Ghost Volcanoes in the Cascades

[Music] so there's a famous place on the Washington coast it's called the ghost forest have you heard about it before it's out here the coast of Washington is famous among geologists at least and the reason it's famous is because just like it sounds a ghost force it's a cool name but it's it's a forest there's a bunch of trees and the trees are dead they've been dead for centuries and yet they're still standing and it was a mystery for a long time like what's up with these trees who killed them why did they die and about 35 years ago a geologist from Seattle showed up Brian Atwater was his name and he paddled into into the area with his canoe and he found a bunch of clues that everybody else missed he didn't really just work with the dead trees he worked with the soil he worked with the sediment layers below the soil he worked with the elevation of the land and he put together all this wonderful field evidence that built a case that those trees were killed by a big earthquake and it was a big surprise to many and he spent years puttin that evidence together and to be a really good field geologist you need to not only be dedicated you must have good skill it's not just luck that you find this evidence you know where to look and then you have to be creative and inspired and imaginative and you need to have confidence and it's a rare field geologist that has all of those qualities but this guy Brian Atwater had it the confidence is important because nobody at the time thought that big earthquakes were possible on the Washington coast I mean like magnitude 9 great earthquakes but his evidence was so compelling that we now understand that was definitely the case 318 years ago so you're checking your program you're like are we talking about earthquakes tonight and what's up we're not we're not I'm starting with the ghost forests and earthquake discussion but that's not what we're doing tonight we're going to the Cascade Mountains tonight the Cascades and those are a line of beautiful volcanoes we all know the Cascades have these gorgeous volcanoes and they look like this they actually look like that I mean they actually look these iconic beautiful columns the scoops of vanilla ice cream on the horizon I mean they're just majestic they're volcanoes but I'd like to take that cool name ghost forest and modify it for tonight I'd like to talk about ghost volcanoes in the Cascades not a ghost forest but a ghost volcano and nobody calls that except me I thought it was a cool name I like the ghost forest and I wanted to come to get you to come to this lecture so we're going to go to these Cascades and look for ghost volcanoes so you're like I'm not quite sure I understand what you're talking about well these are the volcano volcanoes Mount Rainier Mount Adams Mount Hood Shasta down in California Baker Garibaldi take your pick those are the volcanoes that we have during our short time on the planet those are not the ghost volcanoes but there's overwhelming evidence now that between these cones this looks like a pod with a bunch of peas in it between these Peas are a bunch of spots where cones used to stand Mount Rainier like cones and the cones are gone they just went away and we want to look tonight at the evidence to reconstruct exactly where some of those cones used to be there's dozens of these ghost volcanoes again my words not anybody else's ghost volcanoes so instead of Brian out water the guy was talking about from Seattle the star of the show tonight is a partland geologist who spent 40 summers making maps in one particular area and working with evidence that everybody else overlooked to reconstruct these ghost volcanoes and we're going to focus on a place that's up Valley from Yakima in other words Yakima Washington between Yakima and the crest of the Cascades we're going to find evidence for five ghost volcanoes and you're like I've never heard this I live driven that all the time I Drive to White Pass or Chinook pass a ghost balky you drive right through it you drive right through a ghost volcano on u.s. 12 you drive right through into different ghost volcano on State Route 410 so you're like I'm not quite still sure I understand what it goes to all you know is but I'm buying it because I love that Yakima area and I want to learn more about it so we're going to talk about the Cascades as a whole but we're also eventually going to zero in on this area that's been carefully studied by this fella by the name of Paul Hammond who was a Portland State geology professor for 30 years from the early 60s until the early 90s and then after retirement he kept Dolan and he paid kids out of his own pocket to continue the research these young kids with their legs that can go up into the goat rocks wilderness etc and put these maps together so there's evidence tonight for these volcanoes that no longer are there and that's really our focus tonight so that's the introduction let's get into something specific the Cascades run from southern British Columbia down to northern California there's more than a dozen of these cones and those are the Cascades that we know and love there are no volcanoes further north there's no volcanoes further south in this line but there used to be so the Cascades go back 40 million years there's a 40 million year history with the Cascade volcanoes however if we go back 40 million years and look at a plate map so this is North America and this out here is a seafloor spreading center this is a map 40 million years ago 40 million years ago so if you've heard of the mid-atlantic ridge it's a place in the middle of the Atlantic Ocean that makes new ocean crust and then the crust spreads away in both directions we're making new plate material it's an underwater mountain range it's an active volcano it's a whole continuous ridge this is the East Pacific Rise and it used to dominate the bottom of the Pacific Ocean so this is North America this is the western coast of North America 40 million years ago and here are these two oceanic plates under the water the Pacific Ocean and this thing is called the Farallon plate I'm sure you haven't heard about it the Farallon plate that's coming at North America and this is the Pacific plate which still exists today that's the one that's grinding along the San Andreas Fault so when we had this monster ocean plate called the Farallon plate it was heading towards us and then 55 miles offshore of the coast of North America that oceanic plate started to dive it started to subducting artha merica and that's really how we make big magma chambers like this big underground rooms of hot magma that eventually get to the surface and feed volcanoes so my first point tonight is that 40 million years ago we had an intact chain of volcanic mountains from Alaska down to Mexico not just here in the northwest but we had Northwest like mountains that were cone volcano stratovolcanoes from Alaska down to Mexico why we had this huge Farallon plate subducting beneath the entire west coast of North America okay but we're gonna change that story as North America starts drifting west so since 40 million years ago the only thing changing is North America is going to start drifting it's going to char drifting closer and closer to the specific rise so I'm going to flash-forward to today about 20 million years ago the East Pacific Rise the thing that was making the Farallon plate started slipping beneath North America in other words North America started crossing this thing and by the time we get to today now here's North America now here's the west coast of North America now we mostly have the Pacific plate that's offshore of California and there's no longer subduction because this oceanic plate is going towards Japan and we only have a small little piece of the Farallon plate that's still