| 00:07 | Okay, now you can hear me , good. Ah Mhm. Now |
|
| 00:19 | , not every system has classic Okay. Uh but many do. |
|
| 00:26 | obviously when you haven't got platforms, get a bit a bit easier when |
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| 00:34 | talk about Stanislaus, one of those is the law of original horizontal |
|
| 00:39 | which is the idea that, you , to a first approximation federal aid |
|
| 00:43 | horizontal. And the reason steno came with that law is he realized that |
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| 00:47 | that would tilt. I mean, didn't understand the word tectonics. You |
|
| 00:52 | , if the bed is clearly tilted folded, he realized, well, |
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| 00:55 | a minute if it was loose it couldn't have been deposited as a |
|
| 00:59 | a folded layer because it would Right. Yeah. So um we |
|
| 01:08 | at this diagram here and we can all these client forms. Right, |
|
| 01:15 | , is anything flat on this Is anything flat, horizontal? |
|
| 01:23 | is anything smooth? That's a harder . But, you know, kind |
|
| 01:29 | form could be smooth, but certainly flat. Right. It comes back |
|
| 01:32 | with the items, however, Okay. Um ah Now this is |
|
| 01:43 | ? Okay, I'm gonna give you a little quiz. Okay, what's |
|
| 01:46 | vertical scale on this diagram, So is supposed so I helped, I'm |
|
| 02:05 | to so they think this is this looks wrong, scope. Oh |
|
| 02:19 | . Right, thank you. And know this is offshore, yep, |
|
| 02:28 | was too. What's up? Mhm. This is too many types |
|
| 02:35 | I sorry, yes, okay, was there was a distance on |
|
| 02:54 | Oh, the physical distance of the business? Okay. We have to |
|
| 03:01 | the vertical scale, there's there's the scale there? 123 seconds. So |
|
| 03:05 | got three seconds from this from there that point? Yeah, that's |
|
| 03:13 | yes. Right, so what's the the vertical distance? No, you |
|
| 03:26 | . I gave you I think I you the formula yesterday or the first |
|
| 03:32 | . Yeah, I really like you it right down peters, what's your |
|
| 03:44 | ? So this is where like everything said is excellent. Okay, that's |
|
| 03:48 | what you should do legally. But as geologists and I'm we're gonna |
|
| 03:54 | gonna pretend to be geologists here for second, right? Looking at a |
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| 03:57 | client, it's good to just have of some what I call rules of |
|
| 04:00 | numbers. Right, so you're good the one point so 15, you |
|
| 04:04 | uh 1.5 uh Yeah, 1500 m/s a good rule of thumb. |
|
| 04:16 | So in terms of two way travel , you know, a kilometer per |
|
| 04:22 | is pretty good. You know, sediments around 2000 m per second, |
|
| 04:27 | know, two way travel time. 1 2nd to their back with about |
|
| 04:33 | m. Okay, so very Right, given that the so if |
|
| 04:38 | just assume one millisecond equals a meter rock, right? It's variable, |
|
| 04:44 | just rule them, or one second about a kilometer? Obviously things get |
|
| 04:50 | with depth. Right, So if assume that one second is about a |
|
| 04:54 | , how many kilometers of vertical scale on this cross section? Just |
|
| 05:00 | About three. Right. could be be four. If it's faster, |
|
| 05:03 | could be could be Two of its . But let's say it's 3-4 |
|
| 05:07 | Right, Okay, So the vertical here. Okay, so there's the |
|
| 05:19 | , you know, it's probably what It's three seconds to that point. |
|
| 05:26 | , we got some water there. , in terms of the sediment, |
|
| 05:31 | about 12, it's about 2.5 seconds sediment. Right? Which is roughly |
|
| 05:41 | km approximately. Okay. And so 10 km there. Okay, that's |
|
| 05:53 | 20 30 40 0, 10, . So that distance there Is about |
|
| 06:06 | seconds. Is that fair on this section? Right, So that's 2.5 |
|
| 06:15 | divided by 10, 40. So got 40 km on the horizontal |
|
| 06:22 | And that physical distance uh is about km vertically. Okay, so from |
|
| 06:37 | , we can get the vertical So, what's the vertical exaggeration? |
|
| 06:44 | . 40 divided by 2.5 six 16 1 6, I'll give you |
|
| 06:59 | , you know, ah 40 divided 2.516, exactly. Okay, that's |
|
| 07:08 | 16 times vertical exaggeration. Right. the other thing is, so what's |
|
| 07:14 | slope, What's that slope there? . What's the slope magnitude? If |
|
| 07:31 | just look at that, if you that slope right there, what would |
|
| 07:34 | , what would that look like? . Is it 45°? No, it's |
|
| 07:41 | 4.5. Right? So the vertical when you exaggerate at 10, 16 |
|
| 07:46 | a four degree slope becomes more like degrees. Right? So it's just |
|
| 07:50 | really important to remember when you're looking seismic day by and large as geologists |
|
| 07:56 | as sorry, as as industry to scientists, we live in a vertical |
|
| 08:00 | world. Okay, We start looking . There's no vertical exaggeration anymore. |
|
| 08:05 | is parallax. Right? So things look really steep on a seismic line |
|
| 08:11 | look flat, flat as a In reality. That makes sense. |
|
| 08:18 | . So from Stennis point of you know, a one or two |
|
| 08:22 | slope, it isn't going to look tilted beds. Right? So even |
|
| 08:26 | we have these cloud forms by and contact form, all these beautiful kind |
|
| 08:30 | forms that we see on the seismic are damn near close to flat when |
|
| 08:35 | look at them close up in person an outcrop. Does that make |
|
| 08:41 | Okay. And there's some there's some some maybe some provided to that. |
|
| 08:47 | , so let's get into the lecture , I just want to emphasize some |
|
| 08:51 | these things. So you like And all these exercises you're doing your vertical |
|
| 08:56 | is way, way, way larger your horizontal scale. Right. So |
|
| 09:00 | vertical exaggerate. So geometries may look bit funny even on assignment one, |
|
| 09:04 | squish that down to its true geometry all of a sudden it look, |
|
| 09:08 | look more sort of reasonable looking. ? You know, things can look |
|
| 09:12 | when your verdict exaggerate. Okay, this is a problem. This is |
|
| 09:18 | diagram Done by Scrutiny in 1960, the cross section through a programming |
|
| 09:24 | Okay. And folks, if you figured out by now, I do |
|
| 09:27 | lot of research on delta. So do tend to give a lot of |
|
| 09:30 | examples right there, point source. have nice platforms and there's a lot |
|
| 09:36 | oil and gas and deltas. Obviously other systems too. Mhm. And |
|
| 09:43 | on this diagram, you'll see that modern deposition of surface is a cloud |
|
| 09:49 | farm. Okay, So that's that's close to form here. Okay. |
|
| 09:57 | you noticed that you've got a marsh on the top, the delta front |
|
| 10:03 | and sand stones. Then those over pro delta silty clay. And then |
|
| 10:09 | overlying offshore clay. And then ultimately marginal marine probably clays and muds. |
|
| 10:19 | , But you'll notice that the deposition surface is drawn with a thick black |
|
| 10:23 | . But then the older de positional are shown with dashed lines, |
|
| 10:27 | And the faces are shown with a , gently undulating life. Right? |
|
| 10:34 | the faces boundaries are drawn a sharp , method of implies that they form |
|
| 10:40 | layer. Okay. And and the faces a crosscut, the timelines which |
|
| 10:51 | . You got different timelines and you've a tabular layer cake strata, graphic |
|
| 10:57 | . So, so that invites some . Are there any beds in |
|
| 11:02 | Would the beds follow these faces? they follow the timelines? Right. |
|
| 11:08 | what is the relation between faces? is just a general blob of sediments |
|
| 11:14 | in an environment, which is the tabular things versus beds that might be |
|
| 11:21 | with these faces? That that's a question. Okay. And I'm going |
|
| 11:27 | wind the clock forward two, And is work done by Ta and colleagues |
|
| 11:37 | Vietnam and Japan. And this is Mekong delta, big Delta in |
|
| 11:44 | And they took a series of cores approximate to distal proximal inland to offshore |
|
| 11:51 | A to B. And the black with the numbers to represent the ages |
|
| 11:58 | by analyzing the carbon isotopes, the 14 dating of organic material and fossil |
|
| 12:11 | that have carbon and the age of delta. It's it's about 6000 years |
|
| 12:17 | about 6000 years ago. And there the present de positional surface, |
|
| 12:21 | mice chloroform. Again, vertical scale 40 m and the horizontal scale. |
|
| 12:31 | there's 20 kilometers, right? So again incredible vertical exaggeration. Right? |
|
| 12:40 | and then we've got these environments of . Right. We've got the the |
|
| 12:48 | delta, which is the dashed that's over land by the delta |
|
| 12:52 | which is the dipping lines. Then got a sub to intertidal flat. |
|
| 12:57 | then we've got a flu viel and marsh on top. But interestingly they |
|
| 13:02 | the faces boundaries as sharp lines that almost flat to very gently undulating uh |
|
| 13:09 | crosscut the timelines which dip. And again, the question is, is |
|
| 13:14 | reasonable? You know, should the be drawn as tabular units with sharp |
|
| 13:19 | with, with with a a single as the boundary? Okay, so |
|
| 13:26 | kind of the setup for the Okay, so let's look at some |
|
| 13:30 | . This is this is the rocks the book cliffs of Utah where sequence |
|
| 13:35 | trigger was practically invented. And you see 1, 2, 3, |
|
| 13:41 | upward coarsening units. And those are things that we've called paris sequences with |
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| 13:48 | , psych lethem's shingles. So, variety of terms or a facie |
|
| 13:55 | And there's even another one down at bottom here. Okay, And I |
|
| 13:59 | if you look at the the that you look at this middle thing, |
|
| 14:05 | you can very clearly see some different . Do you see that? |
|
| 14:10 | and so here's sorry about the change scale. So now I've kind of |
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| 14:15 | the sandstone and I've highlighted the dipping with orange. Okay. And of |
|
| 14:21 | the beds get thicker at the they thin and they become saltier and |
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| 14:27 | they pass into shales. Right? there's a gradual transition from the thicker |
|
| 14:31 | stones. They get thinner and finer eventually at some distance they grade into |
|
| 14:39 | . So the beds basically have a all contact as they find seaward. |
|
| 14:44 | we and we depict that with this line or the shoes online. Mm |
|
| 14:51 | . Okay. For it. We've the zigzag line and the point of |
|
| 14:58 | . And and the zigzag in the of the transition. So the times |
|
| 15:03 | on the on the on the on on the zigzags are on the sands |
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| 15:07 | the show. Sam's point in the that the sand stones are fading into |
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| 15:12 | . Right? So there's a lot information that zigzag, she's um long |
|
| 15:16 | you draw those, I want you tell me which direction the transition is |
|
| 15:22 | . Okay, so now I'm going vertically exaggerated. So you can you |
|
| 15:27 | clearly see the dipping beds. There is that the there's a flooding |
|
| 15:34 | on top. Okay, let me a quiz. What is that? |
|
| 15:48 | ? The yellow units against the It's a lower surface terminated and gets |
|
| 15:57 | upper surface on lap is a type base lap which means an upper surface |
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| 16:03 | on the lower surface. There's a or truncation. All top lap which |
|
| 16:12 | ? I know it's what it could been. Yeah, it's it's probably |
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| 16:23 | some erosion during the transgression. So it's certainly top lap it could be |
|
| 16:29 | shingles, you know, it could just dipping beds moving out but you |
|
| 16:33 | , there's no U shaped truncation but looks like the beds just stop |
|
| 16:39 | Right? So I'll give you two . Yeah, the keys talk lap |
|
| 16:46 | . And then what about these lower ? What's the lap out? So |
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| 17:08 | units here. What kind of lap is that? That's the bed is |
|
| 17:14 | down and terminating against the lower surface . Okay, so what we have |
|
| 17:23 | delta front sand stones that are dipping those are flattening and transforming into pro |
|
| 17:29 | shales. Okay, so that's how draw it. Right now, I've |
|
| 17:35 | away the dipping surfaces. All I've left is my zigzag. Zigzag implies |
|
| 17:40 | probably dipping surfaces in the sandstone. delta front is separate from the pro |
|
| 17:48 | . With a facist boundary. It's a gradation als contact, it's not |
|
| 17:53 | sharp contact. And the way that draw those creation contacts is with those |
|
| 17:59 | lines, it's just it's it's a arbitrary. Can say like, |
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| 18:02 | I'm going to stop the sand once the sand gets below, you |
|
| 18:07 | a few centimeters thick or you or maybe when it when it when |
|
| 18:11 | got when it drops from very fine to silt stone. You know, |
|
| 18:16 | we'll say, okay, that's where sandstone stops but there's probably a gradation |
|
| 18:19 | zone over which occurs, right? so the zigzags indicated rotational change. |
|
| 18:24 | could also just show, you could pro delta is gray sandstone is yellow |
|
| 18:28 | just do a gradient on it right you wanted to. So you could |
|
| 18:32 | the zigzag altogether. But I like zigzag because it implies that there's |
|
| 18:36 | Right? And so the so the of the zigs point uh implies the |
|
| 18:43 | that the faces transition occurs. The sandstone of the delta front is grading |
|
| 18:49 | into the pro delta shales. So shoes online shows that the sandstone landward |
|
| 18:56 | proximal passes into the shales seaward. I drew the shoes online that |
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| 19:04 | I would imply that the delta front to the right is passing into shales |
|
| 19:10 | the left. That's clearly not the the rocks flow. Okay, so |
|
| 19:16 | would imply that the sandstone is pro from right to left when we know |
|
| 19:23 | actually programming from left to right. , so the direction that you draw |
|
| 19:27 | sham Suzanne lines quite critical. Mm . And so here's more examples of |
|
| 19:39 | stones with these highest platforms. This one, they're pretty strong. |
|
| 19:48 | we've got shot. It's okay, clearly, uh, the Deltek rocks |
|
| 19:56 | not form a perfect layer cakes. , so the shallow marine systems and |
|
