| 00:02 | Okay. All right now, let's about a little bit of fans you |
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| 00:07 | have noticed on the silva that his was actually alluvial fans and negative |
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| 00:16 | they really are different. And so decided to break up the notes and |
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| 00:21 | topics into those two sections. Having that they the process is pretty simple |
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| 00:36 | . There's over that so well, really is a continuing uh just a |
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| 00:41 | articles that take the good ones. , that's a really interesting study that |
|
| 00:48 | like to go over a little Uh, this came out 2020 chinese |
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| 00:55 | fans, which is a nice segue , if you like, traditional rubio |
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| 01:02 | to these negatives. Mhm. We about what determines the fan morphology and |
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| 01:10 | seven mythology. Uh Grady jerry in . That's tectonics, source material and |
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| 01:22 | , discharge rate, area of accommodation space, mainly uh base level |
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| 01:35 | climate into comedy and dominant and the is the dominant fan process And the |
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| 01:44 | fan processes three photos she flows and lamps. Okay, now we can |
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| 01:53 | a little bit of fans and Uh, this is in Northern |
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| 01:59 | We could study them in sand boxes literally used. Yeah, bringing in |
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| 02:07 | . Big box. And we had PhD students who had a really nice |
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| 02:12 | right over there and engineering. Uh engineering describing, you can look at |
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| 02:19 | sand quarry and there's amazing similarities, spite of scale between these types of |
|
| 02:28 | . So we're going to actually kind combine all of the above as we |
|
| 02:32 | about alluvial fans. The other thing to remind you that rubio fans don't |
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| 02:38 | in isolation. Uh, there is source, there is a safe now |
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| 02:45 | the case of source to sink. particular kind of place is pretty short |
|
| 02:50 | . This is a closed basis, erosion in the mountain front clean along |
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| 02:56 | fault gives you all of your they spill into the Jason said now |
|
| 03:05 | gonna look over the next few days the next few electric but multiple environments |
|
| 03:12 | deposition that tend to occur. And said since continental centre. So we're |
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| 03:17 | to look at a little bit of follow black lakes and the only deposit |
|
| 03:22 | they all tend to occur in the region city. Yeah. Now the |
|
| 03:28 | thing, you know, and this in death out modern fan work is |
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| 03:33 | done uh, is a couple of . First of all the size of |
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| 03:38 | fans on one side to be different . Then on the other side, |
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| 03:46 | why that is. And in each the fans along from 10 oh, |
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| 03:54 | this forms a, a feature sometimes on scale called Shahada or a larger |
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| 04:02 | Piedmont. Mm uh huh We can these smaller scale death valley. Uh |
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| 04:11 | car and we see it in larger on the basis of the foothills of |
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| 04:17 | Andes, I'm sorry, the foothills the Himalayas in India where we got |
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| 04:22 | large mega fans coming down grading into gun. She's planning. Yeah. |
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| 04:28 | . Now by definition a fan begins develop where it goes from combined |
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| 04:35 | the unconfined and so the same hair the apex of the fan is going |
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| 04:42 | recur they jumps to business position of from steep slopes to flash. So |
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| 04:51 | you need from alluvial fan is basically big change in slope. What you |
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| 04:57 | for a long lived fan is a lives changing beliefs. And so that's |
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| 05:03 | of the reasons why fans are best false carbs and they are most volumetric |
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| 05:13 | preserved continued sin. Tectonic fault. . Now, as we look at |
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| 05:22 | modern fans, uh, one of things we typically say braided streams flowing |
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| 05:30 | onto the surface in some places slightly . That can be a little |
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| 05:37 | The reason being that often those are really widespread but there are late stage |
|
| 05:46 | . What you see on the maybe not what you see a |
