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GEOL7330 Potential Field Methods - Day6 02-04-2023 PM
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00:03 Alright. So we're gonna look, gonna finish our little uh discussion of
00:14 relative to the Wilson cycle with convergent basins. So basins that form along
00:21 margins include four arts and four lands intra arts for jeeps, things like
00:27 . Um So um yeah, so that little figure I showed you at
00:34 beginning of this discussion on Wilson cycles we talked about stage D. So
00:41 is the final closure. So the figure here, we have already,
00:46 know, there's already been an island that was created onto the continent there
00:53 that's been eroded and Penta planed but it's still approaching another continent to
00:58 east. And then with the final , I guess this is almost the
01:04 stages where they collide. But then , that's been a play and we
01:10 with our cycle all over again. here the fore arc, fore arc
01:18 would be located here in four land will be loaded located on this side
01:23 here as I'm showing down here. yeah, that's the four land Now
01:29 . So you might read literature for example, the Himalayas in
01:34 So if this were for example, Himalayas and to the south would be
01:41 that crashed into it. You might um literature where they called both sides
01:47 this four lands. And I guess a lot of truth to that.
01:51 I mean, I can understand that it would be um, you
01:55 asymmetric into the range on the southern , but also asymmetric on the other
02:03 . So I think uh Folks will about this stuff. We call this
02:11 a rhetoric for land. Is this the overriding plate and this one would
02:16 called a peripheral for land because it's the on the the subduction slab
02:23 But I don't really worry about it much, but just F.
02:26 I. There are different things most of the time people think in
02:31 of a subduction zone with A. are kinda for land. And so
02:36 what this figure shows, doesn't show collision, but it just shows a
02:41 with four our care and the four here and then they each have their
02:48 sort of structures associated with them and own normal nature. So Diesel's
02:54 Diesels came up with this idea. mean this sort of, you
02:57 you have the of course the origin way, which is the mountain belt
03:02 then that's actually, you know, the little sphere to flex the cross
03:08 lift the spirit to flex. And it flexes, it produces the balls
03:13 here. So the bulge has a bulge in the back bulge part according
03:20 peter and then the four deep is , you know inboard of the
03:26 So you have the or genic the wedge top, this is the
03:29 wedge and then the four deep, is completely, you know, there's
03:34 structuring, it's just pushed down. I've made a couple, I went
03:41 this this morning and I made a of adjustments and so I'm going to
03:46 the replacement and anything that's highlighted, it's just two places. So this
03:50 say for art before, it does four are here, I guess it's
03:55 , but I didn't really notice that morning um in any case. So
04:00 four arcs typically outboard, you have a creche in every prison,
04:05 right here, and that's where sediments basically piled up, that are,
04:11 know, being deposited from the, the land. But also you
04:16 it can include bits of cross that scraped away by the slab, you
04:23 , interaction with the overriding slab with overriding plate. And they say on
04:30 archive, I don't know if that's necessary, but I guess, I
04:35 it is, occurs often and that's basically from the crust being, you
04:40 , up thrust related to the down slab. And then on that continental
04:48 , you have a little arc that a little, I mean a little
04:51 that forms outboard of the mountain So that's the idea. And in
04:57 , you have inter art basin. we're gonna look at, you look
05:00 at least one of those that, know, the ark itself might
05:05 you know, there might be you know, to maybe two episodes
05:10 mountain building. I mean the, know, the Andes the Andes sit
05:15 , let's see 1233 or or sort some parallel with three other um or
05:23 episode? There's the pam pain which the oldest and the famous Iranian,
05:29 Gondwana in then the Andes. And there those are all preserved on
05:36 the Chilean, the Chilean and Peruvian . Um Okay, so we're going
05:46 look at a fork basin here in . So there's not a little map
05:54 south America here, is there? me see if I can find
05:59 I think I have a Yeah, Ecuador is right down here.
06:05 And that bit we're looking at is bit sticking out there. So,
06:13 . Okay. And this is actually few lights. This is basically uh
06:22 igneous province material. All this dark stuff that was created on two Ecuador
06:33 the caribbean plate was inserted between north south America. So, this is
06:40 of an example of how continental crust , is uh, is made.
06:47 . It's consists of, yes, tonic blocks and really old. But
06:53 also new crust being created all the with the accretion of large igneous provinces
06:58 island arcs. And they did spectral of gravity and magnetic anomaly data.
07:11 you have gravity anomalies on the left magnetic anomalies on the right. And
07:17 you tell me whether that's if that's or three air on the left.
07:22 it say? Did I put it ? I didn't label. Okay,
07:25 didn't say so. Would that be ? Is there ocean floor out
07:34 Here's the map in upper left. at that. Look at the upper
07:38 for left now compared with this. is it? It's okay.
07:45 It's full gay. That's correct. this is really a high density.
07:50 this is a high density block because is oceanic. This is a large
07:54 province that was created onto it. . But what they say here is
07:59 said the spectral analysis of gravity and , they define three geophysical domains and
08:06 of domain where the magnetic anomalies associated magic rocks. Right. So they're
08:14 that the Mayfair rocks are well defined defined by the Magnetics. That's this
08:21 up here. Okay. This the coastline you can see there is the
08:25 as the white coastline and that spit it's a low so it's magnetically alot
08:33 its affiliates which are ocean floor which you know, assaults and Gabrielle is
08:38 magnetic rocks. Much more magnetic than . That would be you know maybe
08:44 here. So why is it Mm Let's see there's a base in
08:58 . Could it be Salter mojo? , it's perversely polarized. That's why
09:13 magnetic anomalies are all all low intensity I mean it's very magnetic.
09:19 Because it's a it's very magnetic but but it's a low then. The
09:26 thing you should always think of is is that their reversal polarized. Make
09:36 that's not may turn out that's not right. But that's the first thing
09:40 would I mean that's what I would because this is this area is obviously
09:44 . Look at it. It's this a topographic map and it's a big
09:49 like a range. This is the . Have you ever been to California
09:54 or Washington state? No I So you've not heard of the coastal
10:04 ? I think we we talked about when I was in oceanography with dr
10:09 . Okay so here's how that This is the this is this is
10:17 the ark the land arc. And it's the same as for north America
10:24 would be the same as the So you can view this is like
10:28 Oregon, northern California. And then you have the coastal ranges which is
10:33 mountain range and it's the exact same as this. It's a created ocean
10:39 to create a few light. It's exact same thing. So this is
10:43 really common thing. Okay. And very magnetic and their lows here because
10:51 reversal polarized. It's very short wave year which tells you what what does
10:56 wavelengths tell you with magnetic data at shallow. No question on your
11:13 I'm sorry this morning. Like just me feel dumb. So I like
11:17 just feel dumb now. Mhm. shallow short wavelength of shallow long way
11:24 as deep. So what's going on ? It's not shallow, shallow,
11:35 ? It's not shallow. It's Right. Yeah, this is this
11:43 this is part of the coast. is this is part of the the
11:47 before they turn and turn and go and form the what they call the
11:52 Andes that run along, you Venezuela where there'll be more on
11:56 but probably friday. Okay. So um right in our area,
12:04 wavelengths, etcetera. So they have cross section a to a prime that
12:10 model through here. Right the same . So it goes right through the
12:14 lights and right through this gravity and anomaly there. And here's what that
12:20 like. So this is where the crust is sticking out. And this
12:26 the bit this is the bit that created and this is the same.
