| 00:00 | You're having lunch. No, not . I'll have to go through |
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| 00:04 | But I feel pretty good about There's some things I need to read |
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| 00:07 | but I don't I don't feel So I am a great teacher. |
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| 00:11 | that what you're saying? Yes. all great until the grades come |
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| 00:18 | I know how that works. Um . So we're at the halfway |
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| 00:25 | aren't we? This is five right? Yeah. And then I |
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| 00:31 | you said he had a question, question about the exam next week. |
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| 00:36 | how would it be like next Next friday. Hello, Can you |
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| 00:47 | up your volume or something? It's you speak very softly. I can't |
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| 00:52 | you hear me now? Yes. how will the exam on next will |
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| 00:58 | like, so do I need to the exam? No, I don't |
|
| 01:05 | so. What I think what I envisioning was that um I would send |
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| 01:11 | the lecture, you know, at or maybe a little bit before |
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| 01:16 | And then I would just be, mean, maybe we could just launch |
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| 01:22 | , launch the whatever the the But you don't need to record |
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| 01:30 | But I'll just sit here and I'll whatever, do my work. I'll |
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| 01:35 | muted and everything. But it definitely a question she just asked me and |
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| 01:41 | I'll be sitting here. I'll answer and then I can just go ahead |
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| 01:45 | proctor it that way and you can like have the day off. I |
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| 01:49 | unless you want because you don't really to. I don't think it needs |
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| 01:51 | be recorded. What do you Yeah. Yeah I think I will |
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| 01:56 | there and yeah I will not record exam but I mean I mean I |
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| 02:03 | you need to be around to start meeting I'm afraid if there is any |
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| 02:09 | taken an issue like the connecting probably can help solving the problem. Okay |
|
| 02:16 | that's what I was thinking. I just go ahead and send the send |
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| 02:20 | exam Stephanie and then I would you launch the meeting or we would join |
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| 02:26 | meeting or whatever and then and then would just like you know make sure |
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| 02:31 | sitting around here for three hours waiting for stopping to finish and then um |
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| 02:38 | I don't care if you take a bit longer either. I mean you |
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| 02:41 | but it's gonna be just from the and the lectures but you know |
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| 02:45 | I'm just lecturing from the notes so all in there and I mean I |
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| 02:54 | I could do like a take home then I don't know, I mean |
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| 03:01 | would you would you prefer just like have a take home or something like |
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| 03:04 | ? I mean yeah. Do you the time limit was because it's it's |
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| 03:12 | be over just the first four What's your sense, what do you |
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| 03:17 | to do? Stone? Um I it let's see because I know when |
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| 03:22 | had when I did with a doctor he like sent it to me at |
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| 03:28 | I did my final he sent it me at like what was at six |
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| 03:33 | then I just needed to have it to him like email back to him |
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| 03:37 | nine. But then when I took Thompson and dr they just kind of |
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| 03:43 | it to me like the day before they just wanted me to send it |
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| 03:46 | to them the next day by midnight I don't really care. I'll try |
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| 03:53 | send it to you either I'll send to you thursday evening or friday morning |
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| 04:01 | you just give it back, send back to me you know the next |
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| 04:05 | before before class. How's that? so before Friday at one I will |
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| 04:13 | it to you either friday morning or evening, something like that. And |
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| 04:19 | just have to have it back to before class say saturday morning. |
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| 04:24 | Yeah that's fine. That's perfect. so that gives you you know lots |
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| 04:28 | time. I mean I'll try my to get it to you thursday |
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| 04:32 | Okay that's probably when I'll write it fine because I work Friday morning |
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| 04:39 | I usually work from like 8-12 that so that's okay. Okay then all |
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| 04:45 | . All right we'll do it that then I'll just send it to you |
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| 04:48 | that way you don't have to pry don't have to Proctor or anything like |
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| 04:51 | because that doesn't, that kind of a little pressure off you. I'd |
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| 04:56 | have the questions be right than be and you know, you get something |
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| 05:01 | up and I think you're mixed up something and when you're really not, |
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| 05:04 | just, you're just panicked. So , do it that way. I |
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| 05:08 | , you know, I mean it's , it's not like right. That's |
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| 05:15 | I'm saying. I mean, you are the you are the whole bell |
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| 05:20 | and so yeah. Anyways, we'll just do it that way then |
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| 05:29 | I guess we'll do it the same for the final. I'll send it |
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| 05:33 | you maybe Tuesday and then you just it to me by whatever, midnight |
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| 05:39 | or something like that. Okay. , that'll work. Okay. And |
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| 05:44 | the exercise has to be do the because your license is your license only |
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| 05:48 | till the 14th. Anyways, I . Okay. I think. |
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| 05:59 | Anyways, but the exercise will be . I mean, you can finish |
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| 06:04 | right away if you want. I it shouldn't be difficult. So |
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| 06:08 | so we got some of the logistics those things sorted out and you said |
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| 06:14 | didn't have any questions about my excellent for the this morning. So let |
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| 06:22 | just see here. So we can into. So this is where midway |
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| 06:27 | , right? This is the we the crest and now it's all downhill |
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| 06:32 | here. Is that right? Because there's 10, 10, 10 |
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| 06:41 | , right, eight lectures plus two . I see latin things, you |
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| 06:49 | , we're fine. Yeah, I think we're like halfway. |
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| 06:56 | alright, then. So now we're jump into the Wilson cycle or the |
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| 07:02 | kind of cycle, we're gonna look the phases. The first phase is |
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| 07:07 | basis that are, that are produced extension. Let the spirit crustal extension |
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| 07:15 | the first one is is rift Okay, so There's a couple of |
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| 07:22 | models, the classic models, the Shear is the is the classic one |
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| 07:27 | called Mackenzie and he wrote a famous in 1978 that's still cited today, |
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| 07:36 | some remarks, some remarks about but it starts some remarks. |
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| 07:41 | if you ever wanna be cheeky, can start your paper with some |
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| 07:46 | Uh, anyways. Um, but before we get to pick your |
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| 07:52 | basins form by extension, a little tectonic forces And rift bases are on |
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| 08:00 | order of a couple 100 km They, and they can be hundreds |
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| 08:04 | kilometers of links and they're generally up about seven km in depth. In |
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| 08:11 | , most atomic bases do not exceed km in depth. Passive margins are |
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| 08:18 | little different because there they sit atop and oceanic crust together, so they |
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| 08:24 | much deeper. They are the deepest . But most bases including risk seven |
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| 08:30 | is really an upper limit. There some that are deeper but that's kind |
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| 08:35 | a number you can you can stick your head. And of course they're |
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| 08:40 | by rotated fault blocks is mythic flows you know you're cracking a little sphere |
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| 08:46 | you're getting some volcanism associated with that . And so the two main geodynamic |
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| 08:55 | are pure shear and simple shear kevin who who passed away recently was a |
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| 09:03 | at University of Houston, very famous . Um He used to say that |
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| 09:09 | of them is pure nonsense and the is sheer nonsense but in any case |
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| 09:16 | in pure share you have symmetric stretching rifting as the figure down below um |
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| 09:26 | and um it is partly replaced by estamos fear that gradually cools over 5200 |
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| 09:35 | years. As it cools it becomes dense and subsides, right? So |
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| 09:39 | amount of subsidence depends on the amount stretching which is the beta factor. |
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| 09:45 | it's the initial with plus what's been to it by stretching over the initial |
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| 09:52 | . So this was the one that was that I was referring to when |
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| 09:58 | was showing you Nyla Dowler's study the fit reconstruction of the central atlantic. |
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| 10:04 | has a map where she calculates beta the all the extended crust. But |
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| 10:11 | the idea that's the idea the X dx over X. And that's pure |
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| 10:18 | . Now simple shear question real Yeah why why is it called like |
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| 10:27 | ? Because I got I thought shearing just more of like like a term |
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| 10:32 | for I don't know like breaking or like that. Like like a transform |
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| 10:37 | a transformer sort of right like Um I think I think the I |
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| 10:45 | because when you stretch your deforming and this boundary there there is sheer along |
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| 10:55 | this these these faults are sort of they're they're you know they're there ah |
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| 11:04 | rotating around. Yeah I think it's bad I think it's a bad word |
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| 11:09 | I'm trying to figure out why it because when you're stretching the crust this |
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| 11:14 | I mean okay in the in the the upper crust it deforms brutally and |
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| 11:20 | the lower crust it deforms duct really stretching play doh or gum. And |
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| 11:28 | motion um Is I guess sheer. . Yeah that's a good question. |
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| 11:37 | I guess it's not a particularly good word. Um Okay so simple shear |
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| 11:45 | that you have low end detachments on surface but they're offset from the crustal |
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| 11:51 | . So you have something like And in fact this mechanism I think |
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| 11:56 | most is very common. I don't there's a lot of simple shear going |
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| 12:01 | . I mean there's a lot of sugar. I think there's a lot |
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| 12:03 | simple shoot. So this idea was proposed by bryan Warnecke as an explanation |
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| 12:10 | the formation of basin range deformation. great basin which is mostly Nevada and |
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| 12:16 | extending north and south from there. Yeah, so with regard debate, |
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| 12:26 | kind of a substitute crustal thickness for the sphere thickness. But it can |
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| 12:31 | problematic because think about this with with to gravity data, we go back |
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| 12:36 | the first year, you're gonna have that are sort of symmetric over this |
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| 12:42 | , right? You're gonna have maybe broad high related to this upper |
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| 12:47 | right? And then you're gonna have on it. You're gonna have some |
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| 12:52 | attitude anomalies that are, you showing these these sort of riff structures |
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| 12:59 | it. We'll see some examples and get the sense of it. But |
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| 13:03 | idea but the gravity signature would be . But in in simple shear you're |
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| 13:09 | to have a broad hide related to . That's offset from these anomalies. |
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| 13:14 | produced by these uh rift blocks over . So that's something that's important with |
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| 13:22 | to gravity Magnetics. Um Right, now there's kind of a kind of |
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| 13:30 | uh simple shear. Um Well what it? Yeah, okay, this |
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| 13:40 | a typo um It should say simple because this is like simple shear just |
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| 13:48 | with with a detachment, with a detachment, right? With this one |
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| 13:53 | connected. But if you detach and you along some horizontal in some horizon |
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| 14:00 | basically horizontal between the brittle in dr . You can form what they call |
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| 14:06 | core complex is or delamination, that of thing. So I need to |
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| 14:12 | a note um root. Mhm. is lister. And then so I |
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| 14:26 | to correct that I should say something right so but basically it's the same |
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| 14:31 | of idea as more Nikki except that more it's even more of delamination or |
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| 14:39 | detachment along some horizontal plane. But maybe this is just more simple |
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| 14:47 | . I don't know. Okay now a really important paper here that was |
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| 14:52 | in 01 by Jalal Bangor who got Bachelor's degree at U. Of |
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| 14:57 | Um In fact I think he didn't it. He just he just went |
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| 15:01 | um he went to some big he's the guy is a genius, |
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| 15:06 | brilliant and I think he recognized that his talents were pretty great. |
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| 15:14 | He he did go to U. H. I met him one time |
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| 15:20 | they did this study him and his here Boris in Ethylene in Turkey. |
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| 15:26 | did a study of all the risks the world and they found 568 active |
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| 15:33 | passive and they categorize them and tabulate . So there's and down here you |
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| 15:38 | this to 90 and raised 101 in 11 Australia, one in New Zealand |
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| 15:44 | North America 68 South American 16 Alright so here's where they all |
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| 15:51 | And um in here he's got a areas where he's drawn boxes like this |
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| 15:58 | area here around the caribbean and I just more. Yeah this one right |
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| 16:04 | uh in uh Alright this big one all of europe and everything and he's |
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| 16:11 | and numbered them and he has duplicate in this stuff. So it's not |
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| 16:17 | simple figuring this out. You can this table but yeah so here's here's |
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| 16:23 | example, so he starts here and has 123. But then he has |
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| 16:27 | can go up here and you can like 123. So it's not really |
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| 16:31 | in any case I think that's how works. But this is his classification |
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| 16:37 | . He has active and passive. um and then he explains them in |
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| 16:44 | of he has this nomenclature K. G. Which stand for different |
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| 16:50 | Um And then he has passive here he has A C. K. |
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| 16:58 | . And then K. 21 22. And then so so each |
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| 17:04 | right? He adds, he adds is so for these is K. |
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| 17:09 | is K. 31 32 33. . 4 41 42. And then |
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| 17:15 | adds 411412. So that's the that's idea. So 41 411 r sub |
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| 17:22 | related riffs that are related to convergent uh convergent play Bondi risk that are |
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| 17:38 | . They're not not time margin. is the status of the rift. |
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| 17:41 | other words, their fossil, they're moving anymore. And so. Right |
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| 17:47 | there's subduction related collision related. So anyways we're gonna look at some |
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| 17:52 | these, we're gonna look at the . Two which is an inter plate |
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| 17:57 | active the gulf of Suez, that's active rift right now and it's a |
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| 18:03 | . Two. Okay. And then gonna look at Newark rift which is |
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| 18:07 | which is a pat which is It's it's a fossil rift. It's |
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| 18:12 | the east coast of the U. . As the name implies. And |
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| 18:17 | has with previous domes. So it's rift that form down a dome I |
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| 18:22 | . And um. Oh I No, the dome ng is related |
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| 18:25 | the atmospheric uplift. Right? So one didn't have it I guess. |
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| 18:31 | what that's saying. And then trans all riffs and the west antarctic falls |
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| 18:38 | that category is a trans dimensional rift . G. Four. And pull |
