| 00:00 | Well I want to talk about sediment bed forms and the resulting sedimentary structures |
|
| 00:10 | because this is really the basis for to create the architectural elements by which |
|
| 00:17 | going to Uh huh be able to deposition arts. Okay, so this |
|
| 00:24 | one of the reason why I say the exams are slightly accumulative because this |
|
| 00:30 | the background material you'll carry with you transfers waves if you like. Are |
|
| 00:37 | in any variety of things. Air , air, air of sand, |
|
| 00:43 | or sand. This is a repetitive of fluid dynamics. And we are |
|
| 00:50 | interested in water over saying so when look at a typical transfers platform across |
|
| 00:57 | , we see there's several components to late the right height, the slip |
|
| 01:05 | or which is the side we noticed breakpoint where the sediment basically spills over |
|
| 01:13 | avalanches. Isn't necessarily at the So there may be on from summit |
|
| 01:21 | Boy and some presentation we have so which in some critical followers its own |
|
| 01:30 | . Of course it is. Uh would be designed deposition. We'll talk |
|
| 01:38 | about the flow velocity here we can out that you see the water, |
|
| 01:45 | water be pressed last year. increase the Maria in phase motion. |
|
| 01:58 | this is a really huge Exactly. , so you can see that you |
|
| 02:04 | exaggerated human. Now that's the cross . The plan view gets more complicated |
|
| 02:15 | this particular case. It was very genomic. Oh good. And this |
|
| 02:23 | uh wedding ring. He wasn't the hacking. Uh not a good |
|
| 02:31 | Uh He did graduate apparently is still uh pardon? Still married. I |
|
| 02:39 | so. Uh I did tell me was authentic. Uh and we can |
|
| 02:45 | look at the map form of ripples ancient rocks, which to me still |
|
| 02:52 | a bit amazing that something is ephemeral a rippled surface could be preserved. |
|
| 02:59 | they're actually not that uncommon. And uh in this particular case we have |
|
| 03:05 | is a different orientation, different different shapes and cemeteries. There's just |
|
| 03:12 | lot of information that we can actually into the rock record if we understand |
|
| 03:22 | , I can say. And one the things we recognize is that ripples |
|
| 03:28 | by hate direction parliaments. Well, , then ripples form like austin |
|
| 03:37 | Wait, right? Also towards wait, so this would be an |
|
| 03:42 | story ripple, wow. When uh if you like. That's a current |
|
| 03:51 | . We actually, we'll see when look at coastal environments on various combinations |
|
| 03:56 | Curtis. Wait, the current might a long term current and the way |
|
| 04:01 | being generated. We also look at impact flow ferocity. We're really flow |
|
| 04:11 | is measured by what everyone measured with to ripple fault. We go from |
|
| 04:18 | motion to motion First reform straight linear first in two dimensions, there's no |
|
| 04:30 | but notice that you get a warrant stimulus. There's a whole world fascination |
|
| 04:38 | not much except that basically get one regular than the blackout. So what |
|
| 04:45 | see in this transition is a move motion. two dimensional recalls three dimensional |
|
| 04:55 | to play with it. And we've this for a long time. We |
|
| 05:00 | see it in waves as well as currents. But I'm going to focus |
|
| 05:05 | uni directional counts Now. The other is, and we look at |
|
| 05:13 | ripples are the only transfer of Tens or not. Mhm. And |
|
| 05:21 | Mhm. And yes the waves like following just feeling, wait, what |
|
| 05:32 | you think ripples or the order? centimeters. You hear about wow waves |
|
| 05:42 | ripples of more than a meter. huh. The heights the same thing |
|
| 05:50 | ripples and things that don't use another . So there really is a fundamental |
|
| 06:00 | between ripples and dudes. Even though is a morphological similarities, one of |
|
| 06:07 | big distinctions and I'll expand on that ripples do not scale with depth. |
|
| 06:13 | can see a ripple. So okay this James escaped well. So the |
|
| 06:22 | the data. But I want now do see some dudes very rarely. |
|
| 06:30 | we do see dudes in some basic . It goes back to the fact |
|
| 06:35 | sometimes the depth is not water depth it's adapted with a thickness with. |
|
| 06:43 | with that you get the sandwich Yeah, both with respect to hike |
|
| 06:55 | wavelength. You get a similar separation the aeolian reference nearly. Yeah, |
|
| 07:03 | won't really be talking about this right but this separation concept, it's fundamental |
|
