Moses Coulee - Ice Age Floods - New Thoughts

good morning from Moses Cooley not the Grand Coulee but Moses Cooley also a very impressive Canyon here in central Washington we continue today with our reading of the original Jay Harlan Brett's papers from the early 1920s 100 years ago and I'm learning from Brett's directly and I'm wondering if we've lost sight of a few key relationships that he saw with his grad students from the University of Chicago out here in the field so let's learn from Brett's directly and enjoy learning new things together thank you and let's get started all right well here's what the lower Moses Coulee looks like at 7 30 in the morning in mid-june when it's supposed to be 95 degrees this afternoon so I got up early said goodbye to Liz and Bijou at 5 30 and this is what it looks like about 7 30 on a very peaceful Wednesday morning and I don't know let's walk just for a second this is um uh my little white car is down here at a Trailhead I didn't know about this place it's called hungate and it's public land and there's a public Trail coming up through this stretch and I just kind of wandered up to a place that I thought that I could teach a couple of things that Brett Brett's was talking about in his papers but that trail continues I assume up into this v-shaped cut but that's not where we're going to do I haven't been up there but if you want to come to this spot and explore on your own on this hungate Trail by all means so you're looking up Moses Cooley and this is the north wall more or less Northwest wall and can I point out to you please that there's a high cliff and a low Cliff we can agree on that this is all Basalt lava from 16 million years ago but we're not thinking about the lava today we're thinking about the Ice Age floods and because of Brett's papers a hundred years ago I am newly locked in to the talus so there's a high Basalt wall vertical and a low Basalt wall vertical and both walls have corresponding beautiful Talus aprons so this slope is all a bunch of loose material that has fallen off of the cliff high wall High Talus apron going up about three quarters of the way low wall its own little Talus apron going up about halfway we can agree on that let me just pause for a second and let you kind of follow those High walls and low walls and their corresponding Talus aprons I mean I just never really thought about or really noticed the talus that much but a hundred years ago Bretz was really locked in to the talus and that's our main objective today to wonder if that Talus is telling us something about the age of flooding or if there were multiple floods coming through Moses Cooley so I am eventually heading here this is the this is the publication by Brett that many know and it was published in 1932 it's kind of a culmination of the first decade of work that bretts did here in Eastern Washington but I'm not there yet I'm not there I I have started with the first paper by Brett's um that summarized his 1 000 miles of Traverse in the summer of 1922 and was published in September of 1923. and I've gone through that original paper and I'll post this this is available to you at nickcentner.com if you click on floods in the upper right hand corner you'll get to it and I have a little color scheme uh yellow I just highlight any kind of places so I can easily kind of remember which passage is talking about which place but as you can see I've got my three little pens and Brett's has three generations of ice sheet and three generations of Ice Age flooding so from this point forward Red's going to be the Wisconsin advance and the Wisconsin floods which is the most recent and I think it's safe to say that that's twenty thousand years ago and less younger than 20 000 years ago is Wisconsin flooding in Wisconsin ice sheet but if you haven't seen the last few videos I am now locked into Brett's Spokane flood from the Spokane Ice Sheet which is considerably older and maybe this summer I will make progress on trying to tease out exactly how old old is for those Spokane uh Waters but he also has just a little hint of pre-spokane so that's going to be playful all right let's keep going let's keep going so that's the original Brett's paper the next Brett's paper summarizes his much more extensive field work with his students an additional 2 000 miles of travel on foot and hopping trains and other things this before he had a car out here and that was published in November of 1923 and then I'm also taking this age of the Spokane glaciation a much smaller paper looking specifically at this Talus that I'm talking about from 1924 so that's those are the three papers that I'm that I'm running with here today and that's as far as I've gotten with this Brett's reading so uh can I do this I think I can so to remind some of you who have not seen the last few videos this is the famous map uh produced about 10 years ago of the Ice Age floods showing glacial Lake missoul over Montana showing Glacier Lake Columbia in Northern Washington primarily there's the city of Spokane and here's this ice and the talk is that you have all these channeled scab lands in Eastern Washington notified in dark gray because you've got Missoula water dumped into glacial Lake Columbia and that glacial Lake Columbia then spills into these other locations and the