| 20:07 | it's a delta ashore face, they're regressive or if you don't like |
|
| 20:12 | you can say fundamentally pro gravitational circular and just put proclamation is the synonym |
|
| 20:20 | they build these nice upward, questioning successions. Okay, now of course |
|
| 20:27 | can go muddy if you've got a know, floodplain and marsh on top |
|
| 20:31 | it by and large a diagnostic motif procreation along or regressive del taken shorelines |
|
| 20:38 | shallow marine systems is the is the of these upward coarsening facie successions that |
|
| 20:47 | they are bounded by flooding surfaces, do we call those? What? |
|
| 20:55 | . When we have a cautioning upward succession bounded by flooding surface. What's |
|
| 20:59 | sequence strata graphic term for that? coarsening genetically related faces association bounded by |
|
| 21:12 | surface. What is that sequence to unit? Aren't you guys? Glad |
|
| 21:19 | . Yeah. Yes. So what's unit below the flooding surface? What |
|
| 21:26 | you call that genetically related group of sets bounded by flooding surface and the |
|
| 21:34 | surfaces. Mhm. That's a pair sequence. Yeah. Does that make |
|
| 21:41 | ? Right. I'm trying to bring back to the the sequence jargon. |
|
| 21:48 | . And of course in depew delta climate farms when they're building towards you |
|
| 21:55 | from you. They show these land bodies. Right. And what is |
|
| 22:04 | ? What's that, lap out, out called? Nope download and what's |
|
| 22:14 | called? Yeah. So in depew down lap is uni directional. It's |
|
| 22:22 | strike view. You get bidirectional down in two directions. Right? The |
|
| 22:27 | lap occurs away from the axis of delta. Right? So you know |
|
| 22:33 | you have a delta. So there's channel, there's my lobe, |
|
| 22:42 | If I draw a cross section perpendicular parallel to the direction of procreation of |
|
| 22:49 | logo, I'll get uni directional down and maybe top lap and if I |
|
| 22:55 | perpendicular to load I'll get bidirectional down . And here's an example of platforms |
|
| 23:02 | Mississippi and the browsers delta, that's some growth faults in there, but |
|
| 23:06 | all show this very diagnostic geometry. , there's nothing super knew about |
|
| 23:19 | G. K. Gilbert who did lot of exploring of the southwestern us |
|
| 23:24 | the late 1800s, notice these coarse deltas on the margins of Lake |
|
| 23:32 | which is the ancient Salt Lake's Salt when it was much higher. And |
|
| 23:36 | noticed that the Deltas could be grouped a four set. And these were |
|
| 23:42 | deltas with very steep angle proposed beds 10-25°. And they overlay flatter found a |
|
| 23:49 | bottom set. And they were over by gently undulating top set gravels. |
|
| 23:54 | ? So these gravelly deltas had channels the top that was sort of |
|
| 23:58 | They fed a very steep four That's actually uh when you see these |
|
| 24:04 | steep four sets, these are sometimes Gilbert Dalton's after G. K. |
|
| 24:09 | . Okay. And these four four sets indulges in general can dip |
|
| 24:14 | 1-8°. And these very gravity systems they reach the angle of repose. So |
|
| 24:22 | is A Diagram from Joseph Morelle in And that shows the top set four |
|
| 24:28 | bottom set geometry. So Burrell simply Gilbert's ideas to a larger scale delta |
|
| 24:37 | . Rich in 1951 came up with term on a farm. So he |
|
| 24:43 | noticed that, you know, programming systems could be subdivided into undulating beds |
|
| 24:49 | under beds. He called them inclined or klein or beds. So now |
|
| 24:54 | got the words of. Now he's the question, what's the difference between |
|
| 24:58 | little faces and the beds? And was one of the first people to |
|
| 25:03 | these little zigzags There they are. . So he drew the zigzags to |
|
| 25:08 | with some beds, stick out a bit further. Some stick a little |
|
| 25:11 | back because there's variations in the amount sand in any individual mouth bar or |
|
| 25:17 | bed as the delta front migrates three . And so he broke the delta |
|
| 25:22 | into under beds. Clan of beds fondle beds. Anyone know what the |
|
| 25:27 | fondo means? Anyone? No latin greek scholars hair. Okay. Do |
|
| 25:36 | know what the word profound means? a meeting or deep right. If |
|
| 25:48 | have profound thoughts, it's like, , these are, you know, |
|
| 25:51 | doesn't be shocking. Could be you know, get a deep |
|
| 25:54 | right? And the word pro fungal used to to describe deep water |
|
| 26:00 | Pro fumble. Right. So fondo means deep, right? So he's |
|
| 26:06 | undulating beds which which are geometric clone which is inclined and fonda bed, |
|
| 26:12 | means basically the bottom. Right? deep the deep beds so rich was |
|
| 26:19 | the one of the first scientists to these very distinctive claudia forms and and |
|
| 26:27 | the word found a form under form kind of disappeared, but we have |
|
| 26:32 | the term client form that's still used . Okay, now if you look |
|
| 26:37 | , if you look at barrels I've cropped it and expanded a |
|
| 26:43 | Check it out, check this Look there's issues and see it. |
|
| 26:57 | didn't even, he just drew the right? And then drawing the beds |
|
| 27:01 | up with the shoes online. The other thing is he drew a |
|
| 27:05 | wave dominated shore face and he's got much bigger shelf slope platform. So |
|
| 27:11 | had to have the idea that there's common forms. One that's the delta |
|
| 27:14 | , which is a small thing and is much bigger, much bigger thing |
|
| 27:19 | represents the shelf slope break. Now actually, he actually coined the term |
|
| 27:27 | face to describe this little concave up that's formed by waves crashing up against |
|
| 27:33 | shore line. And and and the wave reworked right below that. But |
|
| 27:38 | considered all this stuff part of the . So he sort of saw deltas |
|
| 27:43 | really continental scale features but it still me like What the Heck did Burrell |
|
| 27:52 | at 1912 to get these ideas because was no seismic data. Well, |
|
| 27:57 | had worked in Utah, you know , he's actually structural jobs and invented |
|
| 28:02 | word blacklists based on the Henry There is a place where I work |
|
| 28:10 | . Now the idea of a double was picked up by ask with 1970 |
|
| 28:15 | ask with worked in the cretaceous interior on well logs. And he noticed |
|
| 28:20 | there was this, there were these systems, there was a sandy system |
|
| 28:24 | is your barrier islands, shore face dominated surface. And then he's noticed |
|
| 28:31 | second class of farm that was a basin, right? And sometimes those |
|
| 28:36 | separate. Sometimes they could converge. then he said sometimes there's sands that |
|
| 28:41 | in between the shelf slope break and shore line in his day, they |
|
| 28:47 | to those things as offshore bars. nowadays we suspect what happens is the |
|
| 28:51 | line move here and then move back left the sand behind. But an |
|
| 28:57 | day, he was a bit of fix ist in terms of shorelines. |
|
| 29:00 | so I saw these sand stones as separate. And, and was the |
|
| 29:05 | of the idea of these offshore And here's a system that has a |
|
| 29:13 | quantum form. So here we've got , the college faces are left at |
|
| 29:18 | smutty facings that would be shales with lot of carbonaceous material in them. |
|
| 29:24 | when you pick these things up, get, you get a lot of |
|
| 29:28 | carbonaceous stuff on your hands. I've these rocks before. So I kind |
|
| 29:32 | know what he means. And of , you know, you notice that |
|
| 29:34 | got all these dipping surfaces in Right, see that. And you |
|
| 29:38 | , there's one clan to form another . Another one that's actually producing Suzanne |
|
| 29:47 | an accommodation succession. So what is ? Yeah, that's it actually looks |
|
| 29:58 | it's doing this. Right. So would that be Ap. Exactly. |
|
| 30:08 | . Ap he's not showing any d and there. It is there |
|
| 30:14 | Right. Right. So you can at these diagrams and do these accommodations |
|
| 30:20 | interpretation. And here he's got you , a barrier island could be a |
|
| 30:30 | . He's got his political and flow your faces. Polluted would be environments |
|
| 30:36 | the shore line that have a brackish to them. So the the other |
|
| 30:42 | that I would use for that is alec, have you heard the term |
|
| 30:54 | before? Have you heard the word critic? You know what that |
|
| 31:07 | Yes, neurotic, shallow marine. you've got a bath feel. And |
|
| 31:16 | abyssal. I think that's right. is nothing called caryatids prophecies which is |
|
| 31:23 | deep water. But the word narrative actually an old paleontology term that the |
|
| 31:29 | guys used neurotic would mean you just shallow marine. So yet you |
|
| 31:33 | neurotic, Raphael abyssal and then language neurotic would be poor alec. And |
|
| 31:38 | you're into your non marine or All right. So part of the |
|
| 31:45 | that that these diagrams make is that are two separate platforms. One is |
|
| 31:50 | up and that's a small cloud of that's produced by waves crashing against the |
|
| 31:56 | marine zone producing this concave up shore profile. The other is a convex |
|
| 32:01 | profile. That's mostly muds and Okay. Where silt and muds and |
|
| 32:07 | typically uh, the slope and basin client form. Right. So you've |
|
| 32:14 | to climb the form shown by Burrell . one was a short face Platform |
|
| 32:19 | is the slope and basin and ask , showed the same thing in 19 |
|
| 32:27 | 74. Right. So he just resurrected barrels idea. So, remember |
|
| 32:34 | showed you some outcrops with some dipping . So are those a delta front |
|
| 32:40 | face plant form? Are they one these big slope and basin claudia forms |
|
| 32:49 | the app crops that I showed You remember and I showed you all |
|
| 32:54 | sands with the spasms For those who one or Type two on my diagram |
|
| 33:02 | . You sure. Type one exactly . Yeah, exactly. And see |
|
| 33:06 | a schism. Right. and so in exercise one we had a client |
|
| 33:15 | and I asked you to draw touche with sand in the middle. There |
|
| 33:23 | is on the diagram. Right. that's, so if these are a |
|
| 33:27 | more artistic, but you know, can, you can sort of see |
|
| 33:30 | And even here you see how it's into shales here. Right, So |
|
| 33:36 | your that's your sandy faces with non behind. And then pro delta shells |
|
| 33:41 | front. Okay. And of course a seismic long. We've seen this |
|
| 33:47 | . And you can see a convex chloroform, which is the delta front |
|
| 33:53 | your face. And then you can con sorry, a concave up |
|
| 33:59 | which is the the shore face or front. And then the sigma it'll |
|
| 34:03 | up platform, which is which is shelf slope. Rollover break. That's |
|
| 34:09 | that you see these two common forms is the the last glacial maximum |
|
| 34:15 | Deltito. Uh What does that kind lap out? Yeah. And |
|
| 34:31 | yep. And what would that Which this wedge has? What relationship |
|
| 34:41 | that wedge? Exactly? Right. . See, you got it |
|
| 34:46 | Right. All right. And then would that lack? I'll be what |
|
| 35:00 | ? Exactly? Right, You got two. See, easy peasy. |
|
| 35:05 | so here we have two deltas. down stepping, that's a forced |
|
| 35:09 | Right now, the other neat thing look at the Kelowna forms, you |
|
| 35:12 | how they're low angle and they start get steeper. That's a very common |
|
| 35:22 | . You see when a delta is grading into deeper water as the space |
|
| 35:36 | the hole gets bigger. The delta pro grade as far because it's it's |
|
| 35:41 | bore volume plus the depth of the is getting steeper. And so you |
|
| 35:46 | more at the Kelowna form preserved. ? So it's very common steepening upward |
|
| 35:51 | typical of deltas that are building So as it builds, it builds |
|
| 35:54 | the shelf edge, the water is deeper and deeper, deeper. And |
|
| 35:57 | with each incremental deposition, it can as far. So it tends to |
|
| 36:01 | a steep incline to form. That's . That makes sense. What is |
|
| 36:27 | ? Sophia, yep. On lap it's an elaborate direction. Hi. |
|
| 36:37 | right. What proximal distal land Okay. And then here's the browser's |
|
| 36:57 | building towards you. And what kind down lap is this? All you |
|
| 37:08 | to do is read the slide. you go. And then then there's |
|
| 37:17 | and that I see in this case spasms going two directions, right? |
|
| 37:21 | the sounds are down lapping in in directions. Okay. And here's some |
|
| 37:26 | examples. This is a all this comes from john Anderson who's retired |
|
| 37:32 | He used to work with rice. And this is work done by Phil |
|
| 37:36 | . Look at these beautiful bi directionally , lapping delta lobes. Right? |
|
| 37:40 | a series of delta lopes switching around one of which shows the bidirectional down |
|
| 37:45 | . In the cross sectional view with delta building either towards you or away |
|
| 37:50 | you. I forget which it In this particular case you get |
|
| 37:53 | you can see the same, you that they're, they're still concave |
|
| 37:59 | Right, and that implies quite sandy . So mud stones tend not to |
|
| 38:04 | these concave up profiles, right? just, they don't deposit that |
|
| 38:08 | Right. Sandstone is very commonly produced concave profile and that's partly and |
|
| 38:13 | probably represents some wave reworking. There some just another example of what these |
|
| 38:22 | showing is lateral switching of delta which gives these stacked bidirectional download. |
|
| 38:35 | , we're just gonna take a little breather break, stretch break. |
|
| 38:45 | so now I've given you the concept chloroform. Let's look at how we |
|
| 38:49 | correlate them. Okay, so here's cross section of these modern deltas, |
|
| 38:56 | measured sections. And, but this very much with a strata, graphic |
|
| 39:03 | . We're trying to do better than . Yeah, this is kind of |
|
| 39:07 | interesting story. A little bit of aside, uh, It was probably |
|
| 39:14 | , was in 1999, 2000, , maybe, maybe a bit earlier |
|
| 39:20 | had a PhD student and I was to, and this, it was |
|
| 39:24 | qualifying exam, right? So it , you know, before he'd done |
|
| 39:28 | thesis, but I want him to in his brain, you know, |
|
| 39:32 | idea of that, these were layer correlations and we could do better. |
|
| 39:38 | so I said, well, how you re correlate this? Anyway, |
|
| 39:40 | really stumbled on the question and didn't that. Well in it. |
|
| 39:44 | once he passes qualifying and he ended being so intrigued by the question that |
|
| 39:51 | asked him in his comprehensive exams that decided to attack a record relation of |
|