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| 05:51 | So we're gonna try to distinguish between deposits and how those deposits to change |
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| 05:58 | time. Now in this particular example most fans as we go up towards |
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| 06:04 | head of the fan, we begin see that the stream has entrenched the |
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| 06:13 | . This was an old thanks that in french and work commitments stream. |
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| 06:24 | there's a couple of reasons for this , but it's very common. It's |
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| 06:28 | common you see here as well. , this is a french This entrenchment |
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| 06:36 | can be tectonic lee generated. You're uh tilting and or faulting the fan |
|
| 06:49 | entrenchment or can be climatic. it can also be auto cycling. |
|
| 06:59 | this entrenchment fill cycle we got to has a variety of causes. But |
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| 07:10 | they all looked like here's the chance this becomes a trench. And where |
|
| 07:16 | that set go when it comes Because it's on loan in the lower |
|
| 07:20 | of and there's an interception. Uh that we go from interception or their |
|
| 07:33 | and erosion to load deposition. We see them. What the defense do |
|
| 07:42 | see it like you here is the ahead. Here's some water and |
|
| 07:52 | And so we go back to we can see these abandoned fan |
|
| 08:00 | We see this intersection for it between confined modern settlement. Mhm. In |
|
| 08:09 | deposition. So this is hey See on the fans all over the |
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| 08:21 | now one of the points. So that how did this abandoned fan servant |
|
| 08:29 | ? And it basically formed because these migrants more specific. These folks may |
|
| 08:38 | positive over here. Yeah. And assistant, uh, and the lobes |
|
| 08:47 | to killed now and then of course understand back and Children basically we have |
|
| 08:59 | series of the low filling, the itself there. The evolving to a |
|
| 09:11 | location that gets into this question of side like marcellus, auto cycle changes |
|
| 09:22 | be just put on the truck lobes filling up of all that's just part |
|
| 09:30 | how fans maintain itself or it could externally grip Tectonic pulses with finance and |
|
| 09:40 | answer is, it's all three at skates. Now this idea of entrenchment |
|
| 09:50 | low back feeling is also uh, best recognized influence studies. So here's |
|
| 10:00 | for example, there she blows over sand building up next trip. Now |
|
| 10:10 | got intersection right here and what happens that, Whoa begins to grow, |
|
| 10:20 | begins to tax it and that's So we have this upstream Philip, |
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| 10:27 | tell at some point is choked without . He split off in another |
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| 10:37 | We had this site yes channel Yeah, well it's agent whole deposition |
|
| 10:48 | Cramer finally they got this whole fan any begins to being size with the |
|
| 11:01 | inside then in a different way. we see these loads back yeah, |
|
| 11:16 | now that show here nuts. Here is. Okay, that's still your |
|
| 11:27 | back telling the world lo comes up here finally of boston, this is |
|
| 11:35 | . This is the new role. you see it in the baby |
|
| 11:46 | Excellent. Back selling. This is natural fat of how fans developed and |
|
| 11:59 | again, it's just a look at uh Sam Fox news joint fan they |
|
| 12:11 | here retro grading then backed up the . Mhm Now here they're actually |
|
| 12:22 | they are many came debris flows. that's not the only process but debris |
|
| 12:32 | are one of the main process that building up. Look at this particular |
|
| 12:37 | is building up what we've been called flat. The three stand to lose |
|
| 12:46 | uh re close unlike anything we've talked are a major process in many |
|
| 12:55 | particularly in arid regions. Okay. those the great folks that moves and |
|
| 13:06 | we go upstream, they have these lips. So we're gonna be talking |
|
| 13:11 | the leading channels downstream the brief low as we get into dealing with that |
|
| 13:24 | . Uh, this is just examples that succession again here is looking at |
|
| 13:41 | size that session. We can expect sometimes I agree that you don't get |
|
| 13:53 | you don't have to inspiration. Now other thing you notice on imagery is |
|
| 14:04 | a lot of color variation, Even market. And so what is controlling |
|
| 14:10 | color variation is mainly that varnish, oxide. So the longer the fan |
|
| 14:20 | remained uh exposed as a terrorist, darker it gets, the thicker the |
|
| 14:28 | oxide. So we can actually correlate age of fans surface based on the |
|
| 14:36 | of the desert hearts. The man the box. And so this is |
|
| 14:44 | map june market map showing the relative of the help. I'm sure of |
|
| 14:54 | saints based on the thickness of more and by dating if most Adams we |
|
| 15:05 | actually begin to define, are you ? And we see that some of |
|
| 15:11 | portions just stand up here is only . Then they go down in a |
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| 15:20 | maybe twice saying quote. So we that these fans have been active for |
|
| 15:28 | long period of time in the same or fix feature really hasn't changed long |
|
| 15:35 | hundreds of thousands of years. Now you look at the processes of fan |
|
| 15:45 | we're not so much conservatives watch all are concerned and those floats are maybe |
|
| 15:57 | types of reasons. And then fluid . Yeah. Keep parts like So |
|