conventional story is that all of this flooding in Gray is coming originally from Missoula Montana and assuming that there's really zero or very little water coming out from underneath the Okanagan lobe and the Columbia River lobe Etc okay well that's what I've been teaching for a long time and that's what pretty much everybody talks about but this is the map that got me rolling on this Brett's work and this older Spokane story this is Brett's 1928 map and if I zoom in with one hand can you see that he has an ice sheet over Spokane Washington and I will let you know that he thinks that's the blue ice that's the Spokane Ice and he thinks that these channels were carved from subglacial flow called the Spokane flood this is Branch now in 1922 and 1923 he's not talking about glacial Lake Missoula and he knows about Glacier Lake Missoula from Joseph Pardee in the 1920s but he's not using that Missoula flood angle he's tying all these channels directly to an ice sheet and it's only over here in Northern Washington where he has a Wisconsin ice sheet which encroached farther than the Spokane ice sheet but remember now the red remember our scheme right that Wisconsin is a the last ice advance and the last batch of floods the Spokane Ice and the Spokane flood is older so once I realized that this Spokane Ice was his main story I said I got to go back and start reading Brett's directly and in places like Moses Cooley which generation are we talking about which color pen do I want to use you know what it is now red is Wisconsin younger than 20 000 year old floods and blue is far old that's all we can say so far with the Brett's work far older than 20 000 years ago well let me do it for you Brett says blue Spokane far older than 20 000 years ago is responsible for the high cliff and the high Talus in other words there was at least one major flood that came down Moses Cooley far older than 20 000 years ago and this Talus Brett says in the 1920s this Talus has been gradually accumulating since far older than twenty thousand years ago and it's still accumulating today this is essentially horizontal lava with essentially vertical fractures within it freeze thaw freeze throft freestyle everything's in place this is not from Ice Age flooding this is just in place gravity pulling broken pieces of Basalt down here but Brett says look at the height of the talus up to three quarters up the cliff and if we pick a number let me just pick a number I I don't I'm hoping that the number can have some meaning later this summer but let's pick a number right now let's say that the Spokane flood event down through Moses Cooley happened a hundred thousand years ago then Brett says that we've had gradual accumulation of talus in this amazing apron gradually over the last 100 000 years he says that's high and untouched Talus and so you can go ahead says Brett's you can go ahead and bring in some Missoula floods no you can come in and bring some wisconsin-aged floods and Brett says I have evidence for it that's the lower cliff and the lower Talus I'm in red now right so Brett says I do have evidence for younger than 20 000 years or Wisconsin age floods but they're down here low they're cutting this inset Notch where all the hay fields are today if you're losing it I'm saying that there is a wisconsin-aged story in Moses Cooley but it's only down here low according to the work of Brett's and according to the work of Brett in the 1920s he says the far greater flood that did far more impressive carving happened way older than the Wisconsin age I mean to me that's rather bold and a brand new way to think about things as I drive up Moses cool I don't know how many times I've driven at Moses Cooley with Randy Lewis and plenty of others and how many times have I driven up Grand Coulee and have I really visually picked up on the fact that the height of the talus is potentially a way to measure the age of Canyon development with Ice Age floods the same high Talus walls in the grant than the lower Grand Coulee and the upper Grand Coulee too and yeah bretts is saying that the Grand Coulee also was carved mostly in the Spokane time in the in the blue pencil time the blue pen time Brett says that when you get to Wisconsin ice and Wisconsin flooding in other words younger than 20 000 years ago he says the only place those waters are going are down through Moses Cooley and down through Grand cooling it's probably mostly coming down Grand cooling it's not coming down Moses Cooley much based on what we just said here that's a revelation to me at least in the 20s Brett says there's no younger than 20 000 year old water coming down Cheney Palouse or Telford crab Creek is that right dropping down into the cut made by the Wisconsin floods according to Brett foreign starting to heat up already it's only 8 30. so I don't know I guess I should add that perhaps Brett's himself changed his tune but regardless if he changed his tuner or not pretty much everybody today who is thinking about Moses cool he is confused by it is it really all Montana water that came down through here and did the carving is it really all younger than 20 000 years ago that much is clear I think that really nobody is saying that this Moses Cooley scene is wasn't here at all 20 000 years ago I think I'm picking up on that regardless