| 39:58 | data. So he started by picking upward cautioning faces successions and that's what |
|
| 40:05 | doing with the well are now picking up your upper coursing units up |
|
| 40:09 | finding units, you know? And two here are pretty clear, you |
|
| 40:12 | , there's flooding surface, there maybe another one there, ah Maybe this |
|
| 40:18 | 1, 1 in here could be one there and then he re correlated |
|
| 40:24 | . There's this three correlation. So going to take off my all my |
|
| 40:33 | . That's the before that's the after difference. Right now you can see |
|
| 40:42 | hand, joanie really took my concept Suzanne's to heart, you know, |
|
| 40:47 | said that, you know, this a 60 70 kilometer cross section. |
|
| 40:51 | there's probably a lot of beds in right now in this diagram, the |
|
| 40:58 | looks like it's rising slightly and then falling slightly. Right? So p |
|
| 41:07 | a tiny bit of a. And d ah you could argue that right |
|
| 41:14 | shows the same thing. It's it's als horizontal degradation allele. Then it |
|
| 41:21 | back and then its degradation again. , Ryan shows at least 1, |
|
| 41:29 | , 3, 4 cycles of deposition some intrusion of shales breaking up this |
|
| 41:36 | here into into some dipping compartments, different compartments are completely missing on this |
|
| 41:43 | strata. Graphic correlation. Now, was interesting is this paper was published |
|
| 41:53 | , then published again and I got review it the second time. The |
|
| 41:57 | was a bit different. And I these guys, you're gonna drop this |
|
| 42:03 | you're gonna drop his amazon. You draw the faces with sharp boundaries. |
|
| 42:08 | went and did this correlation. And I went to a conference in Vietnam |
|
| 42:14 | the person that did this correlation and supervisor were there. How tall was |
|
| 42:19 | quiet, you know, didn't want argue that Yoshi's site. Uh Yoshi |
|
| 42:27 | is a very Mhm. Very well japanese scientist. He wasn't take guff |
|
| 42:33 | anybody. So he was like, , you know, I don't, |
|
| 42:37 | don't agree. And then steve hell very well respected oceanographer got up and |
|
| 42:42 | , well, yeah, well, says, I think that this is |
|
| 42:45 | objective than that. Yeah. And Joel ambience. He said, |
|
| 42:49 | but john X correlation implies a very architectural flow units. When they published |
|
| 42:56 | paper, they said this modern analog critical for understanding fluid reservoir architecture. |
|
| 43:04 | said, no, it isn't, is misleading. This implies a single |
|
| 43:09 | of, Of Sand. That would one flow unit. Ryan's correlation implies |
|
| 43:15 | this lower sandstone is broken. There's least one major aqua tard that would |
|
| 43:21 | any water in here from any water there. Why is this important saltwater |
|
| 43:26 | invade. Okay. And saltwater was . Now let's say that you're 20 |
|
| 43:32 | in pulling freshwater out for your For your, your freshwater agriculture, |
|
| 43:38 | ? That's gonna, if you remove from here, the salt water would |
|
| 43:43 | . But in Roy hands view these barriers will prevent saltwater migration resulting in |
|
| 43:49 | different understanding of the aquifer architecture and risk of saltwater invasion. Okay. |
|
| 43:56 | of course If that was buried down two km, it was an oil |
|
| 43:59 | gas field and you're trying to water those shales would prevent the water from |
|
| 44:04 | past that point. Right. so now when we actually published this |
|
| 44:12 | , I gave it to to Yoshi to review said, look, I |
|
| 44:16 | you don't agree with me. That's I'm asking you to review it, |
|
| 44:19 | know, to make sure that I'm going to change my, my my |
|
| 44:25 | . But you know, I'm willing to be a bit more circumspect about |
|
| 44:30 | it, explaining the difference. You , we're still pretty, pretty good |
|
| 44:33 | . So he sort of understood that well. Now this is an exercise |
|
| 44:40 | I commonly give the students to Mm hmm. And that's supposed to |
|
| 44:50 | distal but I think when I, redid these slides and put them all |
|
| 44:54 | this landscape for in this wide format it kind of messed up with the |
|
| 44:58 | stuff anyway, so you can see mostly sales hair. Okay. And |
|
| 45:04 | stands here and these sp logs aren't , But you can see some funnel |
|
| 45:13 | . Right? And you can see bell shapes. Right. Nice bell |
|
| 45:22 | . So the bell shaped probably represent deposits from the funnels represent delta |
|
| 45:28 | Okay, now we can do a strata, graphic correlation, They, |
|
| 45:41 | , hey, sand, base, , they sand, hey, |
|
| 45:50 | sand, sand, top, top, sound, top, |
|
| 46:02 | top the top. Okay. And can correlate these zig zag in |
|
| 46:41 | So that would be a very typical lithography photographic correlation. Right? I'm |
|
| 46:48 | separating the sandy faces from the muddy . I could do the same thing |
|
| 47:01 | and then I could do the same with the base. Okay. And |
|
| 47:10 | would be a very, very, standard Correlation that we would do in |
|
| 47:14 | 50s, 60s and 70s. And so there it is. So |
|
| 47:19 | was published in, I think I believe. I remember. |
|
| 47:29 | In 1972, the Bureau of Economic published the correlation of this system. |
|
| 47:37 | . There's the Wilcock Groups, Wilcox at the base and there's there's this |
|
| 47:42 | lines, right? Uh they've data on the base of the Sparta |
|
| 47:47 | That's the red line. Okay. then they've shown this, uh, |
|
| 47:52 | forget what this unit is. Queen . It doesn't matter. And you |
|
| 47:56 | , on this correlation, you've got Sandy Tongue, one Flow Unit. |
|
| 48:02 | one, Then? The 3rd Right, So three major flow |
|
| 48:08 | Okay, so yeah, it's you ? No. Okay. Yes. |
|
| 48:40 | . So the point I'm making here , is prior to sequence photography. |
|
| 48:48 | tend to lump right? So they of ignored all of these shales in |
|
| 48:55 | sand stones and they would they say Dunvegan sandstone and they would say the |
|
| 49:00 | and sandstone, even though it's an mixture of of sand stones and marine |
|
| 49:05 | . Right? So the inter fingering sort of one of the really big |
|
| 49:11 | were worried about the smallest scale stuff can't be important. Right? So |
|
| 49:18 | the answer to your question. So you asked a great question. |
|
| 49:22 | . Which is, wait a What about all those inter fingering |
|
| 49:26 | Aha. So I took this cross , It took me maybe 20 |
|
| 49:32 | I said I'm just going to do sequence strata, graphic re correlation of |
|
| 49:36 | using the principle of cloud of flooding surfaces and channels. You |
|
| 49:42 | That's my correlation. Okay. There's before, there's the after before and |
|
| 49:50 | before and asked. Okay, do see some differences. Okay, let's |
|
| 49:58 | at the differences. I've got flow one two three four, four B |
|
| 50:15 | and there is a there is at one shale barrier completely missed in the |
|
| 50:19 | interpretation and there are others. um you know, and there's I |
|
| 50:27 | there's a million there, I could that three B or you know, |
|
| 50:31 | mean if every if I call him I could go 123456789. And there's |
|
| 50:39 | or 11 separate sand stones with with shells on top of the right. |
|
| 50:48 | we'll flow unit would be the same an aquifer. We don't use the |
|
| 50:52 | aquifer in petroleum because we're not interested water. Right? So an aquifer |
|
| 50:58 | a porous super portable unit that typically bounded by aqua targets, which are |
|
| 51:03 | of no flow. So flow unit a unit that would be a unit |
|
| 51:09 | would flow fluids out of it. would be more or less isolated above |
|
| 51:15 | below by a flow barrier or no . So that would be great. |
|
| 51:23 | , Yes. Yeah. The other that I I use and and we |
|
| 51:27 | not. I haven't had you guys this yet. I typically use the |
|
| 51:31 | reservoir ceo pairs. Right? So and a seal. Right? You've |
|
| 51:36 | a reservoir compartment and you're gonna see shale on top below whatever. |
|
| 51:41 | flow unit would be the same as reservoirs as now, a reservoir could |
|
| 51:46 | sort of have a bunch of smaller compartments in it. Right. So |
|
| 51:52 | unit would just be, you a a unit that sort of potentially |
|
| 51:57 | separates exhibits different flow behavior or might drained while other units are less |
|
| 52:04 | Thanks. So, floor units in photograph of context, you've only got |
|
| 52:12 | . Right? And there it But Dennis, there's we had a |
|
| 52:15 | here and it's missed in this It's completely missed. Right. I've |
|
| 52:21 | chloroform beds. Sorry about the wrapping . Right? Whereas the con forms |
|
| 52:27 | very obvious in this cross section. . And the other thing is you |
|
| 52:33 | the data. So that red line the data that they used. You |
|
| 52:39 | , they don't allow any sand stones cross that data. I said to |
|
| 52:43 | with that. I bet that sandstone with that with that, with that |
|
| 52:48 | sequence boundary. Right? So here's data rules. Once you draw |
|
| 52:53 | and you won't cross it. So they picked a very bad |
|
| 52:56 | They picked the base of an upward faces, succession. That's a shoes |
|
| 53:01 | . Not a timeline. Never Never will be the worst. That's |
|
| 53:07 | lift. That's a that's a an shiism formation pick. Right? So |
|
| 53:13 | what? Here's where little strategy. it gets you into deep trouble. |
|
| 53:16 | picked a shoes online as a as data because it's a formation contact but |
|
| 53:22 | no time significance. But they refused allow any correlations to cross that. |
|
| 53:28 | actually used that as as the data hang the cross section on. But |
|
| 53:32 | didn't draw a line. Right? hung it on it but didn't draw |
|
| 53:35 | line and therefore happily allowed my correlations my closet forms to dip and cross |
|
| 53:41 | boundary, which means that a sandstone here might be connected to a sound |
|
| 53:46 | up there. Now, let me you where this gets you into legal |
|
| 53:53 | . Okay, Having a lot of with this. I've been sort of |
|
| 53:59 | it peripherally, but commonly the legal to oil is defined both by the |
|
| 54:07 | where the oil is found and sometimes photography, right? So you |
|
| 54:11 | you might say we lay claim to the oil and the spark the |
|
| 54:16 | but our competitor gets all the oil the in the formation below, |
|
| 54:22 | And based on an arbitrary little strata contact the oil down here is owned |
|
| 54:30 | your competitor and you own the oil here. So what if you |
|
| 54:37 | what if they start to suck on oil and drag your oil out? |
|
| 54:41 | it's what a faux compartment they're taking oil, but you're taking oil from |
|
| 54:48 | formation and it's it's leaking into your because you've got a legal right to |
|
| 54:53 | right? Eight. I'm not going call my buddy of mine, but |
|
| 54:59 | person like I've grown to meet but working in Alberta used to work for |
|
| 55:07 | big company and you know, he . Set up a little exploration companies |
|
| 55:15 | and he'd spent enough time the units pressure. They said, look, |
|
| 55:21 | you have a balloon and he let bit of a bit of air |
|
| 55:25 | The balloon is tumultuously softer, Let's say that you let out the |
|
| 55:33 | of gas in my container. But balloon is the size of this |
|
| 55:39 | Will you, will you notice the draw? No. So he started |
|
| 55:44 | pressure data and found that there were that have been producing for quite a |
|
| 55:49 | time with no pressure drop. He at maps in the fields and the |
|
| 55:54 | said those maps are too small. gas field is way bigger. And |
|
| 55:59 | he bid for some land on the of one of these under depleted |
|
| 56:05 | Put a while on the edge of landed intersected the gas field and started |
|
| 56:10 | money. The company that owned this field suit him. I said you're |
|
| 56:15 | our gas. He won the He is now worth $100 million dollars |
|
| 56:22 | he just gave $1 million dollars to a few years ago and he did |
|
| 56:26 | in his garage. You know probably he was, I don't know 35 |
|
| 56:32 | something. He's a little bit older I am. He's worth it Jason |
|
| 56:40 | because they were saying that we were well there. Exactly right. |
|
| 56:49 | Yeah. As they're selling is that's your trust anyway. You know sometimes |
|
| 56:59 | geology you deal with lawsuits. So I call this the you know |
|
| 57:03 | problem with the disappearing data right? know we talked about what not to |
|
| 57:07 | for data, you know and you never use a sham faces bandy for |
|
| 57:11 | , you know. And Andrew. just keep coming back to your |
|
| 57:19 | right? You know, about lower upper daters, right. And of |
|
| 57:23 | , you know, in the Dunvegan use the lower data. Ah let |
|
| 57:29 | talk about the application to So when , I think I told him the |
|
| 57:38 | time here. Yeah, I've only a few slides like, well, |
|
| 57:44 | just push through so sorry for these stories, but you know, these |
|
| 57:50 | stories are about life in the trenches what, what, what you, |
|
| 57:54 | you really have to do. So finished my PhD moved to Edmonton and |
|
| 58:02 | a postdoc. Met my wife to and got a phone call from a |
|
| 58:08 | of mine who is lived in He said john like I was at |
|
| 58:12 | university of Calgary, I noticed that there's this company called Arco looking for |
|
| 58:18 | for a job in plano texas. had no idea of plano texas. |
|
| 58:21 | , I've never heard of. It like a horrible place. Flat texas |
|
| 58:25 | it turns out it's a suburb of , right? And and my roommate |
|
| 58:31 | a grad student at University of I was a postdoc at the Alberta |
|
| 58:35 | council had no affiliation with the University Alberta. And my roommate was, |
|
| 58:40 | name was in the indian restaurant East indian guy. We went to |
|
| 58:44 | together at McMaster. He was my research assistant and was in Albert doing |
|
| 58:50 | masters while I was doing a post and he said, yeah, he |
|
| 58:54 | there's signs up all over you of he's in fact I have an |
|
| 58:57 | So what times your size 10 in morning? I said well I wouldn't |
|
| 59:01 | interview as well but I said would mind telling me the name of the |
|
| 59:04 | after interview? He said sure, . So at 10:30 he phoned me |
|
| 59:08 | said it's Terry Twyman. Okay. so I phoned the University of Alberta |
|
| 59:15 | office said, you know, I'm Donald Bhattacharya understand that you've got terry |
|
| 59:19 | interviewing, you know, could I to her and gave her number? |
|
| 59:24 | phoned me back at lunch. I you don't know me, I'm doing |
|
| 59:28 | post doc. I'd be really keen interview. She says, well all |
|
| 59:31 | slots are filled up with grad I've got a wine and cheese at |