12:30 mean, this cross section could go through Washington Cook should could go right
12:34 Seattle. Um and see that if gave me a model where they had
12:43 profile like this and it was an scale to fit this whole window,
12:47 that that bugs me. That they it like this. Especially in a
12:52 . Um I mean, they can show more more detail in this
12:57 So what are they hiding? This what I think. What are they
13:02 ? I mean, why don't you make it plus or minus 1000 then
13:05 would be a flat line, you ? But anyways enough. But this
13:12 the way you see here is they've that. They've just they've taken the
13:17 and then they just put in a of vertical, almost vertical prisons.
13:21 is what I was talking about with modeling. You know, this they
13:27 what these champions are. I they model these challenges so they can't
13:32 . But even these geometries, the changed from block to block. That's
13:36 28 50 2700. You know, don't know. This is really disappointing
13:42 me. You know, they're just just using this is not a way
13:46 model. I mean if all you're is just changing layer geometries and susceptibilities
13:53 hoc. You know, I mean decided they liked the shape of this
13:59 and they're just gonna make everything There's nothing learned here, right?
14:03 I do see in the in the , I do see in the
14:06 you see this big low, that is because of this thing is reverse
14:12 . So in fact, down here are very low. So something in
14:16 all these organizations are very, very . They're all very, very
14:20 Um Yeah. And in here they've this little area here that there's a
14:27 rift. They might know that maybe interpreted this on the reflection data.
14:31 there's a fall and that's that's That's fine. But in general,
14:35 really would, I would grade this badly because I think just the display
14:42 wrong. And then this approach to . I don't think that's uh I
14:47 know, I don't like it. . Okay, I gave you a
14:52 of this. This is um the is how the caribbean plate evolved.
14:59 is how it happened. North Mhm. You might remember from
15:05 from our discussion of super kind of , North America broke apart from south
15:11 about 1 80 so this is 1 . So it's been growing. Ocean
15:15 has been opening. Nobody knows what looks like down here. They just
15:19 just schematic. But this proto caribbean way, there's an oceanic crust that
15:25 between north and south America. This about 60 million years. Whoops.
15:31 then there's um of course, it's beneath both of these and then complete
15:39 sub ducting beneath, you know, an arc out here. This is
15:44 ocean ocean ocean island arc, you , much like along the west pacific
15:51 then by 90 million years there's, this thing out there called the Galapagos
15:57 track, right? I mean, Galapagos hotspot, it is a small
16:02 . The caribbean plate, they say that this is a little, this
16:08 a little wrong. The caribbean, igneous province. The clip they call
16:15 actually formed as this ocean floor passed the hot spot. Okay, it
16:22 a plate out there floating around. just a silly idea. It was
16:29 the pacific or the fair line was abducting beneath this, you know,
16:37 north and south America before they broke , right? Because this was it
16:45 the the the ocean out here was Panther Lhasa. And this was gun
16:52 in subduction. Beneath this all of area, north and south America.
17:01 as the pacific plate was subduction beneath proto caribbean ocean, it was producing
17:08 island arc which is very, you , typical. But but but when
17:14 passed over as it passed over the hotspot, the crust was under plated
17:21 you know, there was probably volcanism stuff. And so the crust was
17:26 . And when the caribbean and when pacific plate, this thick part of
17:32 pacific plate that was thickened by, know, passing over the Galapagos hotspot
17:38 it crashed between north and south the subduction right? In this case
17:48 abducting to the east. Beneath the seduction zone flipped because this thickened
17:58 could not be subduction is too thick sub duct right? The same thing
18:01 going down. That's why we see overflights that created, you know in
18:06 . And up up here because this would not sub ducting, it's too
18:11 . So that the subduction polarity actually from sub ducting to the east to
18:19 to the west and the T. ridge, which which is right here
18:27 still preserved. It is, and the island of Tobago, which you've
18:33 heard of, The island. Tobago 100 and 200 million year old arc
18:41 right between here and here. It arc rocks that are this old.
18:45 we know this ark existed and and the, in the, in the
18:51 atlantic now is subjecting to the west this proto caribbean most certainly was
18:57 Okay, so then as the, the, you know, this,
19:02 the pacific plate moved in here, switch, it was just basically torn
19:08 parts of its abducted beneath south Parts of it just ended up,
19:13 know, being lifted away. This the Cayman trough. There's to transform
19:19 to the north and south. So so this was actually feral on plate
19:24 was ripped off the pacific because it not subject and then the subduction zone
19:31 . It. Does that make sense you? Everything I said yes.
19:39 , so there's a lot of people have ideas about the caribbean plate.
19:42 just telling you my, the way look at it. Um Some people
19:46 that there was like the caribbean plate here floating around. That's just that's
19:51 a silly idea um when you think it, but that's but serious people
19:55 that in any case. Yeah. the pacific plate, it was subduction
20:01 these two continents when they broke apart it continued to subject until the thickened
20:07 province of the caribbean encountered it. would not subject to the polarity
20:12 And as the plates specific and fair abducted beneath these two continents um it
20:22 part of it was just torn off the caribbean plate was as it was
20:28 between north and south America and the the Tobago trough. I mean
20:35 I'm sorry that she's called Tobago I think this is Chanel go
20:40 she is a student of mine in case, but the ridge still exists
20:44 here because the island of Tobago which right right down here on Tobago has
20:52 million year old art rocks. So we are again, just outboard of
20:57 Grenada basin where I did my she worked on the Tobago trough which
21:01 a fore arc basin. See its of the ark and the slab is
21:06 ducting to the east to the west . And here's a nice beautiful three
21:14 rendering of it. It's showing so the island arc here, there's the
21:19 of ancient this fossil arc that barb Tobago sits on top of and probably
21:26 as well. This whole there's a a basement ridge right through here.
21:32 , so this is not the same of ridge that was shown in the
21:37 with the outer archive that that where's at? It's not this outer
21:46 It's not the same in this case was it's capped, it's a captured
21:51 arc. Um Right so here's free gravity again, I'm not going to
21:58 you anymore asking if it's free air . Um but this island arc,
22:03 is the remnant island. Remember we at this with the with japan.
22:08 looked at when we talked about ocean and back arc basins. So this
22:12 the this is the the island arc arc, the remnant arc and this
22:19 is a four RQ. And the Barbados is actually you know there are
22:27 secretion there. I mean the christian prison because the Orinoco down here in
22:34 America Venezuela just pours out so much . This is all filled and the
22:41 field is enormous and it's actually you push it up so we can look
22:46 right there is a weird look at models A. Two A.