| 16:10 | me just stop for me, 19 in seven uh fluid right? Both |
|
| 16:18 | driven by graft that's pretty clear the flows. But a fluid gravity flow |
|
| 16:26 | that the fluid is moving in response gravity and the fluid motion is in |
|
| 16:34 | the set. So the sentiment is trained within a fluid gravity. It's |
|
| 16:43 | trained by the moving more. It's the movement of the water and |
|
| 16:48 | turbulence picks up the set is everything talked about today. Sediment gravity flow |
|
| 16:56 | different in that you start with a laden fluid, you've got very high |
|
| 17:06 | and it's that high density of the laden fluid that is flowing in response |
|
| 17:13 | gravity. So in one case your , it's up sending military, you |
|
| 17:26 | if you want to send a broader the driving force of gravity is causing |
|
| 17:32 | density. It's £7. We will more about that because now there are |
|
| 17:42 | processes. Well, application development, windowing by open and accepting. So |
|
| 17:51 | look at possible but we're going to on the things that build the bulk |
|
| 17:58 | sand which are the sediment gravity and graphics. Now it's useful to subdivide |
|
| 18:10 | processes into sediment graphic als namely to . He said, that's not the |
|
| 18:19 | she uh she uh and streams. what we're doing is we're looking at |
|
| 18:31 | unconfined. She often performed pretty versus channel lines, stream world and that's |
|
| 18:46 | great book. Could be breaking with end. Yeah, I mentioned earlier |
|
| 18:55 | we could look at the stress strain um to try to define separate Newtonian |
|
| 19:07 | orders being placed. What we're really is separating the Yeah, fluid wrap |
|
| 19:17 | from the seven. It's when calling different work non fluid already this is |
|
| 19:29 | newtonian fluids or things like are shown is a request. They have a |
|
| 19:40 | frank so you have to apply an amount of stress with his float. |
|
| 19:52 | a high viscosity because I said consultation it has a high settlement themselves because |
|
| 20:01 | has a high viscosity. It tends have a low rentals so it tends |
|
| 20:06 | be laminar fault. All of this because there's a high concentration of sand |
|
| 20:14 | more and as it's moving on the flow densely non erosive. We tend |
|
| 20:23 | have these depositions. Yeah. Now of it december. What I described |
|
| 20:34 | terms of fluid flow. The union currents in the sediment transport in earlier |
|
| 20:44 | . But it really is great Mhm. Because if you think about |
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| 20:50 | seven concentration, you're gonna have decreasing pots and you're going to have increasing |
|
| 21:02 | discussing and so you're going to have that starts off in security Tony but |
|
| 21:15 | up to work in the audience. concentrated from eventually you're not already. |
|
| 21:24 | . Anyway, one day walk girl maybe two or 2.5 the guests to |
|
| 21:36 | wall As we in Texas seven documentation , 80. and wait, there |
|
| 21:47 | a radiation good congrats. We are no problem. Basic cuts recognize it |
|
| 22:02 | critical. Yeah. As we gray seven of them were also ready and |
|
| 22:15 | different senator uh types. So let's at this extreme case where we had |
|
| 22:22 | lot of sediment in the fluid and get the free flow deposit. Debra |
|
| 22:29 | right is analogous to turn to So one matrix support random class orientation. |
|
| 22:46 | temples are literally floating in late. fact, when you see a debris |
|
| 22:51 | in the field, you've got these boulders just kind of coming up and |
|
| 22:56 | down. It's really quite extraordinary. there's no set in the truck. |
|
| 23:03 | very much wise. Yeah, this a bit over some product. These |
|
| 23:14 | Yeah, may accept you but basically it. Uh huh. Different orientations |
|
| 23:23 | maybe a little shearing created, but non corrosive. He's a pyro space |
|
| 23:31 | . And although exists plastic maker supported fabrics mainly makes Mhm. But it's |
|
| 23:42 | surprising that in the field it's not to be just before. What do |
|
| 23:48 | think? What free flow? Some , grief. Wrong. Yeah. |
|
| 24:01 | strips. So, this is what looking for with the debris flow |
|
| 24:11 | And it's useful to go back to . Faces classification when we're looking at |
|
| 24:18 | fans. Uh gravel rich. So is a good place to live that |
|
| 24:26 | way of describing box. So here have been upgraded, Matrix supported, |
|
| 24:34 | Gmm. Now here we've got some the non police Except that. |
|
| 24:43 | Mhm. But they are really quite morphological of debris flows. There's no |
|
| 24:57 | a little more type. And what can do if you got a pencil |
|
| 25:03 | not a thick thumb is you can these think helps if you There's a |
|
| 25:11 | , these finger like hearts. These like rose grading up into these |
|
| 25:25 | Okay, and so it's actually a good analogy orbit of different scales of |
|
| 25:38 | an alluvial fan that's built up by grief flows. And if you look |
|
| 25:44 | this kind of pattern here, let's at this gravelly debris flow in the |
|
| 25:52 | rockies where the steep scarf here now not due to a fault, but |
|
| 25:56 | due to glaciation and receive the typical including these bare legs. That's basically |
|
| 26:11 | this is moving as a slug, sides kind of stop and freeze and |
|
| 26:17 | empties out. And where does it the out to the organization? This |
|
| 26:25 | a typical more farm of a debris . It's also a typical morphology of |
|
| 26:31 | re flows in volcanic regions where they're Lahore ours, but that's just basically |
|
| 26:42 | volcanic debris flow. So one of Geologic Hazards. Uh, keep the |
|
| 26:52 | flows typically is coming off volcano. the other thing which I should have |
|
| 26:58 | , but I didn't is you get same morphology with an anesthetic Wallace with |