| 07:11 | sedimentary bed forms and a variety of . Now dudes like rip tend to |
|
| 07:22 | from straight prices in particular. Three delicious with increased philosophy. So |
|
| 07:30 | see that the plant forms vary in acts for the ripples and dudes. |
|
| 07:38 | straight question written vs The three of scenes basically lower velocity the full |
|
| 07:50 | . And as we'll see in a , seven infrastructures are similar as |
|
| 07:55 | differing only escape. Now, if look at the flu data, we |
|
| 08:03 | that no matter what death is The single asking. We go to |
|
| 08:11 | So this is uh at least Within 10 m water depth beyond uh this |
|
| 08:21 | hope so it's death. And the thing we see is we often will |
|
| 08:30 | superimposed. Um I think he's pointing wedding ring? Wasn't sure. But |
|
| 08:39 | are ripples down in humans. And there's ideas notice in each case |
|
| 08:45 | not straight president. They're also not scoops and scallops. So this is |
|
| 08:52 | the lower part point. So these common New Henrik. I point worth |
|
| 09:02 | . Now here we also see dudes they're beginning to be claimed out. |
|
| 09:08 | just as we saw earlier, the that you could have ripples Going into |
|
| 09:14 | DS and it's claimed out but no had dudes, they begin playing down |
|
| 09:19 | well and we came dunes occurring at scales. This is a very three |
|
| 09:28 | type of dude uh elongated scallop. doomed press. I'm very old and |
|
| 09:37 | can't really tell what the scale is until you man, you're playing and |
|
| 09:43 | that these things are meters deep. other thing that's interesting here is that |
|
| 09:48 | just said that the height of the is proportional to the water death. |
|
| 09:57 | depth is typically 3 to 10 times in the height of you did |
|
| 10:03 | That implies this water was really This is the Yukon delta and these |
|
| 10:10 | reform during breakup dish where there's a flood that comes down every spring when |
|
| 10:16 | ice breaks. So you get a grant spikes like this drops down like |
|
| 10:22 | , leaving behind these really big And what that suggests is that this |
|
| 10:28 | be one of the things. We for them trying to distinguish sedimentary structures |
|
| 10:34 | point bars formed by different types of patterns. Okay, so if you |
|
| 10:41 | this very large scale dunes trust The upper part of the dune, |
|
| 10:49 | tell you something about the size and of the hydra graph as it varies |
|
| 10:54 | clients. Uh, here we've this is actually entitled and these are |
|
| 11:01 | , but they're, they're currents that been organized the ebb and flood |
|
| 11:07 | So the unique correction Here we have dudes and a length of about 10 |
|
| 11:15 | . Um, so, uh, can get these features and all sorts |
|
| 11:22 | depths and their patterns are really quite stick. Now you've got this in |
|
| 11:31 | notes. But let me just ask many of you are familiar with the |
|
| 11:34 | regime concept. Well, um, , down now. Okay. |
|
| 11:45 | I want to say shame on you it's not your fault, but it |
|
| 11:48 | a fundamental concept that has really changed way we look at an interpret sedimentary |
|
| 11:56 | . Basically it was derived mainly from done in river river where they saw |
|
| 12:06 | once sentiment got into motion lot of griffin, what did your plane that's |
|
| 12:14 | ? Can you get where is the ? And it also delineates between these |
|
| 12:24 | bit lower flow regime and the transitional bet forms associated with comprehension. Why |
|
| 12:37 | they called they call anti dudes because migrate in the opposite direction. Whether |
|
| 12:44 | uh informed my great in the opposite expect. Okay, migrating strip. |
|
| 12:51 | start to get you. Now there's sorts of characteristics associated for for regime |
|
| 13:01 | the first I'll point out is that are more or less than uh some |
|
| 13:05 | super criminals. So that's the first back fruit of the flow regime features |
|
| 13:13 | are food numbers greater than. there are also some between this continuous |
|
| 13:22 | set of the pen. This diagram out of date now is beginning to |
|
| 13:32 | dunes. We realized that goes back discontinue but for playing that is continually |
|
| 13:39 | motion ripples and news their emotional on backside store concentration increases with increasing |
|
| 13:52 | Yeah. And water services. I'm business how to phrase this is needed |
|
| 14:06 | change that. Uh, so we're to see how the hydraulics of open |
|
| 14:16 | flow is beginning to control the bed and ultimately sedimentary structures. Now we |
|
| 14:24 | able to do that to a large because at the same time, |
