now let's actually go to some real places and look at some real rocks and bring this a little bit closer to home and as promised here's the 30 feet of ash south of Vantage specifically where is this well there's Vantage up at the top you got your bearings now we're looking north up towards Wenatchee I 90s going from left to right or right to left I and here's the Columbia River coming through the saddle mountains up on top of the saddle mountains looking north now Vantage is off on the right we can see it's a bunch of basalt lava stacked one on top of another that's old news to us we know that but if you look carefully there's a white layer and you're like oh I just went to that lecture I wonder if that's that Ash he was talking about in this case it's not that was cruel why did I do that that particular white layer is called the Vantage sediment and if you were with us last week talking about petrified logs on top of the Vantage sediment that's the story there that was a lake story and some hyper concentrated flows of water going into the lake so not don't get carried away now please I appreciate your enthusiasm but not every white layer out there is going to be the supervolcano thing on the other hand I think it's likely now that we've learned about some of these new discoveries of super volcanoes that we will find more Yellowstone ashes in our area in other words I will have people doing some analysis of some of the ashes that were assumed to be from the Cascades but maybe part of this supervolcano story but we're on a mission to go to the 30 feet of ash north of Mattawa on the South flank of the saddle mountains I don't know does this look familiar this is a State Route 243 I think it is we're looking east you're going from Vantage to Beverly down to desert air and then on down to tri-cities that's it it's on private land I need to emphasize this I'm gonna get you all pumped up about this and show you pictures but I got to say you can't just go up there I'm sorry it took me a while to figure out how to get access to this place but here's our 30 feet of ash on the South flank of the saddle mountains these are drone shots from Bruce Bjorn stad last fall we're gonna get in here and look very carefully I'm telling you this is the ash that came out of the sky from Southern Idaho and you're like I don't think I believe you man well let me try to make build a convincing case for you and why what's all these markings why is it such a perfectly steep wall is there's another part of the story here in fact there's kind of a natural patina to this cougar point tuff it's called the cougar point tough because there's a truly a cougar point down at the Bruno Jarbidge area in southern Idaho where this stuff was first studied and now we're tying it to this bed at Mattawa but this is the natural look of the ash and then it looks like snow looks perfectly white why is that do you have a guess it was quarried our thirty feet of ash was used commercially in building the major dams on the Columbia River back in Roman times those guys figured out that if you add ash to concrete and it enhances the concrete strength-wise curing temperature etc even a finish to it and so the next time you see Wanda pom dam or priest Rapids dam think of the volcanic ash from Southern Idaho that's in that concrete and back when they were putting those dams together and quarrying the ash this was an active scene using local pozzolan to make the concrete for these big dams the Columbia irrigation project etc here's the old Quarry Road as far as I can tell from the landowner the last time they were coring up there was in the in the mid 1960s and I'll give you evidence for that in just a second so the first time I actually got up there known about this exposure for as long as I've been here and I saw the scientific papers by Barbara Nash about 15 years ago and I'm like oh my god that that's a super volcanic ash deposit how do I get in there so I couldn't figure out how to get in there legally and I wanted to get up in there and so a fellow who's here tonight John Lasher I want to publicly thank him he had a friend of a friend of a friend who got me connected to the owner of the quarry and last summer went up there with a grad student and John and Karla West and I was more confused than anything else I was excited to be up there and there's graffiti from more a hundred years ago by the way scratched into the air fall tough but I was really confused I knew it was a quarry but there are a bunch of feature I couldn't even figure out how much was ash and how much was like River silt and the confusion continued that's kind of how I operate anyway I'm just kind of wandering around going why is this so you know and everybody's tuning me out but I just I couldn't wrap my mind around a lot of what we were seeing and I was looking for specific evidence that this is a Yellowstone story and not a cascade story in other words I was skeptical that this wasn't a cascade volcano eruption story well one of the reasons we know this ash is so old is it's part of a bed that is below one of our flood basalt layers and in a way the flood basalt layer above it called the Elephant Mountain flow that's the one that has the beautiful columns and I dropped my hammer by mistake down the columns in a different spot that Elephant Mountain flow has acted as a cap Rock all these years