around that says JDF that's the Juan de Fuca plane so the reason we have the Cascades today is because we have the Juan de Fuca plate subducting and making our line of volcanoes that we know and love is the Cascades but that's a remnant I'll make a pea pod with a bunch of peas in it again so that is but the real interesting question is what happened to those volcanoes that used to be in California in other words if the volcanoes used to be here and they're gone are they still there can you point to the volcano and just say that well that's a volcano that doesn't erupt anymore or is it worse worse meaning is the volcano completely erased and gone and you know where I'm going those are our first ghost volcanoes to talk about tonight there are ghost volcanoes in eastern California and we can do this X is tonight are going to be ghost volcanoes places where a cone is gone but evidence is what we need to prove that that cone used to be there so you're like I'm intrigued now I'm putting words in your mouth I'm intrigued tell me more where can I find the way these volcanoes used to be in California the answer is the Sierra Nevada mountains so if you've been to Yosemite or King Canyon Kings can you excuse me or hiked on the John Muir Trail or take an IAT over Donner Pass you're crossing the Sierra Nevada mountains of Eastern California what kind of rock is in the Sierra Nevada mountains thank you granite now granite forms down here so let's get rid of our subducting plate let's solidify the magma let's turn the liquid to stone and now let's do some serious amounts of erosion let's you rode let's see a road let's keep going let's you rode some more hell let's keep going let's he rode some more and by the time we get done you racing we're left with a mountain range called the Sierra Nevada mountains we're even the very tips of the tops of the Sierra Nevada mountains not Whitney the highest point in the lower 48 state is made out of granite that formed underneath a volcano so for the first time we have a ghost volcano can you see it now the ghost volcano was there but it's gone so what's our first way to prove that a ghost volcano existed the answer is magma chamber rock and if there's a lot of that magma chamber rock and we'll go ahead and call it granite but sometimes you can call it diorite if it's got some different chemistry but if there's a hell of a lot of this magma chamber rock we call it a batholith you can have a batholith of granite or a batholith of dier and it just means you got a lot of it okay so batholith eastern california down south here ghost volcanoes from a time when the Farallon plate used to subduct okay so far next big point you love the Cascades you better because they're not going to be here forever you better enjoy the Cascades because they're going away and you're like oh my god really like the glaciers are going away and now the Cascades are going away what do I mean well if you followed what I was just talking about there's work to be done the job of crossing the East Pacific Rise is not complete do you see what I'm saying North America continues to drift west and in the next five million years there's an energy in the room like a sadness like on the Cascades oh you got five million years to enjoy the the Cascades before they go away you got five million years okay relax all right but eventually North America will continue to cross the East Pacific Rise and we will have nothing but the San Andreas Fault coming up through this whole scene and our beloved Cascades which are volcanoes not ghost volcanoes but volcano volcanoes will eventually all go away and we will have Snoqualmie Pass going across the batholith in other words we'll have a Sierra Nevada mountain range here in Washington and Oregon when our Cascades go away so that's the broad story of going 40 million years to five million years into the future okay let's zero in a little bit more on the Cascades in the Pacific Northwest we should feel better this is where we live you are sitting right here and how home center right there we are east of the Cascades okay so the Cascades are 40 million years old but am I really saying that Mount Rainier is 40 million years old or Mount Hood is 40 million years old or Mount Shasta is 40 million years old I'm not individual cones in the Cascades have a two million year lifespan a two million year lifespan that's relatively short I mean we'd go for two million as humans right what are we got 80 90 a hundred years if we're lucky we take 200 years but these cones have a two million year lifespan and yet that's short that's a short life compared to the history of the Cascades so now if you're a step ahead of me you go all I understand why we must have a bunch of ghost volcanoes in the Cascades if these individual cones these circles these peas if they only exist for two million years and we got 40 million years of action there must be dozens of ghost volcanoes in the Cascades and there are each of those X's is a place where a cone had its moment in the Sun for two million years and then it went away and another cone pops up two million goes away and another this is all being fed by the subduction of the Juan de Fuca plate but it's a bit of a mystery as to why these cones only exist for two million years and then they stop and go away completely and then their neighbor pops up and we get a new cone there okay well we would need to explore that a little bit because that's really the meat and potatoes of this lecture what was Paul Hammond the guy from the University of Portland State University finding in the East slopes of the Cascades between Yakima and the crest of the mountain he was finding some batholith material so that's one way to tell us that we had a cone and you're like okay well I I'm not sure I totally buy that well you need to get the age of the batholith the age of the granite you need to get the chemistry of the bath let the geochemistry which minerals are present what are the isotopic cheers etc and you need to build a case just like Atwater was building a case with the ghost forest so Hammond has been building this case for 40 years 50 years really but 40 summers he trained dozens and dozens of young geologists over the years many of whom are professional geologists now so it's a living laboratory for this guy Paul Hammond so if we make a quick list maybe just three so if we make a list of evidence for our ghost volcanoes we've already talked about one we talked about it in California but I'm telling you that there's something called the snow Kwami basileus and the index batholith and the Chilliwack batholith in places that you know which are big blobs of granite and diorite that are the plumbing system of cones that used we used to have a cone right on top of Snoqualmie Pass right that's no Colombia pass it's ironic when you cross the Cascades on i-90 today over snow Columbia pass you never see a volcano you know there's never a glimpse of rain there but it is a volcanic mountain range and there used to be so in other words there's a ghost volcano on top of snow Columbia pass a second way and this is really the main way that Hammond is making a case in this place west of Yakima is to look for partial Cowen's so let me explain what I mean we know these strata volcanoes are cone-shaped we're we're fine with that hopefully so let's draw again I'm not much of a draw but I can even I can draw Mount Rainier okay that's a cone so Mount Rainier is a full cone it's not a partial cone because it's still active if interrupts it rebuilds itself as we'll see tonight st. Helens is a active cone it erupted in 1980 it's rebuilding itself right now Mount Mazama in southern oregon known as crater excuse me yes known as crater lake has wizard Island that's the the mountain rebuilding itself but if you truly are a ghost volcano