22:51 They're both east west. This one here. You can see it down
22:55 as well which goes from the hinge the trace of the subduction zone all
23:00 way up to the arc and then . Two B. Prime which is
23:02 little bit shorter. Right? And what those look like. So here's
23:08 a. two. This one Yeah this is the long one
23:12 2 a. And here's the bit arc that was captured when the when
23:18 so you can see the other subduction was dipping this way and that and
23:24 when that flipped the slab fell away this slab developed after that, that's
23:29 that worked. So you know subduction because this thing would not sub
23:35 I mean this part here wasn't But the old arc would not sub
23:39 the largest province. And then the subduction zone developed going this way and
23:48 B. Two, B. Which just to the north. I'm
23:51 one and two. This is this the old arc right here. So
23:57 is very nice data, very nice . And she did some pretty good
24:03 here. This is all these you know, she had densities for
24:06 these layers and lot of well And there's some refraction data in and
24:12 there. I don't know if it's on these. No there's a bunch
24:16 refraction stations. Okay. And then four arc which is really kind of
24:25 , it almost qualifies as a complex because the sub This uh the the
24:36 basin which is a four art. and the uh cook inlet basin here
24:44 is also part of the forearm. ? So what's going on here is
24:48 have the subduction zone where the you know, plunging to the
24:53 it connects with the transform boundary over . And the slab is dipping
24:58 In fact these are the depths of slab 50,050 km and in Alaska there's
25:10 big fall system called the Denali fault . Now, I don't know if
25:14 if it is um little sphere or . I don't know if it's a
25:20 or if it's just penetrating through the . My sense is that it's not
25:26 hysteric and you have all these other which are sort of you know,
25:33 you know, sort of sub parallel the whole trench system. Um This
25:40 formed in the middle I see middle into early Miocene. Um They're saying
25:46 north striking false. So there's north faults in here. In fact,
25:52 look at the data, the leftist data and the right is um magnetic
26:00 . And right away you can see can see a basis in these
26:05 I think this is a residual, is residual reduced the polling numbers I
26:11 . But right away you can see inside these folks are very um you
26:19 long wavelength and so the gravity didn't estimates of the shape and depth of
26:27 basin and see they what do they ? They did a residual separating observe
26:36 92 components, one representing low density fill and right and then the the
26:43 basement. They say that that together magnetic and gravity and seismic reflection analyses
26:53 an asymmetric basin comprised surprising sedimentary rocks four km thick. So the
27:02 Alright, so there are some models here. Okay, there's models right
27:09 . And you can see that the is deepening to the northwest.
27:15 Which is very interesting. Okay, these months there's a B and
27:20 A B and C. And I the there were, you know,
27:26 wavelength differences in this zone are just . I mean it's very easy to
27:30 this, but the asymmetry, they're deeper this way, not this
27:37 Right. So asymmetry always makes me of four land bases. Right?
27:46 if this is a subduction zone then four land, the asymmetry should be
27:52 other way around with getting deeper to southeast. But they're actually getting
27:57 Right? They're getting I'm sorry, getting deeper to the northwest. So
28:06 what in the world's going on? is this asymmetry in the I mean
28:10 model looks pretty good. Um you , anomalies. Uh yeah, but
28:19 in the world do you think um fact these are magnetic anomalies.
28:25 Right. Uh What in the Tell me why you think it's asymmetric
28:33 the northwest? Tell me what you about that. I'm gonna go to
28:37 this this map gives you a hint saying it's it's getting asymmetric to the
28:47 towards the Alaska range. Any mm I mean why would it be
29:04 sin not a fault. I'm not . Okay, I think that this
29:13 not a for our basin, I , I think it's a four land
29:20 to the Alaska range. And it's this way because it's because because relative
29:29 this, the fleischer that produced it the Alaska rate. And I think
29:34 existence of the canine mountains is also the fore arc basin should be out
29:42 here, should be out here Um I think this is actually an
29:46 arc basin. It's between this I don't know what the age of
29:51 ranges are, but if I were guess, I would say that,
29:57 , this is this is this is They're saying that the base informed in
30:04 to Miocene. So that's like whatever , 50 million years on that
30:09 So they're pretty, pretty darn I think that yeah, I think
30:16 an inter arc or for land which sort of suggests for land and
30:24 it was there before before this stuff had much of an effect. That's
30:30 I think without knowing anything more. mean, I'm not an expert in
30:33 part of the world, but just at these crustal geometries and these basic
30:37 and their relationship to the surrounding mountain . That's what I think.
30:44 I'm not gonna test you on But I think that's I think that's
30:48 going on. Another thing that's going here is, look at this here's
30:53 here's the question, you have areas this magnetic anomaly map. This is
30:58 pass filtered. But it's still high well. Never mind. Never mind
31:02 that. I won't tell you Uh I'm not sure if that means
31:05 . Alright, so let's let's move . Another example. This is actually
31:12 inter art. Right? So this that the island arc and this is
31:18 so now we're in, here's our of the Andes. And before Ecuador
31:21 were looking right up here. But now we're looking down here in
31:26 Andes, chile Bolivia Argentina. And the Andes, usually the bolivian Andes
31:36 call there's this region called the The high plain. And I guess
31:42 know that, sorry. Um but , yeah, atop the Andes on
31:46 of them is just this basin. can see it in the topography
31:49 This kind of smooth area. Um an intra arc, it's the second
31:58 uh what do they call it? do I have? The second highest
32:02 genic plateau on earth. Any guesses the highest one is. Would it
32:09 a rest ever since the mountain. you're close, you're really close talking
32:19 Lap tow would be the highest, , is that the tibetan plateau,
32:26 ? Very well. So, Tibet the highest plateau on earth. The
32:32 highest plateau is the bolivian altiplano. yeah, does it say? How
32:41 do I have a height here? don't, I'm sure it's in the
32:44 . I don't have it here. um it's in this paper by
32:48 Another. But okay, so here's is what is this amplitude of?
32:53 don't know what this amplitude is Oh, I see. They're
33:05 this must be the base of the . I think this is, this
33:09 be the base of the crust. models should tell me. Yeah.
33:12 , that's the base of the crust think. Is that right? I
33:18 know. No, I don't know that is. I don't know what
33:22 is. G oil or something. should know what that is. In
33:31 case, they're claiming that there's a body that's beneath the altiplano.
33:40 Um our analysis reviews that magmatic that means magmatic under planing may provide
33:49 contribution to surplus uplift on par with spirit removal that's called drips. And
33:59 they also say area is a static in islands are roughly zero. And
34:06 they're saying that it's in static That that idea. I mean,
34:13 having a baby, it can't be ice, a static equal living.
34:17 sitting over a subduction zone. I , I don't care if the static
34:22 is zero. It just means you know, it just, I
34:26 know what that means. It means their calculations are, you know,
34:30 just fortuitous. It's serendipity. It's really, I mean this is,
34:36 is a sub ducting slab, it's day, there's seismicity. I
34:41 you know, this area is not , it's not a stable, you
34:47 region. But let's just look at , just look at their analysis
34:51 So here's the elevation and and I this is meters what it is.
35:02 I don't have this pastry. They a couple of things, so it's
35:10 550 500. So this is the , I guess this is some best
35:15 through that. Maybe this is there maybe this is a geode anomaly.