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| 18:45 | rift clusters. Another G. Right? Oh yeah. Alright, |
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| 18:50 | riff stars are G. Two rift . The G three rift clusters are |
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| 18:54 | four rift ness R. G. . Indeed. Yes, that's how |
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| 19:01 | works. Yeah. Okay. So gonna look at the Rio Grande as |
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| 19:07 | and that falls under two categories 411. And it could be a |
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| 19:13 | cluster or rift chain chain. I so. And then we're gonna we're |
|
| 19:19 | look quickly at the rain grab. some of these just, just a |
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| 19:24 | look, but just to show you these things, you know, |
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| 19:29 | they like to classify things. So are most of those right now, |
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| 19:34 | the Newark rift, so this is north America and, and, and |
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| 19:38 | showing you this because I just want to get to get a feel for |
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| 19:42 | at least understand how complicated they can . Um because you see the, |
|
| 19:49 | Newark rift looks to me to be symmetric, it looks like a um |
|
| 19:56 | , simple shear, right? You got one major fault and you got |
|
| 20:00 | outboard, you know, there's some like that, some, you |
|
| 20:04 | smaller structures inside, but you got main, what we call basin bounding |
|
| 20:09 | . Right? So in terms of and knowledge, what would you expect |
|
| 20:18 | be the biggest, what would what kind of anonymous would you expect |
|
| 20:22 | see over this sort of geometries? do you expect to see? Really |
|
| 20:27 | anomalies. The bigger bigger anomalies I mean, high amplitude anomalies over |
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| 20:34 | basin bounding falls is, I higher amplitude than these. It could |
|
| 20:40 | be. I mean, structural I'm not suggesting with a logic |
|
| 20:45 | what I'm saying In the scope of 10-50 mg range, these would be |
|
| 20:53 | the upper end of that because it's base inbounding funds. The base is |
|
| 20:56 | gonna be, this base is probably here. Any smaller structures will produce |
|
| 21:01 | small amount. Now the Ryan grab looks to me like pure sheer |
|
| 21:08 | You have these two sides that are parallel to each other. And and |
|
| 21:14 | these basin bounding faults would be producing higher amplitude anomalies than these solo |
|
| 21:20 | And also these subtle anomalies in the part of the basin. They would |
|
| 21:25 | producing longer wavelength anomalies too, wouldn't ? Okay, so now we'll look |
|
| 21:32 | the, the gulf of Suez, gulf of Suez rift and that's very |
|
| 21:39 | . It has this series of kind like uh braided sort of riffs where |
|
| 21:48 | like going back and forth. So one, this one looks to be |
|
| 21:54 | of asymmetric with the deepest part right . This looks to be asymmetric, |
|
| 21:59 | deepest part to the west and then to the east. This is actually |
|
| 22:04 | of a common, this is the that the east african rift works. |
|
| 22:08 | you remember from that figure we looked earlier, the way those different riffs |
|
| 22:12 | , um, they bounce back and . So they're asymmetric, alternating was |
|
| 22:18 | deepest part is to the west and the east and to the west. |
|
| 22:22 | again though the bounding faults, these ones that, that sort of, |
|
| 22:28 | know, that are in heavy, sicker lines. These are probably going |
|
| 22:33 | produce higher amplitude anomalies where the smaller is fine. We'll probably, I |
|
| 22:39 | , I'm just suggesting this based on , this figure will produce lower amplitude |
|
| 22:45 | , be more subtle. And then damn purist, which is at the |
|
| 22:50 | west shelf of Australia. Um It's it's not in uh singers, It's |
|
| 22:57 | in his list here. I couldn't it. I mean, of all |
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| 23:01 | 500 and some odd whatever, 538 whatever there are. Okay, I |
|
| 23:07 | find the damn pier rift in but it looks to be um they |
|
| 23:13 | the extension is this way and it's of oblique. But even though it's |
|
| 23:20 | , you kind of get the sense it's still sort of pure shear. |
|
| 23:27 | , but this sort of gives you idea gives you a feel for the |
|
| 23:33 | of rift basins. And then these , you should should be reflected in |
|
| 23:37 | data, in the magnetic data as as gravity. Um yeah, we're |
|
| 23:42 | we're gonna look, we'll look at , the Rio grande rift. So |
|
| 23:48 | a couple of papers 90 both 1 killer and Cather and one Russell |
|
| 23:54 | Snelson. And so the Rio grande runs through new Mexico starts up in |
|
| 24:00 | in Colorado and then it ends up down into Mexico. And you |
|
| 24:09 | uh you see, um I I think Big Bend Park is actually |
|
| 24:16 | after the bend in the rift. think that's the idea. And then |
|
| 24:22 | course there's the san juan volcanic I think that's what it's called another |
|
| 24:28 | field. Um I'm sorry. san juan volcanic field. It's right |
|
| 24:34 | and then ST louis basin. So are little sub basins in the rift |
|
| 24:40 | . So here's the Albuquerque basin which right here and on on, you |
|
| 24:46 | , I don't know. So there's these little sub basins, you |
|
| 24:51 | and um, there's volcanic fields they're segmented and it's kind of kind |
|
| 24:57 | crazy. All right, So let's at the we'll take the Keller and |
|
| 25:03 | map and Geo referenced it on top topography. So you can see the |
|
| 25:11 | in the topography, right? It's coming down to here. Um here's |
|
| 25:17 | that volcanic field is, It you know, it's in and amongst |
|
| 25:22 | , I guess these are volcanoes. then you have a rift basin |
|
| 25:28 | Albuquerque rift is right through here and there's other rift basins. They should |
|
| 25:33 | farther south. Let's look at it the geologic map. Okay, so |
|
| 25:41 | obviously very recent sedimentation uh, in basin itself. But then there's looks |
|
| 25:47 | there's some cena's OIC volcanism. These center cenizo rocks in the fields, |
|
| 25:53 | volcanic fields are cena's OIC. But look at look at this, you |
|
| 25:59 | some looks like our key and rocks are exposed at the surface in |
|
| 26:05 | which is pretty interesting. So, then and then you have some paleozoic |
|
| 26:11 | as well all through here. So one looks like this might be pennsylvania |
|
| 26:17 | permian. But there's some, you , there's some dark blues in |
|
| 26:21 | So maybe these are devonian or something that. And then of course the |
|
| 26:26 | is Mesozoic. And you can see the Mesozoic that's exposed around here and |
|
| 26:34 | this figures slides right in there very . Really, you can just see |
|
| 26:39 | in here. Okay, so let's at gravity anomalies and you're looking at |
|
| 26:46 | bouquet and it's probably an upward continuation that's the only kind of residuals. |
|
| 26:52 | do. So, so that's probably it is. But here's the Albuquerque |
|
| 26:57 | . And then here are these are produced by the basin bounding faults. |
|
| 27:01 | you can see what I was talking , see how prominent these anomalies |
|
| 27:06 | right, you're not big like this here, but they're prominent and they're |
|
| 27:11 | and there's, you know, and look at the volcanic field, |
|
| 27:16 | big gravity low. Maybe these maybe these rocks are very forest, |
|
| 27:22 | is why you have a, you , a gravity low there because what's |
|
| 27:26 | what's the density correction for bouquet? density do you always see? Um |
|
| 27:36 | .777 .67. Okay, so if corrected, let's look at the |
|
| 27:45 | if you corrected this high and you that that was Due to 2.67 and |
|
| 27:53 | was really due to two points, was really 2.3, what would that |
|
| 28:05 | if you're Blue gay correction was too ? If the correction was too |
|
| 28:12 | then you'd be over correcting. Remember Nettleton profile over correcting and so it |
|
| 28:22 | produce a low I think. So that's what's going on there. |
|
| 28:29 | thing with these volcanic fields here. very interesting maybe down here as |
|
| 28:34 | This, see, I'm looking at character here and I say this looks |
|
| 28:39 | little bit like that. That looks little bit like that. And in |
|
| 28:42 | , this looks a little bit like . So even though they're not mapped |
|
| 28:47 | here, my guess would be that are also volcanic fields, but this |
|
| 28:53 | actually shaped more like that. But just don't, they're covered right there |
|
| 28:58 | with whatever, you know, senate or something like that. So they're |
|
| 29:03 | not there. But you can like I said, you can still |
|
| 29:08 | , uh, this is a bounding and it looks looks like everything's offset |
|
| 29:13 | , but not according to this Hmm. I wonder what that |
|
| 29:18 | Okay, let's look at the magnetic R. T. P. That |
|
| 29:23 | RTP. So on the left, can see the, I guess I |
|
| 29:27 | the figures on the same side. . You can definitely see the volcanic |
|
| 29:33 | here and same thing up here. at this down here. See, |
|
| 29:36 | telling you. I think that's it . What does it mean? What |
|
| 29:40 | you think these are volcanic? They're be magnetic. Why is this |
|
| 29:45 | What's going on? Why is this is all the volcanic producing not only |
|
| 29:53 | could it be because of is a thickness in that area? Like we |
|
| 30:00 | talking about? Um I don't know it it was this flow occurred when |
|
| 30:15 | field was reversed. I was literally to say that but I was |
|
| 30:18 | no, okay. Yeah right. have to make sure that you're careful |
|
| 30:24 | . Yeah, I know it's kind hard. I'm just inspiring this information |
|
| 30:29 | your rapid fire. But yeah, got to make careful about what properties |
|
| 30:36 | associate with magnetic data and what you with gravity data. And I think |
|
| 30:42 | got it. Can I ask a stupid question. Are these just because |
|
| 30:49 | trying to combine like what I've learned other classes to like what we're doing |
|
| 30:53 | um this area that we're looking at these like structures that were going |
|
| 30:58 | Is this due to the limited progeny is this a different time period? |
|
| 31:04 | well, okay. People think that grande is still active and they think |
|
| 31:12 | because there's like active volcanoes. So like a good clue. When did |
|
| 31:18 | Lair Mind End? 30 M. . I think it was like 62 |
|
| 31:25 | , something like that. We did structural geology and that was like a |
|
| 31:31 | ago. But yes, I always those mixed up. I get a |
|
| 31:36 | preceded um um Let's remind 80-55, 55. So that's into the |
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| 31:51 | So that's whatever petty seen or using the Miocene. And then um severe |
|
| 32:07 | Yeah severe was cretaceous severe was Jurassic cretaceous severe is 160-50, so remember |
|
| 32:17 | by 30 million. That's why I to 30 from the overlap by 30 |
|
| 32:20 | years. So 80-55. Is that I said? Mhm 82 55. |
|
| 32:29 | then um no the only, yeah 1 62 that's a long time. |
|
| 32:38 | 60 to 54 severe. So and Rio grande rift, I mean I |
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| 32:44 | that's tertiary. I think that's related the great basin. Right, let |
|
| 32:57 | see when does out find out. looking at it right now. Rio |
|
| 33:00 | rift Real Grand Red started around So it it is after layer. |
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| 33:17 | it formed when the Great Basin formed that's when the Great Basin formed. |
|
| 33:24 | way to remember is that it's like , right? 30. Emma is |
|
| 33:28 | . It should be tertiary. Um tell you right now um Yeah, |
|
| 33:40 | church, it's a legacy. So Right, that's when the slab beneath |
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| 33:52 | was when the spreading center, the pacific rise, spreading center was overridden |
|
| 34:00 | north America and that's when the san fault developed, it developed as that |
|
| 34:07 | center was was overridden because the plate was converted from a spreading center to |
|
| 34:14 | transport. So part of that spreading pokes out up and connects to the |
|
| 34:21 | fracture zone in the juan de Fuca that we looked at earlier. And |
|
| 34:27 | other end pops out in the, the, in the gulf of |
|
| 34:32 | it separates, you know, the from the Mexico mainland. So that's |
|
| 34:40 | center is interrupted by the san Andreas , which, which is, which |
|
| 34:47 | the spreading center and then all that . That's when the great basin, |
|
| 34:53 | when all the rifting in Nevada And the rio grande rick. This |
|
| 34:57 | also related to that because this is rift, this is a rift in |
|
| 35:01 | middle of the carton. So is , is it going to, is |
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| 35:08 | going to succeed and produce an ocean ? I don't know, but there |
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| 35:15 | folks that don't want it to be but I know that there's volcanoes and |
|
| 35:19 | like to me, yeah, it's . So alright, so here's a |
|
| 35:29 | Adams and Keller that's randy Keller. used to be at Utep then went |
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| 35:35 | Oklahoma, um, here's a little that they did in a couple of |
|
| 35:40 | , the two LaRosa basin basin. Palomas basin. The angle basin, |
|
| 35:47 | these little sub basins down here. , so the um, the Albuquerque |
|
| 35:53 | I believe is just north of I think it's right here and then |
|
| 35:58 | course, here's the volcanic fields that been looking at all over here. |
|
| 36:02 | we're in this this is in the part down here. What did he |
|
| 36:06 | ? It was Palomas where they at they at? I don't see them |
|
| 36:18 | . Let's see uh angle paloma's LaRosa Puerto Palomas is at the very |
|
| 36:29 | bottom. On the right side right it is paloma's so that's the |
|
| 36:34 | Okay, so. Alright so we're not yeah. Okay so we're at |
|
| 36:39 | bottom of it. Okay, that's . Whatever. Um We'll look and |
|
| 36:43 | what they did. Um They did study. So this is their model |
|
| 36:47 | . To A. So they model . To A B. Two B |
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| 36:51 | C. To C. Okay, . Goes the northern part from west |
|
| 36:54 | east to be shorter. It goes the middle of A. And C |
|
| 36:59 | there. And this is using like 1994 version of the software we're |
|
| 37:08 | So it's the same company, this this is in the before times. |
|
| 37:14 | they have some refraction stations and there's wells and some reflection data. And |
|
| 37:20 | They have a mantle density of three that they used. They have some |
|
| 37:31 | source over here, 2.6 and upper . Lower. So you get the |
|
| 37:35 | is typically modeled a couple different ways to lay across, sometimes a three |
|
| 37:44 | across. I'm talking about the crystalline . We're gonna be doing a three |
|
| 37:48 | one as well for our for our and let's see what is observed, |
|
| 37:57 | , observed other pluses. And the are the little triangles. This is |
|
| 38:05 | they even had lines to these And then the key is um there's |
|
| 38:14 | sin here. Alu Veum estrada introduces grab it. That's the right. |
|
| 38:20 | then they had some densities in But I mean, overall it looks |
|
| 38:26 | . Um You know, there's a of different densities. I'm assuming they |
|
| 38:30 | control on this stuff. But here's basically your your rifting structure. |
|
| 38:37 | rotated these shape this way. This this could tell this was modeled by |
|
| 38:44 | because they like they have these just geometries. But you can imagine this |
|
| 38:49 | be like wrote this would be rotated blocks over here on this side of |
|
| 38:53 | basin. Did they label these? , the cerro Yeah. School |
|
| 39:06 | And then B. Two B. this is a short one that terminates |
|
| 39:11 | . So here they just um I , I think that that's I would |
|
| 39:15 | do something like that. I you don't know, I mean, |
|
| 39:19 | does he know that? I don't . In any case um Here's where |
|
| 39:25 | split the mantle and density and then again they made this model. So |
|
| 39:31 | actually have these and then here is . Two C. Prime. |
|
| 39:39 | So the same thing. So I have these. So let me just |
|
| 39:55 | me just open a model. I it goes to the right place. |
|
| 40:09 | see what happens. I see B. C. S. |
|
| 40:24 | It's gotta be this one. looks like I did something here. |
|
| 40:34 | . I didn't want to open that . Let's try B. Oh wait |
|
| 41:10 | second. I want to put I know I have the load |
|
| 41:18 | load backdrop, depth image. Let's . I want image to see 97 |
|
| 41:33 | store information 94 _ seven. So should be able to find it |
|
| 41:44 | I bet it's right in here. ? Oh this is breaking my |
|
| 42:08 | Hmm Let me just okay Adams, me see. I can find |
|
| 42:18 | Just give me a quick second. should I see It's uh It's 94 |
|
| 42:55 | crop JP. Oh wait a There it is, bingo. |
|
| 43:20 | so yeah that's pretty interesting. Does work? So we can slide, |
|
| 43:34 | can slide down just look at the . And I always just I always |
|
| 43:42 | off the that one because I don't . Oh this one has mm This |
|
| 43:56 | interesting. So the model looks So where's my, so you can |
|
| 44:02 | things in here Like I can change color of the model lines. So |
|
| 44:06 | cross sections. Let's see the surfaces black right now. I want to |
|
| 44:11 | them to something that I can see there. Yeah so I traced this |
|
| 44:18 | thing. Um Let me go minus 2 200 to see what happens. |
|
| 44:29 | , let's see, that's interesting. range. I'm just changing the |
|
| 44:37 | Just right, So this is B B prime. Okay, it's this |
|
| 44:46 | right here. So I I think probably using the same data as them |
|
| 44:51 | well. Um I don't know why going like that, but this this |
|
| 44:59 | geo reference and these are some refraction . Let me change the range |
|
| 45:07 | Change range like this. Nine 2 . Yeah. But yeah, this |
|
| 45:26 | really interesting. So yeah, I , see I think that you can |
|
| 45:38 | so when you model you should always from the bottom up, what is |
|
| 45:44 | ? Lower density? So there's I think it's coming back. I |
|
| 45:54 | that this model, I think that something wrong with the reference on this |
|
| 45:59 | that's why I'm thinking it stretched the it is. Alright, I'm gonna |
|
| 46:03 | this, go back to this thing any case, right? Um They |
|
| 46:17 | the well control and then they did some refraction control. I mean, |
|
| 46:20 | don't know if I would model some of feature like that. I think |
|
| 46:25 | best to, you know uh I , I just don't know how they |
|
| 46:30 | where that is. And also single for the mantel should work. And |
|
| 46:38 | my approach is that I think that you have you have two things philosophically |
|
| 46:46 | you're doing models, you have two here. Right? Two things you |
|
| 46:50 | change. You can change the rock or you can change the layer |
|
| 46:55 | If you're doing both ad hoc you , just free willing it. You're |
|
| 47:02 | going to be learning anything, you're gonna be you fit it. But |
|
| 47:05 | doesn't mean. So what could be you fall into the I mean I |
|
| 47:10 | to say you fall into the man trap. Right? So the way |
|
| 47:14 | do it systematically is in models like that are regional like this where you |
|
| 47:20 | have a lot of control on rock . What I do and what we'll |
|
| 47:28 | doing next week is we'll be holding layer geometry densities the same and we'll |
|
| 47:38 | just accommodating everything with geometry. So you can do then suppose the geometry |
|
| 47:45 | looking weird. Well then you infer that case that there probably is a |
|
| 47:54 | change somewhere but you don't know where is. You know, you don't |
|
| 48:00 | its shape or exactly what depth it's . But if you like have to |
|
| 48:07 | push a whole bunch of horizons all way up and a bunch of all |
|
| 48:10 | way down to make things fit. you can search, you can it's |
|
| 48:15 | to infer that there's a density change there. Now should you put it |
|
| 48:20 | there? I say no, leave model looking funny because if you put |
|
| 48:26 | in there then exactly how big do make it? What depth you put |
|
| 48:32 | gonna have to make some decisions on what it should look like. But |
|
| 48:35 | don't know what it looks like. know there's something there but you don't |
|
| 48:38 | what it looks like. So it's to have your model look, have |
|
| 48:42 | warts in it. Uh And then can address those when you present it |
|
| 48:49 | you write your report on it or like that. That's the sort of |
|
| 48:53 | . Now at the other end of scale, suppose you're doing a three |
|
| 48:57 | gravity model in the gulf of Mexico a salt dome that there's been, |
|
| 49:03 | know several versions of three D. and two D. Surveys and there's |
|
| 49:09 | of wells, you just got more than you can even keep track |
|
| 49:14 | Well in that case the geometries for , the top of the salt is |
|
| 49:20 | to be well defined. The densities the salt are gonna be well |
|
| 49:27 | And basically the only variable you would in that case would be the base |
|
| 49:32 | the song. So um and you because the salt density is kind of |
|
| 49:38 | constrained and in that case you're just invert for the basis song. I |
|
| 49:43 | people that work in oil companies, spend their life building three D. |
|
| 49:48 | models in the gulf of Mexico inverting the base of salt. I mean |
|
| 49:53 | like death by 1000 cuts. If ask me, okay There's another |
|
| 50:00 | And I think this is really a study. I mean in terms of |
|
| 50:04 | for in terms of scholarly work this probably as good as it gets in |
|
| 50:10 | of models and presentations and stuff. um The results I'm okay with but |
|
| 50:19 | really like this paper more because of method and the workflow. So Chen |
|
| 50:26 | she's a usgs in Denver. I know who Connell is, but they |
|
| 50:35 | two models and and they were russell . Remember that? They're there. |
|
| 50:42 | actually referring to the original paper This is This is a typo |
|
| 50:49 | This should be 2013 up there. Russell Snout. Some papers 99 |
|
| 50:55 | So I'm gonna make another slide Um ah wow 2013. And this |
|
| 51:11 | uh Anyways they, what they did they they looked at Russell's nelson's interpretation |
|
| 51:18 | was based primary and reflection data and compare it with another paper uh that |
|
| 51:24 | gravity and borehole data. Then they 3 2 d. models. Uh |
|
| 51:33 | where A is a long strike is a two A. Prime is |
|
| 51:38 | And then B. And B. . And C. Um And noting |
|
| 51:46 | the Neo gene basin film. So there's you know, fairly young basin |
|
| 51:51 | that's a lot less tense than the rocks. So let's see Neo Gene |
|
| 51:58 | the. Yeah, I guess. literacy. I guess then the paleo |
|
| 52:04 | and Mesozoic and whatever pelleas or rocks down here. So and they proposed |
|
| 52:13 | model of 3, 3.5 kilometer thick sub basins. So let's look at |
|
| 52:18 | . So on the left is Burch's and um this is gravity anomalies uh |
|
| 52:27 | Milligan's, you can definitely see the of the basin then they're very |
|
