| 00:00 | Okay. Okay. Uh let's look the sedimentary structures that are the result |
|
| 00:07 | these migrating bid forms and to do . One of the things we need |
|
| 00:13 | think about is something we actually mentioned . That is the distinction between beds |
|
| 00:23 | and strategies. For example, somebody cross bedding and I said cross |
|
| 00:28 | Uh you said cross laminated doesn't make difference and it does strata is just |
|
| 00:34 | the most general term of layered rocks different scales. Bedding is a type |
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| 00:40 | strategy that's a centimeter thick examination is centimeter or less mm. And so |
|
| 00:49 | we talk about Cross betting, we're that those individual four sets are more |
|
| 00:54 | 70 thick. Typically they're not. so usually what we describe as crossfit |
|
| 01:01 | Samson's cross lemony. You want to conservatives just across strategy. Okay. |
|
| 01:09 | Betty and lamination are in fact And that stratification, no matter what |
|
| 01:15 | uh could be due to a variety different reasons. It could be a |
|
| 01:21 | . The compositional change size, like lamb enough packing orientation ship center. |
|
| 01:30 | there's a lot of details that go looking at individual patient. We actually |
|
| 01:34 | a whole terminology that actually defines what name a very thick beds. Um |
|
| 01:40 | very thin bed. Uh you don't to know this but you need to |
|
| 01:45 | where it is in order to use terms if you're describing rocks in |
|
| 01:51 | Okay, okay, so how we these machinations? Well rainfall deposition from |
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| 02:00 | is clearly one of the main ways flow avalanche in downslope is a second |
|
| 02:08 | translation. We've actually kind of alluded that earlier in this particular case. |
|
| 02:14 | looking to say wind ripple because this originally a slot for the aeolian trepidation |
|
| 02:20 | holds for So make me as Any ripple migration can lead what's called |
|
| 02:28 | . And um saw suitor lamination, an attraction car. Talk more about |
|
| 02:38 | basically it's a type of plane Now I use Gillian because it's easier |
|
| 02:44 | see the different products of these Um but these processes occur on let's |
|
| 02:52 | a four set of a doomed uh they take me as soon as well |
|
| 02:57 | superior. So here we have the blanket of rain falls eventually over steven's |
|
| 03:07 | as a grain form. Think of great form of these little avalanche |
|
| 03:13 | wow, as the wind ripples across then it leaves behind examination translate |
|
| 03:22 | Uh That's a very tracks well, is that important? Well, it |
|
| 03:29 | out physical properties. Uh the lamination different. And we talked about packing |
|
| 03:36 | example, is one of the ways defining nomination. If you were to |
|
| 03:41 | at permeability. Uh That's just used wind ripped will translate to the screen |
|
| 03:49 | . Mrs Henry permanent. The only huh How difficult and finally available. |
|
| 03:59 | it literally we are potentially interested in permeability differences between one lamination and not |
|
| 04:11 | , usually we think about packages but of one type of lamination and one |
|
| 04:17 | of mixture. Okay now mm most what I'll talk about what are servants |
|
| 04:28 | are possible for set? That's the side of transfer city. It's avalanches |
|
| 04:34 | departed. Yeah I'm going to focus there but I'm going to also begin |
|
| 04:42 | introduce two terms set. The costa a set is basically genetically related examinations |
|
| 04:52 | strength. The Cosette is a bunch And so we'll see that we can |
|
| 05:00 | and describe sediments. Beginning with literally individual force. It's we're going to |
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| 05:07 | them and then package we're going to increasingly large packages and tell eventually we |
|
| 05:13 | to the whole channel or the forward Bar. Okay so if we look |
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| 05:19 | the four sets again we're looking at remember the top maybe uh the right |
|
| 05:29 | seven. Now I am gonna well know what happens to the water water |
|
| 05:37 | as it divergence. It turns out out right, delegates was called |
|
| 05:47 | It's about seven times. And there's kind of awake are wrong here. |
|
| 05:56 | hasn't comes down there's a reverse flow we get some of the water this |
|
| 06:03 | side close side. Next trip. now brother we can and then we |
|
| 06:09 | this number. So we have to that with this first. So we |
|
| 06:16 | to think about our flow lines. the first story. Wait. |
|
| 06:25 | Mhm. How steve does it have be before it gets to avail. |
|
| 06:32 | if you've got longer even though they're strain, they're not going to |
|
| 06:40 | So here we've got a downstream That would be that the point. |
|
| 06:47 | if the dude is big enough for hide up, you can actually get |
|
| 06:52 | so long ago to transport sent back . So these are going to come |
|
| 06:58 | for so they can actually accumulate at base this program downstream migration do. |
|
| 07:07 | , it turns out there's a lot information it's available in that strata graphic |
|
| 07:14 | . Well, they pro grading particularly it do. And one of the |
|
| 07:19 | has to do with shaping force that . Uh They can be and he |
|
| 07:26 | again, it is anger, you be gentle floor heating up case and |
|
| 07:36 | transition can occur both with respect to increase in velocity and an increase in |
|
| 07:45 | that increase uh putting sustainable. And not surprised that they are relevant because |
|
| 07:53 | velocity shear force will also result in increase suspension. Yeah, the two |
|
| 08:01 | process is going to be formally these avalanche and grain for grain flow or |
|
| 08:16 | . So here we've got our anger gentle on. Okay, and that's |
|
| 08:21 | you say. If you're any developments all beginning to act that suspended settles |
|
| 08:30 | have seemed personal. Go in that increased philosophy. Yeah, yeah |
|
| 08:39 | If we looked in detail, we to see that in many cases, |
|