|
| 27:05 | in the upper part and deposition loans , the Realogy or behavior of these |
|
| 27:14 | basically the same. So, let's at some examples beginning uh and and |
|
| 27:23 | look at and galleries. Uh huh . Galilean Hobday wrote a book, |
|
| 27:31 | edition and then we quit. That was the best book on bridges, |
|
| 27:39 | systems that we have is now long of friends. I have a copy |
|
| 27:45 | that you want to look at and it remains a good introduction to different |
|
| 27:52 | system. Some better. Huh. . But the other way is in |
|
| 28:00 | triangular classification since actually geologists, the is basically we think in two and |
|
| 28:09 | . We like to look at variables perfectly, no more than three. |
|
| 28:20 | here's our debris flow fact. Uh Sometimes called Type one. I don't |
|
| 28:26 | it that but it's uh looks like ? And so what we see is |
|
| 28:32 | other part of fan whole serious place more upon example serious. Now the |
|
| 28:42 | change it. So it's not that valet but it's at all. |
|
| 28:51 | And we see that similar. You're votes. Yeah, this is from |
|
| 29:02 | Mcpherson. Uh they probably did the early population. Yeah, you got |
|
| 29:15 | inside. Mm The intersection point. it. As is for now go |
|
| 29:27 | school entities continue. Yeah. Ladies . I tell you now what they |
|
| 29:37 | say what we now know this road sells snowball and what we see on |
|
| 29:46 | surface are mortal enemies and marks and this all the more ladies and and |
|
| 29:54 | this little, you know, Alex basically host fan that reaction Oregon coast |
|
| 30:05 | remember that what's happening here is these are growing episodic, there's a flash |
|
| 30:15 | and then long periods of time between next flash flow. And so there's |
|
| 30:20 | lot of reworking. If you go in between the events these events have |
|
| 30:25 | your events. Okay. Uh So the more quality of this abandoned |
|
| 30:33 | includes the deposition of morphology, the , a little bit of the |
|
| 30:42 | Uh Yeah. Mhm And in this uh yeah, the fans were recent |
|
| 30:53 | that there's not much we work with particular example. Now this was one |
|
| 31:01 | the fans if you look at and most recent for working, what do |
|
| 31:09 | think? Some older brother system. morphology. It's the same thing like |
|
| 31:17 | eight. Let me channel breaking into home gift, those dominating more parts |
|
| 31:25 | sand levees. Now, the nice about this stand, you, we're |
|
| 31:38 | people in different ways. Uh, know as the base for some of |
|
| 31:46 | fans basically this again is showing different hands, no foundation or are levy |
|
| 31:59 | . Let's see what you, here's latest. This is a condom. |
|
| 32:11 | . When you look at the you got the part of you like |
|
| 32:18 | . Pretty much yeah, as you down sand. Great. Now there |
|
| 32:29 | some orientation says that the great clubs have an organization. That's a generalization |
|
| 32:39 | the margins can be orientation. but it's so, so here's our |
|
| 32:49 | fan maybe dominated north and, and what the inferences with a hypothetical, |
|
| 32:58 | separation wall, we're going to see fan, we can see a lot |
|
| 33:09 | lead Frederick size channels, namely levy , they're gonna pinch out two more |
|
| 33:23 | of oaks and in cross section the is namely nested when they can't in |
|
| 33:34 | lower part of fan is gonna the of aid flows. Thanks. So |
|
| 33:45 | kind of their model or a degree fan. And uh, let's look |
|
| 33:53 | a second grade for fan, it's larger and it looks a little bit |
|
| 34:02 | 65 years thanks santa Barbara, major fault. Now here as a |
|
| 34:21 | . Look at these migrants are that's , it's the northern side of the |
|
| 34:27 | . We're still real snuff essentially Yeah, those levees and actually, |
|
| 34:35 | , make that pete look at the already. Two Jeff sessions lady |
|
| 34:50 | Okay, these levees are extending for and if you look closely, you |
|
| 35:04 | see that they are here. So upper fan is levied um, over |
|
| 35:12 | much larger. Every smaller that Yeah. So there's a wide range |
|
| 35:20 | signs of debris flows and debris fans that's clearly in part the relationship |
|
| 35:29 | the catchment area, small catchment area in small fats and smaller debris |
|
| 35:38 | The catchment area of the previous fan much smaller than this, which was |
|
| 35:43 | large portion of the sierra lies. keep in mind the role of sorts |
|
| 35:50 | controlling ST Yes, but I the bath and certain wherever we're |
|
| 35:59 | the emphasize of the table well, , the height affects the things and |
|
| 36:08 | the higher uh, the greater the for a large amount of debris to |
|
| 36:16 | in. So yes, in one of things we see is there's |
|
| 36:20 | change in fans as the, as mountains were down. So as long |
|
| 36:27 | there is continuous movement, you pretty have continuous fans and more or less |
|
| 36:33 | same time, but as the mountain down, you're gonna see it change |
|
| 36:39 | only in the drainage area, but relatively and both affect the nature center |
|
| 36:47 | . Yeah. So here's our distributor fans again. I mean the actual |
|
| 36:55 | where and this is a case where can actually use possible genetic age. |
|
| 37:03 | you really? And they defend the is mostly the same positive. We |
|
| 37:14 | fossil get off right now. There some large areas, there are late |
|
| 37:26 | , but this is one of those when you're beginning to get better technology |
|
| 37:31 | fan grow using the prostitute. And important to, first of all we |
|
| 37:41 | have much carbon 14 so you don't to struggle. They also, we |
|
| 37:50 | no older deposits. Thank you. lastly the reason why we're interested in |
|
| 38:00 | very detailed chronology of surfaces is to fault because the faults are rather the |