it has protected this softer ash so if you've saw those previous photos and like why is that ash still there it's just right there at the surface well why didn't that erase long ago and the answer is that overlying basalt protected it as a cap rock now this one really puzzled me what are these things there's just one portion of the 33 to 30 feet of ash that have these little bb's and they're just about two feet up from the base of the 30 feet of ash what what and we had a big discussion while we're out there and Carl thought they were shells and somebody else thought they were something else and you know Facebook has got a lot of problems but I do use Facebook after I go out and do some geology and I get a lot of interesting comments and questions from people and everybody wanted to talk about these things are those shells or what are their seeds what are those things and I got some help from Jack Powell and a few other local geologists and they said look you idiot they didn't say it like that haven't you heard of a chrétien area lapilli before and like yeah I guess like 30 years ago but I don't remember what it is this is a common feature in thick deposits of volcanic ash during the eruption ash coming from Idaho there was local weather and rain got froze into hail and the hail was coated in ash as it was going through the eruptive column this is essentially fossilized hailstones with the with the the rim of the ash still intact 11 point freaking 8 1 million years old I said fricking didn't I and yet hollowed up because the hail has melted away I'm like that is unbelievable and so I went back to my office and got on my top shelf a book I haven't looked at in 30 years pyroclastic rocks the Bible for volcanologists around the world co-author hans schminke and my god name sounds familiar and then I looked at page whatever it was a black and white photo from this very famous textbook layers of accretionary lapilli in purify tricked us Ellensburg formation Sentinel gaffe I'm like are you kidding me this guy who wrote this book who lives in Germany who's a well-known volcanologist was at this dinky quarry in Mattawa so I found in my email he's still alive and I say hey hots did you ever spend any time in Central Washington he's like I have not been there and back in this is my German accent now I have not been to Central Washington in more than 60 years but I was a young PhD student making studies careful studies of the inter beds between the basalt lava flows and I was at a place near Mattawa where there was a quarry and I'm like are you kidding me and so we went back and forth last fall by email and he had all sorts of great stories here's one so he's like a 22 year old kid from Germany and he says I I was up on the steep cliff of the North saddle mountains where I did some fieldwork for a week or so and I was brought up by some people because my my car couldn't handle the silty roads and then after five days they forgot about me so I started to walk back and then they finally remembered to come get me and my water supply was gone so I so they actually got me and they had some cold but bad beer named Rheingold but in that situation the best beer in the world hans minke we shall loot you and these are the detailed photomicrographs of those lapilli with all these little broken glass bubbles essentially these little ash vesicles basically and down to the the very tiny levels these are in micro my very tiny scale with scanning electron photo micro so it's definitely a volcanic story those lapilli are a big part of the story at this area now here's more evidence that this is a unique deposit this is some video of the cougar point tough we're at the matter of a quarry look at how strong it is number one it's not ash that just falls to your finger even though it's eleven point eight million years number two it was very sunny I don't know if you can see this but there's a lot of fresh sparkly minerals in there and number three there's no black minerals in that ash if you come up and look at the wineries jug of st. Helens ash you'll see some black minerals and I didn't know it at the time but I know it now if you are a cascade ash you have some black minerals in you some bio tights are some hornblende minerals that's a just a thumbnail way to tell if your ash came from the Cascades or Yellowstone black minerals Cascades no black minerals Yellowstone of course there's other more sophisticated ways to make that case this is also what Hans collected in the ash these strange balls that we were confused by then and I have to confess I'm still a bit confused by them they're called concretions they take forever to break open with a hammer they're very very hard I just wanted to prove to you that I could get one open and here's a little video with some of the accretionary lapilli kind of soldered on to these guys the conventional message is these are secondary deposits in other words there's fluids there's water percolating through the ash and forming these concretions but that's not satisfying to me and maybe not to you either some of them are in god-awful shapes that you can find I don't know if what catalogue this is from but anyway Hans had a request after about the fifth email he said I'm out of concretion I used them in my teaching and he must be 80 by now I'm out of concrete can you collect a few and send them my way so