| 08:44 | february lamination events are defined by changes raise us. So here we actually |
|
| 08:51 | . Grady, this particular example is the result operating rainfall average. |
|
| 09:03 | if we get more and more sediment transported including sediment suspension, get more |
|
| 09:09 | sustained. The ostrich is here. let us suspended all steeper. |
|
| 09:22 | So the end of what is it's a failure of that here. |
|
| 09:31 | so much suspended seven that we're getting preserved preferentially young here in the |
|
| 09:38 | So you can see how that sustained , beginning to at total force it |
|
| 09:46 | down. Okay, so we're beginning see this transition now, not just |
|
| 09:52 | shape but also in the uh style betting. Now let's look at that |
|
| 09:59 | culture, let's look at the great deposit. If we actually look at |
|
| 10:07 | green size downslope, it's actually going recourses of Now. That seems counter |
|
| 10:17 | because that is the opposite or Mhm. Yeah. Uh here, |
|
| 10:28 | . Where its forces talk. There's difference of the process of the two |
|
| 10:36 | suspended sediment forces, grain falls first a graceful so that gives you of |
|
| 10:44 | the set top Stephanie with brain flow avalanche, it's actually moving is as |
|
| 10:57 | a completely different kind of process. if you've ever stood, I'm saying |
|
| 11:03 | of kicked it to watch the you'll actually see that Porsche grains out |
|
| 11:10 | reason is they have more momentum greater they move forward. So that increase |
|
| 11:16 | manner with failure resulting there's also a . The grain disperses pressure that causes |
|
| 11:28 | the anniversary. This is the same , traction part so earlier now. |
|
| 11:41 | . Ready, slow. It's a of traction and this inverse trading as |
|
| 11:50 | result of the drain your brain forcing the Porsche brings up in contrast |
|
| 12:02 | radiation Of the Brain Fall Horses So we see the distinction between great |
|
| 12:12 | express both the downslope changing grain size entered lamination verdict change. So you |
|
| 12:26 | the President preservation are correct increased presence the football. The amount of |
|
| 12:44 | Mhm. Yeah. What about Okay, the second I need to |
|
| 12:55 | back to your cause. Yeah, . Yeah the problem with touchpads as |
|
| 13:04 | touch them. Okay. Uh well look at this second. Right? |
|
| 13:19 | , this is actually set. Of all these lamination here and here are |
|
| 13:28 | results of the same debt. So this is what it might lead |
|
| 13:35 | . This is something that this turns the pretty important values set within that |
|
| 13:44 | . We can look at shit and focused on your part. Uh Would |
|
| 13:52 | say this is anger and gentleman Uh huh. Gen gentle. |
|
| 14:11 | what you would look for? You with another is encouraging But in reality |
|
| 14:18 | would say most of these are Okay, so although there is a |
|
| 14:26 | of bending most of it I think be angry. Okay, the other |
|
| 14:38 | is there is a significant variation in size between the interview. No. |
|
| 14:47 | take land nations because it must uh is mainly rainfall baby. Oh, |
|
| 15:00 | . A couple of other things Okay, so we go here, |
|
| 15:06 | closer against this a little bit. , the other thing to notice is |
|
| 15:13 | we actually have preserved seven. That's the segments. Uh huh. So |
|
| 15:21 | looking at a kind of a great in here we appreciate here. So |
|
| 15:28 | could actually think this is upset. set proclamation for the absolute vertical aggression |
|
| 15:38 | . Oh, you'll see very You see an opposite forces. Now |
|
| 15:53 | look at a different set. This still a set migration of it. |
|
| 16:02 | . Like I say it's a dude not, can I say, hey |
|
| 16:08 | simple, right? Mhm. More present. Uh some smaller. |
|
| 16:20 | . And so what might be the ? So big ripple, small |
|
| 16:34 | Yeah millimeter create problems. Uh a less. Okay, so it's kind |
|
| 16:48 | reference, although this might be self . There are times when you really |
|
| 16:52 | to look carefully decision shit, genetic . Okay, so let's ask that |
|
| 17:05 | question. Is it anger and general ? Not everybody wants I can use |
|
| 17:20 | . Okay, Okay. Everybody agree that tan genital like that. |
|
| 17:29 | I'd say it's pretty straight. Uh . Unlike, hey, it's clearly |
|
| 17:38 | spin gentlemen. Yeah. So we are looking at uh sometime tangential |
|
| 17:49 | So now we're beginning to define a set. We've got the zone is |
|
| 17:56 | or less spanish the features on the and it looked carefully beginning option. |
|
| 18:05 | we actually had onset set. Mhm. Increased velocity, increased uh |
|
| 18:18 | deposition of suspension. Uh You would more rainfall than the previous previous |
|
| 18:26 | Was pretty much all grateful. This the alternation of grain slow and |
|
| 18:34 | And you begin to see the variability on how different layers well and then |
|
| 18:45 | a reflection of how the different Now I'm remembering that top sent auto |
|
| 18:52 | , here's here's the way they look similar. Uh uh This is not |
|
| 19:02 | upset. This uniform. Does you gives that uh So here we got |
|
| 19:09 | or the lot of self. Now bottom set consent to be tangential bending |
|
| 19:16 | the force that like the previous it could be battle ripples, a |
|
| 19:21 | of ways that it might be Uh might look something like this. |
|
| 19:26 | here we have to have numbers up . Yeah, everyone see this. |
|
| 19:34 | are the actual here, Michelle, is the bottom set. This is |
|
| 19:45 | top set in the forces. Now particular example is what's interprets unit are |
|
| 19:53 | it could just as easily the I make that point first of all |
|
| 20:07 | the lower part of a programming the one that's most likely to be |
|
| 20:14 | and not it wrote it off. bottom sense really has the highest |
|
| 20:21 | Mr. President otherwise it's the And so we're interested in uh what |
|
| 20:34 | and their relative preservation, their preservation relative to report set upset, very |
|
| 20:47 | but of Violent situations including one in only the successor. Right? So |
|