|
| 38:12 | are there because of active fault. makes a big difference If the last |
|
| 38:19 | was 100,000 years ago, 2000 years , only 100 years ago. So |
|
| 38:26 | in order to evaluate size, risk need a really detailed fraternity chronology and |
|
| 38:34 | specifically policy in order to date offset to date fault group. And that's |
|
| 38:43 | he spent a lot of time on like trying to date time. New |
|
| 38:50 | for dating river fans. So in what date? Something like this And |
|
| 38:56 | just dating services. Yes. Okay. So we got the great |
|
| 39:04 | vary in scale but uh she flood shit for a lot of using kind |
|
| 39:12 | oh, entertainment. We're basically an swirled but it's now good. Not |
|
| 39:23 | sediment that, So let's, let's how that might different. And the |
|
| 39:30 | thing is cheap. Flood deposits are significantly different than the recent causes. |
|
| 39:38 | huh. They are moving in response walk. So there's going to be |
|
| 39:50 | less matrix. They're going to be supported. It's going to show at |
|
| 39:56 | breaking. You may not see the stratification. So the movie great. |
|
| 40:03 | is no, this charge decreases reluctant get implication. So getting upstream and |
|
| 40:13 | not my hope to have this erosion now looking again at real life. |
|
| 40:28 | at the rodeo generalization and face. , uh, we got ready. |
|
| 40:35 | make these crews cross stratification class supported then we begin to see stratified |
|
| 40:45 | Yeah, I believe and what this us is basically travel sand couple as |
|
| 40:55 | is great. I'm great grated uh raised in normally great. But there |
|
| 41:04 | is a fairly the state right between . So we're going to see that's |
|
| 41:11 | characteristic cheap and she's like the Yeah. Now in that case |
|
| 41:20 | uh Oh yeah, this is debris . This is she Again, side |
|
| 41:30 | your 60 points deposition and these earlier lobes reform when that feeling. So |
|
| 41:51 | we're going to look at here are had of those depositions. It's |
|
| 42:00 | We're going to look at the, love your man in the best out |
|
| 42:06 | valley is helping transitional. Uh Yeah. Yeah. Long after where |
|
| 42:21 | are the wall find out. And it started to the west agent. |
|
| 42:33 | really just a tilted and this health geometry is really college throughout the |
|
| 42:44 | This is a technomic set in a geometry uh in which alluvial fans are |
|
| 42:53 | in china Argentina Mexico here uh So save me. Yeah, the |
|
| 43:04 | basically is that there is a master that gives us a lot of our |
|
| 43:10 | and then on the other side, relatively the little debris flow fans. |
|
| 43:20 | saw death now, No, no large things for self here and |
|
| 43:37 | . Well, so these sands, things are more typical uh strength and |
|
| 43:48 | difference of fan talk is pretty The idea that you have grief flows |
|
| 43:57 | . But we have more water generated over here is really reflecting the difference |
|
| 44:03 | the catchment eric what the Caspian area here, which is wonderful. A |
|
| 44:13 | school is not very large diversity, is from the giving you a lot |
|
| 44:21 | sediment coming in matters is the re , but they're not as much of |
|
| 44:29 | they're small debris flows over here. got a why? Like you get |
|
| 44:39 | larger space and lower away warm with water and counting the larger page area |
|
| 44:50 | more water or lady deposition process on on this side. Mhm. So |
|
| 45:02 | face she's here. Well, we'll comforts that said, legends travel in |
|
| 45:12 | and massive. Now most interested in yeah. Uh now before I do |
|
| 45:24 | , let me mention that I'm gonna this talk talking about the popular |
|
| 45:31 | This is a larger fan that was last year in china. And the |
|
| 45:40 | that I want to point out is a lot of this species that have |
|
| 45:47 | in that larger thing muscle are the conversations have seen more specific and she |
|
| 45:56 | battlefield sheet. But I will say absolutely our characteristics of the in front |
|
| 46:06 | . She cheap look. So when show you for the animal baby is |
|
| 46:14 | applicable. Large number uh, this of thing. So let's look at |
|
| 46:25 | basically you've got um sheep blood which basically are gravel capped by planer |
|
| 46:40 | of sand and I'm not going to into reading what you can read, |
|
| 46:47 | basically they are like this. And so this is the first thing |
|
| 46:55 | the same company and they look like change or crude but laterally extensive beds |
|
| 47:07 | you this gravel sand, gravel, , gravel sand. Now locally they |
|
| 47:17 | are little wedges of sam that show stream dips and these are interpreted as |
|
| 47:30 | gypsy. So let's look at take a look here, but rubble |
|
| 47:38 | cup. Remember it's a problem went between these two is a wedge, |
|
| 47:54 | . It turns out the she so actually upper flow regime but it's more |
|
| 48:03 | bits. But when these have been as active you can stand in wage |
|
| 48:10 | then once they're left behind you locally these tax dipping reg is you see |
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| 48:20 | in this fan in death valley, see him in china in bigger |
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| 48:26 | their characteristic this type of flow. so these are some pretty big. |
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| 48:37 | the interpretation is, you know, lot of sediment of the flow |
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| 48:40 | sheep flood by capacity, high competence fairly steep 2 - 5° slopes of |
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| 48:50 | things. Fast forward 20 20 And now we're seeing the same features |
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| 49:00 | much flattered fans less than a So the early literature really focused on |