I've made up a little care package of concretions and accretionary lapilli sent across the ocean to Hans so that's the end of our ash at Mattawa but not the end of the talk there's other places you can find that particular ass from Yellowstone where can you go well there's a place called the Pomona lava flow named after the Pomona tavern it's north of Cielo and the Pomona lava flow is not present at manoa at least in the quarry but it did come in right on top of our ash and when it does that that heat of that Pomona lava flow baked the top of our Idaho tuff our cougar point tuff so you see it looks like we were just looking at at the Sun in the North Face of the saddle mountains a drone photo by Bruce Bjorn stead and look at the top of our cougar point tuff is no longer white it's orange and even kind of reddish brown that's the heat of the Pamona flow baking that thing I share this with you because if you know that drive on the freeway from Yakima to Ellensburg in Ellensburg to Yakima over and over and over again you drive right by our Idaho ash every time does this look familiar to you this is the baked upper part of our zone let me help you find this we're heading south on the freeway we're approaching the county line you got it we're heading south on the freeway to Yakima we cross into Yakima County it's the first outcrop on the left this is the star of the show there's a big reverse fault proving that earthquakes are a big part of our history that's a story for another day Barre off to the south off to the right of this huge cut that was built back in the early 70s late 60s there's our baked Idaho tuff from Southern Idaho underneath the Pomona lava flow and you can even some of see some of the pure Idaho tuff that we can see over in Mattawa much more clearly Jack Powell's a local geologist and he got these photos from me just in the last few days I'm very appreciative of him and you get into that orange brown baked zone it looks like glass it is glass it's an almost an obsidian type of a look so you can see that that overlying pomona really did a number on our white ash fall tuff and welded it and Jack found this in the top of that cougar point tuff that's been worked into an artifact by Native Americans I can't hold it I got to say one more thing you know the big landslide south of Yakima the one that's been creeping along down that Union gap it's looking like the week bed beneath that creeping landslide is the cougar point tuff is our Idaho ash so there's even an environmental part of this story a couple quick photos from the big field trip we led last November bringing you guys up there everybody was talking mostly about why is there 30 feet of this stuff it's not 30 feet everywhere why is it so thick at manoa if you look carefully at the details of the outcrop in the quarry you can see evidence that there's plankton there's there's actually Diet AMA there's actually life proving that there was water during at least part of the ash falling out of the sky and these detailed photos proved that water was at least part of the story can you kind of see this rhythmic betting going on within our ash so to vaguely answer why it's so thick at Mattawa it's been reworked the ash has been remobilize and moved a little bit in the water but I'm being purposely vague because I really don't understand why it's so thick there okay we're promised we're leaving Matt oh and now goodbye Matt oh uh but I still want to go to a couple of places oh wait a minute now if it's a super volcano and we're exploding ash in all directions is it true that this state park in northeast Nebraska damn near Iowa has ash out of the sky from the same source and why do they have a building over there's a shelter for their ash we don't have that Mattawa why are they protecting and actually having museum type displays for their ash in Nebraska well they got some goodies at the bottom of their ash one day about twelve million years ago in the heart of North America herds of rhinos were grazing on wide open grasslands while turtles swam in the nearby watering hole early dogs hunted in the underbrush and long-legged cranes searched the water for food I like to think it started out as a nice day but it definitely ended pretty terribly the air quickly filled with volcanic ash dimming the sky and falling to the ground in clumps forming drifts like snow banks the ash coated everything including the plants the animals ate causing their teeth to become scratched and worn as if they'd been chewing mouthfuls of sand and they unavoidably inhaled it the sharp glassy edges slicing at their lungs they have paleontology to do at the base of their ash from the same source as our ash it's like well wait a minute shouldn't we go back out to Matt oh let's look for some rhinos let's go on a rhino hunt out there in Central Washington there's no evidence of megafauna that we know of at the base of our version of the ash but this has been going on since the 1970s the development of this state park and this painstaking work to find all these wonderful creatures that were living in eastern Nebraska almost 12 million years ago here's the founder my name is Mike Voorhies and I'm the oldest living ashfall volunteer ashfall is a State Historical Park and the feature of ash fall is prehistoric animal skeletons that are buried in volcanic ash this was something that happened