| 20:58 | can go back to this. And we actually have uh the offset this |
|
| 21:12 | we have bottom sense. Um Okay different. And the four sets, |
|
| 21:21 | sets here we have zones for box the they're basically the bottom of very |
|
| 21:32 | set. Oh thank you leo now reason we delineate those is they represent |
|
| 21:43 | only the higher potential but they artifically grain, more rainfall locally, less |
|
| 21:57 | offering flow there. So what these are I was going to compartmentalize the |
|
| 22:06 | within this system. Each of these upset. This package of its usual |
|
| 22:15 | but however we define this potential regional segment based on the box set. |
|
| 22:27 | the flow the lateral. That's Someone positive. Say it again. |
|
| 22:36 | causes once said to stop the next , you know as we go uh |
|
| 22:46 | me get to that later. But me give you the short answer to |
|
| 22:49 | is you either have one bed on on top of another or your |
|
| 22:56 | Yeah. Okay. Now here we're at the prosection field ultimately we many |
|
| 23:14 | is a yellow. Great because Yeah you see here take a horizontal |
|
| 23:25 | The grain floors elaborate discontent that's because avalanche didn't original parts. The grain |
|
| 23:36 | , on the other hand, is laddering unless it's cut out. |
|
| 23:45 | let's look at it. Kind of down, let's look at you. |
|
| 23:51 | gonna cut this up into downslope upper . No. So and what it |
|
| 24:01 | look like, I have to draw fingers because I can't get my pen |
|
| 24:05 | work with A. You come along and then there's a cut out and |
|
| 24:13 | is the green fall. Green Okay, scooped out actually. It's |
|
| 24:22 | of adults. Good B is the of the grain fall. It's a |
|
| 24:37 | . So we kind of have an will scoop the kind of a veneer |
|
| 24:41 | the rainfall deposit, rain flow deposit downslope into a loop. Now, |
|
| 24:48 | we look all the way down that here it is, it looks like |
|
| 24:56 | and it will be covered with green . So, this would be how |
|
| 25:05 | might see uh series of grain flow inter bedded with a series of |
|
| 25:25 | We will get into this more extensively we talk about the aeolian clauses where |
|
| 25:32 | are very distinct, needs anything for time being, I'm just dealing with |
|
| 25:36 | more generalized view their alternating process. there's a few subtle differences between Sebelius |
|
| 25:45 | , real brain falls are not. there's one other process, Another process |
|
| 25:51 | can affect the shape Of a four . Those are reactivation services where basically |
|
| 25:59 | pro gradation erosion for some reason, more pro gradation. So truncation |
|
| 26:16 | we used to think that was mainly function of reversing title currents. It |
|
| 26:25 | pretty apparent that we see these on and union directional flow as well. |
|
| 26:30 | basically it means there's a change in orientation of the for nothing more than |
|
| 26:35 | . And so you begin to rode the top of that slip face and |
|
| 26:41 | re established. You think to kind think about is that rivers and flooding |
|
| 26:48 | flood for a long time or can a flood for longer floods on some |
|
| 26:52 | our rivers can last well in Mississippi can last for months. Okay. |
|
| 26:57 | so there's a lot of variation that occur during that flood. And so |
|
| 27:04 | the active phase of sediment transport during flood can be highly your even if |
|
| 27:13 | quote the same flood. Yeah. lips didn't really, did anyone |
|
| 27:20 | Uh huh. Okay. Uh, one reactivation surface. There's another in |
|
| 27:35 | . Okay. Yeah. Okay. , all right. We talked about |
|
| 27:46 | cents and one set being Typically the sets formed by the migration single. |
|
| 27:57 | look at sets and concepts. here is the fortunate it's migrating and |
|
| 28:09 | of that force. That is one the ways that you got a second |
|
| 28:18 | . Uh huh. So these are properties together all the same type of |
|
| 28:28 | for during the same. Now this police the individual sense if you look |
|
| 28:39 | this is a cut the flow This is a process here. We |
|
| 28:47 | the scoop. This is culture, is the result. Now at this |
|
| 28:57 | those who have to go from and and we cut transfers to something more |
|
| 29:09 | . Now it's apparent because if we it parallel flaw we see again reading |
|
| 29:16 | sets of downstream. Mhm But they a little different. Not showing me |
|
| 29:24 | here but they're gonna look here and and there. Very So what we're |
|
| 29:33 | at is the transition during the same before creamy do great after the |
|
| 29:42 | So what do you think that's telling about flow conditions bottom you can use |
|
| 29:51 | energy and the energy. Yeah. we're looking at some kind of way |
|
| 30:02 | . Yeah bladder artists. And we also say something about Velocities, Shear |
|
| 30:13 | is necessary. How high worthy for was six. Using those to the |
|
| 30:23 | Each of these six. Yeah it formed by similar and so differently so |
|
| 30:33 | Cosette they service it a bunch of . Yeah but save that. Oh |
|
| 30:48 | . So we got set which is bed form in the Cosette between different |
|
| 30:58 | . Now we also have bounding surfaces are the ways we the way we |
|
| 31:06 | that Yes I could draw a line kind of hard is a bounding hurts |
|
| 31:19 | . This one here is the bounding separated customs. So we have a |
|
| 31:29 | of founding service, beginning with the order. That first order value surface |
|
| 31:39 | separately. Six. That's what we when we looked at same set. |
|
| 31:46 | we describe now when there's a change one bit form type or no, |
|
| 31:56 | have a second bounce that's going to this in here, which is it |
|
| 32:02 | direct except. So the second just would be the football on this right |
|
| 32:14 | . That's the second quarter down to . A third over bounded surface |
|
| 32:23 | genetically related cassettes. So it is uh, you can't my blood and |
|
| 32:36 | happened. Third. Yeah. So can see how we're going to get |
|
| 32:43 | people argue that individual lamination zero. , because we are literally going from |
|