you lose elevation and there's no way to rebuild yourself because the magma is gone there's no putty left to rebuild yourself so partial partial cone is just like it sounds let's make a couple more goes to volcanoes and by the way we can assume just for a nice round number that when we have our full cones they're about 15,000 feet high let's pick a nice round number 15,000 I know reindeers not quite that but let's just do that okay so 15,000 feet is the height of Rainier roughly there's a partial cone in other words a ghost volcano just south of White Pass where the bottom half of the cone is still there but the upper half of it is gone has been eroded because it's it goes to volcano this is known as the goat Rocks wilderness and the goat rocks volcano I might as well give you some ages right now two point six two zero point six million years old there's our two million year lifespan and so our goat rocks volcano I'll show you plenty of video clips and other things tonight is a partial cone effect it's truly a half and I'll show you a map of the a chimera in just a second a more severe version of a partial cone is where most of the mountain is gone most of it is gone but we simply have the base that's left the base of the column that's left and there's certain kinds of deposits that prove were at the base there's often times from a map or a Goodyear blimp view a circular crater that helps us reconstruct that we are truly down there at the guts or the floor or the bottom of that old cone so those are a second line of evidence to reconstruct these ghost volcanoes I'm setting up for all these video clips and images coming in just a bit but there is a third way and it's damn clever a third way to try to convince somebody that a ghost volcano used to stand even though the mountain is totally gone you want to try to find flows lava flows or mud flows that came out of the volcano when it was active flowed 30 40 50 miles away and even if the cone goes away we still have the flows can you picture that it's like we got the spiders legs but we don't have the spider anymore if we look on a map and if you study the chemistry of those flows and the age of course of those flows you can reconstruct them so on a map we can look at a ghost volcano these are typically dashed circles on a map as we'll see over and over tonight but we might have a lava flow that traveled oh I don't know 50 miles and I can't hold it I got to say what it is now so this particular ghost volcano you know what I can do that here so I made a map for you before you showed up before they open the doors and we had a who concert and here people fighting for their chairs sorry if you can't see this wealth in the back of the room but if you're a good map reader you can recognize this this is Yakima Washington this is Mount Rainier this is the crest of the Cascades and we have one two three four five ghost volcanoes between rainier and yakima and these white lines their highways here's four ten here's us twelve and I got to tell you I just get a pang of nostalgia every time I say us twelve you know us twelve is a National Road it's a US Highway it goes across the country and I'm from a little town in Wisconsin and us twelve goes through our little town in Wisconsin and our farm is two miles on West stuff down on us twelve that's how we used to say where our place is it go two miles out on twelve you'll see it on the left so when my parents used to drive out here to visit us in Ellensburg from Wisconsin they'd just get on twelve and just follow it all the way to Yakima and then head north when they got to Yakima okay so I was going I was we're on number three here slows coming away from a ghost volcano the partial cone is still there this is go rocks this is the Fife speak ghost volcano this is Mount akes this is Edgar Rock and this is the Titan we'll talk more about them in a second with the images but we're talking about flows coming away from a ghost volcano and an absolute freak show meaning andesite rarely flows andesite is it kind of a lava that doesn't usually flow more than a couple of miles because it's too sticky but for reasons that are still open for debate the titan andesite first of all it sucks because it didn't come out of the titan volcano there's a naming problem here so the titan andesite came out of the goat rocks volcano and it traveled 50 miles the goat the goat rocks eruption produced the titan andesite lava and i'm drawing it on the map here again if you go to Rainier and you see some andesite lava flows currently andesite lava flows meaning in the last few thousand years those andesite lavas barely leave the National Park they don't get very far but for reasons we don't totally understand this one flow called the titan andesite when the ghost rock volcano was a volcano and not a ghost volcano flowed 50 miles this is Rim Rock Lake before the lake existed it came right down u.s. 12 before his new 12 existed this is this is one and a half million years ago when this happened and this Titan andesite made it all the way almost almost to the Fred Meyer in Yakima well painted rocks if you know where that is how witchy Canyon that's the end of the line for this Titan and aside interestingly and I've got this map so I might throw it in here have you ever stopped if you're on US 12 and you cross White Pass and there's a little Forest Service place to stop and have a picnic lunch and use the restrooms it's called Palisades anybody know where it is if you go to pack wood you've gone too far but it's a cute little spot and there's a cliff there and there's some beautiful columns some rock columns that's another lava flow that came from the goat rocks volcano so this goal rocks volcano is a big structure only half as big as it used to be but we're using these flows even though the mountain is almost gone we're using the flow as to reconstruct where it came from I want to do one more thing with these chalkboards and then we'll turn it over to the images have you ever driven on twelve in other words you leave Yakima stop and get some fruit get a pizza and a beer at the new place there take a left at the Y and then as soon as you take a left at the Y and you're on twelve by the up feeding station Oak Creek there's some beautiful rock columns on the Left right beautiful wall and I don't know if you're not a geology person maybe you don't say anything but if you're a geology person you can't hold your tongue you've got to start talking about it right and perhaps you start talking and you're saying wrong stuff like a everybody look out to the left now or don't Creek and that's a basalt lava flow and those columns are from basalt that's cooling and cracking well you're totally wrong you know and you're just going on and on and on and people are like looking out the you know the passengers like doing the math like no we're only going thirty if I do a shoulder roll I can get out of here alive and I work on listen this guy even if I'm seriously injured is better than listen to more of this droning from this guy mansplaining to me about columns well let me cut to the chase here those columns are the titan andesite those columns are not in basalt they're in this 50 mile long lava flow that came down from White Pass and so the last concept which is kind of tricky now we're getting to real details and just that stretch Oak Creek up to rim Rock Lake you know with me kind of rim rock retreat kind of in there you're in the Titan Canyon so there are some columns how can I do this now this is Yakima's over here and White Pass is over here this is crappy image now but we're gonna try it anyway and so there's the columns in the Titan andesite are beautiful they're not only tall they're really exceptionally wide and locally they're called the royal columns and they're the climbing community loves