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GEOL6363 Carbonate Sedimentalogy - Day1 08-27-2021-Part3
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00:03 mm. I don't think he said . Yeah. Oh right. All
00:32 . Change the right. Mhm. use. Yeah. That's Yeah.
00:45 . Okay. Each of these Most happy. Yeah. How do
00:51 go back? Okay. Right now me make sure we're still recording.
01:02 . Yeah. If you see this start with you. Okay. All
01:12 , sorry about that. Everybody got . Yeah. Yeah. Oh
01:38 Okay. Stop. Utah had stopped advancing. Oh boy. I
02:00 Okay. Okay. Mhm. So I think I was on this
02:09 with the penicillin is right. So , more than accounts for all the
02:14 just by the breakdown of the tiny of Reagan ideals and his tissue.
02:18 when you look at the surrounding sediment you see the you see the little
02:25 in the sediment under the scanning electron . See those elongated crystals. There
02:30 the same size and shape as the precipitated in the tissue of the penicillin
02:36 And that's why people associate then with source has been proven geo chemically to
02:42 coming from the penicillin. But not the not all of the sediment is
02:48 needle shaped or reaganite. You can some blocky shape material here and and
02:54 of that sarah genetic and some of time and calcite. Some of that
02:57 mag calcite. So what are the contributors the line. But it's the
03:00 erosion of the other skeletal material in environment. Or a genetic shells calcification
03:06 that get broken down. So that's common source. The disintegration of calculus
03:13 to by erosion of the uh other material is a common source for a
03:18 of the lime mud. So the is when you go back to the
03:22 record, what does it look Well, you look at this core
03:25 from the pennsylvania. Look at all material. It's all very fine grain
03:30 . The color varies right from lighter darker brown. The color is not
03:35 of anything really because later you can the color dye genetically. But when
03:42 look at that core, that scale your eyeball or hand lands, you
03:46 differentiate the individual particles. So that you would call that all very
03:51 My critic fabric, you'd have to to the thin section. And if
03:55 look at the thin section, the arrow points to some of that
04:00 The critic matrix. Look at that printing matrix. You still can't resolve
04:04 individual components that make up that line . And you really need to go
04:08 the next level, which is a electron microscope. And you can see
04:14 , you can see the tiny crystals make up that Mcrae. Now this
04:18 Pennsylvanian age. Right? So this , you know, very old
04:22 And uh there's no reason I left these sediments. All the Reagan I
04:27 stabilized. Uh generally once you get into the middle part of the place
04:32 seen. And so everything is going be cal acidic, but it's all
04:36 very fine calcite crystal material that makes Democratic matrix. All right. So
04:42 understand where it's coming from, potentially different sources. And then the recognition
04:47 well he recognized the composition depends on scale of observation. If you really
04:53 to see the fine fabric, you've to get down to the level of
04:56 scanning electron microscope. And then the point we need to talk about is
05:02 the environmental significance of lime mud? to answer that question, let's come
05:06 to the cartoon here of this platform in transition and you need to know
05:13 anywhere along this profile from shallow to water lime mud can be made by
05:19 or more of the mechanisms we just about. But the question is,
05:24 is the line mud going to Where is it going to stick in
05:26 deposition profile? It's not going to to a high degree at the platform
05:33 . Right? Because that's where you the high energy conditions of oceanic swells
05:38 strong tidal current agitation. Right? mud that's produced there in a
05:43 high energy sand body system is going be winnowed out either to the right
05:48 deeper water or it's going to be to the left to the shallow water
05:53 platform. Okay, so the presence absence of lime mud tells you something
05:59 the energy at the time of the . And so we rely very strongly
06:04 recognizing Mick. Right? To understand de positional setting and some of you
06:10 probably been introduced to the terms pack and wacky stone. And my mud
06:15 . Right. That's the dental classification . And to use denim scheme,
06:20 have to recognize the presence of lime , Right? If you don't see
06:24 lime mud, then you can't call to Pakistan or wacky stoner or mud
06:28 . Right. By definition it's a stone if it has no lime
06:32 So you see the implications for environmental , right? A lot of lime
06:37 , quiet water. The quiet water mean shallow or deep by itself because
06:44 water could be 1000 m quiet water be this deep half a foot.
06:51 , where you get lime mud? I don't think the lime mud means
06:54 water all the time because it Okay, so any questions about the
07:00 of lime mud or the recognition environmental . All right, let's move on
07:06 the next group which are the sand aggregate grains. And the first type
07:11 called an inter class. So by this is 62 a half microns in
07:16 or bigger although most most uh inter or millimeter to Destin meter scale
07:24 And what is an inter class. an irrational Yes. Sand sized grain
07:30 of smaller grains with a mud. . Okay, so the critical aspect
07:35 , this recognized them. A critic Because where do you accumulate line?
07:40 again, only in quiet water So in quiet shallow water or in
07:46 deeper water. But then how do create the inter class you created by
07:50 rip up? Well, where is most likely to impact? Not deep
07:55 , but in shallow water. So most central class form in very
07:59 water settings where line mode accumulates and mud is coherent so it holds together
08:07 than then shale or clay. And you break it up by storm
08:12 you create these inter class like you in this photograph here. So every
08:16 of these pieces of ripped up muddy is what we would call an inter
08:21 sand sized aggregate with the mud Okay, that's the key is recognizing
08:27 mud matrix. All right. And the ancient analog from that was a
08:31 title. Flat. Here's a ancient title flag. You can see the
08:37 uh little rip of class here of same size and shape is what I
08:40 you from the modern. Okay, basically this is a storm rip up
08:45 but with a critic matrix. And this puts you into a shallow subtitle
08:51 title flat environment. All right. one example in thin section, this
08:58 again from the cretaceous, you can one sand sized grains. Note the
09:03 there one millimeter. So this is millimeters across. There's the dark
09:08 My critic matrix. That's very typical of Democratic Matrix. And then it's
09:13 some larger grains here. Most of are foods or some other type of
09:17 material. Okay, so you've got fact that you've got this MMA critic
09:23 defines us as an inter class. , everybody see that. And here
09:30 add mixed with fluids. Right, is we just associated with quite with
09:34 energy lime mud. We we associate quiet water conditions. How do we
09:41 the two together? What does the represent? But where did this material
09:50 ? Had to accumulate a quiet water . Right? Where you had mud
09:54 ? And then what happened? Who got shed back into that quiet water
09:59 to give you a mixture of foods Mick. Right. Right. It
10:04 be the other way around. It be. You're in a new ID
10:07 with high energy and you're trying to mud. That's very difficult to
10:11 Right. Because it's too high energy a daily basis. All right,
10:15 see that? So those are inter . So the key is to recognize
10:21 grain fabric with the mud matrix. other end of the spectrum is what
10:25 call the lump san size grain. aggregate of sand sized material, But
10:33 missing the mud Matrix. Okay, that puts us right off the bat
10:38 a into a into a higher energy where carbonate sand accumulates on the sea
10:47 . Okay, rick carbonate sand accumulates the sea floor. Okay. And
10:54 the question is how do you create aggregate grain? Well, you take
10:58 carbonate sand and either cement it by sedimentation. We talked about before to
11:04 a thin hard ground on the And then you break that up by
11:08 processes into the individual grain that you on the lower left. Okay.