|
| 59:36 | 30 so I've got an hour from 30 to 5 30. I said |
|
| 59:40 | I drop off my CV at He said sure I dropped it |
|
| 59:44 | So I got to school at followed her around while she set things |
|
| 59:48 | . He kind of got into argue sequence photography. I thought whatever, |
|
| 59:51 | never going to get that job. my complete surprise, I got a |
|
| 59:55 | about a week later saying we'd like to come to Dallas for an |
|
| 59:58 | But Dallas I thought it was whatever went down for the interview at |
|
| 60:02 | and on New Year's Eve, I this big package in the mail |
|
| 60:09 | an offer of employment. I looked my girlfriend Cindy, she said, |
|
| 60:14 | said, you want to move to states. She's like, we're not |
|
| 60:17 | . I'm like, well, I we're gonna have to get married |
|
| 60:19 | Right? So That was 33 years . Right? Anyway. And so |
|
| 60:24 | was very excited. I was moving Dallas was like, man, I'm |
|
| 60:26 | , I'm gonna move to texas. , it's gonna be warm, no |
|
| 60:29 | snow. You know, I was excited. And then they said, |
|
| 60:33 | actually for your first assignment, we you to go to Alaska and work |
|
| 60:38 | Prudhoe Bay, which is, which the largest, the largest conventional author |
|
| 60:42 | North America. It's like, you know, I've spent most of |
|
| 60:45 | time in the cold. I guess can manage Alaska for, you |
|
| 60:48 | supposed to be a six month Now, what happened is, I |
|
| 60:55 | tell you a story a bit more is Alaska is a super junk field |
|
| 60:59 | billion barrels of oil in place or may be recoverable. And, and |
|
| 61:04 | lot of the oil in the gravity Pflugerville have been depleted and a lot |
|
| 61:09 | the oil was, it was in in the transitional delta ag faces. |
|
| 61:13 | of course the gravel, you it was like 300 ft of |
|
| 61:17 | very high net to gross and it just like, and it just it |
|
| 61:22 | just like pumping just like pumping oil without worrying about complexity. But of |
|
| 61:28 | as soon as you get the Dell stuff, you got platforms, but |
|
| 61:32 | didn't understand anything about claudia forms. never heard of platforms. And the |
|
| 61:36 | said, well, we're going to the lower reservoir into these poor quality |
|
| 61:42 | . They cross an upward these block , they're probably channels and they had |
|
| 61:49 | a layer of hair Elif, IX pinched out. Then they had a |
|
| 61:52 | layer, another layer. So they what I call the pinch and swell |
|
| 61:56 | and they had these zones, so was zone one, zone 21, |
|
| 62:01 | one A and one B. You , one day was the worst one |
|
| 62:05 | was better to A was gravity and better. And then they had these |
|
| 62:09 | that the tango shale, the Romeo . And the geologists were asked to |
|
| 62:13 | these little shales and correlate them everywhere the field as a flat shale |
|
| 62:18 | like soccer blue. These shales dip they're not flat, what's wrong with |
|
| 62:24 | guys? And then uh that that reservoir overlay a nice pro delta shale |
|
| 62:34 | those days. It was very expensive digitize logs. So they only digitized |
|
| 62:39 | a few feet in the shale and digitizing also when they drill the |
|
| 62:46 | There's this wahoo limestone that's fractured. wanted to avoid that because they didn't |
|
| 62:51 | to have lost circulation. Okay, the field is a big un |
|
| 62:59 | Then you've got the dipping layers and you got the shot sam and then |
|
| 63:05 | got some power sequences in the Those are the only things you can |
|
| 63:09 | for data that strata graphic. But data was mostly not digitized. So |
|
| 63:15 | was like digital. Well logs, . We haven't got a data. |
|
| 63:18 | how the heck do you expect us figure out this geography? So I |
|
| 63:21 | to go get the paper copies of well logs once again get a pen |
|
| 63:27 | draw the rest of the log onto digital log that my tech aid gave |
|
| 63:31 | . So I had someone like you me was and where is the freaking |
|
| 63:34 | ? Like where's the shambles? We digitized those because it's too expensive. |
|
| 63:39 | . But do we have the Oh yeah, they were driven |
|
| 63:42 | You know, they're on the paper . I'm like, Oh my |
|
| 63:44 | like for the sake of 20 ft you didn't digitize it. But in |
|
| 63:48 | days, you know, digitizing is . So I hand traced, you |
|
| 63:53 | , into the shales. Then I a, you know, pair of |
|
| 63:56 | and had to physically cut the you know, the the printouts of |
|
| 64:00 | logs and read a them them and we re correlated the whole damn |
|
| 64:05 | Here's the after before and after before after before and after. So all |
|
| 64:13 | a sudden, you know, there a sandstone in the Kazakh shale, |
|
| 64:17 | different formation that's physically connected to the sand stones. Okay, so |
|
| 64:23 | how did the engineers deal with So after a year and three months |
|
| 64:32 | got there in september went through one , had a beautiful summer Alaska. |
|
| 64:38 | was getting me thanksgiving. I was , you know, we really |
|
| 64:42 | it's time to get to Dallas. know, we've done the project so |
|
| 64:45 | and I moved to Dallas and started work down there. But my |
|
| 64:49 | bow tie, his name is robert nickname is bo bow tie and uh |
|
| 64:55 | person lives in Dallas still there. decided to stay up in Alaska because |
|
| 64:59 | really enjoyed the office and so you , we did the conceptual work of |
|
| 65:04 | the reservoir, He got to start wells And so here's an example of |
|
| 65:09 | of the wells that he was involved . So the 935 well was producing |
|
| 65:14 | 400 barrels of oil a day right . Well, right now it's about |
|
| 65:21 | a power. Right? So you the math 400 barrels a day, |
|
| 65:25 | 100 barrels a day, huh? a day, Times three and 65 |
|
| 65:36 | . That's one, well from Prudhoe field, right? You know, |
|
| 65:40 | , it's good to understand how much there is Northern Gas. Right? |
|
| 65:44 | why you're all here. Right, just wanted a tiny piece of that |
|
| 65:48 | . Right? But the well was 1200 barrels of water a day. |
|
| 65:52 | in Alaska as soon as you produce . Yeah. You know, water |
|
| 65:58 | was just getting started. You can't the water in the arctic ocean, |
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| 66:02 | can't dump it on the tundra. you have to walk away from |
|
| 66:04 | Well, can you imagine walking away $400,000 a day? No, that's |
|
| 66:09 | I gotta leave that money in the . So both said look you got |
|
| 66:13 | little shale above that. Okay. the engineer is always perfect the more |
|
| 66:20 | higher perm sands. So they so thought that was most of the oil |
|
| 66:24 | coming out of this tributary channel. said yeah there's not much oil coming |
|
| 66:27 | of that delta front. Sound bo you know, I think all the |
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| 66:31 | is coming out of the delta I think the water's coming from the |
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| 66:35 | sand. I think that shale is this sandstone which is a flow unit |
|
| 66:42 | the upper sandstone which is separate flow . And by that time in Alaska |
|
| 66:46 | developed the village drills horizontal wells using tubing which drops the cost of drilling |
|
| 66:52 | a couple million bucks a well to half a million bucks per well, |
|
| 66:55 | they re drilled the 9:35 a as horizontal well, they put the slotted |
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| 67:01 | into that lower sandstone. Asbo predicted got the foreigner bells of oil back |
|
| 67:07 | water cup went to zero right now were water flooding the reservoir. |
|
| 67:12 | But none of that water flood was into that lower sandstone. So that |
|
| 67:18 | pretty exciting. And of course, know, here's an example of bidirectional |
|
| 67:24 | lap delta loaves, there's a dip on top strike view on the |
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| 67:28 | And I think you can see the geometries. And so the point is |
|
| 67:33 | a lot of Deltek systems, we these layer cake strata, graphic concepts |
|
| 67:38 | one of the things that I've been hard in supergiant fields all over the |
|
| 67:43 | and I go all over the world consult with whether it's BP impacts in |
|
| 67:48 | . A japanese company called impacts, means Indonesian petroleum exploration company. Most |
|
| 67:55 | the oil and gas comes from And again, they got delta oil |
|
| 67:59 | And I went up there and yeah, you haven't any kana forms |
|
| 68:02 | . And I've been working with the , sorry, the, what's the |
|
| 68:13 | chinese oil company now? The Senate there's so jane on japan's no chinese |
|
| 68:22 | company. Yeah. Anyway. and uh, I remember when it |
|
| 68:27 | my PhD student said now when you the talk show this figure, like |
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| 68:31 | just that conveys them, you know much difference it makes using a different |
|
| 68:36 | of form of strategy because it results a complete different conductivity. Right? |
|
| 68:39 | it was that concept that allowed my , but my former student carrie brock |
|
| 68:46 | find bypassed oil and gas in, mature fields, right, mature |
|
| 68:51 | there's lots of the bypass pockets of . Most of those fields are drilled |
|
| 68:55 | little strata graphic concepts, right? there's lots of little. So the |
|
| 68:59 | company you work for, the the more you can look for those |
|
| 69:04 | . Big companies can't afford to look it because the prizes to smaller small |
|
| 69:08 | company, the more valuable that prize be right. You know? |
|
| 69:18 | okay, Let's take a break, we? It's 10-10, we got |
|
| 69:26 | there particular 10, whatever 10, minute break and then we'll okay and |
|
| 69:35 | start back again. Uh I think going to another lecture. Is that |
|
| 69:41 | ? I just feel it's kind of and I've really only got three lectures |
|
| 69:46 | today. So we'll see how this goes. Um and then uh this |
|
| 69:53 | I'd like to do some, we'll this lecture will see we are maybe |
|
| 69:57 | can start working some assignments. Maybe explain wheel diagrams after this lecture and |
|
| 70:02 | do whatever we going for lunch. then I didn't bring lunch and I'm |
|
| 70:07 | gonna head over to wherever and find place to get something to eat. |
|
| 70:11 | to come join me in chit chat you want. Uh what we do |
|
| 70:18 | , right, went to a great last night, wow Backstreet cafe. |
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| 70:25 | ever heard of it? Okay. so many places. Yeah, there's |
|
| 70:37 | . Mhm. That okay. So got to two more shallow marine lectures |
|
| 71:15 | give. So we've already, we've talked about methods and kana farms. |
|
| 71:22 | this talk is going to really focus the, the reinterpretation of elongate shelf |
|
| 71:29 | introduced this idea that sort of the , 60s, 70s, static view |
|
| 71:34 | there were these shelf sand stones produced shelf processes. The idea that sea |
|
| 71:40 | rose and fall and could be play role was wasn't on the table as |
|
| 71:49 | little aside when I uh, when did the interview job for the for |
|
| 72:02 | . So I, I got I was working in Dallas things went |
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| 72:06 | there and uh they try to close department down Bill Dupree for emailed |
|
| 72:12 | I never had, never met him and said, we got this job |
|
| 72:15 | a endowed professorship said was not very with the applicants. Would you be |
|
| 72:21 | ? You know? Oil prices were good in those days, right? |
|
| 72:24 | always, you know, and things going a little funky at Dallas, |
|
| 72:29 | wasn't getting paid very well. And I said, sure, I'll |
|
| 72:36 | I got the offer. I was , you gotta be kidding me. |
|
| 72:38 | it was, it was a almost a 50% increase in salary. |
|
| 72:42 | was like, I was like, Crap, this is what I've been |
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| 72:45 | for. So I took the job you know, they try, they |
|
| 72:50 | to make a counteroffer Dallas. I like, you know, you've made |
|
| 72:53 | a much bigger school, They've got students and sits in the heart of |
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| 72:56 | old business. You know, companies start to leave Dallas and Dallas was |
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| 73:00 | diminishing in oil city and uh, gotta say I love, I really |
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| 73:04 | Houston. Anyway, this is the I gave. It's changed a little |
|
| 73:08 | , but they really liked it. , so we've already seen the slide |
|
| 73:18 | . Uh, I don't know if can see this. There is a |
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| 73:23 | there. Did you see that? our arm, they're wearing a red |
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| 73:30 | hat. Anyway, so obviously the cretaceous, I called the nutritious |
|
| 73:37 | . You know, the great thing the Southwest US is it's desert because |
|
| 73:41 | the overall uplift of the Colorado plateau the tectonics. A lot of these |
|
| 73:46 | delta systems are exposed because it's, a desert there. Well exposed. |
|
| 73:51 | ? So you can really figure out geometry and sequence photography and faces, |
|
| 73:56 | and everything else you're interested in. know, and the cretaceous was similar |
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| 74:01 | to a lot of other analog petroleum around the world. I mean, |
|
| 74:06 | goodness sake. The Bossier Haynesville is . I mean, it's only a |
|
| 74:12 | . 20 million years older than than cretaceous stuff. Right. And the |
|
| 74:16 | of this stuff is only, you , if some of this stuff is |
|
| 74:20 | million years and you're into that 40 year old. My scene, it's |
|
| 74:23 | it's the world. Wasn't that different of grass? Maybe no dinosaurs. |
|
| 74:28 | here's a classic example of a top preserved delta. Okay, this is |
|
| 74:32 | Faron. One of the fair and wedges and green is floodplain. The |
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| 74:39 | color is alluvial. So you notice there's there's some little flu real |
|
| 74:46 | there's some really big things that may more valley scale. Yeah, these |
|
| 74:50 | of uh lens shaped yellow units are Marine Sand stones of one variety or |
|
| 74:58 | . A lot of delta's, some faces. The blue stuff would be |
|
| 75:04 | back barrier lagoon and the black stuff cold. Okay, so this is |
|
| 75:11 | , the abundance of coal implies wet , very wet floodplains or back barrier |
|
| 75:18 | and lots of preservation of the plant material. And in addition, the |