| 52:31 | And here's his ma here's his model , I mean sedimentary thickness going down |
|
| 52:37 | three km. Now the old uh and Snelson paper, this is their |
|
| 52:47 | , this is this is from the we looked at and here you have |
|
| 52:51 | , you know, some big faults some depot site is going down at |
|
| 52:56 | kilometers. I mean they have this to be these are Milligan right? |
|
| 53:05 | so they're going to a clock which I think a little deep. But |
|
| 53:10 | they're saying there's a transfer zone So on this side you see they're |
|
| 53:15 | suggesting because of the thickness of these . That's their way of showing the |
|
| 53:21 | . So they're saying that you you know, or how I guess |
|
| 53:26 | throw rather. So this is the basin bounding fall on the western side |
|
| 53:32 | it flips to a major base inbounding . You can tell by the shape |
|
| 53:36 | the basin to where it gets how it gets deeper. It's kind |
|
| 53:40 | asymmetric. So that's the japanese from data back in the day And their |
|
| 53:51 | , I'm sorry, 4.7 km. are these Interval 2000 ft I |
|
| 54:03 | Oh the ice. Okay there in of feet. 12,000 ft. I'm |
|
| 54:08 | . Alright. Yeah. Okay that's . Alright. Um Now so the |
|
| 54:16 | control included. Yeah. Side of flashes well and empty soundings. So |
|
| 54:21 | their three D. Kind of your D. Perspective manager friendly figure. |
|
| 54:31 | and on the right is there two . Models from the paper? And |
|
| 54:35 | is what I really like this a . So they put in it they |
|
| 54:38 | a little piece of the geologic map the transect. Then they have the |
|
| 54:45 | and magnetic anomaly profiles. Then they the model window in you know in |
|
| 54:52 | density window. And then below that have a geologic cross section which is |
|
| 54:58 | from that. So. Full on . Mad guys gravity cross section. |
|
| 55:05 | think this is really a nice way doing it. And then um this |
|
| 55:10 | C two C. Which is the one to the south. Again you |
|
| 55:14 | the same the same system of uh view geologic map. And then this |
|
| 55:23 | the model from GM says the program going to use uh observed and calculated |
|
| 55:30 | gravity, gravity and Magnetics and then have um the basin. Now the |
|
| 55:38 | thing that bugs me about this is they really well. Okay so they |
|
| 55:43 | reckon they have good control on the . So that's why they're making all |
|
| 55:48 | density changes in the rocks. And changes as well. Um Because they |
|
| 55:56 | this geometry is well defined by their data and well controlled and everything like |
|
| 56:02 | . So they're sort of forced into . Which is fine to do it |
|
| 56:05 | way. But if you didn't have information, I would never do it |
|
| 56:08 | way. I would change the geometries the basin and of the mojo because |
|
| 56:14 | better to do it that way. you don't have any information. So |
|
| 56:17 | my approach. If you have no then just hold your density is the |
|
| 56:23 | and do everything with layer geometries. if your layer geometries are are well |
|
| 56:30 | , then you're forced to change with densities. But that's not to say |
|
| 56:40 | you should do things that are not , right? I mean you shouldn't |
|
| 56:45 | plug in agency just to satisfy the you know, the reflection of refraction |
|
| 56:52 | well controlled. Um If you if for example, one of these |
|
| 57:02 | blocks had to be like, You the density of 2.3 or something like |
|
| 57:07 | . Which is just way too Then then that's saying something that the |
|
| 57:13 | , you know, something in the is flowing. Okay, so here's |
|
| 57:22 | their final map. Um And there a static residual but here's our final |
|
| 57:31 | showing some volcanic fields up here. then you have the sort of asymmetric |
|
| 57:41 | which are similar, quite similar to Russell and Snelson. But what are |
|
| 57:48 | depths that they have here? These don't show the depths so. |
|
| 58:05 | Alright. Anyway, so this is is their interpretation map derived from the |
|
| 58:09 | mount. Let me see if I done this. This is 24. |
|
| 58:34 | see. What did she say, do they should say? Okay, |
|
| 58:46 | they. Okay. The increase in and complexity may reflect a transition from |
|
| 58:58 | rio grande rift from a well defined depression in the north to multiple segmented |
|
| 59:03 | in a broader region. The crustal in the south. And it differs |
|
| 59:09 | from accepted structural model based primarily Key elements of the previous model. |
|
| 59:15 | east tilted half grabbing block, and north separated by uh separated from a |
|
| 59:23 | half grabbing on the south, by trending scissor like transfer zone that we |
|
| 59:29 | earlier. Right that we saw This is their transfer zone. Um |
|
| 59:37 | , this is what she said, find multiple sub basins with predominantly easterly |
|
| 59:45 | . Okay, that's these. Over , these are tilting east Tripoli. |
|
| 59:52 | uh For much of the Albuquerque a restricted region of western tilting in |
|
| 59:59 | southwestern part of the basin. In northwesterly trending anti form subdividing sub basins |
|
| 60:06 | the center of the base instead of major scissor lake transfer and I think |
|
| 60:11 | a better answer. I mean this idea of scissor things That's kind of |
|
| 60:18 | kind of old school. Um the overall eastern tilt indicated by the |
|
| 60:23 | D. G. Fiscal model generally to straddle tilt observed for syn rift |
|
| 60:31 | , implying a prolonged eastward tilting of basin during Miocene time. Okay. |
|
| 60:39 | extensive north south sim form in the part of the basin of the |
|
| 60:45 | Salvation. Was that at the Salvation? Where's that at? I'm |
|
| 60:56 | sure what that is. Um In case, I'll move forward suggest possible |
|
| 61:04 | for ancestral rio grande during the late or early pleistocene variations of this correspondent |
|
| 61:11 | riff structures in several places suggesting that better understanding of the pre rift history |
|
| 61:17 | shed light on debates about structure inheritance the rift. However, first relied |
|
| 61:22 | characterizing geologic units on the basis of three different density layers and particularly equated |
|
| 61:28 | layer. The lowest density infill assignment filter density does not allow projects an |
|
| 61:35 | with depth due to compaction. very good. Alright. So basically |
|
| 61:40 | saying instead of like two big one with kind of like ah based |
|
| 61:49 | on the west, you know, and the other one here and there's |
|
| 61:53 | connected by the trans the scissor They're saying it's actually just a bunch |
|
| 61:58 | little sub basins mostly, you know towards the east and except for this |
|
| 62:03 | one in the west and then there's is the same form you're talking about |
|
| 62:07 | little sort of anti form structure So, well done. Anyways. |
|
| 62:12 | I like these models a lot. are really what I think would be |
|
| 62:16 | I mean, in a perfect that's why I have a judo |
|
| 62:21 | Okay, um rift basins um this is in the the arctic and |
|
| 62:28 | is, we're gonna look at the sees rift basins in here and they're |
|
| 62:35 | in the southern ocean. So here's , new Zealand. There's actually a |
|
| 62:40 | that flips a bit of the continent . This is called the Daniel |
|
| 62:45 | And on the other side. And can just see the way it lays |
|
| 62:50 | . Here's the gravity data. This this is just this is just like |
|
| 62:54 | map I showed you of the whole . So you have these, it's |
|
| 62:58 | zones and spreading center down here, zones. And then this is the |
|
| 63:03 | sea here, you see a little basin down in here. And then |
|
| 63:07 | it's connected. It was connected by faulting across this thing here when everything |
|
| 63:15 | closed. Okay, that was when was closed before this ocean ocean basin |
|
| 63:20 | . So here's those geometries. And a couple, there's a couple uh |
|
| 63:27 | sections through here and you can just this is all modern day deformation. |
|
| 63:32 | , so Here's your transform continent, transform boundary, three D. |
|
| 63:38 | which is very complicated. And that of lies beneath beneath hair. |
|
| 63:44 | beneath this bit here And then I let's see this is a. This |
|
| 63:50 | B. Where's A. And A. And B. Wait, |
|
| 63:54 | that right? One of these is . One of these is B. |
|
| 64:06 | was thinking I should know that right , right lateral bellini. So it's |
|
| 64:14 | along this Bell. Any fault. don't think it really matters. But |
|
| 64:19 | of these maybe this one this is . Yeah, I think that's that's |
|
| 64:23 | one here. But you can see present day this deformation going on |
|
| 64:28 | These things are really happening but this all sort of translation of this is |
|
| 64:33 | structuring related to this sort of It's pretty interesting. Um and then |
|
| 64:41 | in and you can see this is reconstruction going back to early to late |
|
| 64:46 | , early cretaceous, late cretaceous about M. A. You see what |
|
| 64:51 | happening was as this was opening you were you were having the |
|
| 64:58 | the southwest pacific was extending this And so you got a little bit |
|
| 65:02 | component of convergence here and that's what this this this crazy structure going, |
|
| 65:09 | up this this um peninsula. It's wild. And then here the little |
|
| 65:16 | basins, all these normal faults showing rift basins behind it. So this |
|
| 65:22 | not a part of the world. think about very much but I came |
|
| 65:26 | this, I was just fascinated by fact that you have this ocean basin |
|
| 65:32 | is opening. So it's this ridge like extending is percolating along through |
|
| 65:39 | But at the same time this the pacific is opening and and like you |
|
| 65:44 | , there's an accident waiting to happen here. So that's how that |
|
| 65:49 | And so here's I think they did uh here's the same area, the |
|
| 65:56 | ross sea. And uh let's this is the this is the |
|
| 66:01 | right? This is the victoria land . That's a little rift basin and |
|
| 66:05 | . B. Is the northern basin A. B. Is a |
|
| 66:08 | So these are all the string of which are right in here. They're |
|
| 66:15 | in here and E. V. is another basin and then the |
|
| 66:24 | T. Is a central trump. all these are little basins that are |
|
| 66:27 | are formed by this, you this this kind of oblique translation. |
|
| 66:38 | the aero magnetic data on the you can see the sea floor spreading |
|
| 66:44 | up there. And then here is I think this is the age air |
|
| 66:49 | . I think this white white one the age air base in the other |
|
| 66:53 | are down here I think. Is right? Like coming? Oh, |
|
| 67:02 | edge of the ice sheet. I'm . See the bouquet nominee really tells |
|
| 67:08 | a lot right here. In look at this cross section across this |
|
| 67:12 | section is right through here. I it goes right through here. It's |
|
| 67:17 | shown on this map, but it right through this week to see where |
|
| 67:21 | is the you know the this is , so what's happening here? That |
|
| 67:27 | this is where the ocean floor and crust is out here. This is |
|
| 67:31 | crust in here and that models right . So you can see this bouquet |
|
| 67:38 | nominee going up like that. And here are the two magnetic highs on |
|
| 67:43 | side of the ocean basin. In , they've identified these crowns in |
|
| 67:49 | 12 oh and 13 C. That's . Okay, it's 12 12. |
|
| 68:00 | the spreading center right here and then 13, 13 And then 16 or |
|
| 68:08 | . It's hard to say, I see him. Can you read |
|
| 68:11 | Uh huh. The 16? Yeah says 16 to 18, 16 Y |
|
| 68:19 | Oh this is 18 here, 16, that's 13 12, |
|
| 68:25 | 13, 16. Okay. Yeah those are sea floor spreading crowns. |
|
| 68:31 | then um you have the you know uh continental crust on either side. |
|
| 68:37 | this is like pushing its way Let's just go back to the gravity |
|
| 68:41 | just so you can see so this free air though. So it's |
|
| 68:45 | right? You don't even see that thinning crust in there. But that's |
|
| 68:51 | down through here I think, isn't ? Is that right? Is this |
|
| 68:54 | hard to tell? Okay so this like lots of words but um let's |
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| 69:03 | they're saying that the black lines mark proposed original rift access the black, |
|
| 69:11 | black line. So that must be right here. Right. And access |
|
| 69:21 | 43 A. M. In the risk margin in the eastern rift margin |
|
| 69:26 | actually rotating about coal, the red lines marked the third and four kilometer |
|
| 69:33 | packs, packs For the basics to basin statements three or 4 km deep |
|
| 69:40 | the basics. So here's yeah, this trough trough trough, the basin |
|
| 69:51 | and wrapping around like this. This where that model was. This is |
|
| 69:54 | the gravity model was through here. polar three anomaly was polar three right |
|
| 70:03 | . They so they're they're going with transfer model as well. Just get |
|
| 70:08 | of those things. Uh in the margin of the ross sea transfer |
|
| 70:14 | victoria, land basin, red dash . Uh that's in here, that's |
|
| 70:20 | the right, right there. so they're thinking there's an offset here |
|
| 70:25 | it's driven by this relative motion of thing, which is I guess I |
|
| 70:30 | buy into that. Everything is bending and it's caused by this this motion |
|
| 70:36 | the of that and the air basin up here. So there you have |
|
| 70:42 | . So this is a continuous kind of wrapping around here being offset |
|
| 70:48 | the structuring here. That makes sense you. It's too confusing. It's |
|
| 70:59 | lot, but it makes sense. I'll just have to go through |
|
| 71:02 | But I don't like the question because makes sense. I just gotta |
|
| 71:05 | So let me just okay, so that. Here's here's the sound that's |
|
| 71:09 | . It's not this is okay, , new Zealand Antarctica. Right? |
|
| 71:14 | so there's the southern ocean, here's pacific ocean present day. And you |
|
| 71:22 | this transform boundary here. That's I present day. But back in the |
|
| 71:28 | when you close all this, you , it's it's gonna offset this and |
|
| 71:32 | gonna produce the structures in here. so here's just the same thing. |
|
| 71:39 | the ocean floor, I mean, sorry, free air gravity and gravity |
|
| 71:45 | it shows the sea floor spreading right and the fracture zones going into the |
|
| 71:51 | sea here. And those riff structures all in here. All that |
|
| 71:55 | We're worried about this, this this work is right in there, Same |
|
| 72:03 | right in there and here's these transforms through here and this is north of |
|
| 72:08 | into the idea. So this is over the ocean oceanic crust. It's |
|
| 72:12 | showing the structure of it there the of defamation. Uh with this fear |
|
| 72:18 | defamation of okay, going back down there, we have this reconstruction for |
|
| 72:26 | and then using the legacy. And can see how these these all these |
|
| 72:32 | evolved as as this sort of thing growing. And then you can see |
|
| 72:38 | all the how these this sort of structuring from the strike slip related to |
|
| 72:45 | , this uh defamation. The plate over here, how that is affecting |
|
| 72:50 | local base and deformation here in the sea. So it's really complicated caused |
|
| 72:59 | again the growth of the southern And then at this time um uh |
|
| 73:10 | me just go back to this one . So here you see here they |
|
| 73:17 | a spreading is this way? Is right? Yeah, that isn't. |
|
| 73:31 | is the spreading. This is the center. Sorry, it's going this |
|
| 73:34 | . These are no, the dotted are supposed to be. Data lines |
|
| 73:42 | Cron's So it is going this I was right the first time in |
|
| 73:46 | case, in any case, the is, is that you have right |
|
| 73:54 | dextrose shearing dextrose translation along these And and that opened up in the |
|
| 74:03 | sea here. These rift bases alleged it's textural out here. But then |
|
| 74:13 | turns into like segmenting and that's what what they're saying, is that this |
|
| 74:18 | was moving over and it made everything over Benz bend around it kind of |
|
| 74:27 | that. And then this last this is just the models that support |
|
| 74:31 | . But they're saying everything's kind of around. And this is the final |
|
| 74:38 | , they're saying this curving around this . Okay, we're at 1:44. |
|
| 74:48 | You want to take a few minute . Look at passive margins. |
|
| 74:53 | that'll work. Oh yeah. So riffs end up turning, you |
|
| 82:20 | end up breaking up completely and ocean uh starts being produced and you end |
|
| 82:29 | , you know, with a passive . So as I said before, |
|
| 82:34 | refers to a margin that's not it's not dynamic. It's it is |
|
| 82:41 | margin, it's where crust gives way oceanic crust, but it's not, |
|
| 82:51 | not a plate boundary. So hence called a passive margin. That's where |
|
| 82:55 | idea comes from. And okay, going back to our little diagram that |
|
| 83:08 | had when I talked about super kind . Um So passive margins form after |
|
| 83:16 | rifting and you get the formation of across and thermal static subsidence. They |
|
| 83:25 | be on the order of about 300 wide and there can be thousands of |
|
| 83:31 | long. And they're the deepest basins the world. They can be over |
|
| 83:37 | kilometers, I would say a maximum 18. Although you'll see people report |
|
| 83:46 | some basins are 20 km deep. is not physical, that's not physically |
|
| 83:53 | on this planet. Okay, and then depending on the shape, |
|
| 83:59 | and the right of plastic sedimentation, they they're uh three aspects that we |
|
| 84:09 | worry about with regard to gravity And then there's another aspect that's important |
|
| 84:15 | us about these, these margins that's to the crust. The crystal cross |
|
| 84:21 | forms. So with regard to they can include large volumes of salt |
|
| 84:30 | we said earlier, gulf of Mexico and santos, Gabon and Angola that |
|
| 84:35 | include large values of shale like the delta or or northeastern Borneo. And |
|
| 84:42 | can be dominated by car and platform like florida and yucatan. Also with |
|
| 84:50 | to the crust when when rifting gives to gives way, there's no |
|
| 84:58 | you know, the extension has gone so far that the the continental crust |
|
| 85:02 | no longer thin anymore. It just . What can happen is if that's |
|
| 85:11 | case and um if there's if it's that margin is what we call magma |
|
| 85:17 | . Okay, it is not enough to produce ocean floor messing. How |
|
| 85:24 | that? How is that possible? it actually is um it's just not |
|
| 85:29 | magma to produce ocean floor. It's we call an a magmatic margin sometimes |
|
| 85:35 | non volcanic and sometimes there's like excess . The margin forms over a |
|
| 85:45 | Right? And it's just like voluminous eruptions of flood the salt and stuff |
|
| 85:54 | Iceland for example, then then that's called a magmatic march or volcanic. |
|
| 86:03 | the reason I think magmatic and a are correct more so than saying volcanic |
|
| 86:10 | not volcanic is because volcanism is an property. Right? And these magmatic |
|
| 86:20 | , they're often associated with magnetic under where the there's, you know, |
|
| 86:27 | of intrusions that never never erupt, intrusive, not exclusive. So I |
|
| 86:34 | it's more correct to say magmatic or magmatic versus volcanic and novel. |
|
| 86:40 | so let's just dig into that a bit more so below. There's a |
|
| 86:45 | from Menzies and it's a magmatic So it's a passive margin. Uh |
|
| 86:53 | me just read it as two tectonic break apart. There may be regions |
|
| 86:57 | there are new extension of plate along new extension of plate boundary that have |
|
| 87:03 | supplies a magnet, as I was , to create new crust and |
|
| 87:10 | magmatic margin and regions where the new are magnets start. So envision this |
|
| 87:20 | million years ago, Western Gondwana that Africa and South America, there one |
|
| 87:26 | block and they're gonna break into. along that rifting margin, which is |
|
| 87:35 | and thousands of kilometers long between North . I mean between South America and |
|
| 87:42 | , there's gonna be places along there there's lots of, lots of magnets |
|
| 87:46 | in acuna mantle plume was erupting there's other mantle plumes and then there |
|
| 87:51 | be places along that distance where, know, it's, there's not enough |
|
| 87:56 | , there's not enough, there's not lot of magma being produced in the |
|
| 88:02 | the status here for whatever reason temperature or for whatever reason. Well, |
|
| 88:09 | plates are gonna go, they're doing they're doing. There's a big the |
|
| 88:13 | driving those is far greater. Then forces holding them together. So they're |
|
| 88:20 | to open up and so, you , whatever happens along that rift id |
|
| 88:26 | , that's soon to be passive margin what it is, it's just going |
|
| 88:30 | suffer from, you know, the of whatever is happening locally. So |
|
| 88:39 | magmatic margins um you have a few that are that are interesting that happened |
|
| 88:46 | are often somewhere near there. There's large english province like Hawaii sits on |
|
| 88:53 | of these Hawaii is one of the whole Emperor, Hawaiian Emperor seamount |
|
| 89:00 | is a bunch of seamounts that were over a large igneous products. Um |
|
| 89:06 | Columbia plateau in Washington Idaho, to unions province. The deckhand traps that |
|
| 89:13 | talked about earlier India, that's a unions province. The Siberian traps. |
|
| 89:21 | . Iceland is a L. P. It's a hot spot but |
|
| 89:25 | . I. P. They're actually the same thing. I'll explain the |
|
| 89:30 | , But but so far for right they're just they are areas where there's |
|
| 89:36 | of magma coming up erupting from uh think they erupt from the core mantle |
|
| 89:42 | . So 2900 km down. So happens when these eruptions happen? |
|
| 89:51 | the flood basalt skin spread out over land. And as they do, |
|
| 89:59 | could, you know, they are , flood basalt, but then as |
|
| 90:05 | the rifting in the passive margin forms as thin, those horizontal uh layers |
|
| 90:14 | flood assaults start dipping towards the sea we call those seaward dipping reflectors, |
|
| 90:22 | are just flood assaults that have been on their side because they subsided along |
|
| 90:27 | edge of the mars. That's the . Okay. Mhm. Now, |
|
| 90:37 | there also can be magmatic underplaying because there's enough magnitude to erupt and spill |
|
| 90:43 | and flood over the land, there's a lot of magnetic, there's probably |
|
| 90:47 | magma magnetic material, you know, the crust. And that's where you |
|
| 90:52 | get these pods of, you magnetic material called Gabrielle, whatever that |
|
| 91:00 | itself to the base of the It's called magmatic under plating here. |
|
| 91:05 | calling HDL c high velocity lower Remember that one example we saw of |
|
| 91:11 | India where they had, They had velocity of 7.3 columns per second beneath |
|
| 91:20 | Laxmi Ridge. That's the idea same here. But instead of just being |
|
| 91:25 | the sema, it's under plated the . Um there's some things here that |
|
| 91:34 | think are unimportant, This transitional transitional it's either continental or oceanic. So |
|
| 91:42 | one or the other uh maybe magma , there may be magma chamber. |
|
| 91:48 | yeah, so those are the when you think of magmatic margins, |
|
| 91:55 | probably formed where there's a magma source , like a hot spot or a |
|
| 92:01 | igneous province that allowed for flood assaults , you know, pour out that |
|