35:22 not sure. I'll make a I'll need to look this stuff up
35:27 I'll figure it out. I look this this morning. I thought I
35:33 . Alright anyways here's their model, their bouquet, here's their free
35:38 this is nice. So the comparison free air anomaly. Again it's really
35:45 should really expand this but I mean say it's essentially zero. I don't
35:52 , it looks to me to be plus or -50 or 100 mg
35:58 Um But the bouquet is predictable, ? You gotta have a big low
36:02 beneath the mountain range. And um saying that there's this live magma saurus
36:14 this magma reservoir down here that's sort supporting this thing and they do have
36:21 surface wave anomaly. There is a wave anomaly. So um A.
36:28 . B. M. Stands for altiplano puna magma body. And and
36:39 they have this shear shear wave velocities um they say are supporting it.
36:46 is a there is a velocity low doubt about that. Um But
36:55 so it's not it's not like it's magma because That would have zero
37:02 Um Also the shear wave velocity of mohawk, shear wave velocity of parental
37:11 and is 4.5 and more. Um rose, lower crustal philosophies like like
37:22 rose and granule lights are less than . Typically There are 4.3 which is
37:31 think this check mark here. So is probably, I mean this
37:37 this model goes from this model. is his position? Do they show
37:45 model? Um Oh I think this the model here. So 68.
37:57 it's going roughly from here. It go offshore. Doesn't go into the
38:02 area, does it? Yeah, think this yellow line shows that
38:08 Um So I don't know. I , I think that's a little slow
38:20 upper mantle. Um So they're saying this is the source body.
38:27 so the lower cross, yeah, mantle and the mojo is here and
38:32 have some feeder into this feature here that's this feature here. Right,
38:37 . Um Yeah, I don't I mean, I guess you could
38:43 something in there, but I don't . I mean yeah, I don't
38:50 don't think I really agree with this idea, but in any case I
38:56 think it's any clear. Okay, that's kind of an academic study but
39:02 is an inter arc and they did it. I think the blue just
39:08 be the difference, I guess they , it's like on our modeling,
39:12 is GM says, by the you can probably recognize that um
39:23 I'll learn about these figures, slides slides 14 and 15, Alright,
39:30 move forward. That's like a four basis. Now, foreland basins are
39:34 the most kind of, you passive margin for the bases. They
39:39 the most, you know, those where the biggest fields are, Most
39:44 the most of the oil and gas produced from these kinds of basins.
39:51 on the right Fleming and George that shows sort of like the mechanical form
39:58 . You have a mountain belt, abducting in this, you know,
40:03 rising here is producing a mountain belt that mountain belt in turn flexes
40:09 you have like a bulge back here bulge. And they're typically these are
40:16 shape basins, right? The deepest is near the the thrust, the
40:22 belt and in planet would look like . So, you know, the
40:29 abducting to the south here and then have a foreland basin and then you
40:34 have some four balls through here. implant that's what would look like this
40:38 from peter to sell. I this is a real famous paper and
40:42 again, the figure I showed you which with the whole four land system
40:47 according to them, there's four there's the wedge top, let's
40:53 what do they say? They the four different zones. Um
41:03 wedge top zone is the mass of that accumulates on the top of the
41:08 part of the origin IQ wedge. it can include piggyback and thrust top
41:14 . So you have little mini basins here in the watch top. And
41:18 the four deep deep zone out here consists of sediments deposited between the structural
41:25 of the thrust belt and the proximal flag of the four bolts. And
41:30 typically thickens rapidly rapidly towards the front the thrust thrust belt. Which makes
41:36 . It gets its thinking, you , in this case to the
41:40 the four balls deep zone is the region of the potential flexible uplift.
41:47 the back back bulge is the mass sediment that accumulates in the shadow,
41:52 broad zone of the potential. So are the that's kind of like the
41:59 and these are like again, these also called retro art for land.
42:07 , I'm showing you this just because think it's just a really cool
42:10 Um and this is in the um in the southeast of France. This
42:18 where where the great coat theron theron come from down in here. Um
42:27 uh yeah, so you have foreign and it kind of, that can
42:33 you can have this is called a , right? The with with with
42:39 24 so one formed and and according them. Um Let's see the structure
42:48 the floor thrust is Triassic gypsum and and the and the upper and the
42:59 upper four land throughout system is cretaceous limestone. And uh yeah and even
43:08 top of these little guys, just four land bases that are farming.
43:12 it just shows you sort of like en echelon sort of geometry that can
43:18 . Um I think, you there's a lot of artistic license going
43:23 in here, but these rocks obviously and they're just, you know,
43:29 know these horizons somewhere and they're just them to be here. But it
43:36 a very beautiful geologic cross section. , so let's look at the western
43:44 sedimentary basin which is really huge. can see here there's A.
43:49 C. And this is uh this Manitoba, this is Saskatchewan. Um
43:57 the basin just is just enormous uh geology on top. And you can
44:04 of course you get to the, know, old young younger layers to
44:08 center and older, you know, the outside. And of course there's
44:13 Canadian rockies. So here again is topography zooming in on the topography and
44:23 , it's very nice. This is anomalies tell me Stephanie y this is
44:34 big gravity low gravity loan because where am I Western Canadian can you um
44:52 me? Because it's there's the Mhm. Oh is that mountain
45:07 Canadian rockies, Bernice. Uh Most british, I mean Canadian rockies which
45:15 mostly in british Columbia. Right. , this is Alberta. It's probably
45:34 gravity. Is it? No having low, I'm sure it has something
45:49 do with the crust. Yeah, it's mojo it's because it's rooted in
45:58 mantle. Okay, here's the residual that. The 15 km upper continuation
46:07 . What does that mean that it 15 km? Is that where they
46:20 minimize the topography to the 15th? bouquet correction minimizes topography, but this
46:30 a residual these are residual bouquet What would be the regional, the
46:42 would be the upward continued map. if you upward continue the data 15
46:53 and subtract that from the original you get these residual works.
47:03 so this is this is another just view of it and it's showing some
47:07 the main geologic features. Of course deepest parts are just this hatchet
47:14 the the so this is the deepest of the of the western Canada
47:19 Of course there's the Williston basin down . I guess there's another little tiny
47:23 up here And then just basically the of the basics, of course there's
47:31 big giants fall cycles in the Great Lake. This is the snowbird,
47:38 is the boundary called the snowbird boundary . Yeah. So and all
47:47 You might remember this map when we about super kind of cycles. We're
47:51 in this part of the world where these different trains have been created to
47:57 . You know, basically the core North America with these old are key
48:03 rocks up there. So here's that map. Not not the one just
48:09 the one before that superimposed onto our , onto our residual gravity. So
48:15 the deepest part, here's the And in which you might notice is
48:21 lot of these these shear zone the Great Slave. These faults line
48:27 with some pretty big anomalies. I mean, your first order rule
48:32 thumb, you know, anomalies with order of 10 Milligan's. What's the
48:37 here? We're going from nine plus minus nine. So this whole range
48:41 10 or 20 million girls. So every anomaly, you see anything.