|
| 14:30 | workers were looking at the river on river, we had mainly engineered |
|
| 14:37 | and geologist working influenza car on It's a big loop so they could |
|
| 14:44 | dunes. Things that earlier work couldn't . And what they did is that |
|
| 14:52 | the most part they saw the same , simple cripples and danced again, |
|
| 15:02 | out dams. Find there's any games notice it. This is that hydraulic |
|
| 15:12 | talking about with increasing floated. Where that? I'm not just now. |
|
| 15:23 | problem is that the flow regime concept initially not because they don't feel the |
|
| 15:36 | immediately, but they cannot control actually they had, they were measured ferocity |
|
| 15:46 | floods, but the gun change with flu bed in the chamber inside. |
|
| 15:54 | so what happened is, it became that it turns out that the flow |
|
| 16:00 | concept was only good for certain brain when you got into Porsche grains last |
|
| 16:11 | . Mhm. So the first thing ripple, claimed it the lower plane |
|
| 16:17 | then those went into dudes and notice Preston two dimensional. The threat which |
|
| 16:25 | you complain to get over down here motion ripples, ripple field or straight |
|
| 16:34 | it too. Same to the treaty then into mega. No measurable. |
|
| 16:44 | got to use it. We don't any futures. So they went into |
|
| 16:52 | tv three. So this is like that you got it. This we've |
|
| 17:00 | the dimension of rain site. So we have a two dimensional Goddamn vs |
|
| 17:08 | one dimensional. Now look at the here. Uh huh. It shows |
|
| 17:16 | we're gonna have small crane you got . Except that's not really true because |
|
| 17:24 | did more and more work we realized just this once an upper brain size |
|
| 17:31 | ripple if there was a lower. you find anything you don't get this |
|
| 17:41 | course. Right. Sandy and this or will we change is highly holds |
|
| 17:47 | the president. It is one of things you need to having the mind |
|
| 17:51 | all times. If I ask you draw this diagram maybe by next fall |
|
| 18:00 | couple of differences here. Sand Dudes earlier mega ripples, many ruffles |
|
| 18:11 | gone now sand waves are gone there to the news. These are typical |
|
| 18:19 | . So this is now beginning to . Yeah. So what can we |
|
| 18:25 | about ripples? Well they're formed brain less than about second. Yeah, |
|
| 18:34 | turns out that's the break between hydraulically and hydraulically well so mm rebels tend |
|
| 18:48 | be associated hydraulic smooth out. In what happens is in order to get |
|
| 18:56 | fine grained sands moving. You've got break up that disk of subway. |
|
| 19:02 | it all it takes is one little bump people and that's enough to initiate |
|
| 19:11 | . And ripples form instance if you at the flu and you watch it |
|
| 19:15 | goes from flat to rip just like because the ripples are what are basically |
|
| 19:21 | up. This is like creating eternities height less than 10 cm in depth |
|
| 19:31 | D. To three D. With lost wavelength. Uh A 1000 |
|
| 19:39 | Don't worry too much about it. they're smaller waist. Now there's another |
|
| 19:45 | that you just kind of learned about last 10 years. So these are |
|
| 19:51 | . Yeah these are kind of like and genders but these are discontinuous cripples |
|
| 20:00 | mud flocking. Remember I said that auctions and side. What about side |
|
| 20:14 | And these people migrate avalanche of This and there can they actually have |
|
| 20:29 | for centuries. Just like a record . And This is a picture of |
|
| 20:45 | . And the point here is that they're compact and they're hard to see |
|
| 20:53 | the in him with the ball animal patients groups. But it's an |
|
| 21:05 | So we can't see it has preserved protected as easy because of compassion. |
|
| 21:14 | we look at this and we what we assume? We assume this was |
|
| 21:18 | of suspension. But what it really a series pro grading but trips as |
|
| 21:28 | . Huh? It's a very different . Okay, what about dims? |
|
| 21:36 | . Uh, for sure. Great . I am not tension hide any |
|
| 21:44 | with two d, 3 d increases wait for an interesting stuff. So |
|
| 21:52 | of your review questions for the exam be compare and contrast rubles induce or |
|
| 22:01 | are they similar and how are they Now? There was a lot of |
|
| 22:08 | as you might expect between mainly due . Yeah. So five people want |
|
| 22:18 | keep it all going to be doing sand wave no matter uh, we're |
|
| 22:26 | standardized. Yeah returns bigger. So are just standards. You don't |
|