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| 49:08 | fans. Now we're realizing these bigger that are flatter and wider can still |
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| 49:15 | cheap flow. Okay, um sets a meter to 2.5 m thick hi |
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| 49:26 | . And so they look something like here we happen. Uh huh in |
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| 49:33 | china the same. Uh huh. you understand? So they don't |
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| 49:43 | here's something that step the massive bedded boulder, they're interpreted as in size |
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| 49:57 | , closets. So we see these an example of them pretty messy of |
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| 50:09 | is so gravel rich or not getting in size, much change going on |
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| 50:13 | the size channel but when it spills into the lobe it's cheap. |
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| 50:21 | this is a funny looking diagram because looks like a cross section. |
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| 50:27 | Is a down fan change in the proportion of patients. And what it |
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| 50:36 | is this is 100% the rebels and nominate. Well thank you. |
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| 50:51 | And there are some size channels, upper part of the that were |
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| 50:58 | Uh they're gonna be filled. So just illustrates absolutely. Yet the back |
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| 51:09 | wedges page out towards it. I want and then surface lags and |
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| 51:20 | basically. But they're also it So the main story is that the |
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| 51:29 | channel deposit and a part of the the sheep flood deposits covered the entire |
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| 51:36 | . The upper part of the chief an inter vetted that question causes and |
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| 51:42 | periodic intervals fan abandoned. You could done this church. Let's right. |
|
| 51:51 | this is their kind of generalized perceptual at it. Uh notice there's no |
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| 51:59 | , there's no debris flow globes, no debris for lunch. Yeah. |
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| 52:05 | groups and um we see here the part of the sand you've got it's |
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| 52:12 | to be partial brain. You've got back step wages. I've got some |
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| 52:23 | many intermittently. You got these Uh . I kind of get this apartment |
|
| 52:31 | , You lost your class channel Okay, you lost your back |
|
| 52:37 | You still have the gravel sand. . Now, yeah, sorry. |
|
| 52:51 | particular model from Galloway kind of talks the flow evolution, but also it |
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| 53:01 | pretty example down stand change, decreased are decreasing thickness, decreased channel |
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| 53:10 | is decreased, That's pretty much the of it from hawks in the |
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| 53:17 | There maybe five km maybe. Okay. But the other thing is |
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| 53:26 | actually was, I think thinking about talk because when the fall comes to |
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| 53:37 | , you get a lot of high and you're no clue briefly. And |
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| 53:48 | us as that system begins to you get more water to get more |
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| 54:00 | rich refunds and sheep lights with time the drainage area hatred suspicion perhaps in |
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| 54:14 | the star, the formal water and go into worship. So We see |
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| 54:26 | different types of fans and that's not refunds for the active fault is and |
|
| 54:34 | see shit rolls where the not even thought necessarily it's small. And so |
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| 54:43 | a spatial distribution based on tectonic But it can also be a |
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| 54:51 | I'm sorry, could also be a a careful change is the technomic setting |
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| 55:00 | structure set. Uh This is just remind you that, although, |
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| 55:07 | we have been somewhat fixated by alluvial in uh the mojave desert. Um |
|
| 55:16 | not just desert landforms. Uh We in in Alaska, we got him |
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| 55:23 | other areas. We've even got them um Switzerland. Uh And so here |
|
| 55:32 | we're looking at is a scarf with abrupt change in slope. It gives |
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| 55:41 | a fan. Mhm. Now that in this case and is the change |
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| 55:50 | slope, that's needed for a fan a glaciation scar. Just like the |
|
| 55:54 | show Canada. And so we also the age of this fan. It |
|
| 56:01 | , it had to happen after the melt so we can look at. |
|
| 56:08 | . Mhm. Okay. The band here we're using mhm. When you're |
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| 56:15 | at different radar faces, the subjects have so we can look at how |