11:13 you can do it by organic you can take that carbonate sand and
11:18 can be bound into a sound sand grain by organic activity related to certain
11:23 of foraminifera, more calculus algae. , so strictly speaking, that example
11:30 show you here is a benthic foraminifera we call the glue. Donating benthic
11:36 , But because it creates this lumpy , we also call it a
11:40 Okay, so it's a type of and a special type of lump where
11:46 aggregate the aggregate grain is made up fluids, so it looks like a
11:51 of grapes is called grape stone. , so when we talk about modern
11:55 sands, uh next weekend you'll see the grape stone fits in.
12:03 so here's an example of modern lump from the platform I showed you with
12:08 shuttle photographs uh all of these larger with the arrows pointing to him,
12:14 yellow and black arrows. These are . One sand sized grains made up
12:18 smaller grains held together. Okay, no mud matrix. It turns out
12:23 most of these grains are actually also by the benthic foraminifera. So if
12:28 look at in thin section, you the central chamber of the benthic
12:33 Okay. The test of the benthic is this red stained? The critic
12:39 ? It's high mag calcite. This a special stain we use in modern
12:43 to determine hi matt cal side So everything that's red stain in this
12:50 is heimat calcite mineralogy. Everything that's is inferred to be a reaganite.
12:56 so you can see what this forum done. It is accumulated some foods
13:00 some other skeletal material into its test create this lumpy texture. So you're
13:06 to call this a gluten mating Foraminifera, skeletal benthic foraminifera, but
13:11 also call it a lump because of lumpy texture. Okay. And then
13:18 would be the special type of As you see here in thin section
13:21 most of the aggregate grains are Okay, everybody understand the difference between
13:29 and see the environmental significance lumps forming overall higher energy setting where most of
13:35 macro has been removed by by currents wind wave agitation. Inter class form
13:41 a day to day, quiet water periodically ah ripped up by a strong
13:48 storm or occasional hurricane. And then a term with a class. All
13:54 . And with a class is used lot differently by lots of people in
13:58 . But the the way I view little classes, it's a aggregate
14:03 So it could be a inter plaster that is incorporated in to a younger
14:09 sequence. Alright, so the what me to call something to lift the
14:14 , I've got to demonstrate its older the surrounding settlement, which it
14:18 Okay. Which is not very easy do unless you really know the regional
14:23 or you have some fossil control to that it's older than the surrounding
14:28 But here's a simple example here. if you think back to the think
14:37 to the island that I showed you the subtle photograph, right? That
14:40 pleistocene island and next to it is modern day sediment they call holocene age
14:46 . Uh That's represented here in this . Those older limestone fragments get eroded
14:54 and incorporated into the younger sediments. would be an example of a little
14:58 . Okay. And that left. class could be a lump with no
15:03 matrix or it could be an inter with mud matrix. Okay. And
15:08 why is this important? It's important it tells you had exposure of an
15:12 sedimentary sequence at the time of shedding some material into your environment of
15:19 . So it gives you a better for the regional paleo geography.
15:24 so here's an example of what I call little class. This is core
15:29 from the Triassic in western Canada. bottom of the cores the lower
15:35 The top of the cores upper and you can see the background sediment
15:41 the brown dolomite. Okay. And what happens when you come the upper
15:48 of the core here. It changes light gray fabric. That's a court
15:52 . Okay, so it's over line quartz sandstone. But look at the
15:58 brown fragments of Dulles stone incorporated into sandstone. Right? Older carbonate particles
16:06 into a younger sedimentary sequence. Those be lit. The claps, those
16:11 be dramatized in this case traumatized inter . They were incorporated into that younger
16:16 sandstone. Okay. To see why calling it with a class because it's
16:21 than the surrounding sediment. This is rare in the rock record. But
16:26 , it tells you something about the geography that you had to have some
16:30 carbonates exposed in order to incorporate them that younger carbonate or in this
16:36 classic sedimentary sequence. Okay, fecal pellets. We talked about the
16:45 pellets being the excretion byproduct of Berwyn , shrimp molluscs worms. Right.
16:54 all in jest either directly or by feeding lime mud. What are they
17:00 ? Their after the organic material in line mud. They pass it through
17:03 bodies. They excreted on the sea as a lip Seidel to avoid shaped
17:10 like you see here. Okay. you can see how some of these
17:14 could also be confused with what the class. Right. But inter class
17:20 to be bigger. They tend to more irregularly shaped because they're created by
17:25 processes. When you see things like examples that are uniformly ellipse idol with
17:32 mud matrix, those are probably fecal to begin with. Okay. And
17:37 of the shrimp that I showed you some unique anal structure because they create
17:42 internal striations in their fecal pellets. ever ever seen striped toothpaste? You
17:49 heard a striped toothpaste? How it out of the out of the tube
17:53 a different colors sort of reminds me striped toothpaste. Right? And uh
17:59 that's what some of these shrimp And actually they've given it a
18:04 They call it. Favorited fecal pellets favor. And fecal pellets actually go
18:09 the way back to the Jurassic. , so if you see on
18:15 on the upper right here, if see this kind of fabric, the
18:19 , knit fabric, that's a definitive pellet produced by these burrowing shrimp.
18:26 . Yeah. Yeah. Uh No, I don't know. I
18:34 know where the origin of that comes . I guess I could google that
18:39 figure it out that uh you're the person has ever asked that question.
18:44 would have I would have tried to . Okay. JD or McConnell fecal
18:57 . Now, all of the fecal come out of these organisms soft.
19:01 . So you can pick them up the sea floor and you can squish
19:03 back into the component line mud. right. But what happens after they
19:08 around for a few weeks, a months is they actually become interstitial.
19:12 cemented. They become what we call by a process. We don't
19:17 Okay, but they're so hard that you put it between your fingers,
19:21 like a shell fragment, you can't it. Okay. And there's actually
19:26 significance to the distribution of these soft hard fecal pellets. We can map
19:32 that have more higher percentage of softer pellets versus hardened and vice versa.
19:39 , I'll come back to this later we talk about our modern environments.
19:43 But we do recognize 2 2 different and they do have some sort of
19:49 significance. Okay, so these are are hardened fecal pellets that I passed
19:56 a sieve off the top of one the borough mounds I showed you
20:00 They survived Clorox scene. And uh know, they're hard. All the
20:06 fecal pellets would have broken down in component lime mud. This is what
20:10 look like, intense section. The composition. The internal composition you
20:14 here reflects the composition of the surrounding because that's what they burned through.
20:20 just that the pieces are smaller. Again. These are not These are
20:24 inter class. These are fecal pellets of their uniform avoid to live soil
20:30 . Okay, and the composition again the composition of the background sediment.
20:39 then here's the favorited fecal pellets we about. Here's an example from the
20:42 of scene. Here's an example from brown, dense at the base of
20:46 smack over. Right. The brown was southwestern target for awhile.
20:52 I don't know if you get involved that. I worked on some of
20:55 for Southwestern. Um So in the , when you see these more rectangular
21:01 dark, my critic features with the striations. That's the favorited fecal
21:06 Okay, that's definitely do that due burning activity by a shrimp.