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| 75:23 | and sandstone is also a gas Okay. And what you can see |
|
| 75:30 | and and of course, once The vertical scale here is 20 m |
|
| 75:39 | 10 kilometers. Okay, So that's m. Okay, over 10 |
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| 75:48 | Okay. Which means you've got about kilometers kilometers over five m. So |
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| 76:03 | ah I haven't got the right Ah Sorry, five km over 20 |
|
| 76:12 | . There we go. So what's vertical exaggeration? That's 5000 divided by |
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| 76:23 | , just five kilometers, Which is m divided by 20 m. That's |
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| 76:31 | model by 20. That's 250, times vertical exaggeration. Okay, |
|
| 77:05 | Okay, check this out. there it is. Anyway, non |
|
| 77:28 | exaggerated. If I squeeze that 250 , it looks like a pancake, |
|
| 77:37 | ? So it's it's it's it's really just understanding how important vertical exaggeration |
|
| 77:46 | Okay, there we go. you know, there's the outcrop, |
|
| 78:24 | ? And uh, when I show show you it's squeezed, everything looks |
|
| 78:28 | layer cake here, right? You're seeing these big platforms that you can |
|
| 78:32 | really see when you exaggerate and and squeeze the photography. Right? |
|
| 78:39 | of course, these platforms are subtle , right? They're easy. They're |
|
| 78:44 | they're tractable to determine in in the exaggerated world, but they're not necessarily |
|
| 78:50 | obvious in the outcrops, right? that's why they weren't recognized necessarily. |
|
| 78:55 | people are happy doing layer cakes photography these ancient delta systems, because, |
|
| 78:59 | know, I mean, if you're , right, you know, if |
|
| 79:05 | just doing general outcrop mapping, you , there's a slope. You |
|
| 79:12 | there there's there's a context, pretty . The base of the sandstone. |
|
| 79:16 | the top is barely see there's the , right, Whoops, very badly |
|
| 79:23 | . Let me try to do this here. You can see the top |
|
| 79:33 | the Faron. The base is pretty and it's pretty clear. There's |
|
| 79:39 | there's a slope that Shelley there. . And so in general, you |
|
| 79:44 | , you gotta shale, got a of sandstone and you got a bunch |
|
| 79:48 | shells, right? So, you , at the sort of gross 19 |
|
| 79:53 | , little strata graphic, you've got big thick shell, you've got this |
|
| 79:56 | of saying yes, you know, , Dennis, there's, there's shells |
|
| 80:01 | here. But you know, there's of shells and sand, you |
|
| 80:04 | just just lump it all the more than the stuff above and below. |
|
| 80:09 | . And don't worry about the inter later for that. Uh, of |
|
| 80:14 | . Uh, now, Jim Garrison's very interesting guy. He worked at |
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| 80:18 | Austin graduate with metamorphic metrology, went work for mobile, started doing mini |
|
| 80:24 | on the fare in an outcrop and quit the company. Angela. One |
|
| 80:29 | those guys that quit and he and girlfriend moved out to your wife, |
|
| 80:32 | guess moved out to Emery Utah in middle of nowhere. And he, |
|
| 80:36 | lived there for like five years, , and just went out everyday and |
|
| 80:40 | sections and put together this. And is just a condensed version of his |
|
| 80:44 | . Yeah, I did a great . Wasn't really trained sentiment. |
|
| 80:47 | He's a bit of an odd but, but, but a sweet |
|
| 80:51 | in his way anyway. And so we can do some trajectory analysis, |
|
| 80:56 | ? So it's building up and it down a little bit then it's |
|
| 81:03 | then a little transgression then it's it's too degrading. Then it kind of |
|
| 81:11 | grades a little bit you know? there's a a little bit of bay |
|
| 81:15 | laguna when the system builds up. ? So it's almost aggregation allele. |
|
| 81:20 | there's a big kickback so big retro not even much of a shore line |
|
| 81:27 | and then the system shoots seaward and stalls out and then basically retrograde. |
|
| 81:33 | ? So it's kind of ap P. A. And then it's |
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| 81:46 | a P. D. Again and P. A. Are P. |
|
| 81:58 | then a slash are makes sense. . Okay. And so by and |
|
| 82:12 | . And then the other thing you do is is you know, anytime |
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| 82:16 | see an aggregation of a component component expect to see the development of the |
|
| 82:22 | radic tail and the poor alec Is that the floodplain call channel faces |
|
| 82:28 | ? There is some indication of And so there are some valleys in |
|
| 82:31 | system but it's definitely complicated. And pointed out that that that when a |
|
| 82:39 | is high and positive you get this of sediment behind the shorelines. Okay |
|
| 82:44 | anytime you get a and an aggravation component to the shoreline trajectory you have |
|
| 82:50 | ability to build lagoon all back barrier plain floodplain sediments behind the pro grading |
|
| 82:59 | . However when you've got negative shoreline , right, You don't have that |
|
| 83:04 | normally entail. And in some the trajectory is steeper. If the |
|
| 83:10 | of falling sea level is steeper than basin floor such they converge. Then |
|
| 83:16 | waves will impinge on the muddy shelf create a erosion surface that based on |
|
| 83:22 | short face. Remember we talked about short based shore faces. Okay. |
|
| 83:28 | that led to the idea of of forced regressions. These can be attached |
|
| 83:32 | can be detached and the detect tend be associated with perhaps lower settlement supply |
|
| 83:38 | faster falls, uh and maybe lower . So the sleep of the gradient |
|
| 83:44 | the less the fall will detach the , the flat of the gradient. |
|
| 83:49 | sea level drop will basically jump the the shorelines farther seaward with each increment |
|
| 83:54 | fall. I'm going to talk about Dunvegan in the next lecture, probably |
|
| 84:00 | afternoon in this case. Al remember shows a representational to slightly aggregation. |
|
| 84:13 | , and then it's degradation From 2 1. And the degradation all associated |
|
| 84:18 | the size valley, but the low delta touches the Hiestand delta or the |
|
| 84:25 | Hiestand delta. So it's not a detached system. Right? And you |
|
| 84:29 | see evidence of forced aggression here, they're always attached so done vague in |
|
| 84:33 | of Dunvegan is an attached system. is work done by Simon patterson in |
|
| 84:38 | book, cliffs. And again, got a forced, aggressive shore line |
|
| 84:42 | at the low stand shore phase with regressive surface of marine erosion at the |
|
| 84:47 | . But but it's attached to this face that's next to it. Short |
|
| 84:51 | seven, Which is attached to shore six. So it looks like there's |
|
| 84:56 | a successive down stepping with these shore , but they seem to be all |
|
| 85:00 | together. Okay, so they're not not very detached. But what's interesting |
|
| 85:07 | there's an incised valley here Which is size Valley eight that feeds that shore |
|
| 85:14 | . But interesting. There's a bypass here Now that Incised Valley shall become |
|
| 85:20 | channels ultimately fed ashore face because it's face. Maybe there's only one channel |
|
| 85:26 | the sediment was all reworked by waves when when transgression came back over the |
|
| 85:32 | , basically removed the shallow channels decapitating beheading the feeder systems. Okay, |
|
| 85:40 | that introduces the idea of top Now we've seen these slides before. |
|
| 85:47 | I'm just reviewing them with a bit emphasis on this idea of forced regression |
|
| 85:52 | subsequent transgression. So, this is that Guy Clint did when he was |
|
| 85:57 | postdoc at master when I was a student there. That's another interesting |
|
| 86:05 | Plant was Dennis PhD at Oxford Mhm. And when he showed up |
|
| 86:10 | there was just crazy Australian god named James who had a bit of a |
|
| 86:17 | . Anyway. Dave and I worked at S O Calgary and David. |
|
| 86:23 | come back from Oxford. Dave James to convince esso resources to pay his |
|
| 86:30 | while he was a PhD student at . Now he's working on an Alberta |
|
| 86:38 | which the company was interested in but to get his PhD and got paid |
|
| 86:43 | employ and got to live in Oxford though he was an Australian living in |
|
| 86:48 | . And we were in the core one day and and Dave James convinced |
|
| 86:51 | that I should do a PhD. he was a very influential person to |
|
| 86:54 | . Anyway, as the story his office mate was guy plant and |
|
| 86:59 | course he had all the seismic trickery from working for S. O. |
|
| 87:04 | was, you know the the Calgary of Exxon Corporation. And he claims |
|
| 87:09 | he taught every guy plant everything, everything about sequence photography, right? |
|
| 87:14 | Plant comes to Canada. After having with Dave James and decided to look |
|
| 87:20 | the cardio in formation which roger walker working on and apply some of these |
|
| 87:24 | of sea level change to the Alberta and clinton was the guy that recognized |
|
| 87:31 | sharp based shore phases and they were locally developed a sharp based short |
|
| 87:36 | It would pass into a gradation all on your face and it will pass |
|
| 87:40 | into nothing. Right? And so surmised that rather than these things being |
|
| 87:46 | self shelf sounds, he said, think what happened is there was a |
|
| 87:50 | aggression. Okay. And that's the profile. You can see it starts |
|
| 87:57 | as as a shallow trajectory. It steeper and the steeper it gets, |
|
| 88:02 | more erosion elit gets and the more occurs. So at this point the |
|
| 88:07 | is extreme. Okay. And then kind of slows down and goes from |
|
| 88:13 | two p. Never really much a . Then sea level rises and waves |
|
| 88:21 | ripping across that system and look how they rode. They rode the top |
|
| 88:26 | the low stand, the area of of of bypass that had a very |
|
| 88:32 | unit. That feeder systems are completely and the only record and here's the |
|
| 88:38 | is you'll have marine modes below marine above and ace literally a single layer |
|
| 88:43 | pebbles. Uh and uh, and you get into these units here and |
|
| 88:49 | , the top truncated. Here's the . You've got a marine shale over |
|
| 88:57 | by a marine sand over land by shale with no evidence of a shore |
|
| 89:04 | , no roots, no channels, coals, no paralysis faces. So |
|
| 89:09 | facades model is said, wait a , we've got a marine shale, |
|
| 89:12 | sand, marine shale. Clearly this a marine environment and it was never |
|
| 89:16 | other than marine no, we're This was severely exposed according to plant |
|
| 89:24 | , no, no, this is marine shale, marine sound and a |
|
| 89:27 | shale, there's no evidence of superior . The closest roots and coles had |
|
| 89:32 | two km landlord. That's where the was. Was never here. This |
|
| 89:36 | a shelf sound. And so that the debate. Okay. Uh, |
|
| 89:41 | of course the breakthrough was, was that a lot of the evidence of |
|
| 89:45 | for Severin exposure was removed and reworked the waves. Now there are all |
|
| 89:52 | pebbles here and I was there Okay, I was there when this |
|
| 89:56 | was being done. I remember going an alcohol. Good point. Was |
|
| 90:01 | Simon Patterson Bruce power myself, Kathy was probably there. Roger was there |
|
| 90:09 | Roger said, okay, we got big cliff for shale, we predict |
|
| 90:13 | now they had done these correlations over basis. There should be a pebble |
|
| 90:16 | right in the middle of that You have to understand what this is |
|
| 90:21 | . Still it's a big big cliff shale. Let's just go and find |
|
| 90:34 | cadillac. Get up there, something christian Simon, we're playing golf. |
|
| 90:43 | guy played said those guys are Right? I was a bit more |
|
| 90:47 | . So I was sure enough right they hypothesized there was a, the |
|
| 90:55 | are blocking below, didn't look any , but how do you get petals |
|
| 90:59 | the middle of the share. One hypothesis is that dinosaurs, a |
|
| 91:08 | to break up their food. And did that? Cool. Another theory |
|
| 91:16 | that gravel was carried on the roots trees that fill it out and dropped |
|
| 91:21 | the sea floor. Another way to bravos have ice racket material. |
|
| 91:29 | We can't discount the hypothesis. Why we just count route carry pebbles? |
|
| 91:37 | still say that. That's the way get gravel out of the shells. |
|
| 91:41 | can't we just can't icecaps? Ice pedals? What? Okay, |
|
| 92:06 | why can't we discount ice rafted This is the cretaceous zero. The |
|
| 92:19 | . Exactly, right. There was high security. Right. So forget |
|
| 92:22 | . Right. What about But what you know what I mean? There's |
|
| 92:27 | and lots of calls, lots of , you know, there's there's gravity |
|
| 92:31 | . Why can't they carry some That's right. It's really strong |
|
| 92:45 | Let's just say that that is a , right? Let's accept that trees |
|
| 92:49 | carried panels out and every once in while dropped them on the sea |
|
| 92:55 | Okay. Does that mean we expect see? What do you expect to |
|
| 93:04 | ? But Exactly. Right. We to see scattered pebbles here and there |
|
| 93:11 | a single layer in recent levels in surface that would have flooded trees oriented |
|
| 93:17 | and never again, That's not Right. This is important because this |
|
| 93:22 | a big research project. I'm doing . Federal ice in the cretaceous. |
|
| 93:28 | is unit in Alaska petal shape. . That's about pebbles scattered throughout |
|
| 93:34 | Right. So one hypothesis is that it's uh, it's carried by |
|
| 93:40 | Soundbite? Wait a minute. If was a routine mechanism, then the |
|
| 93:45 | should be several because there's holes everywhere there's angiosperms and and there's big tree |
|
| 93:51 | in the middle of the shales that never any pedals. So anyway, |
|
| 93:57 | seeing if you guys are thinking Yeah. So that they So the |
|
| 94:01 | answer is it's the it's the, , in a sense, it is |
|
| 94:04 | walther's law. If there was a process of bringing all the time, |
|
| 94:08 | should get little pops of pebbles Right? You don't the fact that |
|
| 94:12 | at strata, graphic surfaces implies that had their strata graphically significant. |
|
| 94:18 | that was a big deal. And we talked about the idea that |
|
| 94:22 | you know, these sharp based shore are only in these more so, |
|
| 94:27 | know, approximately here, distills And for every individual shore face at |
|
| 94:32 | given time, there's an area that's for waves and area that's difficult for |
|