going there and rock climbing on those columns now that's the titan andesite and so that lava flow is coming from the Cascades it's coming from White Pass so I'm going to put west up here and I'm gonna put east up here and I want to put some letters here if you don't mind so this is the titan andesite coming from the goat rocks volcano again that's the one that I think a lot of people think are basalt but there are some basalt lava flows at certain places in some places below the Titan andesite and some of those have columns as well now that is basalt but that's lava coming from 300 miles away over by Idaho so these are part of the flood basalts that are famous in Eastern Washington so the Titan and aside from Goat rocks volcano the basalt from damn near Idaho fissures are way over there okay so that's one of our tricks when we visit some of these places visually is you know I try not to say too many times it'll just get you know you'll start to try to get out of the car but are we looking at the titan andesite columns are we looking at columns from the basalt which is 15 million years old and this is my main point is this is a geologic crossroads this area that Paul Hammond is mapping he's not only finding the Yakima tau which Canyon Titan Canyon got rocks wilderness etc he's not only finding the ghost volcanoes but here come the lavas from these cracks out in eastern Washington the basalts that are flowing this way that's this stuff and then here's the goat rocks volcano too small to see on this map flowing from west to east so it's a crossroads of two different lava flows with different signatures and to the untrained eye just looks like a bunch of lava erupted it's dark color so perhaps this lecture can help with that if you know and love this area and why wouldn't you love this area if you don't know this area well it's beautiful I mean oftentimes the best geology places are just boring dry ugly places this has got interesting geology and it's absolutely spectacular scenery as well so give us a second we'll talk about getting set up for the slides here so I'll be with you in just a second thank you alright you're ready there's gonna be a barrage of stuff but most of it is uh pretty pictures so let's go ahead and get started so we do have these gorgeous stratovolcanoes there is no denying this so today what do we have we have Mount Rainier today what do we have volcano volcanoes not ghost volcanoes this is not Adams down by Yakima this is mount st. helens of course that looks a little different because it was active on the morning of Sunday May 18 1980 and young people in the room this is what mount st. Helens look like before 1980 and after the eruption mount st. Helens before the eruption in 1980 and after but the key point is these are not ghost volcanoes they still have magma and they rebuild themselves pretty quickly so we have regular eruptions of these cones after they rebuild themselves we have no video of those first few seconds but we have some photographs that help us understand what happened on that dramatic morning in 1980 this is Mount st. Helens this is the pyroclastic blast out in front of the lahar and trees being blown over like matchsticks and then for the rest of the day ash coming out of Mount st. Helens an active cone still active still has magma beneath it and that fine ash is being blown down when two communities like Yakima and Ellensburg this is Ellensburg on top of Craig's Hill on that day one o'clock in the afternoon too much ash in the atmosphere to see the Sun and the next morning on Craig's Hill a fine ash that you can still find if you know where to dig in your backyard so st. helens are still there it is in the process of rebuilding itself although right now it's pretty quiet now take that ash from 1980 and compare it to the ash that we can find from Mount Mazama which exploded also a cone also an active cone which exploded seven thousand seven hundred years ago and so here's a case where the whole mountain is gone and we're just left with the basal section but it's an active column so it will rebuild itself we only get a ghost volcano if we remove the heat if we remove the magma system completely so these are photos of Mount Mazama better known as crater lake today now ms we're nervous that rainier will do something like that but there's no way to forecast that and so we'll just hope for the best that's not a great strategy but we'll hope for the best and at least we're monitoring these mountains and can get a good sense of when activity is brewing in other words when magma moves we have all sorts of seismic information to help us track that so from downtown Tacoma we can see Rainier from Crystal Mountain and we ski we can see Rainier you can see Rainier from downtown Seattle even on the east side over here we see Rainier it looks different than the west side because it's the side of the mountain you know it looks different over here and you can go to sunrise in Mount Rainier National Park and you can walk right up to the dang thing you know you put your hand right on it and some of you have spent years climbing to the top of Mount Rainier and I applaud you for that I'm not much of a mountaineer personally and people come from around the world to visit Rainier because of these beautiful photographs and these beautiful wildflowers and you can get out of your car and walk just a few feet and gets experiences like this it's a tremendously accessible place and it's not just Rainier of course it's all of our stratovolcanoes in the Cascades now we have been studying these cones for a hundred years and we still can't forecast the next event but with Rainier before we leave Rainier there was a famous event that happened 5600 years ago and I'll show you this old animation which is still the best I've seen of the north east flank of Rainier failing a catastrophic landslide the landslide converts into a mud flow I know this looks like lava but it's a mud flow a lahar or a mud flow is just simply a la a landslide that converts into a flow because of so much water present so here comes this Osceola mud flow it's called 5,600 years ago coming down the White River Valley and when it finally gets down to the flats down at enumclaw it starts flooding the South Puget Sound with all this material we've got tens of thousands of hundreds of thousands of people living on top of this thing now and Rainier has rebuilt itself and so there is some concern interestingly we really don't have this is footage of a lahar a volcanic mudflow it's like liquid concrete coming down a river valley it's a hazard of course or I didn't mean that to be funny but I'm going but we Paul Hammond when he's reconstructing the ghost volcanoes in the area we're talking about tonight there's really not a whole lot of lahars present I'm not quite sure why that is there are some lahars there but they're much much younger than the age of the ghost volcanoes we're going to be talking I wanna stick with this because this is st. Helens now consoled mud flow coming down the turtle River Valley in 1980 but we're sticking with it because now we revisit what Rainier looks like after it did its Osceola mud flow story and there's this huge open horseshoe that needs to be refilled and again it's an active cone so magma will be coming to the surface and rebuilding the top of Rainier which has happened in the last fifty six hundred years of time and so it's an ongoing process and it's it's it's fun to kind of appreciate that okay remember we went broad there for a bit and talked about the Cascades being part of a much larger story and here's the East Pacific Rise which has yet to slip in East South America so another way to say this is North America used to look like South America today South America stratovolcanoes going all the way down its coast from north