21:13 here's the problem. You go back the rock record this example within section
21:17 the cretaceous. You see these dark shaped grains here, the tendency is
21:23 a lot of people to call these pellets. All right. But the
21:27 is there's another way to make grains look like this that has nothing to
21:31 with borrowing activity. So this leads into our next group of grain types
21:37 altar grains. You need to know there is a way on the sea
21:43 to create this fabric that has nothing do with biological burrowing activities.
21:49 so let me introduce you to that . All right, so we've defined
21:57 the carbonate communities to find these two p. Lloyd's encrypt a crystalline grains
22:02 up of uniform a critic fabric. . So it's not like the fecal
22:07 you saw before they had Mc ride scattered pieces of shell material and things
22:11 that. Right? This is all a critic fabric. If it's ovoid
22:16 like you see on the left is the P Lloyd and if it's regularly
22:20 it's called a crypto crystalline grain. . And the term P Lloyd actually
22:30 come from the modern, it came people working the Mississippi and redwall limestone
22:35 the Grand Canyon. I don't know you've ever hiked into the Grand Canyon
22:39 you know the as you go down major trails, the upper part of
22:43 of the canyon wall is pennsylvania and and age carbonate. Alright. And
22:49 bright red Mississippi in units called the limestone. and back in the 60s
22:55 were working the red wall and they these little grains of avoid shape material
23:02 we're a critic but they did not any evidence of bio probation or burrowing
23:07 their rocks. So they didn't feel calling these fecal pellets. So they
23:12 the term P Lloyd has this term uncertainty. Okay. And uh now
23:20 is what we use in the rock . All right whenever we encounter grains
23:25 are ovoid shaped. And the critic call them P Lloyd's we only use
23:29 term fecal pellet. If we can the Mcdonald Mcdonald, the donald
23:34 What's your last name? McConnell. . We only call them McConnell fecal
23:42 . Right? If they have that stray shin. Okay. Otherwise we
23:48 the term P. Lloyd, recognizing some of those could have been fecal
23:52 , but they could have also been as a alter grant. Okay,
23:57 understand I'm saying so when I worked rock record, I don't ever use
24:01 term fecal pellet. I call I the term colloidal. Okay, now
24:06 need to tell you how we produce fabric. We produce this fabric by
24:09 process called mechanization. Where we take pre existing skeletal or non skeletal
24:15 And we converted to a massive nick on the sea floor. Okay,
24:21 how do we do that? we take a grain. Alright,
24:26 my fist represents one little sand sized grain, right? It gets deposited
24:31 the sea floor. We know within day or two. It will be
24:35 by micro boring algae and fungi. is what I'm showing in this diagram
24:41 . What do they, what are organisms doing their boring into the outer
24:44 of the grain first to eat the material and they create open holes.
24:50 boring. Right? And then what to some of those micro boring as
24:54 fill in with finally precipitated Mick, sized marine cement. So not all
25:03 cement our big crystals. Sometimes it's shaped cement. Okay, so imagine
25:11 you fill in the outer part of grain. Right? You converted to
25:15 massive Mick right? By micro boring marine. My critics cement you create
25:21 what we call a Mc right Okay. We use this term in
25:26 to characterize that. All right. eventually those organisms will do what they'll
25:30 all the way through the grain and the whole grain to a massive
25:34 Right then we call it a P if it's ovoid shaped or we call
25:39 a crypto crystalline grain if it's irregularly . Okay. And this is a
25:46 that was documented by Canadian dave code Back in the 70s. He went
25:53 to Jamaica. He put out blocks Iceland. Spar on the sea floor
25:58 what he monitored this process for a of years and he saw that the
26:03 synchronization starts within a few weeks or Mick. Right envelope formation within a
26:08 months or less complete grain mechanization within few years or less. So
26:16 this is a very rapid process. , super tender. Sound the
26:21 Right. This is the way we some of the grain types on the
26:24 floor by mechanization. Now what controls ? So let me ask you if
26:31 take a new ID and we're rolling back and forth every day because the
26:35 title agitation, do you think it's to be easy or hard, are
26:40 to make our ties if it's always around, it's going to make it
26:48 for those guys to jump on it attack it, right by micro boring
26:54 . So, in high energy settings things are getting rolled around every
26:58 we have very low rates of Okay. In quiet water settings where
27:05 grain just sit there, low rates sedimentation, high rates of democratization.
27:11 then what else would limit mechanization, burial? Because this is a sea
27:16 process, right? Has operated the of water interface. So, if
27:20 accumulating sediment quickly on the sea rapidly bearing it, whether it's high
27:24 low energy, you're not going to much mechanization. So, you see
27:29 we're used. We're gonna try to the presence or absence of mechanization to
27:34 us understand environmental deposition. Okay, not only do we use the grain
27:40 , but we use the presence or of the mechanization to tell us something
27:45 the environmental deposition. Okay. It's attribute of the environments. All
27:51 So, let me show you how works. All right. So,
27:53 the thin section from some modern Uh, forget where it comes
27:57 Probably south florida. So, I a thin section of a mollusc shell
28:02 and you can see this. You the darker striations that run through
28:07 That's the background. That's what we micro structure. We're going to use
28:11 in our next lecture to to uh this as a mollusc. Okay.
28:17 then superimposed on it. Are all darker smaller lines? Those are the
28:21 or rings. So the screen is riddled with microbe or it's okay.
28:26 so when you look at these fabrics thin section you can hear is the
28:30 mollusc. You see you see the this crystal structure goes to different angles
28:35 each other. That's called the cross miller micro structure. That's characteristic of
28:40 oregano tick mollusc shells. All In fact, I tried to stay
28:45 this. The red stain again is high made calcite. So nothing everything
28:49 not stained red is a reaganite in view. Okay, So look at
28:54 mollusc shell. This is all original, or reaganite skeleton. But
29:00 at the outer part of the grain , where the yellow arrow points to
29:03 how it's being changed to this area nick, right fabric. Acrylic
29:09 It's just confined to the outer part the grain. That's the big right
29:12 . Okay, now look at these grains to the right and left.
29:16 completely transformed to a massive Mick. ? So you see the problem here
29:21 much mechanization does what it destroys the to recognize that grain. Was that
29:28 Wallace, was that a red Was that a coral? You don't
29:32 that's the problem with too much Okay. And we would call these
29:37 crypto crystalline grains here because there are shaped. Alright but let me let
29:42 prove to you that this zone of is due to to do this two
29:46 process of micro boring activity and marine critic segmentation. So let's blow this
29:55 . This is the same thing. . Same area that I just showed
29:58 in the previous slide with the yellow . But now I put the thin
30:02 under the scanning electron microscope and you see there's the original or magnetic micro
30:09 beautifully preserved across the mellow structure. then look at the zone democratisation.
30:14 these little circular holes are the microbe and some are still open,
30:20 But some are filled in with this precipitated mud sized marine cement nick.