| 92:08 | turned into sdrs as the as the of the the flag of the basin |
|
| 92:15 | . But you can also have under because it's just lots of magnets, |
|
| 92:19 | the idea. And then the opposite a magnetic margins, those are characterized |
|
| 92:27 | hyper extended continental crust and unproved upper . Sometimes often called mental examination. |
|
| 92:39 | And here's sort of what those might like. So here's this is this |
|
| 92:44 | offshore Iberia, this offshore Portugal. this is the one of these the |
|
| 92:51 | place in the world where this this is found. But basically um you |
|
| 92:58 | coming up across which is thin and . But then before you can start |
|
| 93:04 | ocean floor, you just have unwrapped mantle Exume mantle. And some of |
|
| 93:09 | might become hydrated because it's exposed to sea water. So when Perotta types |
|
| 93:14 | hydrated, they turn into soup That's what this is all about. |
|
| 93:21 | And then the bigger here. So talk about M. O. |
|
| 93:25 | O. R. B. S mid ocean ridge vessels. And that's |
|
| 93:29 | out here. So these are now calling this bonafide regular oceanic crust. |
|
| 93:36 | there's oceanic sin reflect this fear. this the atmospheric mantle here and upper |
|
| 93:45 | lower crust are colored in the sort beige colored brownish beige. This is |
|
| 93:52 | so the continental crust is that And yeah, so they have |
|
| 94:02 | alpha calcite and sopranos prototype out here these yellow dots, 13:30 Isil therm |
|
| 94:11 | thought to be the base of the fear. So if this thing |
|
| 94:16 | So, so if you're producing at spreading center, The atmosphere is zero |
|
| 94:22 | . So the 1330. I said must be right there at the water |
|
| 94:27 | . That's what the idea says, the theory says. And then for |
|
| 94:33 | bottom when there's early examination falls and hinge falls. So basically this this |
|
| 94:41 | these curved features that the continental blocks just floating in. Now there's some |
|
| 94:47 | . S. D. P. and ODP wells that have drilled into |
|
| 94:50 | things. So we know this stuff there are what they call these Perretta |
|
| 94:55 | ridges. But again the overarching idea that they're magma starved. So that |
|
| 95:07 | so when when it's when you have magma it can start producing ocean floor |
|
| 95:12 | away. So you don't have So the crust actually the detachment is |
|
| 95:16 | abrupt. The end of the, very abrupt. But in this case |
|
| 95:21 | not enough magnets start producing soul. crust is just hyperextended. That's the |
|
| 95:26 | for that. Now this is I'm this is the uh the only margin |
|
| 95:34 | the world where you see this it has not stopped a handful of |
|
| 95:39 | from just falling in love with this . And there's a there's a gang |
|
| 95:45 | guys of researchers. I used to behind them at the A. |
|
| 95:50 | U. S. I mean of I only went, I didn't see |
|
| 95:53 | at this age, you but like lot of guys with the same pretty |
|
| 96:00 | looked like to me like the same every year, Man Michelle was one |
|
| 96:04 | them just got here. But there's bunch of other ones and they think |
|
| 96:10 | fact I once had a poster was next to him, This was back |
|
| 96:14 | I think 06. And I asked , I asked him if he thought |
|
| 96:24 | every single passive margin around the world up and down the atlantic oceans all |
|
| 96:31 | India, all around africa in the everywhere. If all of those passive |
|
| 96:38 | had a zone of unwrapped mantle because were doing this everywhere and he said |
|
| 96:44 | that's what he thought told me to face. So yeah but there's only |
|
| 96:50 | of these people. But yeah there a guy that gave a talk at |
|
| 96:56 | A. P. G. Once brazil from petrobras. He gave a |
|
| 97:01 | and he said that offshore santos basin a zone that was hyper extended a |
|
| 97:10 | and he said there was a zone next to it that was magmatic. |
|
| 97:16 | so the idea of this is end but he was right next to it |
|
| 97:20 | I don't know how you do I just don't know how that |
|
| 97:22 | And he actually won best paper which just boggled mind boggling anyways. I |
|
| 97:30 | think that's physical. I mean because mean I don't think it's possible if |
|
| 97:35 | have enough magma to produce sea I mean ocean floor readily then how |
|
| 97:42 | you going to hyper extend right next it and what's gonna be blocking that |
|
| 97:47 | ? In any case, these are major ideas for how the crust |
|
| 97:51 | Um Here's the global map from showing his his idea where the volcanic |
|
| 97:57 | nam. Okay, magmatic margins are yeah, so any questions about |
|
| 98:07 | this cost of formation, it's something gonna come across if you haven't |
|
| 98:14 | Yeah, no questions. We kind went over this a little bit in |
|
| 98:17 | structural geology and stuff like that. I took it with Doctor Murphy. |
|
| 98:25 | , did Mike talk about this Can you talk about a lot of |
|
| 98:30 | ? This I'm familiar. Okay, . Well I don't know what mike's |
|
| 98:36 | about this about this stuff is it's more open minded than me. Um |
|
| 98:42 | . Okay, all right then. so he's a lot nicer than me |
|
| 98:49 | . So okay, now I mentioned that passive margins can be dominated by |
|
| 99:08 | some specific types of uh sedimentary They can be saying dominated. Carbonate |
|
| 99:16 | , shale dominated, salt dominated. here's one and two. So here |
|
| 99:24 | um uh sort of just normal classic with some shells and mud stones and |
|
| 99:31 | , but not like excessive shale, ***, delta, That's the top |
|
| 99:39 | . Now, what sort of how you think the magnetic and gravity anomalies |
|
| 99:47 | look over this profile over this What kind of what what would the |
|
| 99:53 | you were to sketch profiles over what would they look like? Let's |
|
| 99:58 | with, let's start with gravity. you don't see it? But remember |
|
| 100:07 | mojo, the crust is getting thin the bottom up as well, but |
|
| 100:12 | always right? So like so like crust is getting, you know, |
|
| 100:17 | getting thin, kind of sweeping and up to this before that starts producing |
|
| 100:22 | oceanic crust. So break it, it down. Think about it in |
|
| 100:30 | of the mojo combination. But thinking terms of, okay, you have |
|
| 100:35 | part of here and then you have basement structures that were, you |
|
| 100:41 | rift rift blocks that were produced. know, as the passive margin |
|
| 100:48 | That's the process. So what would high density, would be low |
|
| 100:58 | Okay, so the oceanic crust is density than continental, Right? Or |
|
| 101:07 | opposite? A little bit. A bit? Yeah. Okay, so |
|
| 101:10 | would show gravity would be higher over oceanic and then lower over the continental |
|
| 101:20 | a little bit. Okay. Um the depth goes higher. So, |
|
| 101:30 | , no, that doesn't deal with . What about the what about the |
|
| 101:36 | ? What's that gonna do? The is gonna give us a hi where |
|
| 101:53 | let's see it's gonna come through. it be coming through right there between |
|
| 102:00 | oceanic and continental like at that No. Would it be coming through |
|
| 102:14 | contrast at the base of the cross um a sharp anomaly or big broad |
|
| 102:24 | anomaly. It would be a sharpen from your silence will be a broad |
|
| 102:36 | . It would be a broad wouldn't it? Okay, so let |
|
| 102:39 | write this down just like remember our . In fact, that's one of |
|
| 102:43 | one of the the atlantic right You see that this is going from |
|
| 102:49 | to ocean. Oh she had a . Do you see that? You |
|
| 102:53 | that? In fact, it's just big broad high. I mean it's |
|
| 102:56 | it's a smooth I mean it's not a sharp anomaly like these anomalies |
|
| 103:01 | Right. It's kind of a broad . It's going to be confident to |
|
| 103:07 | . Okay, so here as So this one so here's your passive |
|
| 103:12 | almost. But it's a risk but this is what kind of geometry you're |
|
| 103:17 | at for crustal? It would be up broadly over that. That's |
|
| 103:25 | No worries. No worries. okay, so that there might be |
|
| 103:30 | little bit denser because ocean crust is little bit denser than continental crust. |
|
| 103:34 | there might be a contrast there. about these? What about the basement |
|
| 103:40 | ? What are those going to do basement rocks? So then those are |
|
| 103:48 | be more dense then what then the around it. Right? Because it's |
|
| 103:59 | then these sediments and overlying. Yeah. So tell me tell me |
|
| 104:08 | the gravity anomaly that's produced by these blocks versus the gravity anomaly produced by |
|
| 104:15 | basement blocks. It's gonna be exactly same. No, it's gonna be |
|
| 104:24 | . What's gonna be different is it's to give us like um it's gonna |
|
| 104:33 | high over those areas. So it probably look like a word like the |
|
| 104:41 | are coming up. So, would be like what dikes? Or tell |
|
| 104:48 | about the wavelengths produced by these versus ? The wavelengths are gonna be broader |
|
| 104:59 | which 1? For the basement? all basement, not the shallow |
|
| 105:10 | The deeper ones gonna be broader over down here. Yeah, that's |
|
| 105:16 | It's gonna be they're gonna be shorter and maybe higher amplitude because it's getting |
|
| 105:22 | over these, right? Gonna have wavelengths. And then they're gonna get |
|
| 105:28 | and broader. And brother, that's this is gonna. And then those |
|
| 105:32 | be superimposed on top of a broad to high. Right? And then |
|
| 105:42 | looking at free air data, you're have that stomped on by this this |
|
| 105:48 | . So, we'll just we'll just just consider this is all for now |
|
| 105:52 | we've corrected for this calm, you , for the layer of water |
|
| 105:59 | So, yeah. What about magnetic for this 1? For magnetic? |
|
| 106:11 | would be, I feel like in front. So like we're from the |
|
| 106:19 | crust to where the continental crust starts . Like that basement. I feel |
|
| 106:24 | it would be fairly flat over Just because there's not much going |
|
| 106:30 | And then once we enter where the coming through then it would get slightly |
|
| 106:35 | . Um But depending on the poles the ocean crust and we might have |
|
| 106:46 | right? You might have to sea spreading and islands over this. So |
|
| 106:51 | though it's all the same composition relatively , it's gonna have reverse polarity blacks |
|
| 107:00 | there. So they're going to produce album. Yeah. And then these |
|
| 107:04 | are gonna produce magnetic anomalies, are ? Yes because basement is Okay. |
|
| 107:12 | are they gonna be again compare this to this one? What's going to |
|
| 107:16 | the difference between the two? The to the far right. Are gonna |
|
| 107:24 | higher anomaly than the ones to the because they're closer to the surface. |
|
| 107:34 | what about tell me about their Remember magnetic data wavelengths we want? |
|
| 107:47 | It's gonna go from like low to or like load abroad. No just |
|
| 107:58 | gravity. It'll be short wavelength over shallow blocks. One wavelength over the |
|
| 108:05 | blocks. Right? Just like So they will be higher amplitude. |
|
| 108:14 | little bit over the shallow ones. not a lot. The big difference |
|
| 108:19 | be in wavelengths. Okay so now know over like basically what we're saying |
|
| 108:29 | and when I say a normal what about this one here we have |
|
| 108:32 | carbonate bank. Let's stick with magnetic now. How how is magnetic |
|
| 108:39 | Are they gonna look like this No, I mean, okay, |
|
| 108:48 | geometries are slightly different between the but you still just have shallow blocks |
|
| 108:53 | deeper blacks like. No. I understand. Yeah. Yeah. |
|
| 108:57 | I mean disk dramatically. Let's assume the same geometry is beneath these |
|
| 109:04 | covenants with the magnetic magnetic data look it was the same. Similar will |
|
| 109:14 | the same because because I mean if was the exact same geometry, it |
|
| 109:20 | look exactly the same because carbonates are magnetic. Okay. Just like just |
|
| 109:27 | plastics, they're not magnetic. So there's nothing they're not going to produce |
|
| 109:31 | anomalies. They're basically invisible. Okay. Let's look at the magic |
|
| 109:39 | is famous for its for um uh for for shale. High over pressured |
|
| 109:50 | being a real drilling hazard. And know when it's over pressured, it's |
|
| 109:57 | with water. And what do you ? Do you think that that over |
|
| 110:04 | shale producer gravity anomaly? Um I to say yes. Yeah. That's |
|
| 110:15 | idea that many people have spent lots lots of money trying to exploit. |
|
| 110:22 | it doesn't it's not, it might anomalies but they're not measurable. They're |
|
| 110:27 | there in the noise that they I've done work in the *** delta |
|
| 110:31 | any time. And that's the idea people. So shale dominated are no |
|
| 110:37 | than saying dominated? So the anomalies on a passive margin over a passive |
|
| 110:46 | that shale dominated would be no different those from a san dominick gravity and |
|
| 110:54 | . So you would have long wavelength over the deep basin structures. The |
|
| 111:03 | basin basement structure. In shorter wavelength produced by the inboard shallower basement |
|
| 111:12 | They happen to be a little bit . But the key thing would be |
|
| 111:15 | wavelengths Magnetics would be. What about in the shale dominated show magnetic? |
|
| 111:30 | , so no difference from the same . Deep blocks in the basin would |
|
| 111:37 | long wave. Like magnetic anomalies. blocks would produce shorter wave until that |
|
| 111:44 | . Okay, what about the last salt? So the gravity Yeah, |
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| 111:53 | is. What's it gonna do? gonna give us that like that high |
|
| 111:59 | . Like I can see the wavelength my head where it goes up over |
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| 112:02 | salt. That's over the part that's the crossover depth. Okay, the |
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| 112:08 | of the salt is going to be density is going to produce gravity |
|
| 112:13 | Oh, so this is similar to a Richter wave look like um ricker |
|
| 112:18 | that up and high thing. Well, but look, that's pretty |
|
| 112:25 | most of the time. This is going to be below the crossover |
|
| 112:28 | Crossover depth is just, you know I say, 12,000 ft say 12,000 |
|
| 112:36 | 1200 ft, 12,000 whatever, whatever says in the notes. But |
|
| 112:43 | so lots of times assault doesn't just above that crossover death. So you |
|
| 112:48 | just be aware because below it's going be a gravity low above it. |
|
| 112:55 | going to be a gravity high but a lot of it rises above |
|
| 113:01 | What about salt? And what about ? I mean in the salt basin |
|
| 113:13 | No but the salt salt is not blood. It's slightly magnetic. But |
|
| 113:19 | mean it's it's only the rare survey you can see it. So this |
|
| 113:27 | is why gravity and magnetic data play each other work together so well because |
|
| 113:34 | magnetic data see the basement in all examples because all the sediments are invisible |
|
| 113:40 | the magnetic anomaly. Remember when I when you're looking at magnetic data, |
|
| 113:44 | are looking at the basement. You looking at anomalies produced by the |
|
| 113:50 | So in this case you're gonna and for the communication you might have a |
|
| 113:55 | gravity high. But the Magnetics will you how deep the basin is always |
|
| 114:04 | . So you would say, oh a gravity high. But the magnet |
|
| 114:07 | there's gonna be something, there's gotta some carbonates in there or something. |
|
| 114:11 | would be a question you'd ask. if you saw a bunch of a |
|
| 114:15 | of, you know circular or globular gravity lows um from a deep deep |
|
| 114:24 | . From the magnetic data. But what does this put these, you |
|
| 114:28 | circular and globular say grab your clothes you say you know is this a |
|
| 114:32 | basin. You know you would just at that and think that so that's |
|
| 114:38 | idea. I didn't mean to put on the spot this stuff but I |
|
| 114:41 | want you to start thinking about this . So I'm the only one |
|
| 114:44 | I am the spot. You You're the only. Fair enough. |
|
| 114:50 | enough. Okay so um I have have a series of three D. |
|
| 114:58 | , three D. I'm a three . Studies three D. Models that |
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| 115:02 | at different parts. And we're gonna we're gonna start up in the Mackenzie |
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| 115:08 | whatever the Mackenzie uh Beaufort, Mackenzie , uh Canadian side that we're gonna |
|
| 115:15 | down to um south the south atlantic I think Namibia or um Angola. |
|
| 115:24 | then we're gonna skip down to the south africa. So we're gonna go |
|
| 115:29 | top to bottom. Okay so this uh became an a passive margin early |
|
| 115:38 | . Um And then it's it's now printed by four lead rocks because of |
|
| 115:43 | brooks range. But it started as passive margin. And there's a three |
|
| 115:47 | . Gravity model. This red box it has control by they have a |
|
| 115:55 | have a structural model, they have wells and all these white all these |
|
| 116:00 | white plus signs, they have some maps and um they have reflection |
|
| 116:10 | So these yellow lines and they have refraction lines, These blue lines. |
|
| 116:14 | they have a lot of control. then down here is the topo |
|
| 116:22 | it shows the elevations going from you over 700 to minus 1700. And |
|
| 116:29 | some major thrust faults. I mean a trust fall here and I guess |
|
| 116:34 | is a fault zone. It has ones. I'm not sure what that |
|
| 116:38 | . I guess that means oh normal . So these normal faults are clear |
|
| 116:42 | . The black ones are thrust falls there's a fault zone here. See |
|
| 116:50 | I have notes on, let me my notes. This is simple, |
|
| 116:54 | , simple, simple. Right. . So yeah they say we integrated |
|
| 117:04 | horizon. Well data. Side effect faction and regional gravity. The mesozoic |
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| 117:12 | part of the model comprises seven classics predominantly the shells. And they say |
|
| 117:22 | is a gradual northeast shift of the depot center. So let's just look |
|
| 117:26 | see. So here's the. so here's their model area. And |
|
| 117:33 | so here's the measured gravity. So is this is this is boo gay |
|
| 117:43 | . This is boo gay data. do I know that? How do |
|
| 117:51 | know it's bouquet? It's gay because men mull topography. It's real easy |
|
| 118:06 | it doesn't look like that. if if it was free air it |
|
| 118:14 | look like that. You'd have highs the mountains, low it would look |
|
| 118:18 | that. It would be dominated by by this morphology. But on the |
|
| 118:23 | hand where the where the ocean is where the water bottom is deep, |
|
| 118:30 | a gravity high that tells you right . That's bougie. Whenever you have |
|
| 118:35 | high gravity anomaly over oceans and a over the continents, you're looking at |
|
| 118:40 | anomalies. Okay. And so here's thickness of their basin in km. |
|
| 118:50 | they have to over 16 km deep . Pretty Darn deep. Okay, |
|
| 118:55 | the model was accomplished by integrating isil and 3D calculate de posadas gradually migrate |
|
| 119:02 | the northeast. So that's this way basin is over 70 kilometers, jesus |
|
| 119:07 | of the base is located in board the thinness crust. Probably related to |
|
| 119:12 | . IQ loading The sedimentary layers tend be more porous and less dense. |
|
| 119:17 | . Okay, shallow continental crust is than 2.71 g per cubic centimeter than |
|
| 119:25 | deeper parts. All right, so just see what they did. So |
|
| 119:29 | is this line goes from south to . Where does it go from |
|
| 119:35 | It is right down here. This model goes from south to north through |
|
| 119:42 | the bouquet anomaly here. So they're it this peak right here is right |
|
| 119:50 | . Um They got it backwards They got to measure as solid to |
|
| 119:55 | as dots. That's against the And so here they end. |
|
| 120:03 | you have all these sedimentary layers, ? All these units going down to |
|
| 120:09 | and then even lower and then you crystal and crust Which is this |
|
| 120:15 | So this is low density premises or 27 10 that light gray. And |
|
| 120:29 | is the geometry that came up with inversion 28 a half C. They're |
|
| 120:36 | this 29 because it's oceanic, this 28.5 28 50 in kilogram. That's |
|
| 120:46 | don't know. Let's see what's Yeah. I don't know if you |
|
| 120:50 | to do that. You see if made this 28, all you what |
|
| 120:55 | doing would be just shaving off a bit of this thickness here. I |
|
| 121:00 | it would be you know, I Yeah, this this is unnecessary. |
|
| 121:10 | the density contrast across that boundary. really hard to map. In |
|
| 121:16 | I don't think it happens vertically I think it happens. It has |
|
| 121:19 | be this way it has to come the bottom up. Right, Don't |
|
| 121:23 | think? I mean, I I mean it's not like it's not |
|
| 121:29 | it's like a vertical all of a it's just building, start going to |
|
| 121:32 | the ocean floor. It's gotta be gotta be some gradation into it. |
|
| 121:37 | think I think it's got to be like that Anyways how much size of |
|
| 121:43 | . 20 x 80 million gallons. sounds okay. Yeah. And this |
|
| 121:47 | that's just the difference of their this and the less calculated and this |
|
| 121:55 | So this is the measured data difference which is calculated and you get this |
|
| 122:02 | which is you know, pretty It's okay. I think it's an |
|
| 122:06 | model. Alright, let's jump down Kwanzaa basis. This is offshore, |
|
| 122:12 | Angola. And these are, what of anomalies are there? Tell me |
|
| 122:17 | these anomalies are. Are they free those are? No. Yes, |
|
| 122:35 | got it. Tell me what made change your mind. It made me |
|
| 122:40 | my mind because there's just game minimizes and you can see a lot going |
|
| 122:49 | so that it would be free The deepest water. Okay, this |
|
| 123:00 | a continental shelf. Right, I was like where's the water? |
|
| 123:04 | do you mean? This is This angle is the south atlantic |
|
| 123:12 | Oh I see. Okay. I'm sorry. Yeah, so this |
|
| 123:17 | africa Angola and Namibia is down here the conservation is just outboard of that |
|
| 123:25 | basin. This is called the lower congo. And you're looking at a |
|
| 123:30 | . They're all deltas, produced gravity or free air highs. It is |
|
| 123:37 | air data because this is an ocean here and it's it's a low and |
|
| 123:43 | it was bouquet corrected it would be big high and all this would be |
|
| 123:50 | . Yeah, so we're gonna zoom this area right here and this is |
|
| 124:02 | lot they've got a lot of character it? I don't know if these |
|
| 124:04 | are but they really just think that you still there? Hello? Yeah |
|
| 125:04 | computer is crushed. So he reboost now. So he will be online |
|
| 125:09 | . Okay. I just make sure wasn't crazy. It's just and this |
|
| 125:18 | has been doing it every now and and it's starting to drive me a |
|
| 125:22 | crazy. Okay. So where are at here? We were I was |
|
| 125:27 | around something around here about passive Oh we're looking at Kwanza. I |
|
| 125:33 | torturing you about Kwanzaa. That's Okay. Um Right. Yeah. |
|
| 125:40 | . Yeah. Yeah. This is air data and we know this because |
|
| 125:45 | ocean is blue instead of red. ? And so there's a continental shelf |
|
| 125:53 | that that sits out here and that be a low because it's thicker crust |