to south they have the Andes so we had an Andes mountain range but it doesn't exist anymore because of North America crossing this East Pacific Rise that's what I tried to do with you on the chalkboard you specific rise he's specific rised and now the East Pacific Rise is only still out in the water offshore of the Pacific Northwest and that's why we've cornered the market on beautiful cones and everybody else has lost theirs from the side this is what it looks like North America coming in here's the subduction feeding the cones feeding the cones but we're getting dangerously close thirty million years ago to crossing over these Pacific Rise at least in California animation in case you can't quite put this together in your mind yet subduction of an ocean plate large volumes of magma they rise they feed magma chambers we're gonna form batholiths of granite and diorite here we're gonna have cones up there until when until we get rid of the subducting ocean crust if we can get rid of the ocean crust then we'll get a bunch of ghost volcanoes and that's what's happened in Eastern California here's another animation in case you loved these the last 40 million years of time North America crossing the East Pacific Rise in the south and has yet to cross the East Pacific Rise on the north here's California losing its volcanoes as we speak as this time goes by so if you go to Eastern California and the mountains called the Sierra Nevadas it's one huge batholith there's different ages of magma so you can reconstruct different ghost volcanoes but generally it's one huge big pile of plutonic igneous rock here it is we froze the pipes we remove the subduction zone and then in the case of Eastern California we actually actively lifted Eastern California and so that volcano didn't stand a chance God he wrote it away very quickly and easily and successfully and the gold rush of 18-49 is part of that story by the way so here's this batholith of granite then coming to the surface and here it all is that magma chamber rock baffle with material today in Yosemite Park I'm saying this is the future of Washington and Oregon Cascades not bad you know you know we're fine well it might lose our cones but we'll still have gorgeous scenes like this to hike to and you're like well I know places in the Cascades that are like this and yes you do those are places where there are ghost volcanoes currently but I'm saying the whole Cascade Range is going to be one big ghost volcano once upon a time in the future so here's our more than a dozen columns strung from British Columbia down to Northern California this is an important diagram I didn't talk about this before let's get our bearings here first of all so this is you're enough what are you you're above Seattle in a hot-air balloon and you're looking east over the Cascades you're looking west to east can you do this Canada's on the left Oregon's down here on the right this is a north to south cross section of the Cascade Snoqualmie Pass is right here so Seattle crossed the pass and Ellensburg is over the horizon okay hope you can see that because there's an interesting difference between the Cascade exposures north of Snoqualmie Pass versus south what's the important difference there's been more uplift of the Cascades north of Snoqualmie Pass than south I don't have an answer for this I don't have a reason why and I've tried to go to all my sources and they all kind of shrugged their shoulders but we know that's true because magma chamber rocks the baffle lists in the Cascades are dominating north of Snoqualmie Pass in other words all the ghost volcanoes are gone oh we don't have partial cones in other words we've either got magma chamber rocks the basileus or we've got active cones like Glacier Peak or Baker but south of Snoqualmie Pass please notice that there's a bunch of these layers here are the partial cones and the lava flows like the titan andesite etc so Paul Hammond this guy from Portland states no dummy he wants to find these ghost volcanoes he wants and deposits to work with so he went south of Snoqualmie Pass for a reason so if we're north of Snoqualmie pass before we get to the Yakima area it's the magma chamber Rock we're looking at here are some specific examples so just east of Mount Baker is the Chilliwack bath of the 35 million year old granite who cares here's why we should care we've got ghost volcanoes don't we that used to stand here they're gone but remember number one on a list of evidence if you have a big batholith you can place some ghost volcanoes on top of that let's go further south here as US to over Stevens Pass heading towards gold bar and down to Monroe index batholith grotto batholith cloudy past batholith a few others I don't know the names of and appropriate ages and the one I'd like to stop and talk about briefly the Snoqualmie batholith from 25 to 17 million years old and you like hold on now you said these cones only have a two million year lifespan well we probably had multiple cones at different times during this timeframe perhaps the cones were actually nested perhaps they were parasitic on each other you've been to the three sisters those are three strata cones that are kind of growing on top of each other so that kind of a scene could be appropriate but notice were right at the pass we're right to the north of the pass some of your favorite cascade hikes are leaving from I 90 and going north if you're not there in a weekend it's a pleasant experience so here's looking east up into Snoqualmie Pass country and I'm telling you that none of those mountains are volcanoes then none of them are active cones and only some of them are part of the Snoqualmie batholith again the pass is up ahead this is the westbound side Franklin Falls is right below this overhanging bridge and this is part of the Snoqualmie batholith there so remember with the Snoqualmie Pass area and North we lose all the cone material and instead we're focusing on these ballasts that are exposed if we can get rid of the cones themselves let's do more with the Snoqualmie batholith it's a B beautiful rock that granite is absolutely spectacular and if you get a good image with a with a I guess that's a dime there we've got real detail with korch and biotite and a bunch of key minerals that can help us reconstruct the chemistry of what that volcano was like so in the case of the snow called me batholith we've got two pieces of evidence to put a ghost volcano or two on top of that what's one the batholith itself what's another a lava flow that flowed from the cone that's now a ghost volcano that makes the escarpment for Snoqualmie Falls so we've got a lava flow and Snoqualmie batholith matching an age matching in chemistry and these are the kinds of things you can do if you're clever and piece those ghost volcanoes together here's an old favorite shot of the sunset highway crossing and near Snoqualmie Falls now there's history of course with Snoqualmie past as well we got model tees back in the 20s and we've got more modern vehicles in the whatever 50s 60s I guess and even today they're blasting like crazy the last few winters excuse me summers to make that a more safe area so what are they blasting they're blasting flows from ghost volcanoes that's the Ohio Picassa formation let me show you some more photographs they're working with the float they don't know what the guys working they're probably actually they do I had filmed a little video up there and the guy says I'm curious about this rock what can you tell me and I'm like I don't know I haven't I haven't done my homework but I know now I gotta need to go back up and tell those guys so this is the dangerous curve that they've been blasting back to get a third lane up in there and these are all lavas andesite lavas rhyolite lavas de site lavas that are too old