if it's Brett's or somebody today doing some work this seems like one of the old places with multiple flooding Generations but boy where you go beyond that is a challenge and my role is not to figure it all out I'm not the one doing the geology I'm just somebody asking questions for myself and ultimately for my students I guess we're all students here including me here at this YouTube channel okay well we're thinking about Talus slopes today how about we try to walk on some Talus do you have experience with that you know that it's not not an easy feat so up close you know this is the towels you can see how much of it there is you can see the general size of the rock pieces the clasps as we call them these angular things and let me just try to walk on this steep slope this ought to be fun all right we're gonna try to Contour here [Applause] oh I'm not sure what the point is except to show you the UPS close this is what the talus looks like are we really looking at a bunch of stuff that has fallen down this slope over the last 20 000 years or the last 100 000 years or even more that's the question let's read a little bit of Brett's here shall we okay well this is Brett summarizing his 1922 field season where he's establishing the pre-glacial drainage lines that are within the mature landscape that'll be something we'll do at a later date but here's some beautiful old photos from 1922. yeah the limits reached by the Spokane Ice Sheet west of Cheney and Medical Lake are not well known since there's no Moreno ridging around the margin the approximate boundary has been located along the southern limits of a Basalt plain with much bare rock and a scattering of glacial Depot debris south of this margin are unglaciated list covered Hills okay so this is the thing that Baker and Waite are both saying no no but by the time we get to the 60s and 70s we know that that's not an ice sheet that there are deposits there south of Spokane Cheney Medical Lake that are are totally different story well I don't know this guy knows ice sheet deposition this guy knows Puget low Brett's I'm talking about he knows the the glaciation back in the Midwest are we sure that that these kinds of very careful Fields observations are just thrown out and then he's just totally wrong I don't know the answer to that but I'm I'm starting to wonder yeah he's getting into his Talus apron four-fifths up to the top of the cliff that Spokane Ice the talus halfway up to the top of that Cliff that's Wisconsin hopefully you saw that uh earlier in this video get these old photos from from this morning as I'm driving but this is from I just wanted to give you a little bit more like directly from Brett's so that you're not hearing me telling you a basic story with without being true to his specific comments foreign Moses Cooley as a drainage line predates the Spokane glaciation many notches coming into the sides of Moses Cooley are two-thirds or more as deep as the main Canyon yeah he calls them great rounded Gables in alignment what did I call them in the last video in Grand Coulee sheer Cliffs that were scalloped I guess that was what I tried to say purple here so he's talking about pre-spokane stuff and then that trunk Valley so he in other words he imagines a regular v-shaped main river valley called the trunk Valley coming down where Moses Cooley is today and then that that old v-shape was uh entered by the Spokane flood and greatly enlarged Spokane Waters could not have entered Moses Cooley if the parent ice sheet had not pushed across or at least well up on the Divide south of the Columbia therefore though no-till or striae left by the Spokane Ice are known on the south side of the Columbia west of Grand Coulee the operation of both Moses and Grand coulees proves that the courtier and Ice did cross the Columbia and the Spokane features of the most schooly prove that it reached nearly as far south as it did in the later Wisconsin Epic though Spokane Ice yielded much greater volumes of water then did the Wisconsin it was carried by many valleys no one of which ever contained the quantity which went through Grand Coulee to the later so he's making the point that by the time you get to Red by the time you get to the late Wisconsin the late the the youngest of the advances of the ice he's got damn near all that water coming down the Grand Coulee Wisconsin younger than twenty thousand and only a bit coming down Moses cruel okay well I I feel like I'm losing you thank you foreign so we are here today and I'm still down here in this stretch of Moses Cooley and if we follow this channel Moses Cooley I think everybody knows it's weird because it doesn't connect to the Columbia like everybody else does upper Grand Coulee connects to the Columbia all these guys collect to the Spokane or the Columbia the Spokane River or the Columbia River but this one doesn't and here he's got there's where he's got the limit of the Spokane Ice and then the the Wisconsin ice is coming further south this is all Spokane Ice he's got no Wisconsin ice on this map and yes if you go to the modern map this map is only showing Wisconsin ice and I'd have I have very little quibble with putting this margin of the Wisconsin ice in where it is younger than 20 000 years ago but I'm wondering don't we need another map don't we