30:27 . We call it the critic marine . Okay we'll talk about marine cements
30:32 detail tomorrow. I just want you know that sometimes what looks like
30:39 And the rock record is actually precipitated . Okay. And when it precipitates
30:45 these little microbe warrants, it creates micro envelope first and then eventually leads
30:50 mechanization whole grain. Okay. Mhm. Yeah. All the black
31:00 process this is just loose sediment. I impregnated with a clear epoxy resin
31:07 make an artificial sample to make the section. That's how that's how we
31:13 section. Modern settlement. We put in a box, we had epoxy
31:17 to let it harden up treated like rock cut it polish it put on
31:21 section. Okay. Okay. Everybody what I'm saying here. This is
31:27 evidence that it is due to this biological alteration by micro boring and then
31:33 re precipitation of or the precipitation of . Right? To make the
31:39 Okay, So just to give you flavor for what these things do.
31:45 the here's a pristine what we're going call benthic foraminifera in the middle of
31:50 black arrow points to that it's staying because it's a high magnesium calcite skeletal
31:57 . And you see it's got all chambers in it. That's the micro
31:59 of um ethic for him. Just of little chambers. All right.
32:04 where the organism lived. All May have lived in more than one
32:07 at any one point time. But mechanization here. Next photograph is the
32:12 type of ethic formative for but a angle of cut. And look at
32:16 higher degree of mechanization, right? can see how you still you still
32:20 this a I think foraminifera because you see the chambers, but you can
32:25 eventually this is going to be transformed a crypto crystalline grain. Okay.
32:30 that's the that's the problem with too mechanization. All right. So now
32:37 need to talk about what gets preserved the rock record when you take these
32:41 . Maker ties grains with the Mc envelope. Like I'm showing here in
32:45 diagram here. Right, right make red envelope and also to read
32:52 material, take that out of Either bury it or exposure to fresh
32:58 ? What happens to the reaganite? Reagan? It wants to dissolve
33:02 Okay. And that gives you the molding ferocity, secondary porosity. But
33:08 doesn't dissolve out? The Mc right actually preserves. Okay, so it's
33:12 common in the rock record to see Mc right envelope preserved and then the
33:17 part of the shell in the middle out. Okay, so I want
33:21 to know that that's very, very now. I also want you to
33:26 from the modern, we can demonstrate mechanization doesn't change the shape of the
33:32 . Okay, so a P. . Something like the P. Lloyd
33:37 this, right, avoid shaped, comes from me this I'm sort of
33:47 computer is changing slides on its own , you know, and I've had
33:51 problem in my zoom presentations on my and I thought it was an apple
33:56 . This is a pc. So something to do a zoom trying to
34:02 it by itself. But her power anyway. Yes, here's the point
34:09 trying to make here is that P come from comparably shaped grains that get
34:15 make critized. So we feel pretty that P. Lloyds are either foods
34:20 fecal pellets, they get completely make and transform to mass stomach right?
34:25 conversely crypto christian grains come from irregularly skeletal particles? Because that's how they
34:31 down? They break down two more shaped grains. If they get me
34:35 , then they're going to have this crystalline grain fabric. Okay, now
34:39 can't tell chris, we will never able to tell a crypto christian grain
34:43 from a coral or a mollusc or algae. But we could at least
34:48 that it probably came from a skull . Okay, not a new
34:51 Not a fecal pellet. Okay, there's some implications there for the environmental
35:00 . So here's the problem. You back to the rock record like you
35:03 in this in section here, this from the Jurassic in France. The
35:08 of space is a hydrocarbon productive And some of the production occurs from
35:13 Jurassic grain stones. This one's not because there's no porosity. But what
35:19 you see here? You see mostly that are avoid to lips oil shape
35:24 um a critic fabric. Right. what's the proper term? What should
35:30 call these P lawyers? Right. don't want to call them fecal
35:38 We want to call them P. , which is just descriptive term.
35:42 . We're not implying any genetic relationship . All right. And so,
35:49 could we go a step further? we actually get to figure out what
35:52 is the what is the origin of of these p lloyds. Well,
35:55 can you can do that by looking these other grants are. Look at
36:01 grains of comparable size and shape that have a new ID coding preserved
36:06 You can actually make the case that is a transition from foods to partially
36:10 ties. Do IDs to completely make ? Do It's so some of these
36:15 lloyds are probably just completely make critized IDs, but we don't know for
36:20 because we weren't there during the Jurassic to see this operate on the sea
36:25 . So that's why correctly, we just call these all P lloyds.
36:29 you could surmise, right that these probably make critized. Do it's right
36:35 they were fecal pellets, what else you need to have in the environment
36:39 get a lot of fecal pellets, mud. Right. You have to
36:44 lime mud accumulating on the sea But what's between these grains? What's
36:50 these grains is what we call translucent safari calcite. And usually when
36:56 see the calcite confined to areas between grains, this is a reflection of
37:01 precursor primary porosity with no mud spent in with cement, Poor filling
37:08 Okay, so that would further argue these are probably not fickle pillows,
37:13 ? Because there's no Mick right in sediment. Now, contrast that with
37:18 sample here from the cretaceous. You see some of these some of these
37:22 shapes are very distinct, distinctly formed shaped other ones are sort of vague
37:29 here. All right. The dark did you see here are not
37:33 They are air bubbles in the thin . All right. But look at
37:39 at areas up here in the upper of the thin section highly MMA
37:43 Right. You've got a lot of critic matrix here. Now again,
37:46 correct way to characterize these grains is call them P. Lloyds. But
37:49 you could look at the outcrop from the sample came from, you'd see
37:55 structures in the outcrop. And so likelihood is that most of these are
38:00 fecal pellets. Right. But you know that for sure. So the
38:04 way is to call them all Lloyds. And then when you're writing
38:08 your report you would surmise. I a lot of these P lloyds were
38:12 probably fecal pellets right? Originally because muddy and I've got evidence of burning
38:19 . Okay. You play it that . Okay. Everybody understand how we're
38:24 these terms crypto crystalline P. uniform a critic matrix or or mass
38:31 on the basis of shape. No implication as to origin. Although there
38:36 some crude relationship as I alluded But again, in the rock
38:42 we always use the term p Cryptic kristen grain. Okay. Uh
38:47 . Yeah, they could be part the critic matrix because the soft ones
38:54 do what squish. Right. Remember hard ones I said you can't
39:00 So go back to that previous I would say the ones that are
39:04 distinct here. We're probably the hardened pellets. And they're going to maintain
39:09 shape. But look it up just above that air bubble here.
39:13 can see vague outlines of P You can sort of see a vague
39:19 outline there. I would say Those probably the softer fecal pellets that are
39:23 to do what they're going to start squish during shallow burial. Back into
39:27 component line mud. I'm going to you this from the modern uh
39:33 Okay, we'll see this happens during few feet of burial. This stuff
39:37 start to squish back to the component mud. If it's soft fecal pellet
39:44 . All right. Heard of Part of it's mud, part of
39:50 screen Pakistan. Whereas Grant supported Pakistan it's more mud supported With more than
40:01 grains. Right. Which I think have more than 10% grains making a
40:05 rock. We'll go through this tomorrow . But uh All right. Any
40:12 about the altar grains then the last type would be the coda grains.