to work with the modern cone so these are ghost volcanoes the location of the ghost volcano still undetermined as far as I can tell but these are spots that you recognize I think at Hyack and other places it's all lavas from volcanoes that no longer exist aka goes to volcano but now we finally leave Snoqualmie Pass and we get down to the yak Ameria which is where we want to be the rest of our time tonight and here's a living color map of what I tried to do on the white chalkboard Yakima we are located here in Ellensburg here's the y us 12 for 10 chinook is here White Pass is here you're in National Park Country there Adams and st. Helens got your bearings now here's Paul Hammond saying look if you really start mapping these ghost volcanoes you got a bunch and we're just focusing on five between Yakima and the pass so you recognize this this is Rim Rock Lake it's an artificial lake it wasn't there naturally but they built the dam in the 20s to make a reservoir there there was no lake at all before they built the dam but it's a beautiful lake and there's cabins and there's a boating community etc on Rimrock lake and there's all sorts of wonderful places to camp and get some snacks at the Rimrock grocery and I'm not a botanist but I think these are ponderosa pine trees that are really beautiful on the east slopes of the Cascades here's the guy we're talking about tonight Paul Hammond the guy who is about to turn 90 and is still at it still working on the maps still working on these stories and training all these young folks so he's had more than 50 years of training of people who are eager and wanting to learn from the master and he's an understated humble guy but these are the kinds of maps that he's been creating hand-drawn maps hand colored maps year after year keep modifying the maps keep getting new samples keep getting more geochemical data to piece that all together and he has devoted his time in past summers to local cabin owners to learn about their surroundings from this guy classic Paul Hammond illustrations colored hand-drawn this is a schematic cross-section of all these different baffle lists at different ages and their relationships from the archives Paul's son managed to find a few old photos of Paul's so these are just a few weeks before Mount st. Helens erupted so this is Paul the guy who's about to turn 90 but we're back we're turning the clock back now to 1980 and he's working with students even back then think of the excitement he's already worked in the goat Rox area for 20 years and st. Helens is about to go you know he's been trying to imagine an eruption and now it actually happens south of his field area it's a lot of pointing in these photos one more example of the detail the fine craftsmanship of Paul Hammond and his geologic sketches and maps now this is me taking Paul's work and trying to make it even more simple which is you know I'm guilty of that I make things sometimes too simple but in the case of Paul here's what I tried to show you on the black chalkboard active cone reindeer here's our goat rocks volcano which is a ghost volcano but not hasn't been ghosts for very long remember this is the one that's still half as half of it still there but here's four 10 and here's 12 and here's Rimrock Lake and can you now see our players mount takes 24 million five speak 23 Edgar rock 26 bumping like pluton 28 million Titan volcano 25 I don't have an answer for why all these ages are close to each other what was going on in the mid 20s 20 million years ago to have all this action in this small area nobody knows nobody knows and I meant to make a professional diagram never got to it so this is a doodle on my desk and my mark my Sharpie markers but you get the idea we have different levels of erosion with these different partial cones and if we put them together I don't know you can pause this if you're watching it and try to connect the dots here between these places we don't want to do that in the case of the Titan volcano another good piece of evidence that you're driving through a ghost volcano you see all these dark blue lines these are all dikes and a dike is a vertical injection of rock through horizontal layers and a stratovolcano typically has thousands of radial dikes they're called throughout the mountain so even though most of the volcana was gone these individual dykes have been mapped hundreds of them have been mapped this time by Don Swanson a different geologist but the point is here's part of the guts of the Titan volcano and even deeper goose egg mountain west wall rocks coachmen Rock chimney rock those are parts of the magma chamber of the Titan volcano so we're looking at rim rock we're looking at parts of the magma chamber of the Titan so we're one of these ghost volcanoes now it's 25 million years old and you might recognize this this is right by the dam you can drive right through one of these magma chambers one of these batholiths so this is Westfall rocks but you're driving through the uplifted batholith of the Titan volcano beautiful craftsmanship on that tunnel by the way and I had help from some locals ray and Steve and John who are finding good spots for us to film and also to take students and other field trips so again baked magma chamber bath think the baths worth of the Sierra Nevada mountains if you like just a smaller version hayatun volcano the ghost volcano the volcano is gone but we're looking at the magma chamber rock and in certain places that magma chamber has been heavily eroded to these pinnacles of klutz man rock so we've been here looking at the magma chamber and I was showing you a photo or a map of the radial dikes of the Titan volcanoes I wasn't kidding you drive on highway 12 right through this ghost volcano if you stop and have a meal that Rimrock retreat now since that I brought my students my central students down there so we have a Pacific Northwest class and so we went down three Wednesday afternoons in a row and they read scientific papers by Paul Hammond and others and we had discussions and we hiked together and these are some of these columns that I want to be talking with you about in just a bit so some of you know that these this Tyus and andesite these columns are right there next to the road and they're part of this story so if this is if this is all the titan andesite where did that lava come from I say if this is the titan andesite where did this lava come from they vote rocks volcano very good there's a lot of beautiful columns in this titan andesite is it an anti side or a basalt it's called the Titan and the side so it's an anti side of course it is good job you're two for two everyone knows the spectacular cone-shaped stratovolcanoes of the high cascades but the Titan River Canyon then west of Yakima a four and a fifth ancient volcano which stood where we now have Goat rocks wilderness the Titan River tumbles from high in the Cascade Mountains down to the sagebrush and lush orchards of Central Washington everyone knows the spectacular cone-shaped stratovolcanoes in the high cascades but here in the Titan River Canyon there are stories to be told of huge cone volcanoes just west of Yakima four of them and a fifth volcano that used to stand at Goat rocks wilderness a Mount Rainier like volcano once stood right here the volcano is gone the lava flows are gone the only thing remaining are monoliths down there above the lake that are part of the magma chamber from 25 million years ago in the dark the magma solidified diorite that's 25 million years old this was the magma chamber the plumbing system underneath that cone the volcano is gone but these monoliths tell us that this was ground zero for a beautiful strata of volcano now let's switch it up just briefly we all live here or many of us do some of us are from out of town and there are some white