need a map that looks like this but from the Spokane time and again is that a hundred thousand years ago or much longer ago than that 500 000 years ago I don't know but if this is a map that Spokane time I think the ice is down here at least Brett's is saying the ice is down here this is all white this ice Advanced all the way down here and if you do that then all these channels been carved by Angry incredible volumes of water are from that Spokane Ice time not this time this is all well and getting excited now this is all well and good for the Wisconsin time and these are big lakes no problem but what if most of these channels are have been sitting here for a hundred thousand years already during this time that's not what the story is among pretty much everybody but I like Brett's work I like his intimate field relations between elevations channels connected that's what these early papers are talking about and if this is the Wisconsin ice let's get it out of there let's go back to the Spokane time this ice is coming down almost as far not only here but here and we have subglacial flow come on man we got some glacial flow if you want Missoula Pro glacial sub-aerial flooding okay great but let's do that late let's do that with Wisconsin time I guess I'm work okay I'm saying it this way and then I'll quit 1920s Jay Harlan Bretz has the ice sheet here and he's got water coming out of my hand fire hoses of water coming out of my thumb and he says that's when damn near everything is carved subglacially water surging underneath the palm of my hand and it's carving each of these channels 100 000 years ago made up number but you know what I'm saying then let's get rid of that Spokane Ice let's have the talus start accumulating on all the walls of these coolies by the way we got coolies here we don't have coolies out here why that's a whole other discussion but then if you want to bring that that ice in one more time during the Wisconsin younger than 20 000 years ago I'm off I'm agree with that and then here's our Missoula story but why are we talking about Missoula only for these channels when we have these kinds of field relations that Brett's is talking about wow thanks for joining us today I think I have a question for you and maybe you have a little time and interest in in helping me out um I I don't know how to easily and efficiently learn or maybe relearn about the potential dates numerical dates for the four major advances that are well known on North America and then are are those same four major advances of ice over North America I don't even remember the order but I think it's like Nebraska and Kansas and Nebraska and Illinois and Wisconsin Iowan I don't remember so maybe you can help with that send me an email or leave a comment down below and then if you are a European viewer or happen to know about European glaciation can I learn about those same four like how much is the globe in sync how much is the northern hemisphere of our globe in sync in the last 2.6 million years and yeah we go to the Marine isotope record I need to do a crash course in that to then come back to these statements the only reason for doing this Global investigation pretentious is to finally come back here and and try to come up with some basic numbers that are the most reasonable numbers for dates for the three or maybe four glacial episodes here in the Pacific Northwest and does it come from Alpine stuff maybe maybe I need to get into the Cascade Alpine records and try to figure that out I don't know if I'm willing to totally buy off on the fact that all of this careful work by Brett's out here in the 1920s is just not useful that he totally abandoned all these observations on the ground like right over here we've got this huge dry waterfall much bigger than Dry Falls that's sitting here in the middle of Moses Cooley and he's got elevations and he's got Talus height differences he's got all sorts of cross-cutting relations between elevations of channels he's got everything reasoned out in the most elegant simple way is that really all just going to be thrown out if Jay Harlan Brett in the 1920s has two major generations of flood carving based on field evidence on foot in every one of these channels why aren't we listening to that anymore why is everything thrown into the Wisconsin and if it is all thrown into the Wisconsin are there really two distinctly different flooding events just within the Wisconsin the most recent advance it seems like everybody including Jerome Lessman is kind of leaning in that direction that everything is in the LA most young but the most recent glacial advance but Brett's is telling us that we need a bunch of time to accumulate Talus and to accumulate other things in between these major flooding events wow this is really fun this is I don't know if it's fun for you it's fun for me yeah just it's just me and a bologna sandwich out here today but having a blast thank you everybody I love you and we'll see you next time goodbye from the Billingsley Ranch on public land nearby in Moses Cooley goodbye

Channel: Nick Zentner

Views: 67,081

Keywords: Nick Zentner, Moses Coulee, Ice Age Floods, Moses Coulee geology, Grand Coulee, Grand Coulee geology, J Harlen Bretz

Id: pHwNpU7UQ10

Length: 33min 15sec (1995 seconds)

Published: Thu Jun 08 2023