40:20 we break out three types to its and pies lights. So what's the
40:24 ? Well, fluids are coated grains have a have a nucleus and the
40:30 can be anything from a P. to the skeletal particle to a court
40:36 . Alright. Doesn't matter what it . So it doesn't have to be
40:39 carbon a nucleus. There are lots foods in the rock record. They
40:43 courts nuclei but by definition they are And they are less than two in
40:54 . And we think the coatings which crystalline. We think that the coding
40:59 formed by direct precipitation out of the of seawater. Okay, So in
41:04 words, the origin is physical chemical . Okay. We don't really understand
41:10 it is for even though we've been for 70 years now. All
41:16 We don't actually understand how you create coatings, but it's pretty clear from
41:22 environmental setting that has to be due some sort of precipitation process.
41:28 It's not mechanical accretion. That's what saying. All right. And then
41:34 would be the other type of A green where you have a
41:38 But now the coatings arm a critic crystalline. And they represent mechanical entrapment
41:44 mud around that nucleus. Okay. basically what acolytes are are the unattached
41:50 of what we're going to call stromatolites the next lecture. Okay. Where
41:56 attached to the outer part of the and they trap that MMA critic material
42:02 then those grains periodically get rolled All right. So one is mechanical
42:09 and one is precipitation. Okay. then piss a light. The way
42:14 going to use the term pies. is as a coded grain Irrespective of
42:21 greater than two in diameter. And reason why I'm doing that is because
42:27 all pies. The lights form in settings. You can have pies,
42:32 associated with soil profiles or cal right. Non marine settings. You
42:39 have things like K pearls in a system that are big goods but they
42:45 form in marine water. Right? form in fresh water. Okay.
42:49 so I'm suggesting you use the term a light as an adjective to modify
42:56 goods or big uncle lights. And definition, I've never seen, I've
43:01 seen a modern uncle light smaller than . Okay. And that's more than
43:08 across. So by definition all acolytes pissed politic. Okay. But sometimes
43:14 users get big, They get bigger two. And so you want to
43:19 pays a political fluids in order to those big rue. It's okay,
43:24 let's just look at some examples So let's start with you. It's
43:28 . We recognize today. two types fluids when we call tangential structure,
43:34 we call radio structure and both of have a nucleus of either carbonate
43:41 So scalpel material, P Lloyd or , crane. Yeah. And then
43:46 question is, what is the orientation the crystal encodings that's around that
43:52 If the crystals are tangential to the , we call them. We call
43:56 a tangential fluid if their radio. the nucleus is like this and the
44:01 that make up the layer go like for particular. That's the tangential,
44:05 . Okay. And today, 90% our modern news are tangential. This
44:11 what forms today in the Bahamas and Arabian gulf. Okay. Radio lose
44:18 actually quite rare in the modern Um but their common in these evaporate
44:24 blockbuster in settings like the shoreline of great salt lake and Utah.
44:30 And they're the raga netted goods. tent, our radio structure.
44:37 But in marine settings of normal marine , it was always form and persistently
44:43 environments where the water is super expected calcium carbonate. You have something
44:49 which to precipitate, you have persistent . You have water renewal.
44:55 So that's high energy sand body systems the subtitle, that speech is
45:02 Or that's a little bit deeper subtitle you can agitate persistently to make
45:08 Okay, That's what you need in to make a new it. All
45:13 . Whether we understand how we actually the coatings around the nucleus, that's
45:19 the environmental association. Okay. The brains called the new it in the
45:25 the accumulation of food sam we call or Olympic sand. But in the
45:30 record we would say what quality grain or olympic Pakistan. If it had
45:35 mud associated with it. Okay, understands. So here's the couple of
45:44 of modern news taken right off the floor. And you can see the
45:49 bright chinese surface of the zoo IDs think that's a reflection of the polishing
45:57 to grain to grain abrasion, but could reflect active precipitation. The standard
46:04 size of moods. It's the one on right, 250-500 microns, But
46:10 was could get up to over two the modern today. And what's the
46:15 association? The bigger the You the more energetic the agitation on the
46:20 floor. Okay, so the size the woods actually reflects the degree of
46:26 . Okay. And then and then all of our modern uh 10 gentlemen
46:31 look like this. This is a Nichols views to the porosity is
46:36 And what happens when you put tangentially under cross Nichols? Because of the
46:43 of the crystals in the layers. produced this black cross. See that
46:49 cross there. Do you remember this ? Optical mineralogy, pseudo uni axial
46:57 , that's a reflection of that unique micro structure of the code means.
47:02 , and that's how you would prove these were magnetic. I mean,
47:06 can also look at him with a electron microscope to and see that.
47:12 , you would not get this with radio. Who? It's okay.
47:14 would not see the black cross. course the question is whether this is
47:18 to preserve in the rock record Reaganite very difficult to preserve or agonized
47:22 the rock records. So but these tangential Or agony goods. Right?
47:27 is 90% of the us today around Earth. Okay. And then this
47:34 a sediment from the the northwest facing of Great Salt lake outside of of
47:41 Lake City catches these winter storms that through. So you get persistent or
47:47 agitation along that that northwest facing side the of the lake's shoreline. The
47:54 is supersaturated specter, calcium carbonate. so you make goods and that's what
47:58 are what they look like. But thin section, completely different micro
48:03 Right. What are the nuclei? would this what we call this grain
48:10 ? The critic. Oh board Give me a P. Give me
48:16 E. P. Lloyd wright. you P. Lloyd. And then
48:20 other white grains are quartz grains. but had a to that carbonate
48:26 All right. But see their Lloyd's or court screens. But look
48:29 the tangential orientation. So one crystal layer. You can see the crystals
48:34 at right angles to the nucleus. , so that's the modern example.
48:40 an ancient example of a radio fluid the cretaceous in Venezuela. The nucleus
48:46 some sort of little skeletal particle What are you looking forward to call
48:50 ? A new it you're looking for concentric layers of uniform thickness and crystalline
48:57 . And here it is the radio . Right? So the question
49:03 what was the original meteorology? could have been a raggedy to write
49:08 regulator. Who is? There's older that suggests tangential woods are always a
49:17 and radio ludes were always cal Except you can blow that out the
49:23 with the Great Salt Lake example. just showed you right. Those are
49:27 . Who is to show the radio . So you can't use the structure
49:32 infirm in urology. So, when go back to the rock record,
49:36 very difficult to prove what the original was. All right. And then
49:42 , you can see the usually larger coated grains, but the coatings now
49:47 not of uniform thickness. They pension . This is called crinkly laminated fabric
49:54 it's my critic. Okay. And where is this forming? Well,
49:59 let my fist represent a mollusc shell down on the sea floor in a
50:04 water environment. Just sits there and going to sit there until the next
50:09 before it gets moved around. So it's sitting there, it's going to
50:13 encrusted by cyanobacteria, what we used call blue green algae. Okay.
50:19 where they're going to crest the top this. Okay. And they're going
50:22 trap any Mc right in the water gets trapped in that upper coating.
50:27 then a little winter storm comes around turns it upside down. Then you
50:31 it on the other side. So periodic non deposition. And then
50:37 by storms is where you produce these . All right. So uncle it's
50:43 have very strong environmental significance. They in shallow clear water because you need
50:49 Clearwater for light penetration. So the bacteria can grow. But you need
50:55 stable bottom rights on a daily stable bottom means nothing is moving
51:02 So the only time these acolytes roll is during a hurricane or major
51:07 A winter storm. Okay, so a couple of modern examples here,
51:14 one on the right shows the mollusc and then the sheath of santa
51:19 The one on the left. Sometimes nuclei are not so well established.