almost 12 million years ago herds of prehistoric rhinoceroses and camels and horses met their death in a waterhole and their skeletons have been perfectly preserved now for twelve million years and that's the whole the whole point of ash fall Park is to give the public a first-hand view of a real paleontology site which is still actively being excavated it's just is that pretty much this a straight ashfall type deposit it almost reminds me of talcum powder it's so fine it's down oh just a few microns mm-hmm you know a lot of a lot of volcanic ash is quite gritty when you we need to feel it but this stuff is so far from the crater that only the finest particles made it this far and if you trace this ash farther west the grain size increases there's a matte wall that shows the OS source yeah it's a beautiful map they have it the park in Nebraska but what's the problem where's Mattawa so do you see I love their map but I see one problem with it they're trying to include Mount st. Helens on the map totally different kind of volcano and they're giving the impression that the winds that day 11.81 million years ago sent the ash to Nebraska which is true the ash did travel to Nebraska but it also went up to us and so with this new discovery in this new set of scientific papers in the last 15 years we can change these kinds of maps so I did this at my desk with my colored pencils so black line is our caldera the Bruno Jar bridge caldera what's the red that's our hundred miles of welded tuff our lethal zone no if nobody survives in that first hundred miles from the rim of the caldera and then ash fall on average a foot of it in the brown and down to an inch later on now we were just in eastern Nebraska they had more than an inch so there's these local reworkings of the ash again which are a complication and we have more than a foot of it at Matta what we've got 30 feet of it right so it's this local reworking that is a part of this that needs to be teased out but let's go to the source let's actually go to the guy that made our ash the supervolcano and I'll do this quickly thirty years ago I was working on this these are from my master's thesis my study area was on the northern edge of the Snake River and I was working with super volcano called arrows that were younger than the topic tonight but part of the Yellowstone story oh here we go sure why not there's my fancy field equipment to rock hammer a clipboard and a backpack with a bunch of pop cards in it and that was about it and I was working with welded tuff from the high sea volcanic field about 4 million year old but the same general idea that you have these buried calderas sending these welded tuff that's the yellow and then those calderas are buried in younger basalt so we really can't see the calderas today again from my thesis some of these nested calderas that are younger than six and a half million and i certainly was not talking about the bruno jar bridge definitely wasn't talking about Mattawa I didn't even know where Ellensburg was at the time here's professional maps from Jennifer Hackett in Ellensburg there's our supervolcano there's Matt OA that yellow dot here's ashfall Fossil Beds in eastern Nebraska a thousand miles away so through time what do we do the calderas get younger and marched their way across Eastern Oregon southern Idaho that's us Bruno Jarbidge until the current location of the Yellowstone hotspot let's add the ash and the welded tuff makes you think doesn't it where's all this ash I know it's almost 12 million years ago or 10 million years ago or 5 million years ago but did it all go away we don't have the calderas anymore I get that but maybe there's a bunch more tephra deposits that can be tied to this Marching caldera story I did get some photos through Facebook from Rob Thomas who teaches in Dillon Montana he said we got a bunch of this ash up in Montana air fall reworked locally now to confirm this hotspot story in case you're new to this we have a trail of Hawaii Volcanoes because there's a stationary hotspot in the middle of the Pacific Ocean there's a moving ocean floor and we get a line of volcanoes one at a time only one is active at a time and those volcanoes get older and older as you go away from the hotspot in the direction that the tectonic plate is moving sound familiar of course it does that's the same situation with the Yellowstone hotspot heats or anything thick continental crust instead of an ocean crust making a totally different kind of volcano a supervolcano now instead of shield volcanoes made out of basalt but in the growth scheme of things it's the same trail of older and older volcanoes I like this one kaboom supervolcano kaboom we're drifting the North American plate over a stationary hotspot I know it looks like that hotspots moving it's not the plate the continent the state is moving to the southwest over you got it now great so the super volcanoes look like this they do not look like Mount Rainier they have the central caldera and the welded tuff as a halo around the outside now it's disappointing perhaps if you actually go to the Bruno Durbridge volcano but maybe not if you like whitewater rafting friend Bruce Bjorn's dad took a rafting trip on both the jar' Bridge River and the Bruno river and rafted right through the guts of our super volcano here's our pink massive cliffs no layering modeled look I