| 94:37 | . And the area of erosion occurs the area where we're in the more |
|
| 94:41 | where waves could affect the seabed. as you go into deep water than |
|
| 94:45 | evidence for wave erosion seasons. So why you get gradation of short |
|
| 94:49 | Short based shore faces and gradation of faces. And that requires This short |
|
| 94:56 | to be physically lower than that Such that the erosion of surface passes |
|
| 95:05 | a gradation of surface. Right. right. Yes. And of course |
|
| 95:11 | understand the concept of shoreline trajectory and see these top truncated sand stones |
|
| 95:20 | Their gradation based and you know sometimes short faces a sharp based and so |
|
| 95:27 | was very excited about. Oh, based short faces. That's diagnostic of |
|
| 95:31 | aggression. But the theory says, , no, actually, you can |
|
| 95:35 | have forced aggression and a gradation of if the if the trajectory resealable fall |
|
| 95:40 | less steep than the than the sea over which the force progression occurs, |
|
| 95:45 | was something that I think I really it. So I'm like, |
|
| 95:49 | you don't have to have a short short face to be a forced |
|
| 95:53 | Okay, what the key thing you can't really have a poor alec |
|
| 95:58 | . So I started working in the area and noticed these gradations rebased |
|
| 96:03 | coarsening delta fronts, but they had razor sharp contacts right to the caution |
|
| 96:10 | . They've got top truncation or top and they've got a razor sharp contact |
|
| 96:17 | marine shale above the shallow marine We've seen these photographs before. Here |
|
| 96:23 | see the contact, it's undulating, it's not a flat to dis conformity |
|
| 96:29 | there's truncation of the sand stones below there's even on lap of the mud |
|
| 96:34 | above. We look at the actual so that's a marine discontinuity that was |
|
| 96:40 | cut by rivers. Okay, And then on that surface there's ripped |
|
| 96:46 | pieces of Marfa. You can see pebbles, there's a pebble there Another |
|
| 96:51 | circled on the upper diagram. I finding this, this piece of |
|
| 96:57 | I took it out and took it one Langston at Ut Austin and he |
|
| 97:01 | me it was the vertebral element from marine plesiosaur tail. I forget the |
|
| 97:07 | of the species, but he knew it was. Anyway, so I'm |
|
| 97:14 | to take this away. This is really old slide. So when I |
|
| 97:19 | this talk in 2004, the cretaceous curate was still the area where there |
|
| 97:26 | debating about the origin of shelf sand . Every once in a while I |
|
| 97:31 | a manager at some company who's been of school a bit too long, |
|
| 97:35 | read a paper in 30 years and still believe in shell sounds, I'm |
|
| 97:38 | , oh my goodness. Anyway, if you encounter these folks recognize you've |
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| 97:43 | an opportunity to set them straight right find those falling gas. But the |
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| 97:48 | why people like this idea of elongate sand stones is that they were marine |
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| 97:53 | stones over land and underland by Maureen and the lack of overlying non marine |
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| 98:00 | lead them away from a delta interpretation a delta, which we have a |
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| 98:04 | from the shore line to the And if you don't see the terrestrial |
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| 98:09 | how do you know there was a there. Okay, and we're going |
|
| 98:14 | , we're going to get to These two points about mutually exclusive interpretations |
|
| 98:21 | disparate interpretations and how to resolve them after this slide, so this is |
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| 98:27 | the classic shelf sand model. This put together by Rod Tillman and Rodney |
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| 98:34 | who has since mended her ways. was a former A PG president, |
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| 98:38 | good colleague of mine, you back in the eighties people excited about |
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| 98:41 | sands, even she in the end out the idea, you'll notice on |
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| 98:46 | diagram that the front cross section is S with 1970 for double clinic for |
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| 98:52 | . But in those days, the , you had a client form |
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| 98:56 | that was, you know, the was the shore line. So there |
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| 98:59 | the shore line. Okay, then had the shelf break and then had |
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| 99:03 | bunch of of sands deposited in the of the shelf. When I was |
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| 99:08 | started my grad studies in 84 in september and I think, but think |
|
| 99:17 | of that year, I went to conference on shelf sands and man that |
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| 99:22 | was talking about sequence photography. people talk about shelf processes, tidal |
|
| 99:28 | ridges, Julius, trophic storm the Hoffmans principle shelf plumes. Guess |
|
| 99:42 | ? Everybody's talking about it again? these physical processes that were thought to |
|
| 99:50 | sand in the middle of the shelf don't and not realized to form mud |
|
| 99:58 | . So all the theory of shelf actually does apply to the movement of |
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| 100:02 | on the shelf. So it's critical exploration of mud stone reservoirs, but |
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| 100:08 | should be abandoned as a mechanism for particularly medium or coarse sand because the |
|
| 100:14 | stresses both are too weak and you don't have enough sand out there to |
|
| 100:18 | it Anyway. So that was the that was very popular back in the |
|
| 100:23 | . And that was the model that that that I was interested in testing |
|
| 100:29 | some some work. So let me you know, so that's the general |
|
| 100:37 | . So let me go through some the ways. So I'm just gonna |
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| 100:40 | you a map. Right? So would be a typical license plat |
|
| 100:43 | you know, and elongate sandstone surrounded shares, right? Without much regard |
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| 100:47 | surfaces or anything else. So sort Tillman Martinson model was that there was |
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| 100:52 | sort of shelf process that somehow concentrated into these elongate ridges and these could |
|
| 100:59 | hundreds of kilometers from the act of then sequenced, really came along and |
|
| 101:05 | not, you know, maybe maybe sea level dropped, deposited the sandstone |
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| 101:13 | then when it rose, it eroded the evidence for the land, |
|
| 101:17 | It rode away any evidence for a environment, rivers, routes, |
|
| 101:23 | which was the hypothesis forest regression I about and in that in that model |
|
| 101:31 | that the sediments basically are being coming the land in that direction and |
|
| 101:36 | you know, being reworked by you know, that are coming in |
|
| 101:40 | and making these linear sand stones. there was another hypothesis that in fact |
|
| 101:49 | elongate sand stones represent deposition in the of elongation with rivers that was flowing |
|
| 101:57 | northwest to southeast. And there was structural bump here that resulted in these |
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| 102:05 | sand stones. So in this the allegation requires these sand stones to |
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| 102:11 | elongated by waves in this model, elongated by other processes. And so |
|
| 102:18 | sand stones aren't wave dominated, you be like uh huh How could |
|
| 102:26 | That's a wave dominated sandstone. That's . Now, we're talking about different |
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| 102:30 | stones. Nevertheless, some of these sandstone to interpret elongate deltas, |
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| 102:36 | as opposed to shore faces. and then another interpretation is that these |
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| 102:44 | full fledged incised valleys, again with coming from northwest to southeast. |
|
| 102:52 | so we've got four hypotheses. Two them have, one of them has |
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| 102:58 | just coming from the area. So like oughta genic auto genic, you |
|
| 103:03 | , sentiment that was there and somehow . Then we got settlement, came |
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| 103:07 | the west and moved east. Then got two hypotheses which have the sentiment |
|
| 103:12 | from northwest and building the southeast, of southeast, right. Um |
|
| 103:24 | sorry about the wrapping here, the faced elongate delta. Now you might |
|
| 103:31 | that it's not likely that all four these can be right, right, |
|
| 103:35 | another interpretation. There is another interpretation is being put up here. one |
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| 103:41 | of these things that there were submarine , submarine deepwater fans. You gotta |
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| 103:48 | a minute. How can a sandstone A flu Evelyn sized valley, a |
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| 103:54 | fan and every and everything in I'm like, that's pretty bad when |
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| 104:00 | can't figure that out, Like you even know what the water depth |
|
| 104:03 | Oh my God, Good grief. , so I'm going to show you |
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| 104:07 | example of elongate sandstone that's associated with Dell. Take process and complicated structural |
|
| 104:18 | . You don't understand this? Let's a bit about incised valley. So |
|
| 104:23 | different types of valleys. The great valley of Africa is a structural |
|
| 104:28 | Alright. You've got rifting of Africa you've got low areas filled with |
|
| 104:32 | Okay. And you can get There's a submarine valley in the mid |
|
| 104:36 | ridge, right? And you can rift valleys at, at continental margins |
|
| 104:41 | those are structural valleys, you get level drops and nick points, knows |
|
| 104:45 | cut an erosion of value and the things. Right. Uh And so |
|
| 104:50 | can get several. And so valleys, not all values need to |
|
| 104:54 | in size. Why is that I was in a meeting once and |
|
| 104:58 | got a lot of colleagues who work valleys and they hate the word in |
|
| 105:02 | values, like, well aren't all valleys and size? I'm like no |
|
| 105:08 | valleys aren't sized. What are you about? Oh huh, I hadn't |
|
| 105:13 | about that about Exactly not all valleys . Right, goodbye. So of |
|
| 105:19 | when when it when cl force forms size valley, you get no tilting |
|
| 105:25 | the of the of the little sphere you get truncation and on lap |
|
| 105:29 | So very demonstrable in the basement with facings and you produce a dis conformity |
|
| 105:36 | you get a tectonic valley, like rift valley, you get tilted rocks |
|
| 105:42 | on lap by flatline rocks. Now got an angular on conforming. |
|
| 105:47 | you get complicated truncation on lap relationships in order to sort of solve this |
|
| 105:56 | . I thought I'm just gonna do thought experiment. A lot of us |
|
| 106:02 | spending all the time in the cliffs around the san rafael swell |
|
| 106:05 | you know, let's just do a experiment. Let's bring the cretaceous seaway |
|
| 106:11 | . Right, let's flood this complex . So we flood the area and |
|
| 106:18 | green is land. The topography you is all underwater. We've got two |
|
| 106:24 | , we got the Price river of green river and they start to build |
|
| 106:28 | . Okay, so that's early, deltas. Late delta's okay, so |
|
| 106:36 | this area is flooded and new deltas grade over this complex Seascape. |
|
| 106:43 | we're gonna have to san rafael swell a shallow island. Right, It's |
|
| 106:47 | pretty big structural feature, but you . And so the delta shapes reflect |
|
| 106:53 | complex Seascape. They have nothing to with wave reworking. Now this delta |
|
| 106:59 | be wave reworked depending how aggressive the are in the seaway. I didn't |
|
| 107:03 | that. So then let's just draw outlines of the sand stones. I |
|
| 107:09 | them. Now we've got a theoretical map. Right? So that that's |
|
| 107:14 | that's the size and shape of the stones we'd expect if we, if |
|
| 107:19 | build deltas newly flooded seaway with complex . So I say voila, we |
|
| 107:26 | elongate and lo bait sand bodies. . And the elongate sand bodies are |
|
| 107:32 | lapping subtle structures, right? Has to do with incised valleys, whatever |
|
| 107:37 | left over. Okay, so now gave this talk after I've done this |
|
| 107:52 | . So in 1994 I was working Arco and I went to the Denver |
|
| 107:58 | PG and the advertised advertised a field to look at the, the |
|
| 108:03 | the frontier sandstone. Go ahead. , the frontier sandstone which was sent |
|
| 108:10 | main ian age. I've done my on the ceremony in Canada. I |
|
| 108:13 | very interested in looking at the age straight up Wyoming. I went to |
|
| 108:18 | outcrop and remember we visit an outcrop was about about a half a mile |
|
| 108:25 | from this one. Through my telephoto took that photograph. I said rod |
|
| 108:31 | term was leaving and I said, are these inclined bets? He mumbled |
|
| 108:35 | said, I think that's the lateral in the channel. I'm like ah |
|
| 108:39 | to me, it looks like it up. I'm like, that doesn't |
|
| 108:42 | like a short based finding up a . It looks like a pro dating |
|
| 108:46 | chloroform. And it looks like I see a, you know, some |
|
| 108:51 | of surface through here that looks pretty and it looks like these things climate |
|
| 108:56 | down and well, it sure looks mud. They're like, huh, |
|
| 109:01 | . And it turned out that there a pebble bed here. So that's |
|
| 109:04 | base of the valley and like that's base of the valley, but there's |
|
| 109:08 | above it. Okay, whatever. and and we were actually standing on |
|
| 109:17 | outcrop, outcrop was in the You couldn't see platforms here because the |
|
| 109:20 | exposure and you could see, you , thicker sand stones above. You |
|