|
| 56:25 | man has evolved in the last 18,000 . It turns out the oldest thing |
|
| 56:38 | about 50% that recourse and a little people. And as that man evolved |
|
| 56:52 | it came down the street and what seeing is the change in the |
|
| 57:01 | Mhm. With the playstation. And you get more and more water less |
|
| 57:09 | less. The brief it shows only a very compact way temperatures. Uh |
|
| 57:18 | . How quickly source area variables can due to comment. Change now |
|
| 57:29 | but I was a seminal work by Mcpherson uh when they looked at alluvial |
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| 57:36 | and things that are called alluvial I said, you know the problem |
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| 57:41 | that there are fans and good old and a great. Mhm. You |
|
| 57:51 | on the gift and really there's no between, with respect to slow between |
|
| 57:59 | and facts that different subjects are really . So they're saying that will say |
|
| 58:08 | . Great. And that these large could have these low slopes shouldn't even |
|
| 58:15 | fans, you're going to be what talk about next time mega facts. |
|
| 58:22 | , and they argue that that makes because the steep slows allow you to |
|
| 58:31 | super. Now Egypt lines is basically distraction but basically subsidized the world is |
|
| 58:43 | proposal on both fortune and it's So the some critical is typical of |
|
| 58:56 | world. Uh huh. In the you think it's difficult for this? |
|
| 59:08 | changing is uh huh. Move your Now. They suggest there's a gap |
|
| 59:26 | that gap we see here. But these are real friends. Me too |
|
| 59:37 | . Yeah. He was made more . What I'm going to point out |
|
| 59:43 | that that yeah, is not as as it looks because once we've gotten |
|
| 59:49 | satellite imagery said that it opened up number of examples we're beginning to fill |
|
| 59:56 | it yet. But having said that really is my most you have transitions |
|
| 60:04 | it's not nearly as separated. First . So those big fans, those |
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| 60:14 | what we're all at one point The big powerful large drainage area, |
|
| 60:24 | area those locks and so what we a very strong. I invited it's |
|
| 60:35 | fans and other things. Mm They acted through this year, which |
|
| 60:44 | 12 fans and through your things? . Uh huh. Mm right. |
|
| 60:59 | plugs and olympic. The problem is you start looking at satellite photos and |
|
| 61:11 | distance system. Well, here's the . That is why 1.8° you get |
|
| 61:21 | we put that here three days. family. Pretty big kind of |
|
| 61:33 | In fact, if you look at slope thought you see that increasingly stupid |
|
| 61:45 | the beach. This is, but steeper and widen in the middle of |
|
| 61:53 | be literally things basically be less than on almost. Well. So what |
|
| 62:05 | suggested by player, bigger fans will . Well now what we're realizing is |
|
| 62:13 | there is this transition. So some the 3200 for now you still really |
|
| 62:23 | but there are differences so it makes to recognize the effect of escape. |
|
| 62:32 | , um, so is this suggesting welcome back. It'll be okay. |
|
| 62:39 | well that's how it was described. now we're gonna, we're gonna, |
|
| 62:43 | going to call it a mega. for distributor in Floreal system. Well |
|
| 62:49 | is, but is that not a bunch of, we've got these things |
|
| 62:54 | are big that radiate out from It hasn't fan shaped, they had |
|
| 63:02 | of a conical cross section. And really the fundamental question is this, |
|
| 63:12 | , it has a good shape. , it as a apex. I |
|
| 63:20 | some size class composition inside what It about 40 km from that table. |
|
| 63:35 | average smoke 26°. Is it a fan alluvial fan or is it a flat |
|
| 63:46 | Already today stream flow fan is Louisville distributed Louisville system. That really is |
|
| 63:54 | question getting into now and and also the, the literature also. How |
|
| 64:00 | you describe these larger features until finally get to something like mhm. Both |
|
| 64:09 | fans of the uh huh gone jeez , based in Piedmont from the |
|
| 64:17 | uh, along the back side of four then basin Vandy's, so that's |
|
| 64:24 | be at the top of the X . Now, we would look at |
|
| 64:31 | . One of the things to note there are small fans. Next big |
|
| 64:38 | . And the reason is there are ready Julius and a big joke. |
|
| 64:45 | small things. You have your facts any stamps basically our rhythm already nothing |
|
| 64:55 | , oh, you know, most the slope. This is a trans |
|
| 65:01 | basis. Again, not unlike half kind of a half rob, not |
|
| 65:10 | Jeff out there are small things, yeah, I like that. It |
|
| 65:17 | in here and it also empties. we have a small red berries and |
|
| 65:24 | than, and when that big river in in position. So, |
|
| 65:34 | nobody would argue about what's, no, there is another thing. |
|
| 65:40 | the first thing is as a matter the size of the kitchen. So |
|
| 65:48 | love with that more streams of keep more water than the teachers. |
|
| 65:56 | , just very briefly, let me out these little things here. Now |
|
| 66:00 | is actually serious trust. Um, these all threats here and there are |
|
| 66:08 | basins. Yeah, your little basis filled with the breed clubs and this |
|
| 66:19 | what we sometimes call a piggyback We talked about it last time we |
|
| 66:25 | a series of implicated thrust And you a little pond seven. That's very |
|
| 66:37 | . Did you have subsidence here? . You've got substance. You |
|
| 66:43 | this is an active crime. trust fund. Yeah. Results. |
|
| 66:51 | there's, there's a high potential for . Absolutely. Yes. Okay. |
|
| 67:00 | now let's go back to comparing And versus 730. So more than one |