cliffs out by thorpe on highway 10 the old road to clear those white cliffs are part of this ghost volcano story from Paul Hammonds area the volcano 10 million years old younger than the ones we're just talking about used to stand just north of white pass between bumping lake and White Pass and that volcano made a lahar a volcanic mudflow and followed an old river valley up to here this is before man - - ridge and i'm tantum ridges groove so even in our little valley our picturesque Valley we've got tentacles of flows that came from the ghost volcanoes down by us 12 those are not sand stones those are lahars if you don't believe me I'll take you out and prove it to you it's all sorts of pumice and other deposits that mean it has to be a volcanic mudflow cannot be a sandstone there is sandstone in the area but not here ghost volcano 10 million years old flowed volcanic mudflow material - thorn okay to finish up we're back to our area that we've been studying with Paul Hammond crappy photo of Mount Rainier crappy photo of the goat rocks volcano half is baked we've chewed off the top of it and again we're now zeroing in on the goat rocks volcano one flow heading towards the Palisades picnic tables and the restrooms another flow this is the titan andesite flowing 50 miles almost to the Fred Meyer in Yakima now how can we find that tie at than andesite what does it look like well here's one way to do it again this is a rather dangerous curve to stop and lead a geology field trip but this is all tie it's an andesite and we're going to pan up with the iPhone here and this is all Titan andesite the lava flow that's not the salt that came from the goat rocks volcano now keep in mind that there's different kinds of volcanoes worldwide and the volcanoes have different silica content and we have been firmly in this picture the whole way tonight but if we are talking about basalt and we at selected places in that Canyon the Titan Canyon we got to go to this kind of a picture so here's a quick departure and reminding ourselves that completely different volcanic story involving cracks and fissures and flood basalts from damn near Idaho and flowing all the way to the ocean are invading this Paul Hammond area we're still way out in Eastern Washington now looking at all these lavas but if we follow those lavas approaching Yakima you can see how thick some of these lava flows are they're gonna invade the Yakima area nat cheese and they're gonna work their way right up to the rim Rock Lake area so do you see what I mean it's a crossroads we got lava coming down highway 12 and we got lava coming up highway 12 depending on which lavas we're talking about so these are the fantastic columns of basalt not andesite out in Central Washington in Eastern Washington and yes these are basalt and yes guy who's explaining this all to us that is common for basalt it's rare to find columns in things that are not basalt lava but you can find them like in a place called the Titan Canyon so this is another little episode from our TV show and I think we're just gonna skip it no we're not because it we're gonna kick to keep with this because we paid some money to make a little animation to show how these columns form so let's get our money's worth here this is fun I can put my own words on top of this instead of being confined so I'm talking about the columns forming from cracking the LOB as it cooled I'm hanging on to my hammer very carefully in this particular shot drone footage going down on top of these columns and looking how perfect these columns are from the air oh you like that shot okay good I do too the Hammers right mm-hmm and now we're comparing it to Hawaii which doesn't really work because the scale is totally wrong but the chemistry is right and now here's the animation so we say to the guys at the animation studio hey can you make one lava flow can you start to cool it but keep the inside red-hot and these cracks are going to start crackling away towards the interior of the flow as we do that they're like yeah I think we can do that and then I'm going to cut it right here but they finished the animation by having the Ice Age floods out in eastern Washington rip off the top of this lava flow but in the case of the titan andesite it's a perfect analog for what we have right here i'm going to show you some photos now of the titan andesite and there's going to be columns at the bottom half and there's going to be this weird chaotic zone called the entablature which no geologist still really understands but it's just like in a simple drawing like this the next time you drive up US 12 you'll see this and please keep in mind that this is one flow I know it looks like two different layers I know it looks like two different flows but the next time you see this or in a second when you see this with the video this and this are from one eruption of the titan andesite coming down from the go rocks looking look at that so here's the bottom of the titan andesite flow here's the top and this is that boundary between the columns at the bottom that are insulated as the lava cracks and cools and then this chaotic and tablature up above so the point is we study the yakima area and we realize we have invasions of basalt lava which is really kind of getting in the way of our story but this is not basalt lava again this is the Titan andesite these are the royal columns and the entablature up above so I've been showing you some photographs and basically right in here and some of you might know those trails right in there it's really a gorgeous place and we had a big field trip in June and we took people to some of these spots again ty Athene andesite Colin's at the bottom and tablature up above go across the swinging bridge people of all ages on the trip it was quite a circus we had too many people on that trip but we met we made it work and have you stopped here at Oak Creek and walked across this bridge and again the columns of the Titan Anderson I can't say that enough beautiful you know May morning and this is an interesting spot because you can actually see what the valley shape was like when that Titan Endocyte flow came down in other words it's very rare to actually have this is I'm getting carried away now this is a ghost valley you can actually see the exact geometry of that valley that this lava flow came flowing down and if you get the base of some of those columns they look just like basalt but they're not we've made that point a million times one beauty thing beautiful thing about the titan andesite is it has a very distinctive look in hand sample it's got these big crystals in it and the crystals are there regardless of where you find it so it's rare for a lava flow to have this kind of a distinctive look and this is a beautiful photograph from Daryl Gussie who were going to meet in just a second but we have turns out there's actually two Titan and decides to separate flows from that ghost volcano so here's the older flow of Titan andesite columns and entablature there's that valley wall but I was showing you photos before at this dangerous curve and this is a younger Titan and aside flow and so for many weeks I was out there with my students and like I don't get this why is the old flow up high and this flow which is about 250,000 years younger lower and next to the river I just couldn't get that geometry in my head and they thought they had it made and then they'd start to get confused in the middle of their drawing and we went back and forth on this for a while and so for at least me I don't know about you but it only works for my head if I can get it drawn just the right way so this is my attempt to show you how we can get to different heights and andesite lava flows into the same valley and have the young flows lower in elevation in the older so panel wise here's