told you to memorize that before in New Mexico here we are again how old is this stuff it's eleven point eight million years the chemistry of these welded tufts match perfectly with the ash just south of Vantage Washington that's the evidence that we have found the smoking gun the supervolcano in southern Idaho to connect this story what an amazing place you like this photograph and I don't blame you welded tuff deposited on the surface of the ground very close and within the caldera at Ground Zero now I have to be careful each of these major supervolcano calderas erupted many times it wasn't just one kaboom and so in the case of our caldera in southern Idaho one two three four five six seven there's at least eight different welded Tufts of different ages and so again we're looking for different ash falls around the Northwest to tie to these different repeated explosions we finish with this the last of our supervolcano sites and you remember why we have a caldera close to Washington don't you the clockwise rotation gets us there so here's our map driving down on this blue line that's us 97 you know Redmond you know Bend and here's this impressive newly discovered caldera unknown to anybody until 10 years ago the caldera is now in Oregon but it was originally in California lined up with the rest of the calderas but since the caldera was formed twenty-nine point five million years ago it has been moved into Oregon a well along with a couple other Oregon supervolcano areas so here it is again huge pink cliffs welded tuff this time welded tuff from The Crooked River caldera making up the walls of Smith Rock these are the two geologists who made the discovery we are going to feature them on this field trip that would crib that we visited last fall and Chris smart who's with us tonight from central who makes the PBS programs with me Chris and I showed up in different vehicles at different times and Chris filmed with his drone and then we found a quiet morning to interview both of these very important geologists one of the biggest geology discoveries in the Pacific Northwest in the last 20 years in many of our opinions and so I'd like to give you a sneak peak this is the current state of this program it's not finished it will show up on tell next winter but it fits nicely with our discussion of supervolcano's so here's three clips from the Smith Rock episode in Central Oregon Smith Rock in Central Oregon what a spot rock climbers come from all over to enjoy these challenging walls that tower above the Crooked River but this gorgeous pink Rock what happened here long ago to create such unique looking features geology is full of stories from long ago and the story here it's about as dramatic as we get with mother nature Smith Rock is volcanic it's rhyolite tuff from a series of absolutely mind-blowing explosions there were thousands of times larger than mount st. Helens in 1980 Smith rock is just a portion of a supervolcano that exploded here 29 million years ago The Crooked River caldera a crater 25 miles wide outlines where the eruption did its thing one of the things I think it's so exciting about The Crooked River caldera is it stretches from here at Smith Rock all the way to the og ko Reservoir grizzly to powell butte it's a big feature if you get right on these walls in the caldera in the state park the light tan that's the rhyolite tough but there's these individual angular blocks of rock some of them are lime stones that are 500 million years old hundreds of millions of years older than the volcanic activity here so the innocent limestone beds were involved in this incredible explosion collapse deposits and these angular blocks are recording that drama from long ago the ash cloud during this explosion must have been amazing but why are there ash flow Tufts within the caldera rim I think that's because the the bottom is dropping out of it so fast that basically it's like a vacuum that sucks all that material back in we now know this is a Yellowstone story right here in Central Oregon the formation of Smith Rock and its origin has been a debate for some time more recent work suggests that it has more relationship to Yellowstone type eruptions and maybe some of the earliest eruptions related to the modern tract of Yellowstone in the Snake River plain Oregon geologist Jason McLaury and Kerry Gordon have helped find newly discovered calderas all across Oregon with their dates and locations the calderas showed that the Yellowstone hotspot has a much longer history in the Pacific Northwest than was recognized before Smith rock a popular state park within an hour of Bend Oregon and a serene spot to enjoy by the whole family hey thanks for coming everybody I sure do appreciate it we'll see you next week about that thank you you

Channel: Central Washington University

Views: 722,842

Rating: 4.8526716 out of 5

Keywords: Yellowstone, supervolcano, ash, volcanic ash, caldera

Id: NcreTTI9Rew

Length: 70min 49sec (4249 seconds)

Published: Thu Apr 25 2019

Reddit Comments

[u/dsauce]

I had a feeling it was gonna be this guy from the title. He's great, check out his videos on the Missoula floods.

[u/jpspyro]

Love watching his videos, very interesting geology around WA.

[u/whatfuckingeverdude]

http://www.nickzentner.com/#/downtown-geology-lectures/

He has a website with a bunch of his lectures and podcasts, good stuff