|
| 67:11 | the bank. I just switch these , I just did, Uh, |
|
| 67:23 | is about 4.7° the complex days 26-6 the face he's insane with one |
|
| 67:34 | We do have some uh huh was unconfined straight for what was supposed |
|
| 67:42 | I think they're cheap and created but then the pumps fan going, |
|
| 67:54 | got some surface on. Uh, they got the old, but it's |
|
| 68:02 | similar in terms of fish cheeks. let's look at what's going to |
|
| 68:07 | First thing that I would go, is a, and the arid reached |
|
| 68:12 | very and so there's so much evaporation literally you have a decrease in debt |
|
| 68:22 | with, but chance they should go if you're losing discharge as you go |
|
| 68:32 | . In fact it empties into, can play now in addition. And |
|
| 68:40 | also and with his wider what it in yesterday. So that channel comes |
|
| 68:48 | and it just kind of spreads out is losing more due to infiltration. |
|
| 68:58 | now if we look at the face , the inside channel deposits pretty much |
|
| 69:08 | without mid faith. The stream political street. Hello. These are difficult |
|
| 69:18 | what was described in the end gravel published. Oh yeah. So |
|
| 69:30 | for which but they gray into is unconfined stranger. There's nothing quite like |
|
| 69:39 | in the smaller handle fan. But it's still poorly sorted, crudely |
|
| 69:51 | stratified gravel. Yeah, well finally . So with the bigger fan, |
|
| 69:59 | main difference is the volume flow over larger distance tends to cause a little |
|
| 70:06 | down dip change, but it's still floor regime. Uh huh. I |
|
| 70:14 | open but these surface ponds occurred throughout actually. Yeah. And they're rated |
|
| 70:23 | extremes. Now, what we're going see the second is that these features |
|
| 70:33 | Are one phase of fan development. bravest dream is another phase and then |
|
| 70:41 | an abandonment. Yeah. So if look at and that deposition or this |
|
| 70:51 | looks an awful law like that. opposition while it was described for the |
|
| 71:00 | , any form to say you've got inside channel people hard, still hard |
|
| 71:09 | . The federal laws that kind of because what they are particularly on the |
|
| 71:16 | side. Uh, this is You can obstruct then during the a |
|
| 71:26 | time. So we're beginning to look a fan because we're talking about fans |
|
| 71:31 | are hundreds of thousands of years racial interglacial, we got a lot |
|
| 71:36 | significant climatic change. So this is the wet, very wet. And |
|
| 71:45 | with implementation, you've got a rise the water table. You just hold |
|
| 71:50 | lies where water is seeking getting So you can see this on aerial |
|
| 72:00 | and satellite images with 40 sweater where intersect. And so this is a |
|
| 72:08 | of a sketch about the change in science in the transition cheap floor to |
|
| 72:17 | you. Find strange. Now that one when the climate gets well erin |
|
| 72:32 | . Where smaller but more frequent get and you are forming very different. |
|
| 72:45 | get again we get ready and stream over most. And here's the |
|
| 72:53 | Okay, natives between front may be dry. Dill water on the preparation |
|
| 73:04 | . Now you just Yeah, little trying get up this morning. But |
|
| 73:13 | Yeah, so it's still a sheep fan, but it's really big. |
|
| 73:21 | going back to that question of, there a gap? Well, 11 |
|
| 73:26 | I had my students when I had students in this class, uh just |
|
| 73:31 | as an exercise. See if you find some fans on reading errors that |
|
| 73:39 | fill the gap and you begin to them. They are there. Of |
|
| 73:44 | the popular is what? Yes. for all that it is is probably |
|
| 73:55 | a good idea. Mhm. To what has been traditionally called. It's |
|
| 74:02 | for the same different think about So the great showmanship recognize that these |
|
| 74:20 | here in front of it, but still kind of a bible really. |
|
| 74:26 | you saying are fan shaped political You really are article bad shit. |
|
| 74:38 | opposition party. And we've got all of names for let me clean, |
|
| 74:50 | it an internal Cleveland, distribute, it through the system. All these |
|
| 74:59 | . Uh I've settled on the No, never big. Yeah. |
|
| 75:06 | key is, it really is strata a river system. So in terms |
|
| 75:14 | the deposition of violence, it is river That is migrating about eight |
|
| 75:22 | Yeah. And so it does give distributed. Hello, The doves have |
|
| 75:32 | secretion and it's often associated with major of clothes. But the source area |
|
| 75:38 | much bigger is what's coming into that great is a major river that they |
|
| 75:47 | on. So that's the reason of lectures. And that's the required stop |
|
| 75:56 | because and engaging the notes of which is about my guess stops. |
|
| 76:05 | . Uh let's break. I'm losing voice. And uh yeah, let |
|
| 76:14 | remind you that I will give you study guide. Either tonight or |
|
| 76:21 | The exam will be prompt at one . Um because it makes no sense |
|
| 76:28 | me to lecture before an exam. Nobody was focused. Uh And you |
|
| 76:34 | about an hour and a half. time it based on what I think |
|
| 76:39 | need. But uh uh in the guide, I'll give you some detail |
|
| 76:47 | relative waiting, have different topics as as the questions. And I may |
|
| 76:55 | the question verbatim, or I may a derivative question that is derived as |
|
| 77:01 | component of the study guide question. , I will tell you now. |
|
| 77:06 | will include mhm sketches. They will interpretation of photos of sedimentary structures. |
|
| 77:16 | They will include probably uh couple of matching. The rest will be |
|
| 77:26 | essay questions. Okay? So if have any questions about what I've covered |
|
| 77:33 | , I have time. Mhm. not uh enjoy your abbreviated weekends |
|