|
| 125:59 | the ocean oceanic crust out here. you know it's free here. Um |
|
| 126:05 | . So what did they do? They did a three D. Model |
|
| 126:10 | um here's this line is right The seismic line is right here and |
|
| 126:16 | think these are well controlled I And this is a cross section through |
|
| 126:21 | area. So you have a little domes here and then you have some |
|
| 126:27 | rift blocks down here that they're not sure what's going on with the continental |
|
| 126:33 | , hazel. Yeah the all these on West africa. They all all |
|
| 126:42 | just talk about a hinge zone. And it's been in the literature for |
|
| 126:50 | and decades. You don't see that passive, It's just these offshore gabon |
|
| 126:56 | of West africa basis and then there's they're calling a transition. In other |
|
| 127:01 | , crosses getting thin. That okay, here are the free air |
|
| 127:07 | three D. Model and so you see that the shelf is really |
|
| 127:11 | but there's also a local gravity high here and that's kind of interesting. |
|
| 127:16 | what is producing that? Well, to these guys, what they did |
|
| 127:24 | so here's here, this is a section through their inversion. Right? |
|
| 127:28 | uh west to east line here, the measured data, here's the calculated |
|
| 127:38 | and of course you have all these densities and everything. And the lower |
|
| 127:44 | is what they inverted on. So is this structuring that they produced on |
|
| 127:51 | lower crust. To fit the It's kind of an unexciting conclusion, |
|
| 127:57 | guess. It's okay. Um um the end of the day, they |
|
| 128:03 | that the northwest, I mean, southwest northeast oriented Reflection line is Figure |
|
| 128:10 | . And then they have the they the inverted for a death to the |
|
| 128:14 | of salt. Which is this map westernmost scarpetta and they say um results |
|
| 128:32 | that high density lower crustal bodies similar the ones found in the northern |
|
| 128:38 | another part of the central segment I present in the southern part and thus |
|
| 128:43 | to be a general feature of the of the central south atlantic thinning crust |
|
| 128:49 | gradually rather than abrupt manner. And faulting played a significant role during rifting |
|
| 128:55 | indicated by the strongly structured upper In contrast we find brutal little evidence |
|
| 129:02 | thinning or examination of the deeper litmus . Well, that's a relief as |
|
| 129:08 | as suggested by others. More likely the magmatic intrusions prevent that magmatic intrusions |
|
| 129:16 | mantle examination by sealing crust. Yeah. I don't think I'd buy |
|
| 129:20 | but anyways um Yeah, let me what else. Okay, yeah. |
|
| 129:25 | that's what that's what they concluded they this little model here and they inverted |
|
| 129:31 | and they inverted on the basis basis crust or the lower crust. Lower |
|
| 129:37 | . Yeah, I'm sorry. They this horizon. The base the horizon |
|
| 129:43 | the upper crust and the lower Okay. They just inflated it it |
|
| 129:50 | they just added mass here and here bring it up. But I don't |
|
| 129:55 | why they why they made the model here and that. I would be |
|
| 130:02 | in knowing what this is. First all I would want to model because |
|
| 130:07 | might just be the water bottom You know because this is free air |
|
| 130:12 | . That's the problem with free our . You don't really know that these |
|
| 130:16 | are just produced by you know the bottom. So but they're sea bottom |
|
| 130:24 | really pretty smooth. Well at least here. I wonder what it looks |
|
| 130:28 | through here anyways, that's uh that's interesting. And this is the westernmost |
|
| 130:37 | of the atlantic hinges. And that right through here. Is that |
|
| 130:44 | Yeah, it's very interesting. Okay, so now um another three |
|
| 130:53 | . Model, this is the Otani passive margin um along the whatever along |
|
| 131:03 | south africa. So it's inboard of Agulhas Falkland fracture zone, which is |
|
| 131:11 | . F. F. Z. there's a whole bunch of these oblique |
|
| 131:15 | and that's because when the south atlantic the Falkland Islands and the platform |
|
| 131:23 | they were, they wrapped all the around to here. So they pull |
|
| 131:28 | as the south atlantic opens up and and it produces all these oblique structures |
|
| 131:33 | these oblique basins down here, it's interesting. This fracture zone ends up |
|
| 131:39 | right along the northern edge of the and ewing banks off of off of |
|
| 131:49 | south, the off of Argentina. will show you that later because I |
|
| 131:54 | some work there. Alright, have maps of that rather. Okay, |
|
| 131:58 | this there there's a bunch of these sub basins that formed as, you |
|
| 132:03 | , as the Falkland Islands or if you like. Um and uh |
|
| 132:10 | bank scraped along as the south atlantic and sort of open produced these sort |
|
| 132:18 | oblique structures. And this one here the western part is called the the |
|
| 132:26 | or the brightest or basin. And that's what we're gonna look at |
|
| 132:31 | . So here's a little uh key that shows the control again. And |
|
| 132:37 | have two D. Seismic lines. black lines, they had depth section |
|
| 132:43 | . So that's I think there's gonna a profile along this line here. |
|
| 132:46 | some wells with a bunch of log . All these well symbols. And |
|
| 132:51 | coastline of course is up here. model area is this black box here |
|
| 132:57 | think. And there's a basement high . Where is that basement high |
|
| 133:06 | A. A. G. I. N. A. I |
|
| 133:10 | know what that's talking about. I see that. Okay. But we're |
|
| 133:16 | look at two lines. We're gonna at this d. 15 which goes |
|
| 133:24 | way. I really like this D. 92 001 which goes southwest |
|
| 133:31 | northeast. And I got to live the southeast. So maybe go southeast |
|
| 133:35 | northwest. We'll see. Yeah it south east. So it gets |
|
| 133:41 | So you're going ocean word to the . And in this case you're going |
|
| 133:46 | ocean world to the southwest. So both sort of looking with the |
|
| 133:50 | the deeper ocean to the to the hand side. And here's their their |
|
| 133:56 | seismic interpretations. It looks like some darn good data to me. They're |
|
| 134:02 | mapping structures way down here. This uh Over about 3.5 seconds down to |
|
| 134:09 | bottom down here. That's pretty Um Now these are west to east |
|
| 134:20 | sections that go through here. Um is a northwest striking striking basement |
|
| 134:26 | So this line is not these these three separate lines, there's 2 11 |
|
| 134:32 | 22 that you go west to east the three D. Model and they |
|
| 134:39 | on I think the base of crusting or the or the or the horizon |
|
| 134:44 | upper and lower crust. And this their final model. So you can |
|
| 134:49 | that. I think that dash line to be observed data maybe, |
|
| 134:57 | and so here are those models to and 22 as they go through the |
|
| 135:05 | here's the measured data, here's the gravity and it looks pretty darn |
|
| 135:12 | Um Yeah, let me see what bear and others say they have a |
|
| 135:21 | say we focus on the proximal section the larger brad historic sub basin, |
|
| 135:26 | westernmost of five southern South African offshore sub basins. As I said, |
|
| 135:33 | , and that. Okay, our predicts a cumulative eroded thickness of 802 |
|
| 135:45 | m of tertiary centers, sub crustal to shadow and deep crustal extension regimes |
|
| 135:51 | just that basin initiation is typical of mental involvement. Deep seated pull apart |
|
| 135:59 | that is associated with the development of goals. Welcome dextrose shear shear zone |
|
| 136:04 | I was talking about. He has be a senior sedimentation rates. |
|
| 136:08 | blah blah blah. Therefore the they're differential thinning of the crust and the |
|
| 136:16 | with a sphere typical for strike slip ? Yeah, fair enough. |
|
| 136:23 | Alright. So those are kind of typical very boring studies that we do |
|
| 136:31 | three D. Modeling these days. quite often to estimate how thick the |
|
| 136:38 | is and the reason they do that they want to they want to assign |
|
| 136:43 | thermal, they want to sign some genic heat flow value to it so |
|
| 136:47 | they can estimate uh maturation properties for hydrocarbons. That's why they want to |
|
| 136:56 | about this. But the basic model do these things do this, this |
|
| 137:00 | of work. So that's that's the of all this stuff that we're looking |
|
| 137:04 | . And I think a lot of co authors, I think a lot |
|
| 137:07 | these three talks, I think they some co authors. Okay, that's |
|
| 137:11 | they were also similar. But um , there's some good data in |
|
| 137:16 | Alright. Any questions about this No. Do you think you learned |
|
| 137:27 | . Yeah, I mean, I need to go back and kind of |
|
| 137:36 | . Alright. The last section of day, 3:00, I can plow |
|
| 137:41 | this, this is ocean basis and we're in good shape we'll just if |
|
| 137:49 | want we can just not do a and we'll just plow through the end |
|
| 137:53 | we had my little mishap in So is that Okay? Okay. |
|
| 138:02 | . So you've seen this map This is the gravity data free |
|
| 138:07 | offshore bouquet on land and um you , it's free air because it's all |
|
| 138:14 | can see that whatever the topography in . And then here is zooming in |
|
| 138:20 | the central atlantic. Some people call the north atlantic. I tend to |
|
| 138:25 | the north atlantic is up there. but these are fracture zones And they |
|
| 138:32 | have names. This is the this is the chain. This is |
|
| 138:38 | Atlantis, know Atlantis is a where Atlantis at? I think this is |
|
| 138:44 | Atlantis Canaan 15 20 I think that's my curious so on and so |
|
| 138:52 | And if you look at these fracture , you can see that when this |
|
| 138:58 | down this side curves up and that's as I said before, once you |
|
| 139:04 | producing ocean floor, all the motion the plates is accommodated by sea floor |
|
| 139:10 | . So if the rotation pull migrates little bit well then that will put |
|
| 139:16 | little bend in the flow lines, fracture zones which we call flow |
|
| 139:22 | And there it is only a transform the rich sight mints. Some people |
|
| 139:27 | to pretend these are trans are actual and they like to push them up |
|
| 139:31 | the continent and stuff. That's just how it works. These things grow |
|
| 139:38 | from the margin as the ocean basin . That's how it worked. Um |
|
| 139:47 | , so as I was saying the is actually the little segment there and |
|
| 139:52 | fracture zones are the off axis traces the transform, and here's the best |
|
| 139:59 | to think about that. It's very . So say for example, here's |
|
| 140:02 | America, here's africa, here's some ridge transform rich transform ridge, part |
|
| 140:11 | the spreading center of the mid atlantic . So right here, this one's |
|
| 140:19 | this way, this one's going this , so there is dextre will motion |
|
| 140:24 | , this is going this way this this way, so there's a sinister |
|
| 140:28 | motion, but the off axis trace you go over here, this plate |
|
| 140:33 | going the same direction on all sides these fracture zones. That's why there's |
|
| 140:38 | emotion there because the plate right here the same place as here, they're |
|
| 140:43 | going the same direction at the same . So that's why there's only faulting |
|
| 140:51 | . So, um it's important point people like to think these are false |
|
| 140:57 | they are not. They are actually well preserved for a couple of different |
|
| 141:02 | mostly because um at at this intersection crust is very thin, it's on |
|
| 141:11 | order of 2.5 kilometers, three kilometers . It's the thinnest, the thinnest |
|
| 141:16 | on the planet is in slow spreading zones and transforms also quite often at |
|
| 141:25 | slow spreading transforms and fracture zones, magma star because you're sitting right |
|
| 141:31 | it's 10 million years old, it's literacy is already growing and thick, |
|
| 141:34 | colder. This is hot. So end up just unwrapping its magma |
|
| 141:40 | it's too cold. I'll show you . How do these things form? |
|
| 141:46 | I said, they form at the and they grow as the ocean basin |
|
| 141:52 | . And quite often you can line up with features on shore like an |
|
| 141:58 | suture or rift or contact. And what leads people to like draw these |
|
| 142:04 | from the basin, ocean basins on continents. But that is just not |
|
| 142:09 | it works. They just don't understand . They can, as I |
|
| 142:13 | they can nuclear at these pre existing of weaknesses, but that's where they |
|
| 142:19 | and they grow basin work. So just don't jump in. Right, |
|
| 142:24 | , so I want to make that , You can look at these things |
|
| 142:29 | detail and they're wide, they're 30 where there is, there is wide |
|
| 142:35 | a distance across Houston almost, so they're big features, they're big |
|
| 142:40 | valleys and there's structuring in them and know, there's where the rich segment |
|
| 142:46 | to transform inter sectors, lots of in what they call the nodal basins |
|
| 142:53 | here. And if you look at cross section, where is this |
|
| 142:58 | This isn't one of these things um domain and just shows a transfer. |
|
| 143:06 | there's transverse ridges that form along these too and which are some parallel to |
|
| 143:13 | fractures owner or transformed. Yeah, here's another one. Here's um |
|
| 143:22 | ridge transform valley ridge, This is kilometers, so in this case there |
|
| 143:27 | about 20 kilometers wide and this a A prime is here. So here's |
|
| 143:33 | you have the older, the 10 year old crust, here's the rich |
|
| 143:38 | where there's zero little sphere, you know, little spherical mantle and |
|
| 143:44 | jumping, you know, maybe 30 to a hot atmosphere next to this |
|
| 143:50 | . So that's why these these these these little note of basins are sometimes |
|
| 143:57 | star, not for fast spreading You have these secondary and tertiary uh |
|
| 144:08 | continuity. So you say the transform is a First order. This |
|
| 144:13 | D one. You might have some where there's a little jog in the |
|
| 144:19 | the fracture zone. I'll show you right here, these guys here, |
|
| 144:24 | these little things. So there's a zone there, but there's not really |
|
| 144:29 | transport. So, these are what they're calling, what whatever Macdonald |
|
| 144:34 | secondary discontinuities. And then not to , not to let that go, |
|
| 144:42 | tertiary and quaternary discontinuities. You get idea, but basically this is just |
|
| 144:49 | sort of morphology of the sea floor that's what ocean basins mostly is |
|
| 144:57 | It's about the morphology of the ocean with the primary features that you see |
|
| 145:03 | fracture zones and spreading centers just like the map of the world, right |
|
| 145:08 | zones and spreading centers. There are things. There's hotspot tracks. There's |
|
| 145:13 | igneous provinces, you know, there's seismic ridges, some out here, |
|
| 145:18 | back arc basins. All these basins here are back arc basins. So |
|
| 145:23 | other things. But even all those basically about the morphology, the shape |
|
| 145:29 | landmass, the shape of the land . And why am I spending time |
|
| 145:33 | this for classes? You know, all about petroleum geophysics? Well, |
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| 145:39 | reason is because as we explore you know, deeper water or in |
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| 145:45 | areas, we might, you we find ourselves sitting looking in areas |
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| 145:52 | are sitting on top of oceanic And quite often people have this view |
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| 145:58 | ocean floors. It's just this monotonous, you know, uninterrupted flow |
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| 146:03 | crust, but it's just not. it has um, it can be |
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| 146:08 | in a lot of different ways. , so here are some some sea |
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| 146:14 | spreading anomalies this time over the central and going into the north atlantic. |
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| 146:20 | yeah, you can see them just through here's Sikma East Coast magnetic |
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| 146:24 | There's the blake spur magnetic anomaly. then these are Cron's um, M |
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| 146:33 | to M zero, which m means mrs electrons. The centers of |
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| 146:38 | They just use the number. Sometimes put the letter C in front of |
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| 146:43 | . But that's it. So here's spreading ridge here and here's crimes. |
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| 146:49 | . Whatever. C. One A 30 for remember 34. And in |
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| 146:56 | part here, that's the magnetic quiet . In the cretaceous magnetic quiet zone |
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| 147:01 | there. And it is, I this is the M. S. |
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| 147:08 | . So the cretaceous quiet zone here between here and here. Between here |
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| 147:14 | here. Okay, well here's here's little bit simplified. Okay, so |
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| 147:21 | have this in the central atlantic and is, you know, you can |
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| 147:26 | of this for a lot of ocean . You have the medic, the |
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| 147:29 | atlantic ridge or the mid ocean ridge the ocean basin basically open, symmetric |
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| 147:36 | that. And then you have the , here's here's the sea crowns from |
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| 147:43 | to 34 which is remember it was point something million years old right |
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| 147:49 | And then you have the cretaceous Quiet , also called the long normal. |
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| 147:54 | were no reversals during that time. then you have the M the Mississauga |
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| 147:58 | , the M zero to M. . And there's even more um now |
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| 148:05 | yellow dots are control points that I to reconstruct this. This is from |
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| 148:10 | , from my dissertation, this is paper that was published in geo |
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| 148:14 | but this is a chapter of my . Okay, if we look at |
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| 148:21 | yeah, I'm gonna show you maps this area, this area, this |
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| 148:26 | and this area, right? So you look at the the north american |
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| 148:32 | the published crimes M 04 10 21 25 of these green ones. |
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| 148:39 | then I picked all these in So M whatever M2 to uh I |
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| 148:45 | em 40 here. So where it's , it's just there's actual anomalies and |
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| 148:51 | it's dashed. I'm just connecting these lines, blake sperm and economics just |
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| 148:57 | of that. And then East Coast economic is here in these dark purple |
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| 149:02 | our limits of oceanic and continental So it's definitely oceanic outboard of this |
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| 149:10 | and definitely continental inboard of this So you could call this transitional if |
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| 149:16 | want. And then then there's some stations, these red inverted triangles that |
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| 149:24 | in the literature from published sources. this is the yellow area is the |
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| 149:33 | , the blake plateau. Okay. , these are the same crimes. |
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| 149:41 | now the open file ones that are red instead of green. And I |
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| 149:48 | plotted the magnetic data as a yellow of green to yellow scale. And |
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| 149:54 | put on the my blue picks and there's blake spur and there's Sikma. |
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| 150:00 | then inside here that some called the magnetic quiet zone. And here is |
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| 150:05 | Jurassic magnetic quiet zone. So the Jurassic. Now there were reversals in |
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| 150:10 | Jurassic quiet zone there. But they very quick in the field was very |
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| 150:16 | and we even see looks like there be some crayons in the inner magnetic |
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| 150:21 | zone. But M 40. I , I don't know. I think |
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| 150:25 | 41 is the oldest oldest oceanic Cron have identified. So there's some work |
|
| 150:31 | be done here. There has been done as well. There's a guy |
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| 150:36 | now works at Exxon, his name Green and he did work on this |
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| 150:41 | as well. Okay, we can to the other side. So the |
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| 150:49 | and uh here we have crimes. only mapped crimes in this corridor here |
|
| 150:58 | the data is just the coverage is not very good elsewhere. And then |
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| 151:04 | think at least we were saying back that S one and S. Three |
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| 151:08 | the conjugate. It's two. Um for and Sikma, but that but |
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| 151:15 | has a very small gap. And let me just go back to the |
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| 151:19 | here. The distance from the minute to the coastline here is greater than |
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| 151:30 | distance over here. So that means there had to be rich jumps and |
|
| 151:40 | jumps do happen. There's no, mean, the amount of asymmetry spreading |
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| 151:47 | spreading an ocean basins is very There's the east coast, the east |
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| 151:53 | rise maybe has 10%. Everything else like less than 5%. So, |
|
| 151:58 | that sort of makes sense. I , why would one, why would |
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| 152:01 | side of the, of the, know, the spreading center, Why |