48:46 these anomalies are on the order of , 10 millions. They're not high
48:50 though they are low amplitude. They're big anomalies. They're actually pretty
48:57 So, you know, it makes sort of think that these structures are
49:03 these anomalies, right? And you really see the low in here in
49:09 gravity data. So let's move Let's go up to the northeast to
49:15 . We're gonna go up here to part, the uh there's a fossil
49:21 that turned into a race that's now low again called the Peace River
49:27 And uh it's in this area Um Peace River Arch and the southernmost
49:36 of the Great Slave fault. This Hay River fault. Right? So
49:40 the dash line, right? This british Columbia here. This is
49:44 So we're at the northern part of two states right here. We're looking
49:49 this part right in here. And if you look at that on
49:54 of the gravity, you can see there's definitely another. Again, these
49:59 anomalies that are, you know, well, but there's also some other
50:04 . But again, remember these are big anomalies. In fact from here
50:08 here, that's probably only 20 mg probably the highest range. So they're
50:13 subtle. Well, let's just look there's there's a there's about a bazillion
50:22 wells in this basin. I mean is well studied. Um This is
50:29 this is a fan of ice pack means it's paleozoic, mesozoic and cenizo
50:36 in that time frame. So with crustal thing, it's a sedimentary thickness
50:43 um of the fan or a Zoe Yeah, surface to pre Cambridge basically
50:54 Cambrian basement And the Contour O is . But then in the shaded area
51:01 500 because you know, it gets thick is the asymmetry of the
51:07 We can lay down on top of residual anomalies. And all of a
51:12 it's a little more confusing, isn't ? I mean these gravity anomalies aren't
51:20 . I mean there's some curtains some know there's some pull around these anomalies
51:25 so these anomalies looked to be structural um Yeah maybe here. So
51:37 Yeah so this is basically the the shape of the basin and it's not
51:44 reflected in this graph. You But remember like I said, these
51:48 not really big knowledge, these are showing something else. And we're going
51:53 get to that here. Here's just map pre Cambrian structure. So instead
51:58 the fan rizzo thickness this is preconstruction . They are of course quite
52:06 And we can look at the residual anomalies on top of that and you
52:11 . Okay this is not showing any now. Um So that means there
52:17 be this must be um Maybe there's topographic topography. Let's look just like
52:23 topography real quick. Yeah there are highs in here. Okay. That's
52:31 . Alright. That makes sense to . Okay. Alright so now let's
52:38 at the magnetic so here's total magnetic anomalies. This is just just
52:45 And by the way there's two cross . I'm gonna show you the end
52:49 correlate I mean that that that coincide these this line here and this one
52:55 , that's what those represent. But magnetic anomaly dated. I mean just
52:59 mean the Canadian, the three countries collect the best mag data are Canada
53:06 and Finland. Can you guess Because of how close they are to
53:14 polls. No because of mining. there are those countries don't have
53:23 I mean they have wide areas where where there's outcropping basement rocks basically
53:29 Okay. That's why. That's Okay so the but these these anomalies
53:36 just beautiful and you can really see shape of this just basin in
53:41 Right? I mean you have this wavelength stuff. You know basically the
53:45 is outcropping over all these areas. then as you get close to the
53:51 know the Canadian rockies are over here you get close to them. The
53:55 starts you know plunging to the southwest it's getting you know these phenomena wavelengths
54:02 a little bit longer. Then these here and then in the deepest part
54:08 long smooth magnetic grab magnetic anomalies. is telling you that the base is
54:14 really deep. And then they're even beneath. All of a sudden you
54:17 to pick up this chatter. The wavelength stuff so you can really see
54:22 shape of this basin. You know probably getting deep. Looks like to
54:27 like there's a there's a it gets little shallow and then deep bronze and
54:32 you get and then down here into Williston remember is down here. So
54:38 can really see the shape of the . Canadian basin in this magnetic and
54:42 only data, It's really stunning. you ask me um here's the
54:48 T. P. What does our do remember? We're Northern hemisphere.
54:52 gonna shift everything to the north. where is the north pole at its
54:57 over here? It's over here So it's going to shift things kind
55:01 northeast. And if you look, I go back and forth, you
55:06 see that it's doing that. In . Look at the tsunami right
55:12 Right when I go to total field TPc it moves everything to the north
55:19 little bit. All right, we display the uh pre Cambrian, right
55:28 basement contours on top of that. can definitely see that you know they're
55:33 deeper deeper, deeper down into this here. And remember these contours are
55:39 from wells. So it's it's no what's causing those big anomalies? We'll
55:46 the terrain boundaries. And here's a of the basement terrain. Remember this
55:50 and crust? Where's the trans I think the trans Hudson is is
55:56 a bit going through here and you the Wyoming terrain that are down
56:01 Wyoming creighton. I think this is slave up here. Um And superior
56:08 over here. This is the Where's the trans Hudson? Okay so
56:26 . Internal trans hood. Yeah that's these are. This is an old
56:31 genic event and our key and provinces these reds and pinks. And you
56:35 some protozoa like up here. These . These are also protozoa. Okay
56:43 that's the geology map of this. this is this is not well I'll
56:48 I'll get to that. But here are looking at that on top of
56:50 magnetic data in color trans here. if we if we make the magnolias
56:59 , this is really very nice. it shows you some of these boundaries
57:04 to be sure they had to have this magnetic data to help them do
57:09 right? It's just not not a but still there's a lot of wild
57:17 to remember. Okay, here's our anomalies. This is our teepee
57:23 And now we're gonna overlay it on same sort of map but separated by
57:29 which are solid colors to sub cropping is you know, just hatched
57:36 So it's it's nearly the same map you can see. So so you
57:42 an outcropping here and then it's you , remember we had all those wells
57:45 here. So that's how this thing defined and there's enough penetrations here and
57:50 combine that with the magnetic day. can make a really nice basement train
57:54 . So I think there's a pretty degree of confidence that these these are
58:00 trains and yeah, here it is the color film. I mean what
58:08 what the color is gone. So a really interesting, really important um
58:14 of study of basement and foreland basis there's just so much data and
58:22 Okay and then here's and then here's cross section through this. So you
58:26 see it's it's I can't read. is that's only four km I
58:34 But we're not at the deepest We're gonna look at another foreland basin
58:41 in in europe. Uh here's some alps, there's France um uh
58:52 I mean that's that's german Switzerland Germany italy Austria and Czech Czech
58:59 And we have a four land base this is the elevation. So you
59:02 the alps right here. But as up to, yeah, it's called
59:14 molasses for invasion. The molasses Now they're saying measured gravity. That's
59:21 not right. It's bouquet and that and you know, I can tell
59:24 bouquet because there's a big load when took the alps rooted into the
59:29 here's their basement death. And they contours that goes down to just,
59:35 is just not at all correct. no basin on this planet. The
59:41 basin in the world is probably Bay Bengal and that's about 18 km.