51:23 you can see the the the this all cyanobacteria and incorporates a lot of
51:30 . Right? Also incorporates shell So don't be surprised to see coarser
51:34 material incorporated into that. That Okay. And then here are the
51:41 examples Jurassic from east texas. These coated grains. If you look at
51:47 coatings, just trace the coatings they and swell. It's a dark Irma
51:53 fabric here, here's the thin So there's a nucleus. Most of
51:57 nuclei are pieces of shell material and look at the dark coatings, they're
52:03 and thinner. They got some admits grain material but their democratic matrix.
52:09 ? So these are coded grains but acolytes because of the critic coding.
52:15 ? So they don't form in a high energy setting even though some of
52:19 acolytes and the rock record as big my fist. Okay. So this
52:26 one of the things I told you forget your plastics concepts. Right.
52:30 classics you equate grain size with Energy. Right? But in carbonates
52:36 because the grain is big, doesn't to form a high energy setting.
52:42 . Because yeah, this is a grain but it had a lot of
52:44 . Right. And a lot of and the density probably wasn't that much
52:49 than seawater. Okay. So it didn't take a lot of energy to
52:53 it around. So we have to careful about using grain size and carbonates
52:58 and for energy. All right. then sometimes we actually see the filaments
53:04 in the rock record. That's a a clincher that this was cyanobacteria trapping
53:09 of that. The critic fabric. . And then pies alights. I'm
53:15 again, we use it as an to modify course of grain. New
53:19 or or Uncle is greater than two diameter, recognizing the people also talk
53:28 so related pies. Lights and they cave pearls, Freshwater pies. The
53:34 . Right? But when we're talking marine coded grain Sanka lights or fluids
53:40 they're greater than 2 mm Modify that calling them pies elliptic if they're greater
53:46 two. So there's a famous example west texas, I don't know if
53:51 ever been out to the Guadeloupe national , but if you uh if you
53:56 to the national park and you go the famous geology trail now that you
54:00 walk up the front of the mountains the national park, you'll come across
54:05 map, a bill faces belt that like this. And these are big
54:12 and you can see the scale Some of these are More than 10
54:16 there, a couple of cm across scale. They're and they're interpreted to
54:21 formed by physical chemical precipitation. All . So there are fluids, but
54:26 big woods. So they're pixelated Okay. You would call them pays
54:30 lot of goods. Okay. And this last example here or division
54:37 Most of these bigger grains were inter to begin with. But you see
54:42 they took on a uncle. It'd see this. So their acolytes with
54:49 class nuclei, but they're big, ? They're well above 2 mm in
54:56 . So what does that make them allergic? No, not do its
55:04 like uncle lights. Right. Because are not crystal encodings. These are
55:10 critic codings reflecting entrapment of Mick, ? By santa bacteria. Okay.
55:19 questions or comments? I'm throwing a of terminology at you. It's my
55:23 in the next couple of days to this. And trust me, I'll
55:27 that. We'll start to see how all fits together within the context of
55:32 sedimentary environments. We'll talk about next and then we'll put that into a
55:38 package of sedimentation and and then ultimately reservoirs. Okay. Yes. And
55:49 a spanish language. They use these . Uh huh. I think it's
55:56 standard terminology about the only the only is different than what I told
56:03 He would be the use of the the class. Sometimes people use the
56:07 with the class if they see a particle that's different than the surrounding
56:13 But I used it specifically to be than the surrounding particles. So it's
56:19 little bit more nitpicky detail. But . All right, Danny. Any
56:33 ? Well, let's take a little minute break and let's see if I
56:36 screw things up again here. so we need to talk about the
56:48 types of uh carbonate particles related to breakdown of the skull, hard parts
56:52 organisms we call these skeletal grains. the first slide shows you historically why
56:59 studied skeletal grains first we studied it bios treaty graffiti to age, date
57:06 Our sequences. And then uh when started studying modern carbon environments back in
57:12 50s and 60s, we realize that is a strong paley environmental implication to
57:19 the skull particles. And so we've that organisms are specific to environments with
57:25 to water depth or sunlight penetration or clarity with respect to the substrate types
57:31 organisms for muddy substrates and prefer sandy and prefer hard rocky substrate. Then
57:39 course some organisms like corals prefer high . Right? So greater degree of
57:46 or the other organisms can survive in energy environments. Right? They have
57:49 skeletons and they want to live in water whether that shallow or or
57:54 Okay, and then part of this has to be for you to gain
58:00 appreciation for the morphology of the skeletal , the grain shape because grain shape
58:08 impacts the packing density. And this part of a denims classification scheme,
58:14 ? Determining whether something is grain supporter support to do that. You have
58:18 have some appreciation for the three dimensional of the shape of that grain.
58:24 so you've already seen some uniform leaf grains like goods and p Lloyd's.
58:29 , well you woods or spheres, ? Spheres packed differently together In three
58:35 . than a elongated plati potato chip skeletal fragments. All right, so
58:42 of this discussion has to be giving a feel for the morphology of these
58:46 grains. In fact, that's part what we use to identify some of
58:50 grains. And so I sent you that's gonna be hard to do because
58:56 digital. But I sent you a page sheet on quick look criteria for
59:01 of skeletal grains. And if you pull that up and have it out
59:06 to this discussion, that would be because it's a simple way for me
59:11 try to illustrate the shapes of the kinds of the way the grain
59:16 uh can be used to eliminate certain types and more easily identify other types
59:22 grain types. So anybody anybody access . Yeah it was it was part
59:29 the black as part of the file this lecture At one page Sheet
59:36 And so maybe Angela, you can the read me the the different morphology
59:43 plenty. Mhm. Ah Okay so are those are sort of the expressions
59:58 these different grains and they can be to to identify certain grain types.
60:03 you know there's some there's some overlap . Like the plate grains can be
60:07 but they could be Floyd algae which not a bolus. Alright. And
60:12 this is where you have to look some other attributes and the of the
60:15 type in order to better identify the . But uh we'll try to we'll
60:21 to use that as we go through uh work our way through these different
60:25 types. Of course I told you , you know we need to pay
60:29 to the mineralogy. The grains. non skeleton a skeletal are they originate
60:34 high made calcite or low mad calcite that is one of the drivers for
60:39 genesis, right? A reaganite uh to dissolve as you'll see tomorrow,
60:46 doesn't dissolve easily. Heimat calcite loses magnesium but tends not to dissolve.
60:52 , so that's what we're going to attention to the want to pay attention
60:59 the starting meteorology. Now, one I don't want you to do is
61:05 think that we can just jump on grain type and make an environmental
61:11 Right. If I if I if we play word association and I
61:14 coral, what do you normally associate with reefs? Right. Everybody associates
61:22 , reefs. Right. But one doesn't make a reef. Okay.