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| 152:04 | side four out faster than the other . It just doesn't make sense. |
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| 152:09 | it's probably a rich jump in And then we think also there's a |
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| 152:15 | jump inside the inner magnetic clasp that's why these these are so close |
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| 152:21 | and there's a gap here. So a little strip african with this fear |
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| 152:29 | here and probably elsewhere as well. that's what's going on there. |
|
| 152:37 | Here is a comparison of the These are the line. I'm gonna |
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| 152:40 | you these lines and the magnetic anomalies them. Just to show you how |
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| 152:45 | things are correlated. I know I you a little uh I showed you |
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| 152:48 | little example with Jim her Slurs paper earlier. But I'm going to show |
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| 152:56 | something that I did here in the lake. Um And uh yeah, |
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| 153:01 | there's a through whatever w on this and a through N. On this |
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| 153:08 | , I'm gonna show you M 0 m. versus M zero to |
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| 153:16 | 25. So the youngest part that gonna show you whatever M. 25 |
|
| 153:22 | M. 40 and M. 25 M. 40. The older |
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| 153:25 | Right? So here's the younger North America M0 to m. africa |
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| 153:32 | that little corridor. M zero to . 25. And these are the |
|
| 153:39 | that I'm picking here. So you see what I'm picking. And now |
|
| 153:46 | you're if you're a person who does you know, coherence modeling, this |
|
| 153:54 | just gonna make you nauseous problem, ? And again, this is the |
|
| 153:59 | polarity reversal scale going from young to . And here it is again, |
|
| 154:06 | from young to old. And the profile calculated from that is the first |
|
| 154:15 | . All the other ones are measured . Okay. But what we |
|
| 154:20 | what we do is we pick like of anomalies like this triplet here looks |
|
| 154:25 | we can sort of see it sort percolating through here. Right. And |
|
| 154:30 | the way you think about it. , so the spreading half rate for |
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| 154:37 | is 12.6 for North America is 14.4 North America is 10.5 10% fast. |
|
| 154:46 | is, you know, that's right the edge of asymmetry. So there |
|
| 154:52 | be something going on in here. , now the old ones, so |
|
| 154:59 | at the geomagnetic polarity reversal scale You see, you see all the |
|
| 155:04 | fast the field was was flipping. not even producing individual anomalies. They're |
|
| 155:11 | like anomalies associated with groups of these . Well, okay, so when |
|
| 155:18 | was looking at these data And and if you measure if you measure the |
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| 155:25 | from M28 to M40 on the african versus the north american side. Let's |
|
| 155:34 | back. So if you measure the from M 28 to M 40 on |
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| 155:38 | side versus M 22 M 40 this . M 28. M 40 is |
|
| 155:44 | on this side. But I I 20%. And that's outside our 10% |
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| 155:51 | . Right. So does that mean there a rich jump in there? |
|
| 155:56 | then I started looking around for repeated and I decided that these two anomalies |
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| 156:01 | a lot alike. See what would is if there was a rich |
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| 156:07 | you might have an extra one on side and a missing one on this |
|
| 156:12 | , right? Because it was left . This was this was a little |
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| 156:16 | of north America with a sphere just in here between S. S. |
|
| 156:24 | and S. Three. There's a of lips. You're missing on this |
|
| 156:29 | . That's over here between black spur here. So what's the story |
|
| 156:34 | The story is that in the early of opening, right? The spreading |
|
| 156:42 | not uniform. It's not it's not , you know, it's not like |
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| 156:46 | cartoon. Right? It basically they're know, this is this, remember |
|
| 156:52 | is north America rifting in the central was the first ocean basin produced during |
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| 156:59 | opening breakup of Pangea. Remember north broke away first. So maybe this |
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| 157:07 | breakup was was was a little Maybe there was some jump jostling |
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| 157:12 | And so you had initially you had rich jump on the north America |
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| 157:22 | You reach up on this side between in here, leaving a little strip |
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| 157:27 | africa here. Then you had some floor spreading from M. 40 to |
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| 157:31 | . 28. Well I'm sorry. , just right after M. 40 |
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| 157:34 | had another one almost uh here that left left some with this fear of |
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| 157:40 | America on this side. So this what we're suggesting. So when did |
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| 157:46 | this happen? When did all this ? It happened around I think. |
|
| 157:53 | see this is around one uh 25 is around. Did I date |
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| 158:01 | somewhere in here? I had to it. Can I put it in |
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| 158:05 | somewhere? Oh it's killing me. . So but anyways m. I |
|
| 158:14 | it's like 1:54. I think it's think it's I think it's 1:54. |
|
| 158:22 | here's so why was it doing Well what else happened around 1 60 |
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| 158:27 | . A. I think it's 1 . What happened around once? The |
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| 158:33 | this one here would be like 25 is like 1 60 to 1 |
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| 158:38 | for. And then that would make you know the the Blakes for that |
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| 158:49 | make possibly the Blakes for uh At like 1 61 65. 1 |
|
| 159:01 | But what else happened during that time gulf of Mexico started opening up? |
|
| 159:06 | what happened. So maybe maybe and you know that was right there right |
|
| 159:11 | right there in north America. So it had something to do with it |
|
| 159:14 | just postulating that but that's that's what resulted from, that's what we sort |
|
| 159:19 | suggested in the thesis. Alright, fine and dandy. Um Ocean basin |
|
| 159:26 | flow. Ocean basin, this is slater 1980. And then Stein and |
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| 159:33 | , that's carol and Seth published this Nature in 1992 and basically uh from |
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| 159:44 | spreading center. So this is agent of years, both of these |
|
| 159:48 | millions of years. The flow kind decreases log, rhythmic, meet |
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| 159:53 | rhythmically um away from the spreading center it's mostly substance, I mean its |
|
| 160:01 | and you know just heat dissipation. and here the top one here is |
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| 160:07 | flow which correlates with this one, the bottom one here is actually the |
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| 160:12 | the elevation of the sea surface. did it for let's see, they |
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| 160:18 | it for several areas africa south is that right? Yeah, |
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| 160:31 | Um Now spreading centers can become They can just, you know, |
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| 160:36 | basic can stop opening. This is coral, this is the Tasman |
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| 160:41 | You know, this is this is and Tasmania. This is part of |
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| 160:45 | Zealand and this is an extinct spreading . It's a fossil spreading center and |
|
| 160:50 | is all, you know, nothing active in here. These are all |
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| 160:53 | zones, you know that are passing that so that can happen. Um |
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| 161:00 | actually magnetic anomalies. And they identified crowns, this is 33 through 27 |
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| 161:07 | 34 was 83 point something M. . And then I think, I |
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| 161:12 | know what Cron 24 is. But think it's I don't want to guess |
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| 161:20 | whatever, tens of millions of So that's when that basin formed |
|
| 161:25 | The south china sea basin. So here's here's Indochina Vietnam, here's |
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| 161:35 | island's name. Follow on follow on . There's there's um Taiwan is up |
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| 161:43 | and then but here's the south china and then the Philippines is just off |
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| 161:48 | the east here and they reckon they the crowns over here. They |
|
| 161:55 | Here's the magnetic data, here's the data and here's the topography. So |
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| 161:59 | is the ocean basin. And what here was that you had a spreading |
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| 162:03 | here in this part and it jumped . So there was a rich jump |
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| 162:08 | early on. But there's a bunch them and I just listed a bunch |
|
| 162:14 | references for the Asia ridge in the sea. The labrador sea cape rise |
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| 162:20 | that towel basin. This is south Chicago ridge. This is east of |
|
| 162:25 | , the west Philippine carl c, is just north of Tasman and Magellan |
|
| 162:30 | . So there's a lot of these fossil spreading centers uh subduction zone. |
|
| 162:38 | here's This is from Gerard in 1986 , it's kind of a summary of |
|
| 162:45 | world's world subduction zones. The dip the slabs. The seismicity, the |
|
| 162:52 | rates, the velocity overriding plate etc . And here's the Benioff zone. |
|
| 162:59 | you know what Benioff is? I don't think I've heard of |
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| 163:05 | Benioff is the seismicity. It's it's a trace through the earthquakes. |
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| 163:12 | this is the earthquake zone beneath all different island arcs or all these, |
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| 163:17 | these subduction zones. So for example Mariana very famous one, it's a |
|
| 163:25 | one. Class ones are very steep . And then he had all different |
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| 163:30 | of them. Um And you he's, this was this is from |
|
| 163:36 | . This data is much more comprehensive beneath South America, there's some that's |
|
| 163:41 | very shallow in South Chile. And there's two more and up to |
|
| 163:46 | seven. So northeast Japan is kind an interesting one. Sorry, Tonga |
|
| 163:59 | . Isn't that where some of like deepest earthquakes found? Our the |
|
| 164:07 | Uh well yeah, okay, these over 600 km Marianas to 650 |
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| 164:14 | This is five less than 600. , they are because this these these |
|
| 164:24 | are drawn from earthquake data. Benning zones are the traces of the seismicity |
|
| 164:34 | of earthquakes. So this is kind a nice paper because it shows them |
|
| 164:43 | relative to each other. But there some abandoned subduction zones here in |
|
| 164:52 | here in the, this is africa africa, this is the southern ocean |
|
| 164:58 | this is the south atlantic. There a subduction zone here but it's |
|
| 165:04 | It doesn't exist anymore. And the and lucy basins, The sushi and |
|
| 165:12 | seller Bc bases are thought to be trapped basins. So they were once |
|
| 165:19 | were once subduction zones bounding these that aren't that don't exist anymore. So |
|
| 165:26 | subduction zone, why not? now there are triple junctions out ocean |
|
| 165:33 | . So there's the buffet triple junction here in the south atlantic and there's |
|
| 165:38 | triple junction out here in the the east pacific rise and then there's |
|
| 165:44 | spreading center here that extends off and the Galapagos and into whatever. South |
|
| 165:53 | plunges terminates there. Um There are all kinds of triple junctions. Subduction |
|
| 166:01 | subduction. There's strange subduction subduction. all different sorts, right? There's |
|
| 166:10 | bridge. Um Here's, here's a a rich transform uh ridge transform. |
|
| 166:20 | triple junction. So yeah, and subduction transform, transform subduction transform. |
|
| 166:28 | there's a there's a lot of different of triple junctions and some of them |
|
| 166:32 | unstable. They don't last very Yeah. Okay. And right here |
|
| 166:37 | san Andreas, remember I said see subduction zone turned into a transform and |
|
| 166:42 | it's a spreading center again once you to the gulf of California. So |
|
| 166:48 | happened um out there again. These all morphology, right? So I'm |
|
| 166:54 | kind of showing you the different sorts things. I'm trying to show you |
|
| 166:58 | and I got to get to where can um Here's a here's a transverse |
|
| 167:04 | That runs along the Romance Transform. the offset of this ridge segment from |
|
| 167:09 | to here is 1000 km. It's the longest in the world. And |
|
| 167:16 | has this big transverse rate that's that's . It's like they call them leaky |
|
| 167:22 | . Because basically what happens? let's see. Yeah. What happens |
|
| 167:30 | you have This will go back to one this distance on a spherical |
|
| 167:39 | you know, this rectal rectilinear Jamboree really work well in the spirit of |
|
| 167:45 | . So they end up having to like this, they kind of jump |
|
| 167:50 | . So the transformers actually has And I think that they're showing that |
|
| 167:59 | where they say that there's this suspended here and this and they think there's |
|
| 168:04 | there's a fossil spreading center here and fossil fractures on here that's in this |
|
| 168:11 | ridge right there, that happen. occurred just because this is just really |
|
| 168:17 | transform segment. It it just doesn't . So it's it's kind of a |
|
| 168:24 | . So yeah, there's that um marginal ridges. So or shear |
|
| 168:32 | So that's where you have a continent , that's not a rift boundary or |
|
| 168:38 | subduction zone, but it's a continent up against ocean floor. But the |
|
| 168:43 | boundary is actually a transform or in case was a transformer. And these |
|
| 168:49 | very interesting, there's a handful of around the world. And how they |
|
| 168:53 | is when the uh when the plates apart. You know, you |
|
| 168:58 | you have your basic counting transform, then a spreading center pops up and |
|
| 169:05 | center just rides along the side of continent. And you can imagine you |
|
| 169:11 | like, you know, 200 kilometer little sphere Right next to zero thickness |
|
| 169:19 | here. So there's gotta be some incredible temperature thing, you know, |
|
| 169:26 | thermal gradients going on there and took often what forms. This is what |
|
| 169:31 | call a shear margin. And here's reflection line through it. So this |
|
| 169:34 | right, this is this line The drop off in two way travel |
|
| 169:39 | is four seconds And that is over distance. Let's see, that's that's |
|
| 169:46 | kilometer. That's over a distance of 40 km. That's amazing. So |
|
| 169:54 | the drift section and here's the you can see the rift section beneath |
|
| 169:58 | drift, right? And this is there's there's a refraction line along this |
|
| 170:03 | too. Do you do you do about refraction data? Right? Seismic |
|
| 170:09 | data for, I'm not talking about statics. I'm talking about for crustal |
|
| 170:16 | crustal thickness. Are you familiar with ? It sounds familiar, but we |
|
| 170:24 | go over. It's been a I think so. Refraction data basically |
|
| 170:28 | have its long offset data and you big sources, you know, like |
|
| 170:34 | of dynamite back in the day and , you know, you're, you're |
|
| 170:42 | , you know, as the, the wave, as the wave front |
|
| 170:48 | , hits the different horizons. There's critical angle, right that probably rings |
|
| 170:51 | bell. There's a critical angle at that that wave front travels along the |
|
| 170:58 | at the velocity of the deeper Does that ring a bell? |
|
| 171:05 | Okay. So then as that wave travels along that, that refractor, |
|
| 171:14 | like, you know, it's you know, reflecting reflecting back |
|
| 171:22 | So that when you you can measure long business you can measure its just |
|
| 171:26 | , you measure the depth and velocity deeper crustal layers and even the |
|
| 171:34 | So that's what you're seeing here. seeing a bunch of different now, |
|
| 171:38 | are these are densities in here. there's a corresponding figure in this |
|
| 171:43 | this is Edwards and others 97 where show they show the velocities, but |
|
| 171:49 | this is the crustal geometry of the coming into here. And this is |
|
| 171:56 | is the crustal geometry and this, this is a fracture zone. So |
|
| 172:01 | crust is very thin, maybe three thick and and over a distance of |
|
| 172:07 | know, let's see maybe what is 70. You know, over this |
|
| 172:12 | a 35, 40 km across seconds almost 40. So, I |
|
| 172:17 | you know, it's almost 45°. That's for one. So yeah, so |
|
| 172:22 | produce these big ridges. Well, this is the one we just looked |
|
| 172:29 | , we can look at the other of africa, this is kenya |
|
| 172:35 | And you see this is the Davie . This is another marginal ridge that |
|
| 172:41 | um in the same way it's a an ocean con it's a ocean continent |
|
| 172:46 | boundary. And here, remember we at the uh oh, oh Tanika |
|
| 172:51 | and the bread is whatever basin was down here. But then remember the |
|
| 172:58 | Falkland fracture zone, that's right And so it has a marginal ridge |
|
| 173:02 | well. Because remember I said the , here's the Falken plateau, here's |
|
| 173:06 | ewing bag. All of this is cross. And it was it was |
|
| 173:12 | off and just scrape right along. this thin line here is the marginal |
|
| 173:19 | on that. So it has conjugate ridges, just like they did. |
|
| 173:25 | , all right. But again, morphology. So now there's um there's |
|
| 173:33 | seismic ridges out there that we really understand, but they do exist in |
|
| 173:39 | in the central atlantic. Again, the lesser antilles. So there's Puerto |
|
| 173:45 | , there's Hispaniola and you know, martinique and so on and so |
|
| 173:54 | There's Barbados right down there. And these size, these a seismic ridges |
|
| 174:02 | Here there's this one the barracuda Richards a really big one, It looks |
|
| 174:06 | it's being subduction and there's even evidence it's poking up the other side, |
|
| 174:10 | the caribbean plate just like crashed into and it's overriding this part of it |
|
| 174:15 | then south of that is called the ridge. And then there's the ST |
|
| 174:20 | ridge and maybe even another one in . So, here's the topography and |
|
| 174:28 | right? Here's the barracuda ridge here it looks like it's coming out right |
|
| 174:35 | . That's what it looks like. coming out. Here's the gravity anomaly |
|
| 174:38 | it. Here's the gravity over the . Here's the Tiburon ridge right here |
|
| 174:44 | here's the other to the ST Lucia . This one down here and then |
|
| 174:48 | course there's Barbados um McKenna cites this worked way back in 84 on |
|
| 174:55 | So, here's the barracuda to burn ST Lucia and they suggest there's even |
|
| 175:00 | further south that they're calling, what they call it? The something like |
|
| 175:04 | crypto crypto bridge or something or But yeah, here's barracuda ST Lucia |
|
| 175:12 | Lucia. And now you can see this residual, you can see the |
|
| 175:19 | part poking out here a little bit . Okay, um now some people |
|
| 175:28 | that these, these a seismic they're related to the, the plate |
|
| 175:33 | between north and south America. But look at that later, maybe. |
|
| 175:39 | I talked about hotspot tracks in large provinces and here they are again, |
|
| 175:48 | this is by Duncan and Richards and is an idea that may not may |
|
| 175:54 | really be worth, may not apply , but back in the day, |
|
| 176:00 | hotspot tracks, or hotspots rather were to be fixed and that the place |
|
| 176:07 | moved over them and they and they in motion and back and back |
|
| 176:13 | You know uh 30 years ago. they thought that there are two families |
|
| 176:23 | hotspots, the atlantic and indian ocean family is here and the pacific hotspot |
|
| 176:31 | that were sort of fixed relative to other but here's here's the idea they |
|
| 176:39 | mantle plumes are thought to originate at core mantle boundary in this double D |
|
| 176:44 | layer. Remember these are all the the super kind of cycle. These |
|
| 176:48 | all the slab avalanches in the slab down here which feed these things and |
|
| 176:55 | the plume comes up erupts and causes kinds of mayhem. Um Then and |
|
| 177:04 | one example in the pacific of course the famous Hawaii Emperor seamount chain. |
|
| 177:09 | this age kinda logic, you volcanic rock samples hold on. Then |
|
| 177:20 | one that I work in the south a lot. And so the Rio |
|
| 177:23 | rise and the Cameroon, I mean mean and Walvis ridge, these are |
|
| 177:28 | to be ridge centered was produced by ridge center hot spot right now tristan |
|
| 177:34 | cunha which is the island. This volcano the last eruption was 50 years |
|
| 177:40 | I think. But but this this interrupted when western Gondwana in south America |
|
| 177:50 | africa were connected. There's a huge assaults here on south America called the |
|
| 177:58 | flood basalt. There's flood assaults here the acting deca. And yeah so |
|
| 178:05 | ridge center means it was beneath the center. Like Iceland is now Iceland |
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| 178:12 | a rich centered plume. Hawaii is intra plate plume makes sense. The |
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| 178:19 | in line is thought to be a room and there's other lies in these |
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| 178:24 | around. So let's see here. what am I looking at? |
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| 178:31 | Okay. So this is some work we did over a couple of different |