| 109:25 | , you could see some upper cautioning sets, you know, something just |
|
| 109:29 | like upper coursing delta to me. the interpretations that he was suggesting is |
|
| 109:35 | these were estrogen, incised valleys and sounds and like, I don't |
|
| 109:40 | there was no hunky cross stratification, is typical storms. There was nothing |
|
| 109:45 | looked like it was formed by I'm like this, this, this |
|
| 109:49 | like a pro grading tide dominated You know, I had some discussions |
|
| 109:54 | other people, the field trip, tidal, the tidal influence was |
|
| 109:59 | which is why tillman interpret as an , okay, which is a drowned |
|
| 110:04 | valley. You know, there's there's tides, you know, it |
|
| 110:08 | a terrible interpretation and beautiful heterocyclic a few plant salads, lots of |
|
| 110:14 | and start sedimentation. When you go in the cross bedded sand stones, |
|
| 110:19 | can see evidence of Evidence of a a of a four set mud rape |
|
| 110:30 | ripple going in the opposite direction, mud rape another four set and that's |
|
| 110:37 | the ebb tide flowing out, which strong, the flood tide coming |
|
| 110:41 | which is weak, goes in the direction, it stops, you've gotta |
|
| 110:44 | water uh and then it comes back again, you get double madre being |
|
| 110:48 | slack water periods, the sand stones the flood and the and the the |
|
| 110:54 | energetic peptides that are going in the of Delta's building. Fantastic title |
|
| 111:02 | Then what I did is and we a year, two years doing the |
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| 111:06 | work and then I went back to and started correlating all the wells, |
|
| 111:10 | powder river basin. And these are maps I made beautiful elongate sand stones |
|
| 111:18 | to locate sand stones. Now you see where my thought experiment came |
|
| 111:23 | I already made the maps I had figured out, but I said, |
|
| 111:27 | just thought, you know, let do a thought experiment to kind of |
|
| 111:29 | the relationships. I'm saying in the of basis with respect to topography that |
|
| 111:34 | already know here is always interesting. this sandstone here, the willow sandstone |
|
| 111:42 | wave dominated in this area and increasingly title features as you go to the |
|
| 111:48 | . This elongate through in sandstone which mapped out as a finger In |
|
| 111:53 | ended up being two fingers and didn't a sniff of wave form features |
|
| 112:00 | not a single thing that you would , oh that's clearly produced by |
|
| 112:04 | That was very problematic because the map the sandstone showed that it faced the |
|
| 112:09 | ocean and everywhere else in the cretaceous , all the open ocean sand |
|
| 112:15 | a classic wave dominated shore face, not this fruin sandstone, 100% of |
|
| 112:22 | ng tide dominated delta. Like that's weird. Now, what's interesting is |
|
| 112:29 | have some timelines, there is a line that's bentonite. Okay, we |
|
| 112:36 | the low bit willow, the elongate ins and below that there is a |
|
| 112:43 | that turns into a pebble bag and looks like it's curving and it's it's |
|
| 112:51 | and underlying by Ben tonight's that are curving bentonite. Start depositing. How |
|
| 112:56 | you get a curving bentonite? A pebble bed and a curving bentonite. |
|
| 113:01 | huh. Like that should all be . Like I don't get it |
|
| 113:07 | And that was the incised valley. that's the incised valley, it should |
|
| 113:12 | into the bentonite, not be parallel it. The other thing is that |
|
| 113:18 | section five where the Bruins is We've got these large meter scale cross |
|
| 113:25 | . Okay. And as you go the sandstone, the cross gets smaller |
|
| 113:29 | the beds get thinner, so if unit was a clot to form, |
|
| 113:40 | , you should get thicker sands here since the base. Big cross beds |
|
| 113:47 | small cross bets. And here you get the more distal faces. |
|
| 113:54 | In section one, you've got these big cross beds Implying the same tidal |
|
| 114:01 | and the same water depth as a five. But the top of the |
|
| 114:06 | here was maybe 10 m to the bed And in section five it's 20 |
|
| 114:13 | 30 m to Pelham Bay. So think you can understand where this is |
|
| 114:20 | . I said, the only rational is that that sandstone and the and |
|
| 114:26 | and the bentonite were folded before the and sandstone was deposited had to be |
|
| 114:32 | , there was a structural high, was a delta on the right, |
|
| 114:35 | structural high on the left, creating elongated trough down which the ruins delta |
|
| 114:42 | . That was my explanation gate. the fringes on lapping the old willow |
|
| 114:47 | , that's more that we even tied . And it's on lapping this structural |
|
| 114:54 | . Right then I went and had look at this sandstone below. There |
|
| 114:59 | the upper bentonite, there is the band tonight and way down south in |
|
| 115:04 | area called big sulfur draw. There about um 30 m with three beautiful |
|
| 115:13 | up precaution in Paris sequences. The two kept by cross bedded conglomerates. |
|
| 115:17 | looked real to us. And as track that to the north, there |
|
| 115:22 | this whopping transgressed the surface of erosion beautiful truncation all top lap and the |
|
| 115:31 | m of stat shore faces in section in, in the area where we |
|
| 115:38 | in the very first field trip was thick shale, a single pepper bed |
|
| 115:42 | thick shale, incredible. All the was gone. How could it be |
|
| 115:48 | ? And how could you remove 30 of three shore faces? The other |
|
| 115:53 | that I noticed, you know, I, you know, I had |
|
| 115:57 | at Mac and I understood sharp bayshore , but these are all gradation all |
|
| 116:00 | on like these answers their way out the middle of powder river basin. |
|
| 116:06 | all the erosion is on top of sand bodies. There's no evidence of |
|
| 116:08 | sharp bayshore faces in the more proximate . You know, here's, |
|
| 116:14 | here's the top one of these shore and there's a nice maybe 10 centim |
|
| 116:18 | pebble conglomerate. We go out, on the basin and look at this |
|
| 116:23 | stones, mud stones and the mud above and below look the same. |
|
| 116:27 | a fist sized kabul that came out the outcrops takes a lot of shear |
|
| 116:32 | to move that kabul, a river across that area. The river got |
|
| 116:37 | away by waves, but the the river was carrying and cobbles couldn't |
|
| 116:41 | removed. So we get a single of these transgressive conglomerates. Here's another |
|
| 116:49 | , a little bit younger than the that we first worked on with a |
|
| 116:54 | lateral pinch out. So it's it's vertical exaggeration above, vertically, exaggerated |
|
| 117:01 | . So myself, precaution ng outcrop transgressive conformity across the top. Top |
|
| 117:08 | truncation and a sand body that pinches mm hmm, courses upward. There |
|
| 117:17 | a transgressive ravine, mint surface, surface of erosion. And we look |
|
| 117:24 | the lower in the sandstone and now get these burrowed shore face sand stones |
|
| 117:32 | land by hunky sand stones here. we see little clusters of pebble |
|
| 117:37 | These aren't tree deposits. These are storms ripping up pebbles in the beach |
|
| 117:42 | shunting them into the lower shore In the end with a lot of |
|
| 117:46 | , we actually found me too thick beach deposits. I don't have a |
|
| 117:50 | picture of those, but it took a while to find them because their |
|
| 117:54 | a lot of places, but they preserved locally and the and the cross |
|
| 118:01 | pebbly sand stones overlying erosion of So there's the cross bedded sand |
|
| 118:08 | There's an erosion of surface, the and you can see that they think |
|
| 118:12 | can see the cross bedding. The thing we noticed is on top of |
|
| 118:18 | surface, there were Villa Sonora. burrows filled with with with with the |
|
| 118:27 | sandstone pebbly sandstone. Okay, and implies a glossy fungi tease ignore |
|
| 118:37 | So the idea behind this ignore faces you know, the system is pro |
|
| 118:43 | so it's maximum aggression then turns around starts to transgress and you have an |
|
| 118:49 | of wave erosion. Okay. That that exposed the firm substrate, the |
|
| 118:55 | that like to live in a firm burrow or bore into that substrate. |
|
| 119:00 | eventually the transgressive lag faces ride over open burrows and fill them up with |
|
| 119:07 | transgressive facings, which is this public ? Okay. And so there is |
|
| 119:14 | example of this is actually a tidal but at low tides the pebbles are |
|
| 119:19 | armoring the older sediments below similar kind process. And of course the way |
|
| 119:26 | operates is we get, you during forced aggression we get a flu |
|
| 119:30 | surface which is the red surface, low stance shore line. But when |
|
| 119:36 | come back across that surface, Given that transgressive erosion can remove 8-15 m |
|
| 119:42 | of, of faces. If you've , you know, two or three |
|
| 119:46 | deep distributor and channels that are carrying bit of gravel, they get wiped |
|
| 119:50 | . The only thing that's left is gravel and you get these areas we've |
|
| 119:53 | shale above and below and the only that there was a forced aggression there |
|
| 119:59 | the pebble lags. Okay. And my PhD student brian Vaccarella off decided |
|
| 120:06 | work up the second frontier sandstone and , he noticed that the upper shore |
|
| 120:10 | faces were progressively removed and were missing that point. So there you've got |
|
| 120:17 | shale of the overlying para sequence on shore phase. And he's got marine |
|
| 120:22 | of the upper unit sitting on distal face. So in addition to logging |
|
| 120:29 | irrational truncation alcohol, he also correlated subsurface using the wells. And the |
|
| 120:36 | of the wells is you've got spent two nights there. Ben, |
|
| 120:40 | there, Ben, tonight's there, , tonight's there, there's a Benson |
|
| 120:44 | there, probably one there. And see how the bentonite are converging and |
|
| 120:50 | sandstone is pinching out right there. . And in general, and this |
|
| 120:54 | a shore face. A wave dominates face, not a delta. And |
|
| 120:59 | this is more like the shore face that I showed, okay, land |
|
| 121:04 | probably in that direction, but you've marine shale here, marine shell here |
|
| 121:09 | the marine sand in the middle. the erosion but the erosion that but |
|
| 121:15 | that the land would pinch out is erosion of margins, not a deposition |
|
| 121:19 | pinch out and you've got top top truncation associated with that with that |
|
| 121:28 | And so buoyant reasoned that this lambert was being tectonic lee uplift. So |
|
| 121:36 | as well across sections these cross sections from ah southwest to northeast. |
|
| 121:44 | the sandstone maps basically like this. that's the sandstone. Okay, and |
|
| 121:51 | red line marks. The land would . That's the language irrational limit. |
|
| 121:56 | that's this point on the cross And that's why I went back and |
|
| 122:10 | dated this cross section right, which talked about before. So initially I |
|
| 122:15 | the bottom data because of Angela's But then when I realized, wait |
|
| 122:20 | minute, there's there's tectonics going on these Ben tonight's and the only way |
|
| 122:25 | decide how much tectonic deformation occurred is flatten the upper band tonight and see |
|
| 122:30 | folding of the oldest photography. And we saw is that there's basement faults |
|
| 122:36 | are moving. And that's where we the truncation of these sand bodies where |
|
| 122:40 | get these basement reactivation of these basement . And we get several nonconformity ease |
|
| 122:47 | about 400,000 years apart. And we that there are are subtle tectonic deformation |
|
| 122:53 | the, of the atmosphere probably controlled interplay stresses that reactivate these fault, |
|
| 122:59 | some areas to lift up and some should drop down. So we get |
|
| 123:03 | some grob ins and some horses. in the final example, another unit |
|
| 123:10 | I worked at with our co. the patron tongue in Utah. We |
|
| 123:16 | love working in Utah. And this another sandstone that programs from north to |
|
| 123:22 | , Most of the shore faces in cretaceous seaway progressed from west to |
|
| 123:27 | The Pantheon is kind of an It not unique but but but but quite |
|
| 123:35 | different from most of the other classic dominated shore face sand stones and that |
|
| 123:41 | is sort of a broadly elongate too bait geometry. Okay. And we |
|
| 123:49 | cliffs that were perpendicular to the direction paleo flow and parallel to the direction |
|
| 123:54 | paleo flow. And a variety of that we could look at here is |
|
| 123:59 | example of class that's, that's parallel the flow direction. We see it |
|
| 124:04 | upward, we see inclined beds, top lap against a marine flooding surface |
|
| 124:12 | transgressive surface erosion. The head analytics the base show evidence of deposition from |
|
| 124:19 | turbine lights, probably from river Uh Sometimes the faces get a bit |
|
| 124:27 | bar debated. Sometimes you're a little more laminated and we could contrast the |
|
| 124:35 | faces with lots of great advance versus bar debated faces. To contrast riverfront |
|
| 124:43 | stones from mud stones deposited far away the effect of the river. So |
|
| 124:48 | technology allows us to interpret the deposition . Okay, when you see these |
|
| 124:55 | faces and they've got wave ripples implying beds, spice borrowing, implying that |
|
| 125:02 | environment was never very conducive for robust but was still being debated by shallow |
|
| 125:09 | organisms, but probably the sedimentation rates too high to allow windows of colonization |
|
| 125:17 | the info ona and therefore we see degrees of motivation. So we use |
|
| 125:21 | low borrowing it as a proxy for sedimentation rates as well as probable. |
|
| 125:26 | water stress from all the fresh water by the delta as we go high |
|
| 125:32 | the sand stones with beautiful we see inverse and normally graded beds and these |
|
| 125:38 | represent delta front, grain flows and ites. So the delta front and |
|
| 125:44 | delta faces record tonight's low density, fauna, and these observations suggest that |
|
| 125:53 | river is right there, spewing despite the fact that we may never |
|
| 125:56 | the river. The evidence of of of the salt water and excess sediment |
|
| 126:03 | , particularly with mud being delivered can't explained in a wave dominated environment. |
|
| 126:08 | we don't we don't have a wave system. Right, So we see |
|
| 126:13 | of of physical sediments that looked like were delivered by river processes, waning |