| 32:53 | to mystery act and the. And doing so we're beginning to define the |
|
| 33:04 | scale different architectural By the metformin short changes like changing the law Stadio three |
|
| 33:18 | the mega form, which is a , which is active. That maybe |
|
| 33:28 | of a bigger package are quite boss point bar maybe Montreal you think your |
|
| 33:35 | service face, Which is a And though the Andrew surfaces maybe with |
|
| 33:45 | Andrew channels may form a larger group meander belt, the sandstone that consists |
|
| 33:52 | a challenge. That might be a . So we're going to go from |
|
| 34:00 | for me and you will is the our view these deposits. So they're |
|
| 34:07 | back over here we've got this now the first order of service. A |
|
| 34:16 | of other things pointed out the terminology types of that not really interested in |
|
| 34:25 | accept when you get down here. get in here. Okay. We |
|
| 34:37 | this quiet. Uh, but it's the simple concepts in front. |
|
| 34:47 | So yeah, the point is that variability and sets and cassettes as you |
|
| 34:59 | at longer time in larger scale architectural . Now, the other thing again |
|
| 35:07 | to talk about how the create a set. Uh we definitely have find |
|
| 35:15 | saying yeah whether not be ripple times not great deposition compared to the rate |
|
| 35:25 | migration. So for these ripples because a hard greater sense. So in |
|
| 35:35 | particular example there's almost no relation So coming down here is more just |
|
| 35:48 | total set scallop so that multiple sad first of all. And what if |
|
| 36:00 | didn't No. Is that what thing upset is all mothers things like |
|
| 36:10 | A little bit of rose. That's telling you that there's a little |
|
| 36:20 | well you can use the thickness and began to approximation animal rights and veteran |
|
| 36:27 | , this goes back to denver versus and also the Scale of relative to |
|
| 36:36 | death climbing ripples basically occur where ripples climbing on top of it because a |
|
| 36:49 | amount of that coming on the So it's that awesome and I haven't |
|
| 36:57 | at the time. It doesn't have to mind to increase. Conversely no |
|
| 37:08 | so sorry. Along with except and Jeanette woods There is what the state |
|
| 37:21 | suspended. Now ignore these types. a detail. But recognize what's |
|
| 37:31 | Look at this vertical oppression. Now beginning at some of my patients but |
|
| 37:37 | what we got reservations. Can we to hear getting emotional? Let's go |
|
| 37:45 | here. Uh, you see the styles. You see, I can't |
|
| 37:55 | it very well, but you can it better than in some cases the |
|
| 38:00 | side is truncated. In other cases least side is perfectly formed. There's |
|
| 38:08 | some downstream migration but we've got a of vertical accretions, that angle of |
|
| 38:24 | is a function of deposition. And those climbing ripples, we we basically |
|
| 38:31 | this song where you got deposition of side to something arguably on uh, |
|
| 38:42 | to erosion. So we can have get down to the point where we |
|
| 38:46 | a script, there's so little sand you're getting mainly between races and it's |
|
| 39:00 | these here or you're not giving you getting vengeance scope sandwich and recording the |
|
| 39:09 | here. Recording from them like so bet and then of course looking at |
|
| 39:18 | emphasis in itself now mm the case over here. If you look |
|
| 39:28 | you can actually see the four But what if you couldn't see for |
|
| 39:38 | ? The individual wow are not so . And as a result, what |
|
| 39:47 | really see a balance. So that's we call translate threat. It looks |
|
| 39:58 | lot. It's parallel there. what you're looking at, what is |
|
| 40:04 | the examinations are actually the first This is very common in the aeolian |
|
| 40:17 | because the process deposition on the least is different. An avalanche on horrific |
|
| 40:27 | waiver, an avalanche ng and some prefer. So there's very little |
|
| 40:34 | This is very common. Look at . This is also what's forming the |
|
| 40:41 | and lower except they're not ripples is of but rather is no answer to |
|
| 40:49 | form. So sometimes we call me this is a detail nothing. And |
|
| 41:04 | looking at the variation, wow, critical fight I say. Therefore misplacing |
|
| 41:14 | . Yes. Uh Did you see from emotion instead of to increase |
|
| 41:23 | Picture? So this particular sequence here looking at deposition during increase blood |
|
| 41:33 | Yeah. Whereas earlier we were looking three D. To two D. |
|
| 41:38 | decrease. So we can have sediment during the waning fall over flood. |
|
| 41:44 | we can actually have segment depending on you are. Okay, now, |
|
| 41:52 | go back to get to the versus process for tuning news because they're relatively |
|
| 42:03 | west. You think it's slice parallel that dip? It's got an |
|
| 42:09 | it's almost you not exactly position. . Mhm straight. You never get |
|
| 42:19 | . But uh you're gonna see these in the central. Oh I yeah |
|
| 42:27 | here you get very little variation in things of that. Yeah. Here |
|
| 42:39 | got much more saying was impressed with lot of scholar and fiddle. So |
|
| 42:47 | can see this trough across the asian . And here we'll see less lateral |
|
| 42:58 | set because we're scout. So this a cross tabular cross strata, trough |
|
| 43:12 | in this shape owns for ripple or this genomic all for ripples as well |
|
| 43:19 | to Yeah, so here we've got each you see it's for my ripple |
|
| 43:30 | really because but you know are you define the sets um by looking at |
|
| 43:45 | bounding service. The first thing I do when I'm in the field is |
|
| 43:52 | to define the bounding services. Where are truncation. Mm Okay, now |
|
| 44:03 | this flow orientation parallel or perpendicular? isn't easy parents were destroyed from left |
|
| 44:13 | let's turn the corner. Here's another . Again, one of the things |
|
| 44:17 | notice here, I'm defining the first bounding surfaces. Um There's a difference |
|
| 44:24 | color of the four sets that's reflecting difference in composition. So there's a |
|