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| 178:38 | . Uh dr hall and I he uh, he taught potential fields at |
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| 178:45 | university before uh you know, he before dr some uh he recently retired |
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| 178:51 | a couple of years ago. And is from a paper that we |
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| 178:56 | Well these are from actually abstracts from A. G. U. But |
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| 179:01 | we're, what we're looking at so the flood basalt are outlined in |
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| 179:05 | , right? And and the public crimes are mapped and green. Much |
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| 179:12 | I did for the central atlantic. our identification of crimes is these are |
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| 179:18 | red dots. Right? And then we have satellite derived free air |
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| 179:25 | Here's the paranal flood, the salts the steeple. And then we use |
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| 179:31 | uh ion let's use some seismic lines then there's some refraction data in |
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| 179:36 | We did a reconstruction of the south that we that we had a little |
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| 179:44 | that we presented um at the G. U. So here is |
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| 179:49 | reconstruction I think this is This is this is crime 30 crime 84. |
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| 179:57 | this is I mean 84 million. is crime 34. So it's just |
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| 180:02 | to the magnetic class zone. And then um yeah these so these |
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| 180:09 | anomaly. And then here is the . This is This is not |
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| 180:19 | 34. Wait a second. No sorry. This is present day. |
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| 180:28 | is just present day. This is . This is just the way it |
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| 180:30 | right now. This is the So the Rio grande rise and the |
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| 180:36 | is rich connect like this when you're . Yeah. And here's the difference |
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| 180:47 | from our model. All right. sorry. This is the observed from |
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| 180:50 | model. This is calculated response from three D. Model. So it's |
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| 180:54 | darn good. This is the reconstruction the difference between those two is right |
|
| 180:59 | . The difference is This is five gals. So it's not a bad |
|
| 181:06 | . Alright, so large in these . So what's the difference between a |
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| 181:12 | igneous province in a hot spot? source is the same. They're both |
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| 181:17 | plumes. But the difference is largely provinces represent areas where there was just |
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| 181:24 | enormous eruption of magma and flood basalt whatever. And and that was |
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| 181:30 | They don't last for a long Whereas hotspot tracks. Hotspot produced tracks |
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| 181:36 | are the linear features right? That over time. Like Hawaiian uh like |
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| 181:43 | the Hawaiian Emperor seamount chain or these uh hotspot tracks in the south |
|
| 181:49 | But in terms of the source, both produced by core mantle boundary, |
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| 181:57 | source magnets that they're depleted in uh depleted in uh, you know, |
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| 182:06 | elements. And they erupt differently. of them erupts slowly over time would |
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| 182:13 | the hotspot tracks and one of them all at once in java. This |
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| 182:18 | one here is bigger than texas. an enormous eruption. I mentioned |
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| 182:27 | the central atlantic magmatic province before it's to have erupted right here in the |
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| 182:34 | between north America africa. Remember this the first, the first breakup camp |
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| 182:39 | at 200 million years, 201 I , say, uh Samar Zoli and |
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| 182:45 | . And the breakup happens, You , 15, 20 million years |
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| 182:53 | So here's the here's the extent of , it's just enormous, you |
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| 182:59 | 60 million cubic kilometers of magma that estimate from it. Okay, another |
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| 183:09 | that you see in ocean basins are arc basins. These are little tiny |
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| 183:13 | basins that form over subduction zones. , um right, so how does |
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| 183:22 | work? How do you have an of basin over subduction zone? Remember |
|
| 183:26 | talked about slavs being routed and in in the fore arc sometimes you have |
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| 183:36 | in the fore arc because this is in the overriding plate moves back a |
|
| 183:41 | bit. That's what's happening here in Mariana four arc. And then here's |
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| 183:47 | Mariana island arc, which is produced the slab melting down below. But |
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| 183:53 | here's the Mariana uh Mariana trough. , I see. Yeah, |
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| 184:02 | this is the backyard base Mariana trough the back of the Mariana trench is |
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| 184:07 | deep, the deepest part of the basin that we all know about from |
|
| 184:12 | Geographic. But this is a nice three D rendering and it shows you |
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| 184:16 | relationship between the seduction zone, the arc, the arc and then the |
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| 184:22 | arc. So this is an extension basin that's forming because the overriding plate |
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| 184:27 | pulling back. And quite often there's and the reason it breaks here is |
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| 184:32 | this is where it's hot from from the island arc. Right? |
|
| 184:37 | quite often there is a remnant island left behind. Um not in this |
|
| 184:43 | , but sometimes there is so back basins, they're all around the |
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| 184:51 | there's the, in the Tonga there's the loud bass in this little |
|
| 184:54 | one, there's a South Fiji there's the North Fiji plateau, there's |
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| 185:00 | then going up, here's the Mariana , here's the here's the tire is |
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| 185:06 | in the shikoku, right? Those all these are back arc basins |
|
| 185:10 | Okinawa trough is the back arc the sea of japan, they're all |
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| 185:15 | because these slabs are all plunging, all dipping to the west and they're |
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| 185:20 | there steeply dipping. If we go and look at Gerard's paper, you'll |
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| 185:24 | that these are all steeply dipping uh . So this basically they're rolling over |
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| 185:31 | they, that's what they call And the plate is pulling back and |
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| 185:36 | producing these, these little these little back arc basins are being generated. |
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| 185:43 | and the weirdest thing is this south basin is actually a ridge ridge |
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| 185:48 | back arc basin, which is just wild. Okay, so now I'm |
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| 185:54 | show you a little case history. is this is from some work that |
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| 185:58 | is from my master's thesis at Of age. And this is the |
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| 186:02 | we're looking at the caribbean plate. this is the leading edge of |
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| 186:08 | It's going uh eastward relative to the atlantic and here is Barbados again. |
|
| 186:18 | and of course Trinidad and Venezuela, rico. There's that very deep subduction |
|
| 186:25 | . There there are the trench, the main ridge which is thought to |
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| 186:29 | part of barracuda. And um we at the if we look at the |
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| 186:37 | air gravity on the left which we at before and then the residual, |
|
| 186:41 | all we also looked at before. it all looks very similar. Uh |
|
| 186:46 | is the back arc basin, this the active island arc, The Aves |
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| 186:50 | here, the Aves ridge that's a island arc. So this is a |
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| 186:56 | arc basin that left behind an abandoned arc. So it's not active. |
|
| 187:03 | here's the magnetic data. So this uh now the magnetic data is kind |
|
| 187:10 | weird because it has these anomalies that sort of oriented east west. And |
|
| 187:16 | some workers uh thought that pendulum Barrett that it opened this way, |
|
| 187:26 | So it's sort of like opened orthogonal the motion of the plate as it |
|
| 187:31 | being subjected. And another idea was it just opened normally. And another |
|
| 187:41 | um was that it opened sort of with the spreading centers are oriented this |
|
| 187:47 | . So there was three ideas of this thing opened pendulum Barrett Tomlin and |
|
| 187:54 | Boys down here. But so we at it and um what we found |
|
| 188:02 | okay, first of all, the is that these these anomalies at the |
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| 188:09 | that the basin was formed in the time, the caribbean was further south |
|
| 188:16 | it is now. Um You there's been the with regard to the |
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| 188:24 | , the pole position And in terms inclination. That is, I mean |
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| 188:30 | where it is. But the the inclination was was was 23° instead of |
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| 188:38 | is now, I think it's 43° something. So the field was very |
|
| 188:42 | latitude, very little inclination. And what that means is, remember from |
|
| 188:47 | we were talking about that stuff was remember the 30 degree inclination ones where |
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| 188:53 | was almost, you know, where low was taking over. That means |
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| 188:58 | they're elongated. The you know the west anomalies are enhanced at the expense |
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| 189:03 | north south plus. So that when made it reduced the pole of |
|
| 189:08 | these trends went away. Do I that map? I don't have that |
|
| 189:13 | here. But and so then we to be basically like normal back arc |
|
| 189:19 | form. And in fact this is an idea folks have. But if |
|
| 189:24 | flipped this is this is another back in in the indian ocean in |
|
| 189:32 | So so the this is called the is called the uh it's um the |
|
| 189:44 | sea. Right? This is the sea. This is the Andaman sea |
|
| 189:49 | . And so this has this the ridge segment geometry. Right? |
|
| 189:54 | what we did was um yeah, just a magnetic anomalies, we did |
|
| 189:59 | all these three D. Models. mean this is this one of these |
|
| 190:05 | D. Models and we integrated with data and model the geometry of the |
|
| 190:12 | . And as I said, we up with this geometry which is quite |
|
| 190:16 | what you would expect from back arc all the rest of them around the |
|
| 190:20 | where the where it just opens up of like you know the extension is |
|
| 190:26 | the direction of you know, subduction plate motion. So makes sense. |
|
| 190:33 | there is this one basin, as was saying, next to the indian |
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| 190:40 | called the Andaman sea where you have oblique extension. And so if you |
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| 190:46 | trace that bleak oblique extension in the . Um and see which is right |
|
| 190:51 | . If you project those segments back the subduction zone, you can see |
|
| 190:56 | they are subnormal too. That if flip that upside down, here's the |
|
| 191:03 | plate motion. Relative to that Here's the atlantic plate motion, relatively |
|
| 191:10 | during the opening. So, Our is very similar to that in any |
|
| 191:17 | that we just closed the ocean That's a little case history. It's |
|
| 191:22 | tectonic physics. I mean, not tectonics, 93. I think The |
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| 191:29 | publication was from Uh basins of the . vol, vol four. |
|
| 191:37 | so more more of my stuff. is some work I did with kevin |
|
| 191:42 | and this again shows the opening of center Atlanta because this is the original |
|
| 191:46 | up of of Benji, right? is Western Gondwana and North America is |
|
| 191:54 | green uh texas was the state all way back then. Um then you |
|
| 192:01 | the red the kind of the mobile here or the kind of whatever the |
|
| 192:06 | ones the ones that are kind of for the reconstruction rather, here's the |
|
| 192:12 | black with its you know, the think I'm using the what's the |
|
| 192:18 | I think I'm using one km, km Isil Bath. And so it |
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| 192:28 | the gap here. So between, know florida and and Mexico and then |
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| 192:35 | the watched a marathon suit. Then these, these blocks after um after |
|
| 192:44 | and Dickinson, Dickinson a lot. I'm ghosted in south America. I |
|
| 192:49 | central America and here's where the Bahamas . So in the reconstruction of africa |
|
| 192:55 | south America they're getting those in the terrorize lineup and the Bahamas start the |
|
| 193:03 | . So I think the Bahamas and not the first person to think |
|
| 193:07 | but I agree with, I think bob I can't remember his last |
|
| 193:17 | It was but it was 1973 where first this idea that the Bahamas set |
|
| 193:22 | top on top of the camp plume . Okay. Remember the campus, |
|
| 193:28 | big uh the big large in his . And right, so here's here's |
|
| 193:38 | . 41 65 M. A. I picked two M. 40 in |
|
| 193:43 | and then I think if we, , I don't have those. |
|
| 193:49 | so this is how At once an . 40 just with the reconstruction and |
|
| 193:55 | everything fits together. Alright. Um how all that works. So as |
|
| 194:07 | it opens up, this is this is from Dickinson a lot that |
|
| 194:10 | just mentioned and these are those bits , these are those bits of crust |
|
| 194:15 | , the yucatan in the block the block, the the del Sur block |
|
| 194:22 | right here, right here and those the same ones that I have right |
|
| 194:27 | . Okay, so and this is it looks. Once. Once the |
|
| 194:32 | opened up the south Atlanta, I the gulf of Mexico. So 2 |
|
| 194:41 | 60 for everything is closed. Here's Pacific Ocean, here's john one and |
|
| 194:48 | , here's Lorenzen. And you have these terrains of paragon paragon one and |
|
| 194:53 | in here. But anyways this is up the gulf coast and the |
|
| 194:59 | So that's this shape right here. job has come from And then what |
|
| 195:08 | I say here with Cron 1 65 close to M 40. Right? |
|
| 195:12 | is 1 64. So it's almost same. And then it opens up |
|
| 195:18 | This is I think 1 20. yeah, this is 1 20 because |
|
| 195:21 | had this Guerrero super terrain coming in then that's how this all forms. |
|
| 195:27 | right, So this is and this the gulf of Mexico today. Um |
|
| 195:37 | have all these refraction profiles. Remember , these are long offset these big |
|
| 195:43 | of energy. And you're measuring, can measure because you have the head |
|
| 195:47 | that travel and you can measure the and the depth and the velocity of |
|
| 195:53 | layers, crystal and crustal layers. there's pretty good control. I made |
|
| 195:57 | these different cross sections A. C. I mean five of |
|
| 196:02 | And then I've outlined here these big gravity anomalies that we call the Keathley |
|
| 196:08 | after this concession area and the yucatan because it wraps around the yucatan And |
|
| 196:16 | this this cross section here, it through the goes through the western part |
|
| 196:23 | the gulf roughly through here. And is based on all these refraction control |
|
| 196:28 | by Ibrahim. And it's showing the of the crystalline layers. Right? |
|
| 196:33 | they have a basement block right That's this, right here, it's |
|
| 196:37 | feature here. They're not really showing one. It goes, I think |
|
| 196:41 | they don't cross it. So here's Mojo, right 8.2, .2. |
|
| 196:49 | the crustal layers and then the set material layers on top. And here's |
|
| 196:58 | our cross section, this is A . A. Prime. So this |
|
| 197:01 | this this cross section here which goes this Keathley Canyon structure out over the |
|
| 197:07 | plain. Over this this other structure ends right here and we modeled whatever |
|
| 197:16 | layers of salt is probably only but its schematic in any case. |
|
| 197:21 | here's the crustal structure of this Beneath Keith of Kenyan only, which is |
|
| 197:27 | . It's it's like 80 mg and this anomaly here is really is really |
|
| 197:34 | . So this is just you could parallel structure. Now I mentioned that |
|
| 197:38 | looked at all these, all the around the world, their velocity structure |
|
| 197:43 | their thickness and geometry. And it for this reason this this crustal |
|
| 197:49 | These crustal witnesses are consistent with all models. So we suggested that there |
|
| 197:56 | a and by the way, nobody this idea. In fact, people |
|
| 198:01 | hate it. So here's the yucatan anomaly. Here's the Keathley Canyon |
|
| 198:07 | gravity anomaly. And we and we the trajectory between 1 60 to 1 |
|
| 198:13 | of north America, uh north american and the trajectory is tracked right through |
|
| 198:26 | thing. Right? So he came with this idea that there was a |
|
| 198:31 | centered mantle plume, much like I , much like tristan and that it |
|
| 198:40 | for much of the time that the opened up right from over 2.5 over |
|
| 198:47 | million years. But then because there two relative motions here, right, |
|
| 198:53 | the motion of the plate of these plates of these two, you |
|
| 198:58 | the yucatan block in north America over mantle plume. And it's also the |
|
| 199:04 | rate of the ocean basin itself. what we, what we suggested was |
|
| 199:11 | they were coincident for five million but that the mantle plume was actually |
|
| 199:17 | faster. Then the plate, the plates motion over the plume was actually |
|
| 199:24 | faster than the spreading, so that plume ended up only beneath the yucatan |
|
| 199:33 | . So we came up with this . Now The 10 million years is |
|
| 199:42 | half the time for the opening of gulf of Mexico. So you got |
|
| 199:48 | of it being continental extension, half sea floor spreading 20° is roughly half |
|
| 199:57 | complete the total rotation of the So if you plot this, this |
|
| 200:06 | on top of the gravity anomalies, looks like this. So we use |
|
| 200:10 | pole here. This pool is from , Which is you know, my |
|
| 200:16 | author here. But yeah, so can track it at 20 at at |
|
| 200:23 | day is here. And then if go back to like in the present |
|
| 200:27 | . But when the gulf finished say 1 40 M. A. |
|
| 200:32 | 1 40. Um This is This five million years or 10° rotation, |
|
| 200:44 | million years or 20° rotation. So lines up nice. But like I |
|
| 200:50 | people really hate this idea. Um well we plot all that on a |
|
| 200:57 | . This was published in a a texas A and M. Book |
|
| 201:01 | a part of a series. And here is this marginal ridge. If |
|
| 201:06 | have a transform here, you have have a marginal ridge consistent with the |
|
| 201:12 | stuff I've showed you here's the yucatan here is to keep the canyon only |
|
| 201:17 | the salt distribution And this is kind a trace of what we think the |
|
| 201:22 | kind of boundary might be. And here's here's the opening at the beginning |
|
| 201:27 | sea floor spreading in this how the lays on it and here's the full |
|
| 201:32 | with like 40° of rotation. So that's how we think the Gulf of |
|
| 201:37 | opened up and how we think it . And the other work I showed |
|
| 201:41 | how we think. the central atlantic up and how they might be connected |
|
| 201:46 | those rich jumps out there. And this is done with magnetic and gravity |
|
| 201:51 | . And it tells a nice little story that maybe people don't like that |
|
| 201:56 | , but that's okay. Um, good science. Um, and then |
|
| 202:01 | noted in a publication and 03 that every single continental block that was broken |
|
| 202:09 | , uh, that every single block broke away from Pangaea was preceded by |
|
| 202:16 | man to flow. So, yeah, so maybe this idea is |
|
| 202:22 | so stupid after all. Uh, though people hate it. Right. |
|
| 202:28 | , but actually this idea of the yucatan rotating yucatan being tucked up |
|
| 202:36 | in the gulf of Mexico is is old. This guy named Boris Schobert |
|
| 202:43 | publisher in 1935. So we're just reinventing the same wheel over and over |
|
| 202:49 | over. Um, yeah, so , that's it. I went a |
|
| 202:55 | fast. I'm happy to go back any part of that if you |
|
| 202:59 | I could just page back. if you want to look at, |
|
| 203:04 | me just do that again. Where you want to start at just |
|
| 203:09 | and we can go quickly through, did the riffs riffs and I went |
|
| 203:14 | the rift section again, didn't Uh, yeah, I think we |
|
| 203:22 | over that through that. So this all ocean basin, there's a lot |
|
| 203:28 | slides here. But I mean I'm going to focus a lot on |
|
| 203:33 | so. Alright, well, let's here, let's let's just let me |
|
| 203:39 | go back. I'll just go I'll just flip through it and then |
|
| 203:43 | stop me if you see something that your eye. And so there's so |
|
| 203:50 | um there's pure shear, there's simple , there's simple shear on steroids um |
|