59:47 this is just, this is just wrong um Alright, the mojo depth
59:55 down from 24 to 55 kilometers. buy that. Um And then the
60:00 . A. B. Goes from kilometers down 245 I guess. I
60:06 that. And then they actually have cross section here. So from north
60:10 uh going north to south. And is a really good example of what
60:17 talking about. When I say this this is not observed gravity. This
60:22 boo gay gravity. And it shows it's going down and it's basically following
60:28 base of the crust. Right? have all these short wavelengths superimposed on
60:34 , but it's basically following the bases now, if we and then they
60:41 the L. A. B. I guess I guess that's about I
60:46 , I don't think they modeled the A. B at all. I
60:50 , I think this model is too to do that. But any
60:55 yeah, you can see the asymmetric of the basin right here in
61:04 What about do we have another Yeah, the Himalayas, the
61:09 Tibetan Plateau. So here's the, highest continental plateau and here's a geologic
61:20 of sorts to have all the basins blue, I think. And um
61:26 study that they're working on is this right here. It is called the
61:31 right here. And this is right the northern sort of flank of the
61:37 Andes and zooming into that area. is their geologic map. And it's
61:46 interesting because it doesn't give the impression this is like asymmetric in anyway,
61:51 this is, I guess they're calling a four land. But it seems
61:55 me it's more like an like an arc I think. Um Yeah yeah
62:03 they made a cross section uh through cross section C. And they have
62:11 an empty data. So many caloric and they're showing um hi res
62:19 This is receptivity. Um Yeah so recent of course in the base then
62:26 have a cross section here so that have buddha and alleys in red and
62:32 anomalies in this blue. So there's much really going on. They have
62:37 residual gravity in black bhaskar. Yeah don't know. That's weird to
62:56 This is very weird. Um Let's there's G. 1234. Do those
63:05 up? They're not identified here. well okay so they see they have
63:13 this would be the this is the part. Yeah the southwestern part.
63:18 here you have the thrust but then have back thrust on a normal
63:22 So this this is sort of I to me I don't see any asymmetry
63:28 typical of four land. So I know I would call this an intra
63:31 just because you have things going on here and the range here. So
63:39 the total range Is about 80 So these guys are on the order
63:46 20. So these c I would I would agree with this. These
63:51 being um I'm not sure what they for a residual but I like the
63:56 profile better than their and this residual you can really see the structures these
64:04 . These are acceptable I think I never remember, you should never model
64:12 data. I don't understand anyways. , so that's the last example of
64:20 four land and of those where we We're at 247 jeez I went through
64:26 too fast. Any questions on that on that material? Um No I
64:37 to go through it again but not . Alright well let's just see,
64:50 me just breeze through it so you catch that part because this is um
65:01 right so last stage conversion margins for you know at the last the final
65:08 , the second phase of the Wilson , the conversion phase and then a
65:14 zone with four arc inter art possibly land basins of course for our christian
65:21 . And then the four land fore basin and the four land has Wedge
65:29 Deep 4 Bulge back bullets components to . We looked at a couple of
65:35 examples Ecuador which you have the impression a few lights there. And that
65:46 a little study the open lights The low was reversed polarity probably.
65:51 you can see the basin getting deeper with these longer wavelengths on the magnetic
65:57 and of course this is booth because has a high out here. The
66:03 section through it which is as I would be quite similar to Oregon,
66:09 California Washington kind of the coastal range . Um I did I did argue
66:16 their ad hoc rock properties here. decided what they decided the general trees
66:22 they just put in place rock properties they made these curves fit. And
66:27 think that's just a flawed way to things. I don't think you can
66:31 anything from that. I think if want to make models you want modeling
66:35 be useful you want to challenge the people. And they would what they
66:40 claim with this, what this seismic would say well this supports our,
66:46 supports our interpretation and a lot of are happy to do stuff because you
66:52 they're supporting their interpretation and you know just repeating what the other people are
66:58 . But I think it's a disservice want the models if they're not going
67:03 challenge any aspect of it. If you're doing is making your models fit
67:07 other people think then you're not really anything. I mean just just doing
67:13 . So yeah, that's horrible. we looked at the Tobago trough and
67:19 went through this long explanation of how formed and how you know, Tobago
67:25 is bounded by an active bridge. art and a fossil island art which
67:34 formed out here during the you know the when the pacific plate or fair
67:40 plate was abducting beneath this great art central America, as some people call
67:47 . And then we looked at my friend here, the Canada basin which
67:51 a back arc and obvious ridge roman . But then the Tobago trough which
67:57 students Chanel worked on and which is between this fossil art that extends north
68:06 Tobago trough is concentric with the lesser active island art. The Tobago trough
68:13 in here. And then it's the is that it's this bit of um
68:19 our current million year old art She made a couple of gravity models
68:27 that. And you notice, you tell she worked with someone like me
68:31 it's not just a bunch of billion blocks. These are all the same
68:35 colors, are the same density. it's all the same density, same
68:40 . And you know, there's not lot of, you know, arbitrary
68:45 stuck in there doing this and which is something that I just I
68:49 don't allow. Okay. And then looked at this setting. The basin
68:53 is thought to be a foreland But I think I'm gonna differ from
68:58 basic, based on the geometry of basin. That is, it's asymmetric
69:03 the deepest part to the north and rather than to the south and
69:09 which is what a foreland basin geometry be like if it's related to the
69:15 slab. If it's if that remember a certain there's a certain geometry to
69:21 things, where is that? We'll back to our cells model right,
69:26 a certain geometry, if you have mountain belt here, the four land
69:32 be asymmetric with the deepest part going towards the mountain belt. And in
69:39 example it's going the opposite. So makes me scratch my head. And
69:46 I just look at these other I this is very complicated area anyways,
69:54 this is a Miocene basin, You . So maybe no older than 50
70:02 . A. It may be older the key name out. So it
70:11 be a four land related to the range. And I'll bet if I
70:17 for literature, I'd find some papers say that. And we looked at
70:24 gravity magnetic data over this over this , you can clearly see the basin
70:30 deeper right here. Um Yeah. then we look at the cross
70:35 these are man profiles showing that asymmetry things dipping to the northeast Northwest
70:44 then we jump down to uh an known inter arc basin, which is
70:51 Andes altiplano. So you can argue there are two inter inter art
70:57 And I think I should probably say that way from now on. And
71:02 idea is that the altiplano is a aesthetic equilibrium and that um that the
71:14 it uh huh Beneath the altiplano is low density um is a low density
71:25 uh whatever magma reservoir that is, know, kind of supporting, supporting
71:35 the central part of the altiplano. don't know if I believe that.