61:27 fact, if you look at this from the devonian western in western
61:33 Look at the distribution of the corals , relative to where the reef
61:37 The reef occurs along this inflection right? The high energy part of
61:41 platform margin and their corals there. look at the corals extend out into
61:46 deeper water. The coral's actually extend up onto the platform. And that's
61:51 point. That usually you can't just one green type and say, oh
61:55 a reefer. That's a deep water . Or that's a title flat.
62:00 , what you normally have to do look at the diversity of the grain
62:05 . So where do we get the diversity of grain types? We get
62:10 greatest diversity of the grain types Where have open marine conditions. Normal
62:15 Good circulation of ocean water through that . Good circulation doesn't mean high energy
62:21 means good exchange of water. My exchange. Okay. So on this
62:26 , where would that occur? That occur basically where you see the corals
62:30 Sturm atop roids extending back to the . Word direction to the left.
62:36 , That's all open. Marine. where you have normal solidity. Good
62:40 circulation. Some of that, shall ? Energy. Some of that's
62:43 low energy environments. Yeah, Scale the grains quickly. Yeah.
63:00 the quick look. Yeah, that's right. It's so much easier when
63:08 had handouts. You just And a . Um Okay. So, and
63:18 where would be the more restricted part the of this profile? Be toward
63:21 platform interior where you get sluggish you get elevated salinity ease. All
63:27 . So, in terms of skeletal , where would you find the poorest
63:32 always be toward the platform interior, the solidity is, is higher and
63:37 circulation or sluggish. Okay, that's really what you want to pay
63:41 to in the rock record when you're to decide where you drill that
63:45 right. You're looking at the you're trying to decide that I drill
63:49 open rain on front of the platform or the platform margin? More
63:55 This is one of the things you to be looking for. Okay,
64:01 can get fresh water carbonate material. , yeah, Yeah. We'll die
64:10 are suspicious, not curb unaids, you can get you can get cal
64:15 what are called Osterc odds associated with lakes. And we'll talk about Osterc
64:21 as part of this lecture. So now here's the challenge. You
64:27 back to the rock record. You a slab of limestone like you see
64:31 . And you can see some of some of the grains like the corals
64:35 have the have the micro structure pretty preserved. See the correlate structure right
64:41 . So that's easy to identify as coral. But then look at all
64:45 other fragments here, what I've called t the fill Oid algae or called
64:50 Roids. Those are not you without experience. Those are not just
64:55 obvious skeletal particles in terms of their . All right. And this reflects
65:00 fact that I was talking about All of these fragments started out as
65:05 organisms, bigger Skeletor organisms. And what happens is they get broken down
65:10 smaller pieces by the crunchers. This is what stingrays do. They
65:15 shells and break it down. This what nurse sharks do on the sea
65:20 . And then once they get broken into smaller pieces, then this is
65:23 the bar erosion comes into play to it down to smaller pieces and then
65:27 activity related to storms. Okay, the challenges. First of all,
65:34 don't if we could see these particles three D. It would be a
65:38 easier to identify what they were. can only look at them in two
65:42 . Write an outcrop core thin And this this presents a bit of
65:47 challenge. All right. And so challenge is reflected by this diagram here
65:53 shows you a little cone shaped or coolie hat shaped particle. Right?
66:00 of the large benthic foraminifera in the cretaceous have this morphology. They sort
66:06 look like this, right? And several million. Their big relatively speaking
66:10 several millimeters across for scale. Imagine they what that would look like if
66:16 did a two dimensional cross section of angles through that grain. Right?
66:21 you cut it plain A. You a triangular expression. If you cut
66:25 plain B. You get more of lift deuttel cross sectional view. If
66:30 cut it plain see it be more . Okay, so that's the first
66:35 you almost have to remember is when look at all these publications, let's
66:40 you the classical expressions of the different types And the and the best
66:46 Is that a pg memoir 77, think that I referenced in your
66:51 They pick the best examples, If you change the angle to
66:55 everything looks different. Okay, so got to keep that in mind.
66:59 so that's why we pay attention to things like the size some grains are
67:04 very big. Like the foraminifera foraminifera, millimeter scale corals are
67:10 right? It can be big. then if that's not good enough to
67:13 us identify it, then we go to the skeletal geometry and form.
67:18 , that's the quickly criteria. Is potato chip like or play D is
67:23 ? Uh I forget the other I used swiss cheese. I'll explain
67:30 this later. But uh if that's good enough, then you drop down
67:34 the next level, which requires thin . And you look at the preserved
67:40 and you look at the orientation the in the skeleton. That's called micro
67:46 . And fortunately that turns out to pretty definitive in differentiating these different groups
67:52 molluscs from bracket pods or corals from atop roids. Right? So,
68:00 then mineralogy comes into play in terms the preservation state. Anything that's originally
68:06 tends to be highly re crystallized or out. Anything that was more calcifications
68:11 be very well preserved. So sometimes helps us identify the grains.
68:16 so here's a here's a gastro a big gaster pod and you can
68:24 the ornate spines that come off of castor pod, a gastro pod has
68:28 central column and then the open pore just whirls around it. Like
68:32 It's all open pore space. So you were to cut this right down
68:36 middle, In cross sectional view. see this open whirling four space,
68:41 ? It would be easy to identify a gaster pod, right? Based
68:44 this and the size of the hole and the way it's oriented. But
68:49 if you just cut it off to side or you just cut through the
68:54 ? You would never know that's a pod. But you would know from
68:57 micro structure of the spines that that a mollusc, which is what they
69:02 part is a type of mollusk. , so at least you could identify
69:05 as a mollusk. Alright, Because micro structure is the same in the
69:10 as it is in the main part the body fossil. Okay,
69:15 in your notes that I sent I did this for every skeletal grain
69:20 . I put a summary sheet that like this that shows you the age
69:25 . You always have to pay attention the age, right? Because some
69:27 these organisms are through going all through fan or is OIC. So from
69:33 and all the way up to But some organisms come and then they
69:37 and then they come back. Or sometimes they never come back.
69:41 right, so, you have to that in mind. And then I
69:44 you what we think the starting meteorology . I give you a description.
69:48 give you environmental significance. And then we think is good diagnostic criteria.
69:54 , again, this is usually based your scale of observation whether it's your
69:59 versus thin section. Okay. I'm not going to show this for
70:06 of the groups that I go but you have it in your slide
70:09 okay. Because I'm gonna I'm gonna from From diagrams that look like
70:14 So we've only got 15 minutes left . So let me work our way
70:18 the first couple of groups here, we'll break for the day and pick
70:22 up tomorrow. But so let's start the foraminifera, right? For a
70:27 for single celled organisms that secrete a curious structure called a test. Most
70:34 are tiny millimeters scale, right? tests are multi chambered, like you
70:42 illustrated here. All right. So start out with one chamber, then
70:47 grow another chamber, then they grow chamber. Now the question is,
70:53 they live in all the chambers at same time or they move from one
70:56 the other? Who cares? They a multi chambered aspect. Okay.