| 203:57 | then sang Ors um classification of riffs the world. Um and his little |
|
| 204:07 | here. And we're gonna, you , and then I show you some |
|
| 204:12 | , some geometries how riffs champions might . Then we looked at the rio |
|
| 204:19 | rift, but you know, this fields and we looked at it with |
|
| 204:23 | , we looked at it with gravity and magnetic data. Looking at the |
|
| 204:31 | , you know, the volcanic fields the rift geometries with that way. |
|
| 204:35 | we looked at These two D. through that and we looked at gen |
|
| 204:44 | uh Albuquerque basin modeling. Um And up with a new model for that |
|
| 204:52 | their beautiful representation of these things that did. And then her finding model |
|
| 204:58 | she says that that shear shear boundary make sense. She just thinks |
|
| 205:02 | you know, some easter dipping basically some basin. And I'm just |
|
| 205:07 | complicated example that shows um ocean transform in a very rare case to a |
|
| 205:15 | of continental crossed, but bear in that the transform existed before the, |
|
| 205:24 | the ocean base. Right? So just it's just kind of an extension |
|
| 205:28 | it of what was already there. then we showed some reflection data to |
|
| 205:33 | that, you know, there's a of really complex structure going on. |
|
| 205:37 | looks like there's some convergence going on here. So that that sort of |
|
| 205:41 | make sense of this stuff that there a component of convergence in here. |
|
| 205:47 | then a nice a nice matte, really busy showing all the different, |
|
| 205:52 | these different transform or or strike slip deep. I think that most of |
|
| 206:00 | are probably crustal and not really little . And then anyways, but how |
|
| 206:05 | producing these rich these rift basins uh the other side of uh this little |
|
| 206:13 | in the ross sea. And then we connected the dots here between the |
|
| 206:18 | these different basins and how they bend here. And we looked at this |
|
| 206:25 | floor spreading this bouquet anomaly, And then the cross section that goes |
|
| 206:30 | that. And yeah, this was complicated one. So, I think |
|
| 206:36 | a reason I have to text in , I think that helps explain |
|
| 206:40 | And then we looked at passive margins margins versus a magmatic margins. We |
|
| 206:49 | a lot of time to consider other passive margins, how they might be |
|
| 206:54 | by sand and shells and lime stones salt. We thought a lot about |
|
| 207:00 | and talked about anomaly wavelengths over shallow deep structures. Then we looked at |
|
| 207:05 | this this set of 33 D. over some passive margins. This was |
|
| 207:12 | was in uh Beaufort Mackenzie basin. all of these models had a lot |
|
| 207:18 | control out of wells refraction seismic, meant that were just really modeling for |
|
| 207:23 | basic crust, which all these studies . So yeah, so here's the |
|
| 207:28 | anomalies and here's their base and thickness then here's their cross section where they |
|
| 207:34 | you know how they model the this here. Yeah, that's how it |
|
| 207:38 | . And then we'll jump down to Kwanza Basin offshore Angola. And this |
|
| 207:44 | free air day to remember. And did a little three D. Model |
|
| 207:48 | there's a seismic session, stage And then here's where the model |
|
| 207:53 | Again and here's a uh east west through that model measured calculated data. |
|
| 208:02 | pretty good fit. And again they're on this horizon here. This is |
|
| 208:07 | of typical for um ah well this of work and I don't know, |
|
| 208:13 | don't think they made this this map gravity Magnetics. Which is a shame |
|
| 208:18 | . But yeah, okay then we down to the atomic elevation and this |
|
| 208:24 | bread bread historic basin, This oblique . Remember I said about the |
|
| 208:30 | I mean about the Falklands and ewing . They were peeled off of |
|
| 208:35 | And we looked at that later. this kind of reminds you how that |
|
| 208:39 | was fractured Falklands fracture zone. And then we looked at like all |
|
| 208:46 | three models. Again, there's a of control, a lot of |
|
| 208:50 | a lot of seismic and in this probably the best seismic of all these |
|
| 208:57 | . And yeah. And then we at three east west to east lines |
|
| 209:03 | their model. And um you it's a pretty good fit that the |
|
| 209:07 | version and they're modeling. I think , is it this horizon or |
|
| 209:13 | I think so in any case, the measured data in the model and |
|
| 209:19 | a really, really nice comparison. good. Then we launched in the |
|
| 209:24 | basins. And we look at this um this one. So what was |
|
| 209:30 | thinking about just a second ago, was gonna say, we could look |
|
| 209:33 | that later, talking about killing And we look at the central banks |
|
| 209:50 | work I've done there kinda explained explained these fractures are transformed difference. And |
|
| 209:57 | we then we started looking at a of the morphology around their of ocean |
|
| 210:04 | . Of course, sea floor spreading have to do those. Um And |
|
| 210:09 | sort of kind of launched into this long story that kind of kind of |
|
| 210:15 | through all this stuff I'm talking about . But again, all this ocean |
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| 210:19 | stuff, remember. It's mostly about . You just have to, you |
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| 210:23 | , kind of remember what these things . Yeah, so these are this |
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| 210:28 | the work I did in the central and correlate these anomalies similar to what |
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| 210:33 | showed you with the Heinz. I with her slur paper, but but |
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| 210:37 | lot more to compare. Right? then we suggested ridge jumps. I |
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| 210:44 | you this heat flow. Um I'm not sure why I did |
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| 210:47 | But anyways, it's important. I , he flows potentially. We're going |
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| 210:51 | talk more about the flow later. And then of course, there are |
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| 210:55 | there, fossil spreading centers and then there's fossil subduction zones. And then |
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| 211:00 | looked at all these Benioff zones and , they're pretty important features. And |
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| 211:07 | here's a couple more subduction zone and we, you know, there's |
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| 211:11 | rich, rich spreading centers, There's different kinds of triple junctions out |
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| 211:16 | Um There's there's transverse ridges that form transform boundaries or fracture zone boundaries. |
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| 211:24 | then there's um shear margins where there's continent, ocean transform boundary, which |
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| 211:31 | , there's a there's a handful of the world and they produce some distinctive |
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| 211:35 | . These these big giant margin. mean, these elevated uh uh features |
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| 211:43 | then there's just a seismic uh structures the world to that you can come |
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| 211:48 | and here's a bunch of that go the the leading edge of the caribbean |
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| 211:55 | . And yes the speculation on some ones of those. And then we |
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| 211:59 | about hotspot tracks and large english provinces and I mentioned that you know, |
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| 212:04 | tracks basically. They think they used think there's a couple of families of |
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| 212:10 | , not so much now. And we, you know, we talked |
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| 212:13 | how those form and we looked at Hawaii ever and mentioned their age kind |
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| 212:18 | logic. So that the idea is the the plates moved over the hotspot |
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| 212:23 | and this Ben is recording a change plate motion. Um Then more of |
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| 212:31 | hotspot tracks and in the south atlantic we consider this rich centered one like |
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| 212:36 | which is rich center. Whereas Hawaii a Hawaii is a inter plate, |
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| 212:43 | ? There's no spreading centers around It just popped up in the middle |
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| 212:46 | the pacific ocean. And then I you this bit of work that we |
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| 212:51 | to reconstruct the south atlantic basically. yeah, you know, doing a |
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| 212:57 | D, three D gravity magnetic but just gravity rather three D gravity |
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| 213:02 | of the south atlantic with a So that was kind of fun. |
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| 213:07 | we talked about large igneous provinces and they're produced the same way as hotspots |
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| 213:13 | terms of a mantle plume, but L. I. P. |
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| 213:18 | Lips are just there's a massive eruption at once. And then they don't |
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| 213:23 | to, you know last for millions years as the plates move over them |
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| 213:28 | hotspot tracks do. And then I you that we that the camp plume |
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| 213:35 | though people have a hard time finding origins. I think it might it |
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| 213:40 | be exist beneath to the Bahamas and not the only one to suggest |
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| 213:46 | Um. Uh Yeah and right and we looked at we talked about back |
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| 213:54 | basins which form over subduction zones by by splitting the active art because it's |
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| 214:03 | and the reason they do is because the slabs are rooted and there's been |
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| 214:09 | plate the organization and the plate pulls and so it breaks where it's |
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| 214:14 | it's where its weakest and that's why are back aren't they form behind the |
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| 214:20 | ? That's the idea and there's a of them in the in the Western |
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| 214:25 | and um and then there's one here the Caribbean called the Granada basin which |
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| 214:30 | some work that I did for my thesis. And you're looking at you |
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| 214:36 | gravity and residual gravity and the Magnetics explained that the conflicting miles for how |
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| 214:43 | formed. And um I have both these papers or you can actually download |
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| 214:49 | from my website and then I explained you know we we examine the space |
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| 214:53 | we did a bunch of models by refraction data. And then we came |
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| 214:59 | with a model which is unsurprising very to modern day models and then the |
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| 215:05 | possible conflict is this and um and and some people depicted with with rich |
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| 215:12 | with spreading center this way but that's it. This is the actual sea |
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| 215:16 | morphology here map from the sky. then we showed that if you flip |
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| 215:22 | upside down it looks a lot like we did here and and then you |
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| 215:27 | we just closed that. So um then I launched into this whole gulf |
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| 215:34 | Mexico thing. I sort of hinted about that with these bridge jumps that |
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| 215:39 | proposed for the central atlantic that their is co evil with the beginning of |
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| 215:46 | opening of the gulf of Mexico. you take 20 at the gulf of |
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| 215:51 | went opened up around 1 60 which lot of people think that number is |
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| 215:56 | and it lasted for 20 million years 1 40. Okay. And then |
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| 216:01 | showed that these all these geometries for bigger picture, they fit in with |
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| 216:08 | in a lot of work here and how those opened up the gulf of |
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| 216:15 | opened up and this is present day . And then we looked into the |
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| 216:20 | of Mexico basin and some models and models I did supported by refraction data |
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| 216:26 | you know this this was not the one to say this is a structural |
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| 216:30 | was actually said. So from refraction and so I just model that up |
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| 216:35 | integrating all that stuff together. This model. And I did that with |
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| 216:39 | other models as well. But I'm showing you one and then okay, |
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| 216:44 | we have the gravity models, we these features, what does it all |
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| 216:47 | ? So then we just came up this kid a Matic model that shows |
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| 216:52 | if you started if you started after million years of continental extension and then |
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| 216:58 | start opening the ocean basin in five steps which coincide with 2.5 million years |
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| 217:07 | that you can accommodate the next 10 years with 20 degrees rotation that sits |
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| 217:14 | top of the data pretty nicely. this actually made the cover of a |
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| 217:21 | G 2005 March. Um so that probably as good as it will ever |
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| 217:26 | for me. But uh yeah and then um This paper, this was |
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| 217:34 | in a book that was finally published '05, that was published in |
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| 217:40 | This figure was from 11 and I you know, the relationship between the |
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| 217:45 | and these and these proposed hotspot And then as well as as a |
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| 217:49 | rich because because of the Gulf Yucatan out, they had to rotate along |
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| 217:54 | transform and a lot of people like , I mean except that there was |
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| 217:58 | transformer not so much a rich that's in dispute. Okay, and then |
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| 218:04 | finally made the point that if you that idea is nutty, we can |
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| 218:09 | look at most of the most of big continental fragments that that led to |
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| 218:19 | breakup of Pangea were preceded by So this camp, here's tristan, |
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| 218:25 | Karu, here's a far right in Arabia. Now, it's not it's |
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| 218:33 | like the plumes are dynamically breaking the the continents apart. It's just that |
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| 218:41 | there's hate rising right because of the , the thermal id idea. And |
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| 218:48 | we think is that these plumes, like upside down drainage, they find |
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| 218:54 | weak spots, so they find these and erupt they're not like pushing things |
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| 219:00 | , but they're just like, it's fortuitous that they're just they're there. |
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| 219:04 | they are signs of, you um some, you know, intense |
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| 219:09 | and thermal thermal issues going on. then I made the joke here that |
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| 219:17 | we're doing is already been redone you know, it's almost 100 years |
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| 219:21 | since Boris Gilbert suggested this. I this, I had this frame in |
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| 219:28 | office here because well, it's kind cool kevin gave me that gave it |
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| 219:33 | me. Alright, so thank you much. I think I have like |
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| 219:38 | and pages of references attached to So All right, That was an |
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| 219:47 | minute summary, maybe 20 minutes, questions? I do not have a |
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| 219:59 | right now. So, the good is you can go to the recording |
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| 220:03 | go back to this. This is I blasted through and then make notes |
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| 220:08 | then go back and find them and answer your questions and then if you |
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| 220:12 | I'll send you the papers or you find them yourself I'm sure but I |
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| 220:16 | if you want some of them are little little I mean I don't have |
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| 220:20 | still bears paper. I don't think do I have papers about that paper |
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| 220:24 | I don't have that paper. Oh if if you don't have questions if |
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| 220:31 | just sick and tired of hearing me which I wouldn't blame you. Oh |
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| 220:40 | I guess we could call it I will I sent you the instructions |
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| 220:44 | for getting the software right? Yes husband's gonna do it for me. |
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| 220:50 | great so then you'll be set for and then uh you know when we |
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| 220:57 | we uh you know if if you problems just let me know we'll get |
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| 221:01 | sorted. And then um exam is Lemon's gotta write the I got to |
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| 221:09 | it on thursday better make a note then um I'll send it to you |
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| 221:16 | right exam thursday. So I'll write exam thursday and I'll send it to |
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| 221:23 | that night and then I'll get it you before class saturday morning. So |
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| 221:29 | not actually gonna meet on friday right just gonna basically take my test. |
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| 221:34 | I'm just gonna send it to Just answer the questions and send it |
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| 221:37 | to me. Okay, Don't No, you gotta go up |
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| 221:41 | Right way Jose and then All so that so Oh, I |
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| 221:56 | there's a little, there's a little in the thing. It's yeah, |
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| 222:00 | saturday morning will be the exercise and and in the afternoon will be uh |
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| 222:08 | on convergent margins. The following friday my last, so I have only |
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| 222:13 | more lectures. The exercise is really and I would just do that. |
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| 222:21 | will do the exercise in front of . So, so you'll be able |
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| 222:25 | watch me do it and so you'll able to do it yourself easy |
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| 222:33 | Okay, that'll work. Are we ? We had enough. Have you |
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| 222:41 | enough of me? I think the is just, it's made me very |
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| 222:46 | today. Well, no problem. , that's just um yeah, it's |
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| 222:52 | of creepy. I mean, I'm we didn't have on campus with that |
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| 222:56 | be pretty horrible. I guess. , you're up there, aren't |
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| 223:03 | Yeah, on campus. What's Yeah, I'm on campus. |
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| 223:11 | Alright, Well, um Okay, I guess, you know, we |
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| 223:17 | take a break this afternoon and we a 45 minutes, so I don't |
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| 223:21 | . I think we did pretty good um Again, let me know if |
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| 223:26 | have any questions about the material this or this afternoon or any other any |
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| 223:31 | time. And you know, I'll your questions and yeah, see |
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| 223:39 | I guess I'll see you a week today in the A. M. |
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| 223:44 | . Sounds |
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