| 22:36 | They just know where to go to that there are some dudes that have |
|
| 22:41 | over 100 m heights of over Yeah. Uh huh. Also Because |
|
| 22:53 | scale with death. We use this 10.30. Death turns out I'm going |
|
| 22:58 | talk more about that because there's a more discussion about that in recent |
|
| 23:06 | Okay. So here's a typical blood And we're gonna look at definitely I |
|
| 23:12 | this is santa, santa river So we've got some small guns |
|
| 23:21 | Oh, you mean that's bigger So many questions. Are these large |
|
| 23:28 | very large dudes? Oh, what they? Something else? Um, |
|
| 23:38 | they are superimposed excellent. But what you call these large students? Union |
|
| 23:43 | ? Yeah. it turns out that are there is a really confusing concept |
|
| 23:53 | distinction person between dunes and books and are just the things we've been talking |
|
| 24:01 | Children's but a unit bar is another feature, transfers future. Uh huh |
|
| 24:14 | can actually fill the flow. So depth is limited clothing, it can |
|
| 24:21 | much larger than do. And these the mid channel bars that we used |
|
| 24:29 | thinking in british troops. But they're he knows it's so important. Confidence |
|
| 24:40 | and for the longest while when I see these in the rock record I |
|
| 24:46 | just think they were large. It a while for me to realize I |
|
| 24:53 | looking at apples and oranges. There dues and there are unit box and |
|
| 25:00 | talk more about those distinctions a little particularly talk about fluid because it's So |
|
| 25:07 | is it that controls those bed Well, there's some fluid stuff and |
|
| 25:11 | particle stuff. Close strength stuff and there's a lot of variables. And |
|
| 25:18 | are the variables that all controlled and but let's Uh huh. Make it |
|
| 25:27 | . I'm size but all the fluid here on sediment variables here. Water |
|
| 25:32 | here. This further or say let's fresh water. 20°C that use |
|
| 25:41 | Uh huh. So what that does gives us a settlement an example. |
|
| 25:49 | strict favor. And let's forget about for a moment. But think about |
|
| 25:58 | many flow velocity. I said Mhm This is this concept is two |
|
| 26:08 | bed things which is the successor to in concept of it's really what we |
|
| 26:16 | today. This geometry with no motion . No more cripple prepare complainer, |
|
| 26:33 | . It really pretty much the same we have here in europe. We |
|
| 26:41 | use this gym. So those are based what's missing is the effect of |
|
| 26:52 | . Now. Okay, this is uh it to the news. Three |
|
| 27:00 | . Mhm. But I want to out on what they call in phase |
|
| 27:04 | or any deals they take out. don't have to be when the water |
|
| 27:17 | are more than this. We don't any any get at least as we're |
|
| 27:26 | with me with typical floating issues. things like God density currents. So |
|
| 27:35 | is an effective float. Yeah. In fact we could look at flow |
|
| 27:43 | and flow velocity difference, range And so one of the things I |
|
| 27:52 | take time to ask you which is course is rate size. And I'm |
|
| 28:02 | say that if you're looking for the of the brain size, Look for |
|
| 28:08 | Children. This says they go from motion lower player than excellent. It's |
|
| 28:19 | finest great size for young. No ripples. A pleasure if you want |
|
| 28:31 | look for medium grained sand. This for the you notice that Uh huh |
|
| 28:40 | really only the anti still one that see on magic uh that you see |
|
| 28:50 | lot of very issue. Now some is based on field, there is |
|
| 29:05 | . So you got gaps and lots time. Some people have tried to |
|
| 29:12 | this to reconstruct slow death. why would you want to do |
|
| 29:16 | Well, you want to if you to understand the paleo hydrology of your |
|
| 29:22 | . Slow death is a critical in is fundamental to the focal method. |
|
| 29:29 | I talked about earlier of reconstructing the . Gm budget upset about it. |
|
| 29:40 | problem is, well, we don't is the very first of all Mr |
|
| 29:50 | . He said it's very very Just too much exploration. You've got |
|
| 29:58 | he wants as a confidence velocity. , you probably with didn't cross |
|
| 30:10 | You're probably from one meeting 40 each . That doesn't help. Uh You |
|
| 30:17 | see this diagram and this concept used try to reconstruct a slow death. |
|
| 30:24 | lot of the human pupil we don't . Well first there's not a lot |
|
| 30:30 | changes. Blue, yep. Uh . Uh The only thing I |
|
| 30:39 | you know this didn't face. back. Uh huh. Yeah and |
|