the old valley we're gonna fill it almost to the top with titan andesite coming from the goat rocks volcano getting all the way to the Fred Meyer in Yakima one point six four million years here's the Shocker between one point six four and one point three nine million these are dates from Paul Hammond to his team that's you know less than half a million years and we're removing damn near all of this and aside we're only leaving little fragments of this beautiful thick stuff perched on the walls of the canyon and then this next flow comes in the valley floor is actually deeper than it was originally so was that just river cutting to take all that basalt away as that excuse me is that River erosion just to take all this and aside away or their glaciers involved well the glaciers didn't get this far down the valley the glaciers only got to the rim Rock area and not any further south excuse me further down away from the it's the crest of the Cascades so with that concept to go back with that concept of perched little fragments of the Titan and ascent let me help you try to see some of these things they're absolutely gorgeous and you'll never not look at them again when you're driving this drop this stretch I think does a double negative this is one little leftover piece of the first Titan in descent that used to fill the entire picture it's all gone except for this and a couple other places on a map that used to be a purple car caterpillar all the way through here in other words the Titan Endocyte flow filled the whole valley but today this is Daryl Gussie's map we've got these individual little clumps let me show you a few more examples that footbridge there's another little remnant of this major flow that filled the entire valley unbelievably and Endocyte lava flow almost made it to what is now the city of yakima look at these columns right along highway 12 this thick titan andesite used to fill this valley wall from side to side and most of the lava is gone most of the columns were taken out of here and there's just a few scraps of thick tilted columns perched precariously above the busy highway 12 between White Pass and the city of Yakima all right if we go to White Pass and cross and head over to pack wood this is the spot I'm talking about maybe you'll stop next time if you've never stopped there before and sure enough we've got those same columns across the draw and that's another flow another anti site flow actually I think it's add a side flow from the gold rocks volcano this is from the panel there they don't talk about the go rocks volcano on this panel they're on a date we're going to finish by going up into the go rocks itself and actually look for where that Titan andesite came from specifically [Music] a much much younger story of an ancient volcano is also here in the area between White Pass & Yakima the goat rocks volcano stood tall for 2 million years but the volcano died a half million years ago and the top half of the mountain is now gone ravaged by powerful glacial action up here near the goat rocks wilderness there's a volcanic rock layer the titan andesite that's super distinctive look at these crystals inside of this lava rock their enormous FINA crisps of something called plagioclase feldspar and normally when you have a lava flow with big crystals the lava flow does not travel very far but this Titan and aside flowed 50 miles away from its source but if we get up on Pine Grass Ridge we can see those same fat columns way up in the mountains now in addition to finding those big fat columns down by highway 12 and pine grass ridge if you know it is very flat because it's on top of the titan andesite flow so we're getting closer and closer to the source the vet must be up in the wilderness area itself and that's what we're going to finish with we're gonna get right up there so Daryl and Jon are going to get us up we're gonna hike up to or we're gonna drive up into this trailhead to Bear Creek Mountain we're gonna get up my knees were shot last summer but I managed to get up with these guys to an overlook looking into the goat rocks on a Monday morning Daryl thanks for taking me how'd you know those were the two vents distinctive chemistry chemistry of the rocks is different enough for each of the vents that they relate to the chemistry we have for the inside flows [Music] here are some photos from Daryl to show the exact vents and only a few geologists in the room might recognize that this means we're right at the vent we've got a glutton it we've got spatter we've got all sorts of deposits that are falling out of these vents there's all sorts of very special volcanic deposits that tell us this is ground zero up in the goat rocks for those two Titan andesite flows the big one the thick one and then the smaller one that managed to flow into a lower valley Daryl and John working in association with Paul Hammond so we got Daryl on front of the camera with this with this little short TV show 100 years ago field geologists speculated that the distinctive Titan andesite erupted from Mount Rainier but recently Forest Service geologists Derald gussy has traced the titan andesite on foot back to its precise source deep in the remote goat rocks wilderness it took the older Titan insight lava flow about 12 years to flow from Bear Creek mountain to Cal witchy Canyon just outside of Yakima the older flow was dated at one point six four million years old and the younger flow was dated at one point three nine million years old a difference of about 250,000 years between the lava flows those dates put us squarely in the Ice Age where lava flows and glaciers were competing for space if this cascade stuff intrigues you and you know the Cascades like the back of your hand and you want to know more there's lots more that has been figured out in addition to this work by Paul Hammond how they recommend this roadside geology book written by Pat Pringle it's mostly of Mount Rainier National Park but he goes outside of the park including the areas we were talking about tonight and it's beautifully done there's tons of references for that as well and one of the areas that I'm just started to get interested in and may follow through on a lecture down the road there's between the goat rocks and Portland every one of these black dots is a very very young vent much younger than the goat rocks during the Ice Age we've got cinder cones and other little volcanic events that are like erupting into ice and you've got spatter and ash falling on top of glacial ice and burning holes underneath the ice and I don't know hardly anything about these vents you might know but I don't yet even the hills outside of Portland are full of these very young volcanoes cinder cones around Goldendale and other places like that so that's on my list and maybe on your list too so here's hats off to Pat ham if all excuse me hats off to Paul Hammond for all of his work a lifetime worth of work helping us see evidence for the ghost volcanoes in the Rimrock area and perhaps one day even Mount Rainier will become a ghost volcano thanks for coming tonight everybody thanks for coming I feel let's look

Channel: Central Washington University

Views: 132,007

Rating: 4.9035344 out of 5

Keywords: Cascades, geology, Nick Zentner, lahar, Mt Rainier, Mt St Helens, Goat Rocks, Tieton, Tieton Andesite, Yakima

Id: 6H18xVnb14I

Length: 71min 15sec (4275 seconds)

Published: Wed Apr 04 2018

Reddit Comments

[u/alllie]

Central Washington University geology professor Nick Zentner discusses new research on ancient volcanoes in the Cascade Range. Filmed at the Hal Holmes Center in downtown Ellensburg, Washington.

[u/YOUREABOT]

Thanks for posting. I only had to add the word "basalt" to my search to get more than the usual GeoNat stuff. Appreciate Mr. Zentner's enthusiasm. Fascinating stuff!