| 44:37 | of variability. Even something as seemingly as a pro rating. Yeah. |
|
| 44:46 | and right angles. It looks like . So what we're beginning to see |
|
| 44:52 | that sets are basically hus state scours field. So even though these look |
|
| 45:04 | parallel, they're really not. There's fair amount of variation in thickness And |
|
| 45:13 | variation in thickness is better appreciated when look at the strike section. So |
|
| 45:20 | looking at three D. This case , three D. Ripples there are |
|
| 45:27 | cross strategy. No, sorry. . Trying to hurt you. But |
|
| 45:41 | . Okay, this set this orientation , is this orientation here? |
|
| 45:50 | this orientation here, is this orientation . This is actually from the |
|
| 46:00 | You can kind of see where I it over here. So this these |
|
| 46:06 | exactly the same and they are exactly to this here. So you can |
|
| 46:14 | , well, you can't necessarily tell deacons from three kids, if you're |
|
| 46:20 | at a depth section. Yeah, harder but they're pretty similar. But |
|
| 46:31 | there is a more Regular thickness with D. But in reality when you're |
|
| 46:41 | the field, you always want to to find a dip section. I |
|
| 46:44 | a strike section. Okay. Or least in the bleak section. |
|
| 46:49 | Now, the other thing you might about is uh any occurrence if you've |
|
| 46:57 | to di dooms pretty easy to take bunch of dips of the force |
|
| 47:03 | And get an indication for floaters. got three d. Dude, you |
|
| 47:08 | make a rose doc because they're dipping , right center in part because they're |
|
| 47:14 | deposited within a trough. So here actually have the trough prospecting that is |
|
| 47:24 | of exposed in here. And so it in the field. You don't |
|
| 47:29 | to do this in court, you take the orientation of the trough as |
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| 47:35 | best measure of floating bridge. Now the other thing is if you |
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| 47:40 | the to erode this flat, you would get what's called ribbon |
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| 47:47 | Which is this where you've got this cut by another trial cut by another |
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| 47:55 | for another troll is filled. so again, this is a little |
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| 48:02 | typical. You usually don't see Exum's quite so nicely. Okay, |
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| 48:07 | again, this is the flow Mhm. By looking at the elongation |
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| 48:13 | , otherwise you have to basically take average of a lot of tips. |
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| 48:18 | elongation of control open for shoots. , here's the trump. Okay and |
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| 48:27 | that is is an elongated scour has filled. Uh Here is the elongated |
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| 48:37 | . This yeah. Okay so it's it's the slip face is dipping within |
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| 48:52 | scalp. So it's like any other uh self critical bed for erosion filled |
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| 49:02 | deep face. The only difference is erosion very laterally because it's a three |
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| 49:08 | . Do. So in front of dune is a scour pool that is |
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| 49:16 | from the upstream side and extended them strips. So what you're doing is |
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| 49:33 | it like that. So this set filling in that scalp. It's just |
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| 49:42 | scour is a and elongated scalp. in that culture with something that dried |
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| 49:53 | like that, you know, it's covered with some more muddy deposits. |
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| 49:58 | when it was lit the fact and he wrote it. Uh, more |
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| 50:02 | deposits were stripped away. Uh, this, this is an unusual out |
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| 50:08 | and I like it because it's The other thing that's interesting about this |
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| 50:14 | is that the paleo currents below it this slightly nuts. Uh, next |
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| 50:22 | union, our right angle to And what this records is uplift along |
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| 50:31 | major layer. My fault so that lower age units were flowing in this |
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| 50:38 | towards me. Uplift occurred and the was diverted writing. And so in |
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| 50:46 | area here we're actually seeing the tectonic controlled diversion of a river turns out |
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| 50:53 | stream. Well, look at it a case study. Uh, it's |
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| 50:58 | big bet, uh, in Doctor marquis. Uh, that's one |
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| 51:05 | the things we looked at with paleo when we did our field trips with |
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| 51:11 | current. Absolutely. Because that's part the paleo geography. Paleo geography is |
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| 51:17 | apartment and fun. Okay. okay, let's, let's go to |
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| 51:25 | outcrop. And so the first thing would always do, uh, is |
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| 51:33 | the bounding surfaces. So, which another about what? On an |
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| 51:59 | I might give you a, and call photo and ask you to think |
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| 52:06 | the bounty units and interpret strep. , so let's look at the lower |