71:03 I don't know the answer by the , whether they live in all of
71:08 at one time or they grow from they moved from one to the
71:10 But they probably moved from one to other To be on the outermost
71:14 So they can feed. Right? but so what's diagnostic small scale for
71:21 of these? Multi chambered aspect. . But then what's different? There
71:27 two types of farming differ. There the floaters that we call plankton core
71:32 tonic foraminifera. All right. And do they look like? They look
71:36 this globo's they look like a That blue box morphology is adaptation for
71:43 . Okay, because they're floaters, live in the upper part of the
71:48 column, not right at the They have in the upper part of
71:50 water column. And but they live deeper water. Okay, in the
71:56 water setting, they don't live in water to live in shallow water,
72:00 then when they die, they settle deeper water. Okay. And they
72:05 cal siddiq, their low mag which produces more of a light colored
72:12 glassy. My infrastructure. Okay, globo's millimeter scale glassy structure, its
72:22 of planting formative for. Okay, then what's the limitation age word?
72:30 don't exist in the paleozoic. So you were paleozoic rocks, you're never
72:33 to counter plankton foraminifera. They don't until the upper part of the
72:39 They really don't become common until they part of the Jurassic. Okay,
72:43 course, today they're everywhere in deeper settings. Okay, now the benthic
72:49 the other type. Benthic means they in the sediment or attached to something
72:53 the sea floor. The benthic are the small benthic. Foraminifera are all
73:00 made calcite, which produces a dark critic micro structure that's a primary fabric
73:07 not a byproduct of mechanization. so when you see tiny multi chambered
73:14 with a dark my critic micro Those are benthic. Foraminifera.
73:19 not floaters now. What's the exception the exception of size is when you
73:25 to the upper paleozoic, you get are called fuselage needs right? And
73:32 can see the this few selected shape . Use the form shape,
73:37 Looks like a cigar sort of in sectional view. And these are
73:44 These are centimeters scale. They're too to be floaters. Alright, so
73:49 still benthic, but they're not heimat there. Loma calcite. So they
73:54 a glassy micro structure generally. All . But some can be my
74:00 That's the problem. All right. of course when you pick them up
74:04 , you pick them up in the . When you come out of the
74:07 cretaceous into the lower tertiary. You the you come back into these big
74:12 foraminifera with this fuc form shape. famous one is normal. It's
74:18 It's is what makes up the lime that they the sphinx is made out
74:23 and the pyramids are made out of Egypt. Okay. All right,
74:28 so let's look at some examples All right, so modern.
74:32 So this is Yes, the Well, they don't come out of
74:47 . They don't come out of the like a hermit crab gets rid of
74:50 shell and finds a new one to into it. Show you have to
74:55 seven. Sure show up. Yeah. There's the treaties the treaties
75:09 right there. So you can take look you know I just don't
75:14 I mean I think that I think probably integrated. Yeah. Well it
75:19 to be in the shell. Yeah. I mean sir it's a
75:31 well you take an oyster out of shell is going to die and you
75:35 a Sure. Yeah. Mhm. . School. Mhm. No.
75:55 they don't make them they looking to this thing busy stuff. Mhm.
76:05 . Herman's hermits just cannibalize somebody else's . They move into it so they're
76:10 body crabs that have to live in shell for protection. So then I
76:15 eaten. Mhm. So. Yeah. Okay so benthic benthic foraminifera
76:30 can see here they're multi chamber. relatively small scale. This is what
76:35 of the modern ones look like in section. They would look like
76:39 You would see dark critic micro structure primary fabric related to the climate
76:44 The original heimat calcite. You see multi chambered aspect. Most of these
76:50 have 5-7 chambers internally. Look at orientation how it changes if it's if
76:56 has this american football shape look longitudinal . You see it like this.
77:02 if you cut it sideways it looks this. Okay so you have to
77:06 that in mind that the the two appearance will change depending on the angle
77:11 cut. All right. And then you come into the upper paleozoic.
77:15 Mississippi and pennsylvania and per man. is when you get the fuselage
77:20 And there's some debate about the starting here because all the ones that I've
77:26 seen have this uh Dartmouth critic micro . And to me this suggests is
77:32 more high made calcite to begin Okay, so for these upper paleozoic
77:38 , but when you get into when you get into the tertiary,
77:42 evolve into these larger forms. Like see here, this is normal.
77:47 right. I mean, these are . I mean, these things are
77:49 big. You could you could throw as a skipping stone across the
77:54 But look at look at their still chamber. Right? Even though they're
77:58 and in thin section, this is a normal. It's but I have
78:04 in your in your notes that are it's But this is another different type
78:09 like Lena. And you can still the same relationship multi chamber. But
78:13 look at the lighter, the lighter here. These are low mag calcite
78:18 more of this glassy structure. And why they why they're low mad calcite
78:23 begin with. It really doesn't make difference whether a slow mag mag cal
78:28 , they're still going to preserve pretty . All right. So you're gonna
78:33 this multi chambered aspect, well preserved the rock record. And then the
78:37 take foraminifera. This is again a example here. Uh some of these
78:43 little spikes that come off of their that don't preserve. But the takeaway
78:48 this photograph is again a small right? Usually less than a millimeter
78:52 for scale glow boasts or balloon shape , adaptation of floating. And then
79:00 know from the modern that these things live right at the top of the
79:05 column. They all want to get blasted. Okay. They live down
79:10 the water column and the average step you see from this diagram here Is
79:16 80 m. They go anywhere from 22 to 200 m of water
79:21 That's where they like to live. of course when they die, they
79:24 down into even deeper, deeper And then the other observation is if
79:29 on the modern day shallow water carbonate And trust me, I've looked at
79:34 from from all the modern ones in Caribbean. You don't find pelagic foraminifera
79:40 water depths less than 10 or 15 . Okay, so they stay off
79:45 platform. Yeah, Right in the from 15, 20 m of water
79:50 down to about 200 m of water . That's where they live.
79:54 so they actually have very strong environmental in terms of being placed in that
80:00 environment. So here's a couple of examples here. You look for the
80:06 size again, that is 250 microns scale there. Look at the balloon
80:12 or globo's morphology. Small size white micro structure of the test. Because
80:20 is low might calcite material. All . And then ancient analog. This
80:25 from the austin chalk in south You can see again the same
80:30 the same size. It's just The shell structure is what the arrow
80:36 pointing to. Its the white outer layer. And then this is later
80:41 cement in the middle that filled in ferocity. Alright. So, after
80:45 organism dies, the organic material You're left with open pore space
80:50 It filled in with the glassy calcite . Okay. Alright. I think
81:00 just call it a day here. for me to start with the next
81:04 of colonial organisms and and just do all together. So, you
81:08 the difference is all right. I can't talk you into doing virtual
81:16 . Okay. Okay, well, . All right. Yeah. Or
81:22 you want to push it back? do you guys been doing?
81:27 Been doing at 8:30. So go 30 - five. We gotta tell
81:35 . I don't care. No, stick to it. I'll stick to
81:41 . I stick to schedule. It's It's just I want to know when
81:46 starting. So, I know when stopping the schedule set up for 8-4
81:50 . If you want to do a then we'll just push everything back to
81:53 . But uh we'll finish uh A 30. You don't care.
82:06 . Okay. 8 30 here tomorrow . Hopefully we don't have any more
82:11 with this. But now I know tie we got your computer bring it
82:17 in case we'll try to I'll tell what if we can't project, I'll
82:24 my own projector that I know runs of this and we can project it
82:29 the screen, so All
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