| 30:54 | is the hiding games versus the depth the broader, wow, cool. |
|
| 31:06 | their existence. No, I believe . Yeah, there are. We |
|
| 31:13 | looked at that. We don't have good damage Even after 40 years, |
|
| 31:20 | years ago. I talked about that here between hydraulically smooth. That's a |
|
| 31:30 | thing that we can take back into uh, into the field. They |
|
| 31:35 | importantly, I think that this than . If we see mhm Marshfield ostentation |
|
| 31:48 | pretty much so wearing this here. see just by looking at sediment |
|
| 31:59 | we can say something about the Now going back to look at the |
|
| 32:04 | plane, you're of course it rained equipped. It turns out they're not |
|
| 32:14 | playing debts. They're really low amplitude were migrant. And so this is |
|
| 32:24 | that would look like if you took snapshot. Yeah. Um Hide is |
|
| 32:38 | New York 5 - 10. They're water depths. Uh here we see |
|
| 32:47 | with time as the doom passes a one. And they give us something |
|
| 32:51 | this. They give us cleaner but it's not due to just |
|
| 32:59 | Uh it's due to the migration of low amplitude bits. Well, look |
|
| 33:08 | this later where we'll call this with of these translates? Well, that |
|
| 33:14 | stratification due to the translation that notice here we got out of phase |
|
| 33:33 | . Yeah, here we have in . Well, I said earlier uh |
|
| 33:41 | credit, we actually have two kinds planer betting which is defined as recognized |
|
| 33:55 | lower playing. You're an upper Mhm. Upper player like lower player |
|
| 34:02 | largely the result of migrating logo. logo. Very hard to say you |
|
| 34:08 | really see the meeting the profit rather the translation of those migrants. Low |
|
| 34:16 | methods. That's is that right now we increase the velocity Within the super |
|
| 34:33 | 12 start personal standing ways. then they become unstable. It begins |
|
| 34:44 | . We've got breaking standing waves, quality jobs did she? And |
|
| 34:51 | We'll see later. Steps were really is the area that's been focused on |
|
| 34:59 | recent expanding this both influence and then . So what are you saying that |
|
| 35:06 | floor regime increased? Uh huh We're preventing upstream migrations. It's another world |
|
| 35:17 | that upper float. So this is latest of the bit for body we |
|
| 35:30 | so again, it's the limited flow 100 because this is the one I |
|
| 35:38 | you had in your box corporate Oh is that to the three treatment |
|
| 35:51 | the player and the news. We of pitch out of the grain. |
|
| 35:55 | to shoot okay with something like The any days are at least in |
|
| 36:17 | . Typically a few centimeters time wavering me around me. Okay, low |
|
| 36:25 | here they are kind of standing You're kind of breaking the double points |
|
| 36:34 | these are the ripple forms that we . These are the candidates that typically |
|
| 36:39 | on beaches. The most common place see an anti dunes on beach, |
|
| 36:45 | velocity, low water depth. My number upstream migration. So here they |
|
| 36:56 | dipping matters. These were stable and do. They get unstable before |
|
| 37:07 | right, get more depth. You see the beginning to break right here |
|
| 37:15 | students. Uh you get more and kind of motion shape. I'll talk |
|
| 37:21 | about this sediment instructions. But the of the bed for waiver and getting |
|
| 37:28 | and bigger as we get into higher . And the significance of the high |
|
| 37:35 | jumps are getting more and more significant we get into the fucking moose |
|
| 37:42 | we're looking at those mainly through But we're seeing the sediment to record |
|
| 37:48 | equivalent in sediments as well. And you look at the same side |
|
| 37:54 | but it's great some of the Let's endless submarine canyons on the order |
|
| 38:02 | the kilometers heights, tens of Small ones on the border 1 5 |
|
| 38:13 | . God, but these are comparable bigger dooms that we get and rivers |
|
| 38:23 | we can get these in big Yeah. And here's what those way |
|
| 38:29 | what you can speak. He smells and look what happens. Talk the |
|
| 38:44 | , the seat side deposition. These version definition. So the fed fullness |
|
| 38:55 | migrated the depths or free what is upstream christian. And that whole for |
|
| 39:07 | type of steps in your orders of difference. All right. I'm gonna |
|
| 39:15 | here because it's convenient place to stop lecture. What I want to do |
|
| 39:20 | now begin to look at the sedimentary that are formed under the different bed |
|
| 39:26 | . And we will start that after . So let's stop their voting |
|