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| 52:16 | or half. Um, sure. this is a tricky question. You |
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| 52:24 | you're looking at ripples are doing? you. Uh Maybe why do you |
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| 52:37 | ripple? So and I simply mean lower part. Why ripples mm |
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| 52:50 | the results? Okay. The thickness the set is less than 10th |
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| 52:55 | Remember what I said about what the of the set indicates if there is |
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| 53:03 | , it indicates the minimum height. there's a unless we actually see the |
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| 53:11 | set, we don't know if that's height of the bed form. In |
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| 53:17 | , the abrupt truncation makes me think probably not. So my interpretation is |
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| 53:25 | we're probably not looking at ripples to but we are looking at a change |
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| 53:31 | the sense they do. There's a there. So uh I'll give you |
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| 53:35 | hint. This is coarse grained sand to be duped. It's actually two |
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| 53:46 | . Okay, so we know we've dooms. What kind of dudes? |
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| 53:55 | who start calling names? I'll tell what Dylan tell me what type of |
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| 54:02 | stratification we're looking at in this lower ? Remember we're looking at a dip |
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| 54:12 | Well and I'll even help you a more. Do you think it's plainer |
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| 54:19 | that is or trough? Do you this is tabular cross stratification for |
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| 54:30 | Cross stratification trump talk what USB and deadwood? Oh I I didn't hear |
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| 54:40 | I'm saying. Uh Okay. Why you say that? Mhm. |
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| 54:48 | Mhm. Okay. Uh huh. help me out. You're right. |
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| 55:01 | is your wife. Yes. Why Why no? Why do you |
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| 55:08 | it's happened? If what is it you see here That makes you interpret |
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| 55:14 | this tablet across the application? I'm sure you make that call with the |
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| 55:25 | . Why not? Then? We look at a model where I made |
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| 55:30 | comment. I don't see any You strike section. You do want |
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| 55:39 | look at the strike section. We have but within this blame. These |
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| 55:45 | really surprisingly parallel. Equal citizens. look it up here. There's a |
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| 55:58 | stage we're playing the if section sets in a different section says that |
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| 56:10 | And what that tells you is it's difference in Samuel's now is this perfectly |
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| 56:16 | two dimensional areas that are too. there's always gonna be a little bit |
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| 56:22 | variation in the same curiosity of that D. U. And therefore that |
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| 56:29 | result in a little bit of a in the down florida. I think |
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| 56:36 | is about as good as you'll see . Yeah. Um Somebody help. |
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| 56:53 | would you describe this? Thanks More Swales extra too well except |
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| 57:02 | Not type of application would be So this is a trough cross stratified |
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| 57:17 | . Okay now in addition to looking uh shit um when they look at |
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| 57:28 | the nature of. Yeah right because first step and it's fairly fair you |
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| 57:41 | again what I told you that he's going off. But It looks like |
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| 57:50 | being two dimensional rules With angular four are relatively low velocity Going up into |
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| 58:03 | divisions, suggest increase. Okay, , the other thing we see is |
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| 58:10 | sets here are recognizing that you are things. Nonetheless, it does appear |
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| 58:22 | be pretty systematic. And here, terms of things, it's a |
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| 58:32 | So we're going from two D. three D. Dams and we're going |
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| 58:36 | thicker dunes. What is the thickness the thickness is at least the first |
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| 58:44 | to dune height. So what would say about water depth is probably |
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| 58:52 | So what we're looking at is flow during a rising flood. Okay. |
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| 59:02 | . Now, oh, the other it reminds you is that when we |
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| 59:07 | right in here, look at the shit, we're looking we're almost up |