|
| 126:21 | of river sediment and not not the directly, but the plumes of sediment |
|
| 126:26 | by the river. Once it the standing body of water produces very |
|
| 126:30 | faces. The top of the sandstone top truncated. There is the erosion |
|
| 126:35 | surface. You can see a nice walled, passively unfilled burrow. You |
|
| 126:41 | see these are big pebbles here. are actually pebbles of cemented sandstone. |
|
| 126:46 | there was a beach that had a bit of of of segmentation from carbonate |
|
| 126:51 | then that got that got ripped ripped as a as a pebble lags, |
|
| 126:54 | didn't travel very far and the sandstone up to lower coarse grain sandstone. |
|
| 127:00 | some oyster fragments in here, so looks like a and there's cross |
|
| 127:05 | right in general, the cross beds like they're kind of going landward, |
|
| 127:10 | again, is more compatible with When Exxon looked at this john bandwagon |
|
| 127:16 | that as a river. Yeah, the cross beds are going landward, |
|
| 127:20 | looks more like a or they were along shore said it looks more like |
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| 127:24 | shore face, you know, a shore face than a river. And |
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| 127:30 | in the end we realized that. we we we suspect he said, |
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| 127:34 | , wait a minute. Why is panther said first of all, we |
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| 127:37 | the panther tongue was pro grading parallel the mountains and it seemed like the |
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| 127:42 | of tongues was shifting westward westward towards mountains. And like, well, |
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| 127:47 | only way from that to make sense if something in the middle of the |
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| 127:51 | is lifting up and actually pushing the westward. If there was an island |
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| 127:58 | was that was high, maybe wave over that and creates a protected area |
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| 128:05 | that, the delta flowed down. , And it meant we had this |
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| 128:09 | dominated system flowing down elongate trough, by subtle structures that disallowed a wave |
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| 128:18 | environment. Once that filled up that accommodation was covered. Tectonics stopped and |
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| 128:25 | next phase of short faces came like would like they used to, which |
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| 128:30 | from west to east and that's indeed you say in the younger pair |
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| 128:35 | So of course, I think the tongue basically pro graded as an elongate |
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| 128:40 | probably with the san rafael area being , but a much earlier earlier and |
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| 128:47 | subtle expression of that same tectonic So the modern day tectonics probably had |
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| 128:55 | precursor that was far more subtle. never gone. I've thought about trying |
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| 129:00 | go back and used the mapping of bench nights regionally to reconstruct that |
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| 129:06 | Never done that project. And I think anyone else has and probably pretty |
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| 129:10 | anyway, because the san rafael is is caught by uh, Jurassic and |
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| 129:16 | faces and and the overlying shales credentials long gone. So the conclusion is |
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| 129:25 | least some of these examples, we've delta's deposited down elongate troughs. Despite |
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| 129:35 | , we think some of them, think they're all low stance because they're |
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| 129:38 | out in the middle of the And when, when waves come back |
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| 129:43 | the top of them, they rode , all of the direct evidence for |
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| 129:47 | actual rivers that fed the shorelines. they leave evidence of the rivers that |
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| 129:52 | have been there by evidence of the process is recorded in the sedimentation rate |
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| 129:59 | the pro delta mud stones as well the sedimentary deposits of the plumes such |
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| 130:05 | turbine ites as well as the evidence the course material that could only have |
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| 130:10 | carried by rivers originally, but it's left as a reworked transgressive leg. |
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| 130:16 | sand bodies have elongate to locate geometries the parallel currents of parallel or radiating |
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| 130:22 | that's not consistent with the wave dominated shoreline. And we see a precaution |
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| 130:28 | successions now short faces coarsening upward as , but these have a lot more |
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| 130:32 | on them and short faces by definition environments when we start to look at |
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| 130:37 | muddy faces, what were struck with features like aggregation alway variables, which |
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| 130:44 | a lot of sand being delivered. graded silt stone beds, which implies |
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| 130:49 | lot of sediment being delivered and lack marine motivation. And although I didn't |
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| 130:56 | a big deal of it, a , very, very sparse, typically |
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| 131:01 | foraminifera. We're now doing work on ribbons which are a freshwater uh um |
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| 131:12 | animal. And uh, and we a bunch of those in these, |
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| 131:16 | these faces as well. We point most people think that tides dominantly transgressive |
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| 131:23 | nature, but we said, we see a lot, a lot |
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| 131:27 | tidal evidence here in the system is proclamation and regressive. So it's a |
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| 131:32 | , it's building seaweed. It's tide and it's 100 ft thick sand |
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| 131:35 | It's not trivial. Of course it sit landward of this ultimate low |
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| 131:42 | So it could be, it could the late low stand, but you |
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| 131:46 | , it's not an estuary filling and size valley. It's a programming tide |
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| 131:51 | Dominic Dominic delta feeling, feeding and low that was left over from a |
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| 131:58 | of structure and some sedimentation of an delta. We can also start to |
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| 132:04 | the stacking of these things laterally. ? So we can start to see |
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| 132:08 | stacking both cross section and in plan . Uh huh. We observed that |
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| 132:15 | major irrational surface are at the tops the sandstone bodies. We still think |
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| 132:19 | are forced aggressive but we don't see evidence of sharp based your faces. |
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| 132:24 | doesn't mean that they don't care in other examples. But we just say |
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| 132:27 | this example which is more delta We can get these gradations based shore |
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| 132:32 | and something that that I certainly wasn't when I started to study because I'm |
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| 132:38 | bad structural geologist. I avoid structure the plague. Ah don't feel |
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| 132:44 | And I know that you're doing a thesis. I just wasn't very good |
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| 132:48 | it. But in the end I I can't ignore it forever. So |
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| 132:52 | , I I wrote some papers in I had to admit that structural geology |
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| 132:57 | in fact in my last days at remember saying, look, you |
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| 133:01 | we have a strong army group. have a structural geology group. But |
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| 133:05 | just don't know it's work that demonstrates structure can have a first order control |
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| 133:10 | distribution of sound. So how come not thinking about that more right. |
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| 133:13 | know, you know, we have we have to integrate all the tools |
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| 133:17 | geology. Not just assume that it's uh photography, shoreline trajectory is a |
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| 133:24 | concept and it's critical on a sign when trajectories are negative but less steep |
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| 133:31 | the sea floor, you can get all based shore faces. And so |
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| 133:35 | think the more critical observation for identifying force progressive sandstone is the lack of |
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| 133:40 | pyre alec non marine laguna slash coastal wedge. Okay, the other |
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| 133:49 | just go back to Angela's question is lot depends on your data. Use |
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| 133:54 | different data. The data distorted If you're not thinking, you can |
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| 133:59 | the strategic graffiti badly. If you understand how your data has distorted the |
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| 134:05 | . And that's why I went back you know, just said, let's |
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| 134:14 | show this through with a couple of and see what can I explain with |
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| 134:17 | lower data. And how does that change? If I if I flip |
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| 134:21 | a opera datum or if I use data, right? So sometimes you |
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| 134:26 | to play with diatoms to sort out ultimate story. Okay, and of |
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| 134:32 | , here's an example of modern work Bruce Hart, another colleague of mine |
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| 134:38 | max student, he shows a nice forming uh last glacial maximum quaternary |
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| 134:44 | He's got a transgressive surface on And he's got beautiful gravelly dunes on |
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| 134:50 | nice planet forming delta deposit with beautiful down lap boy, that seismic example |
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| 134:58 | platforms and and and gravity dunes on is exactly what we see in these |
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| 135:04 | truncated deltas. So it's good to that the President is key in the |
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| 135:09 | . So, part of the conclusion that, you know, without good |
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| 135:13 | ology, without understanding the the both technology and microfossils as well as |
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| 135:21 | mapping of the bound of discontinuities. could never figure the story out. |
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| 135:25 | had to start understanding that structure and are a parent process. Strict structures |
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| 135:31 | always critical, but certainly it's don't it in low accommodation settings, particularly |
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| 135:39 | you were sort of in the more part of the basin, remnants of |
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| 135:43 | . All systems are important. And Martinson went back and wrote a nice |
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| 135:47 | of papers and a PG on All relevant remnants in the cretaceous |
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| 135:52 | It was obviously very excited by our and not all valleys are cut by |
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| 135:58 | . Not all, not all valleys so very exposed, you can get |
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| 136:02 | topography. The sea floor is not flat, right? And when, |
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| 136:05 | sediments fill over the over the sea , if there's highs and lows, |
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| 136:10 | sediments will tend to differentially fill those you might get on lap. That's |
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| 136:14 | the result of inherited sea floor Okay, I'm actually getting a little |
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| 136:21 | of breath, my breakfast has worn . So I'm gonna end there. |
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| 136:32 | 11 |
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