71:38 think it's I think it's absolutely I think it's okay to publish a
71:43 like, don't get me wrong, not saying this is worthless, I'm
71:47 saying that, I don't agree with conclusion. You know, this is
71:50 course is a nice way to compare air to bouquet, even though this
71:55 air does not really follow the Um Yeah, then we looked into
72:02 of the normal nature of the components four of four lands and sort of
72:08 mechanics of how they form and um those elements I look at this fun
72:15 example of of a foreland duplex in court theron area in the southeast of
72:25 , which is, you know, is just north of, what's that
72:30 spanish topping Catalan uh what's the city Spain? It's up here in the
72:39 northeastern coast it's called anyways. I it, I hate losing my
72:48 Okay, so um and then the of the western Canada basin, which
72:54 look at a bit of a lots of maps and the surface
72:59 which is sort of, you very predictable, you know, getting
73:05 um younger to the center to you know, as you go towards
73:11 mountain range. Um Here's the Again, we did look at a
73:20 of the things we looked at the of the arch area closely. And
73:26 we looked at the other areas as . These cross sections of course are
73:32 lines to cross sections. Actually at very end I gave you a hard
73:36 but this bouquet anomaly the low is by the by the crust. Remember
73:42 is these are anomalies. These wavelengths you know, hundreds of kilometers
73:48 There's there's no way something in the could support the anomaly. It has
73:53 be produced by the contrast at the of the cross. Alright. And
73:59 we residual. Is that with a km continuation. Right. Regionals made
74:05 up to 15 km. subtract that the observed and that gives you a
74:11 . And then we sort of looked that against some surface features that are
74:16 well well known and well understood. just the basic thickness here but also
74:22 these regional false um made a point they correlated with this map from
74:28 Hoffman, famous Canadian geologist. I a question. Can you explain back
74:36 back to the residual gravity anomaly. you explain what you're saying earlier?
74:40 know you probably explained it before but the difference between the regional you
74:47 So you make a regional, you make a regional first and you subtract
74:52 the original data. Right. You make a reason when you, I
74:59 you could do a high pass filter data but I think those are really
75:07 maps because they just they have so artifacts from that short wavelength you know
75:12 filter matching thing that goes on. not necessarily wiener matching but but but
75:18 that in the frequency domain high pass past noise. Right? So I
75:26 know I mean I I think it's to make a low pass filter first
75:30 make a upward continue the data first makes a regional those make smooth regional
75:38 . And then you remember from the that we went through right we showed
75:42 the regional which was a very smooth field. Then we subtract that from
75:47 from the original data and that will leave you with a residual. Right
75:53 the regional field of this is gonna a big broad high high up
75:58 This big broad low you know it's of it's going to be some kind
76:02 saddle shape if you can visualize Just thinking of the longer, if
76:07 can just smooth out all this short in your mind in your eye you
76:11 see that the region would just be smooth. Right? It would be
76:17 high and broadly low. Then when subtract that from the original data you
76:23 up with a residual. Okay and what this is. Okay and were
76:35 thinking of Barcelona spain earlier? Yeah I've been there. I gave
76:43 talk? There was. Um where are we at here?
76:48 Um, why was I think in , where was I thinking of?
76:53 slide was that? Oh, was year? There was this one
76:58 Yeah. Barcelona is just down Yeah, I don't know why I
77:06 . Anyways. Um Okay. So then we were laying on,
77:11 were laying these um, different maps top of the data, which is
77:18 nice thing to do. And showing that there are anomalies that correlate with
77:23 things. So, these are low anomalies. So, they're, you
77:31 , they you would, using rules thumb, you would say these are
77:35 , but we know they're not because a bunch of wells, right?
77:40 a bunch of well control on these . So they're not structural. I
77:44 , there may be a little bit structure in them, you see,
77:46 some pull of these contours, but not structural. So they're not
77:53 And they line up with these big margins. What do you think's going
78:01 ? This is not an obvious Do you want to take a shot
78:04 it? Hmm. It's not It's not present day structure. Could
78:20 be drifting or something? I don't . It's no, this is,
78:27 whole area is under convergent, convergent . There's no there's no extension?
78:33 no diversion is going on here. . But I don't know.
78:39 what's going on with these? Remember showed you kind of hinted around,
78:43 showed you these terrain here. These are all these big these terrain
78:49 and and how did this, how this terrain building happen? How
78:54 how do all these? I mean her that's a continental fragment superiors the
78:59 . Right. But are separated by our key and our genic zone.
79:03 was kind of plain and he wrote off and later. I mean,
79:07 how does all this happen? Um how old is our, how old
79:28 our key in rocks? Those are old. It's like old old,
79:37 I don't know like the our key rocks are older than 2.5 billion years
79:45 . So there are four billion and billion years old, photos or rocks
79:50 2.5 million to how old now. should know. You should know the
79:56 of the pre Cambrian boundary. Do you know that? I've always
80:01 really bad with the timescale. I do a lot of geology. You
80:06 you should know the major ones I is 5 30 to 5 32
80:12 A. So 5 32 2, . So it's almost two billion years
80:18 protozoan. So what you're looking at are different terrain that docked and were
80:27 on to what was once Llorente, was this the superior Creighton is one
80:35 the oldest on the planet. I it goes back to, you
80:40 three billion years. I mean it's , really, really old and you're
80:46 at hundreds of millions of years, ? Like five times the federal eon
80:55 terrain that just kept creating over different and being sutured onto this crate on
81:01 then eroded away and made smooth. what's happening here. This has all
81:07 eroded away. But you have this . These are these over here are
81:11 terrain and they were, you created, you know, sutured onto
81:19 continent. And then he wrote it and suturing of it when it was
81:26 , it produced this strike slip fault . These big strike slip fall zones
81:33 once sutures were once plate boundaries. know, play their their fossil plate
81:41 geologically when when someone says they mean fossil plate boundary where one plate was
81:49 onto another. It's a plate tectonic , it means a plate has been
81:55 onto another plate. That's what we when we say suture in plate
82:02 it means there were once two different . So these big train boundaries,
82:07 actually sutures. This origin. Trans origin was a mountain range. It
82:13 as big and broad as Grenville. range. And it was sutured onto
82:19 Creighton and then later the Wyoming time onto that. It was structured onto
82:26 . So when we look at something this, let me go back to
82:33 other one gravity. Because we're talking gravity. So we look at something
82:39 this. Yes, this this the the western Canada basin. It's
82:50 paleozoic basin. The sentiments in I mean they're pretty old. They
82:56 they go back to the sloth Have you learned about the sloth?
83:01 . L. O. S. . That doesn't sound familiar.
83:06 never heard of. So that's Don't worry about me. I'm not
83:13 take my comments wrong. I don't that way. It sounds kind of
83:17 a real jerk. I'm not trying be a jerk, but um I
83:22 help myself sometimes, but but the was sloth was a man, a
83:27 who famous geologist that in the city he met um empirical, you know
83:35 empirical means? He met the appearing that cross most of uh it's A
83:45 . S. A. 1960. bringing up right now. That's why
83:48 kind of stalling. He wrote a paper In 1963 entitled sequences of the
84:01 interior of north America. And there's very famous uh sequences that he
84:08 Let me go here. Um let's see, he mapped their maps
84:18 here, The sock, the tip canoe and the cask Askia. Those
84:24 the three big sock s au que canoe and cast Cascais sequences. And
84:31 crossed look at texas, Oklahoma Missouri Illinois Montana and into Canada uh
84:42 these are these were deposited during periods uh what they call empirical sees,
84:50 shallow seas that crop that extended over almost all of north America in the
84:57 , in the sort of the bony into I think our division to um
85:03 , our division devonian salary in up the yeah wow into the Jurassic and
85:10 so at the bottom of the basil of um the basil sequence of the
85:21 Canada basin. I've got it here you go sock, tipo,
85:32 , CASS, CASS Kia. And are uh you know the oldest oldest
85:40 says pre Cambrian but Cambrian or division in. So that's at the base
85:46 these. So even though the point I'm trying to make you, even
85:52 this basin is um even though the blocks in this basin were created over
86:04 of millions of years, there was time for those to be eroded
86:09 And then when the and then when uh you know when the antler progeny
86:16 then later the the rockies came they deformed that whole surface And that
86:27 flexed downward. And these sentiments reported top of all of that, all
86:31 that very old deformation and the pile sediment sits sits on top of all
86:37 that deformation. Does that sort of sense now? Yes, sir.