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| 59:12 | con que We certainly are tangential, concave. And so not only is |
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| 59:19 | a change from two D. To D. And from smaller to larger |
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| 59:27 | , dunes were getting more and more itself. So all of these things |
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| 59:33 | predicted by our increasing flow velocity. look at this again, pretty clearly |
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| 59:47 | ripple down here, we're beginning to some changes. And again, this |
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| 59:54 | without my pen. It's hard to . But I've got a bounding surface |
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| 60:01 | . Vanek surface here in here and up here is a mudcat. |
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| 60:24 | Okay, so the first question am I looking at dunes, ripples |
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| 60:30 | both reports on the top? Depends the block. Um Now this is |
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| 60:38 | uh it gets less clear. We're at two D. Dunes or three |
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| 60:44 | . Dudes that hurts. This is of those cases where um you'd want |
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| 60:53 | see the dip section which actually is . I couldn't find that picture. |
|
| 60:59 | . Um But what we do see a decrease in the thickness of the |
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| 61:04 | set or the set. Now again is erosion but it does at least |
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| 61:11 | the possibility that we're dealing with smaller with top and that would be consistent |
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| 61:23 | decreasing flow tips. I don't know sure but that's at least a |
|
| 61:31 | But then we get up into the . Now we're looking at a VIP |
|
| 61:38 | ripple cross stratification. Do you think are two D. Or three D |
|
| 61:47 | trading? Absolutely. It's hard to but see how much pension swell there |
|
| 61:54 | Was the three D. So we're from dunes to ripples and then mud |
|
| 62:00 | deposition suspension. So the first thing note is that we're looking at low |
|
| 62:09 | ah city dunes but I would argue kind of transition from tagger within the |
|
| 62:16 | . And then right about here we from tim's direct. So let's think |
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| 62:27 | bounding surfaces. First order. First . Second because among dads are ripped |
|
| 62:40 | here. First order. First First order it said. Mhm. |
|
| 62:48 | this is a second order as well what you can't see is the top |
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| 62:55 | the mud, but if you that would be a circle because what |
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| 63:00 | mud says is this package ended the period of deposition. This set |
|
| 63:09 | concepts ended with a month. So we've got a Cosette here, |
|
| 63:17 | said yeah. Um you could actually a lot from the port. So |
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| 63:26 | our core that And so we The first thing you would do is |
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| 63:31 | to define the bounding surfaces. Then would define uh the cross gratification, |
|
| 63:44 | would reconstruct the type of bed And you would essentially try to reconstruct |
|
| 63:52 | flow conditions under which it was So we've got a nice little flood |
|
| 63:59 | that's going to be a part of point ball. It's gonna be part |
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| 64:05 | a flu real system. Effluvia And clearly this mud here. |
|
| 64:13 | Is going to be a an influence the vertical permeability of this programming point |
|
| 64:23 | laddering migration. Now, this was , this is uh an example of |
|
| 64:35 | people would typically try to do. will look at the minimum dune height |
|
| 64:46 | on the minimum thickness. I'm let's do this. They're going to |
|
| 64:54 | of all, look at the thickness the sets and try to correlate it |
|
| 64:59 | the inferred dune height. So the here, the assumptions everywhere. So |
|
| 65:06 | trying to show you how tenuous to what we do it. Uh The |
|
| 65:12 | heights about two or 3 times So I multiply everything back to. |
|
| 65:19 | so then we get a dune Yes. And then we scale that |
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| 65:26 | mean water depth by multiplying that in dune high bye. 6 - 10 |
|
| 65:35 | . That's why we can go here we can say this was a really |
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| 65:39 | flood maybe 20 m above that. . The problem is, well, |
|
| 65:49 | good news is at least they give a range. But in reality we |
|
| 65:55 | use the range we take. Your are How about 22. Now, |
|
| 66:01 | really you look at this range here you can see well it could be |
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| 66:04 | times six or three times 10. a big variation 63. So that's |
|
| 66:10 | first thing then if you look at debt, you see a lot of |
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| 66:19 | between flow depth individually. Yes. ordered back over there is also a |
|
| 66:32 | right about here. Uh So the recent work on trying to reconstruct flow |
|
| 66:39 | from dune height is this paper by and the needy. And it gives |
|
| 66:47 | a probability distribution, which is really we need to be thinking about because |
|
| 66:53 | probability distribution goes into the probability of water height, which goes into the |
|
| 67:01 | of the water discharge, which goes the probability of the beadboard equation of |
|
| 67:07 | to predict sediment district. Mhm. what I hope you're beginning to see |
|
| 67:14 | that we have a a tendency to about regression lines and absolute values when |
|
| 67:24 | reality, we're looking at probability particularly we tried them all. So |
|
| 67:30 | keep it in mind here, we a strike oriented gravel. You can |
|
| 67:37 | of all the reasons big dunes uh clearly looking at a strike orientation |
|
| 67:44 | Here, we're looking at a dip . This is clearly even on this |
|
| 67:50 | scale, a dip orientation of three . Guns because of the variability. |
|
| 68:01 | looked at that earlier and of here's the cross section of that same |
|
| 68:06 | just around the court. Okay, we have. Yeah, a little |
|
| 68:15 | complicated. There's a line that I'm here and here, within which I |
|
| 68:23 | a whole series of first order bounding that our laws in shape. And |
|
| 68:32 | you look carefully on the screen, least you can see dipping lamination of |
|
| 68:40 | rebels down here. You've got what is referred to as a sigma little |
|
| 68:49 | . And this is something different. , this is a second order bounding |
|
| 68:53 | between a dune on the bottom ripples the top. The ripples are clearly |
|
| 69:00 | dimensional ripples and then it stops right at the end of the flood |
|
| 69:07 | So, we're going from dunes to rules. Now, the thing about |
|
| 69:12 | doom is that it's concave, here's bring point. This is here and |
|
| 69:26 | a lot of oppression of the top up here. So there's a lot |
|
| 69:31 | suspended sentence. This is really pretty velocity, lots of suspended sediment. |
|
| 69:38 | fact these bands here Dark life. you're looking at is organic material that's |
|
| 69:48 | in suspension and finer courts material that's in traction. And the banning is |
|
| 69:57 | result of ripples that are coming in you kind of alternating suspended bed |
|
| 70:06 | suspended sediment bed load. So we're a variation here that reflects the large |
|
| 70:14 | of suspended setup. We kind of it by the time here. Not |
|
| 70:21 | . And we could make those same from a 4" truth. Uh court |
|
| 70:27 | of all, top set for set set. The nature of the bed |
|
| 70:33 | high suspended sediment definitely do. And here three D route. So even |
|
| 70:44 | outcrops are nice, there's a lot can do record. Wouldn't it be |
|
| 70:49 | if you add core for everything you . But don't assume that this is |
|
| 70:54 | applicable this for outcrops. Yeah. Yeah, let's just go to this |
|
| 71:05 | . Are those unit bars talked Okay, they look a lot like |
|
| 71:12 | dudes in fact. Uh huh. were called very large Sabah Quiz Dunes |
|
| 71:18 | 1990 have now been recognized mainly as . And it's an important distinction because |
|
| 71:29 | bars here are scaled more to the river the river depth than with and |
|
| 71:40 | to the float. Mm Yeah. what do they look like in cross |
|
| 71:45 | . Well, I've had to go reinterpret uh oh my stuff. |
|
| 71:51 | ignore these lines somehow. The they when I enlarged the zoom in this |
|
| 72:03 | large four set here. It's more that's a ball. And then these |
|
| 72:13 | these are dudes. Right? Uh what I used to interpret as larger |
|
| 72:22 | . I'm now beginning to realize our law and in the field we, |
|
| 72:27 | kind of saw that for example, got these large scale slip faces With |
|
| 72:36 | of Tens to 100 m. And within it we have a lot of |
|
| 72:42 | . So there was clearly two different or better said two different assemblages, |
|
| 72:51 | , bar forms in a case like . And what we're looking at is |
|
| 72:57 | point bar being a compound bar. . With these unit bars migrating along |
|
| 73:09 | compound bar, which in turn consist a series of flood package generally dooms |
|
| 73:18 | top. So that's what we would here. This larger scale bar for |
|
| 73:27 | and being covered by this material Mhm. Um it's pretty more evident |
|
| 73:39 | . The first time I really began recognize this was on the sand, |
|
| 73:44 | center river and it was clear that was something different about these slip faces |
|
| 73:52 | and here. Then the bed forms here dunes. No problem. Unit |
|
| 73:59 | different. So we put a So here's our trench and here's the |
|
| 74:07 | of that unit bar. Yeah. here's what it looks jim. And |
|
| 74:15 | on top of this we were getting dunes. So I've been seeing this |
|
| 74:27 | more complicated units and I hadn't realized was part of this unit for and |
|
| 74:32 | keep making this distinction between they scale than do. Yeah. So here's |
|
| 74:41 | example of one in the field. Look at the lateral extent of this |
|
| 74:48 | wall. It's just migrates downstream and downstream. But also what you can't |
|
| 74:57 | very well is there are a series reactivation services coming those reactivation services on |
|
| 75:07 | that. I'm good. You know mark my blood drips. So even |
|
| 75:16 | this is very gladly continuous saying overlay underlay by ripple cross examination, which |
|
| 75:24 | less friendly. It still has a situations where there may be slight |
|
| 75:33 | There are some what we've done this all Mhm and speak here. It's |
|
| 75:44 | reactivate individual flood migration. We're going for a while but it doesn't destroy |
|
| 75:50 | uniform is still there. So there'll a little mud erosion. There's |
|
| 75:57 | So these things can go on hundreds meeting people. It's this is the |
|
| 76:06 | looking at side scan and now we're to see these large scale features in |
|
| 76:12 | on top dance on top of So the thing is that uh well |
|
| 76:25 | a think of it as a photograph the surface of the river bought no |
|
| 76:34 | . What you're doing is you're sending a sound way and you're mapping the |
|
| 76:43 | by the change in return time. what it is is a map of |
|
| 76:50 | and the color bars are basically the of topographic contradicts. Okay. And |
|
| 77:00 | what yellow is topographically high? What's is topographically you're looking at Matthew? |
|
| 77:09 | . Uh Besides scan sonar you cannot a cross section. You need something |
|
| 77:16 | ground penetrating radar for that. So know that's an important distinction. |
|
| 77:24 | So. Oh. Mhm. Let sleep. It's about 2:00. I'm |
|
| 77:34 | take it down five minutes or So let them stretch your legs and |
|
| 77:41 | we'll continue on with upper floor regime structures after this. Yeah. |
|
| 77:49 | |
|