86:45 so continents are like that. You , you have basins that form but
86:50 sitting on top of just all this old deformation. You know? Um
86:56 and then of course you can really it in the magnetic, it's really
86:59 map with just you know there's all long wavelength here and yeah so I
87:08 I I mean yeah, I'm not you don't you don't know sloths and
87:14 . I mean that's kind of like geology stuff, sequence photography stuff.
87:21 sorry just regular rocks, photography And yeah so we went through this
87:27 showed all these different terrain bonding with magnetic data um sub cropping versus
87:34 Um And then the cross section through . Now we look at this other
87:41 basin, the molasses or land basin the central europe. Um They call
87:48 measured gravity. I don't know why do that. And then of course
87:52 basin depth, this is just 28 clubs. That's just ridiculous.
87:57 mojo death L. A. But this is really even so this
88:01 really a nice figure because it shows cross sectional E. I mean do
88:06 find that useful that it's showing this of the that regional curve? Uh
88:12 how it just fits the shape of cross the crustal thickness. Mhm.
88:21 . So it's like if you can this same curve going through the gravity
88:27 nominee the gravity map of the western but turned around so instead of going
88:33 west to east going from east to . This would be like the part
88:36 beneath the beneath the Canadian rockies, ? This would be the rest of
88:41 Western Canada basin. Look at this complicated. I think it's another intra
88:47 , frankly, because they're calling it four line in the paper, but
88:51 not a symmetric. Even this country here. No, it's not it's
88:57 a symmetric, it's like a high the middle of two to uh to
89:03 . Um although I think this this is pretty good. It's one single
89:09 , you know, they don't have lot of density blocks in here,
89:12 I love to see. And these ranges an amplitude, tens of tens
89:18 milligrams. Which tells you, you , rule of thumb that they are
89:22 and boom boom, boom boom, line up just bouquet, I don't
89:26 what this residual is unless they you know. Okay, so a
89:32 a residual is actually, you know you want, right? And sometimes
89:37 residual is actually the long wavelength, , what you're interested is in long
89:43 and not short wavelengths. And I that's what they've done here. They're
89:46 at, they're trying to, oh , they're trying to make estimates into
89:51 , deeper elements. And so they filtered out the short wavelengths and they
89:57 to look at the long wave. why that looks like that.
90:00 yeah, yeah, I get it . Yeah, they want to look
90:02 this stuff here. So that's Yeah. And that's it. So
90:07 know that man, I just feel bad. You're not asking me any
90:12 . So it's It's quarter after We did we managed to do the
90:18 I think also it's faster teaching just student, you know? Yeah,
90:23 can imagine it's just me. I , because if you had if you
90:28 more classmates, I'd probably getting more people would be interrupting me.
90:32 you know, and so yeah, maybe maybe that's that's I guess that's
90:37 excuse with it. I like but that's good. So um I
90:46 probably be able to get through the . I'll probably get through all the
90:50 because, you know, I've been been going fast and we have half
90:54 this lecture to go. I unless you want me to go through
90:57 rest of this lecture tonight, I , but we can probably do
91:04 The complex part complex my uh How many slides do we have
91:17 It's a total of 107 and we've through 50. So we've gone to
91:25 about half of them. And this doesn't go that this doesn't take
91:30 long to do this and I don't it's 100 sides for the other
91:35 So we could probably finish this stuff on friday and I'll be really happy
91:41 I will have presented all the material you and you will always be able
91:46 enjoy hours of recordings and so we'll this up, we'll pick this up
91:54 if you don't mind. Okay, fine. And if I mean you
92:01 do if you want but if I you, I would finish that model
92:04 today that way. You don't have worry about it ever again for the
92:08 of your life. So which I'm I'm gonna try to finish it today
92:14 sure. When do you want it if I don't get it done
92:19 Um I think I said let's do last day of class on Wednesday
92:25 Okay, that'll work. Yeah, definitely have it. I do whatever
92:30 want. I mean, I just frightened that you won't be able to
92:35 it again and have some problems, maybe I'm just, you know,
92:39 over think I left it open. haven't even I didn't close out of
92:44 . So it's sitting there and you say that one last time before we
92:49 doing this stuff. Right, Alright . Well, all right,
92:54 I think I think I think I I have had enough of this.
92:58 stay with the difficulties, but it's your fault. And you know,
93:01 I said, don't worry about I I didn't I hope you didn't take
93:05 . I said personally, no, fine. I was just like,
93:08 know how to use a computer like don't know what's happening right now.
93:13 , I mean you're a mac person you know, so like the
93:17 the logic, the logic is quite . I mean, I don't
93:22 you probably run into this stuff before that not being, you know,
93:28 , I don't know, I'll bet like Youtube videos out there that like
93:32 something like pC logic for, for users kind of thing so you
93:37 you know, understand some of I think at least once a
93:44 even in my undergrad, like I an issue where one of my classes
93:49 something for Windows and then I have max then I'm like, oh my
93:53 , what do I do? So think it's just, it's just time
93:55 me to get a Windows laptop and have it. Well, I
94:00 yeah, you know, I know had a, I had an ipad
94:03 I hated it because I hated having go through all the itunes sinking and
94:08 that crap. I thought, I , what a what a weird way
94:12 do things. You know what I ? I mean with with my
94:16 I just, I just have a chip that I load up my data
94:20 you know, I had, but I basically, I don't have anything
94:25 it other than it's called good notes like that's what I did my test
94:29 or when I do the slides, I can just everything. So I
94:33 just use it as a notebook. your handwriting is right on the
94:37 Uh huh wow. Yeah so like test that I sent you like I
94:41 did that all on my ipad and you can just export it as a
94:45 and then just send it wherever you . I can't even think like
94:49 Okay well well you're you're you're a person and more advanced or stuff like
94:55 than I am. I can't even like that. I have to I
94:59 if I'm if I read a paper closely I print it in and I
95:05 read it on the screen. I want to read it closely. I
95:08 print it so it's pretty old Alright then. So I'll see you
95:15 evening and that will be the last I guess. Huh, friday evening
95:19 mean yeah okay friday afternoon. And that will be the last lecture
95:26 then I just have to write one . I haven't scored years yet so
95:29 do that. I don't know. today. Maybe that I don't
95:34 All right, see you later. you next week later. Thank
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