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Author Topic:   Growing the Geologic Column
edge
Member (Idle past 1706 days)
Posts: 4696
From: Colorado, USA
Joined: 01-09-2002


Message 628 of 740 (734944)
08-03-2014 7:37 PM
Reply to: Message 620 by Faith
08-03-2014 6:29 PM


Can only assume it got deformed in that particular way.
Actually, this probably isn't the case, particularly since the yellow unit (upper Cretaceous rocks) pinch out completely to the left.
It is not uncommon for sediments in a basin like this to be thicker near the center.
There is no real strong deformation here of the mountain-building type, it is mostly uneven compaction of the sediments and some faulting extending into the basement caused by sedimentary loading.
I've been looking at this section for a while now and see that it had a very particular purpose. The creators of it were proposing deep drilling through the salt to tap a very large oil and gas target. So, I'm guessing that the details are probably pretty much selected for that purpose. For instance, the Albian rocks, are mostly (I think) mid-Cretaceous sands and were probably a nice target for previous drilling and now pose a datum for the intended audience of the section.
I'm thinking that this is what I call a 'presentation graphic', and may even have some errors.
Anyway, moving on...
The evidence that includes it with the other layers as already there is the fault lines that penetrate into it from the layers below, ...
Well, actually not. In the area below the yellow unit there is a set of faults that only penetrate into the salt and maybe a little bit above it.
... most clearly those to the left of the salt dome, and the salt dome itself which rises right through it.
Yes, those are what I would call late Cretaceous faults, and even though only one of them seems to pass entirely through the yellow unit, I would say from all cross-cutting relationships that these faults were active more recently than the ones on the right side of the diagram.
Isn't it clear that the green layer was already there? It extends all the way from left to right, broken by many fault lines.
The green layer, which underlies that salt everywhere is one of the older units. So, yes, I would expect it to be affected by the earliest to latest faults of all the faults shown here. This is not surprising.
The separate sections of it wouldn't have been laid down individually, it had to be a continuous layer that was displaced by the faults.
This is exactly what we would expect of the oldest layers. And yet the youngest layers (Tertiary, in purple) are the least affected by faulting. This is what I have been saying all along.
By the tan layer you mean on the left that says Oceanic crust? No, that's not part of the strata.
HBD may be referring to some sandy colored layers below the green unit. It is not clear what these are, but I'm guessing that they would be Triassic sediments. It appears that they may have some more convoluted bedding that the layers above. Unfortunately, some of the stylized bedding lines are extended into the Paleozoic rocks beneath. This puzzled me earlier, but it could just be a mistake.
And all the pink wavy layers were there because they also stretch the full width of the diagram, and so does the red Albian. It really looks quite straightforward to me. Layers get laid down as one continuous deposit.
They probably were continuous, but that's not really important. They are certainly of variable thickness and show some deformation related to faulting. However, they are still older than the yellow late Cretaceous rocks and the topmost Tertiary rocks, so they may show older deformation than those younger rocks.
Also if any were deposited later, they should have a different surface than the ones already deformed beneath them, because they would always deposit horizontally and have an originally flat upper surface that would deform separately. The Albian on the left shows that sort of difference I would expect, except that its upper surface conforms to the wavy pattern to the right so that difference on the left has to have some other cause.
Your characterization here is a little bit misled. It is not uncommon, and it is apparent from the section, that different layer will vary in thickness. For instance, as I mentioned above, the yellow, late Cretaceous rocks do not even seem to exist on the left side of the diagram; while the Albian sands thicken in that direction.
The only real question is whether the one at the top labeled Base tertiary was already there, and there is a question about that because no faults go up through it.
Assuming there is no gross error in the drafting of the diagram, the conclusion would be that it is less deformed because it was present for less time as the sediment pile compacted.
But I'd argue that its nonhorizontal surface and the fact that the salt dome pushes it up shows it too was already there along with the others.
Well, it was there before some of the salt dome forming process. But I don't see it there before any of the faulting. Once again, you fail to recognize a process that that maybe incomplete.

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edge
Member (Idle past 1706 days)
Posts: 4696
From: Colorado, USA
Joined: 01-09-2002


(1)
Message 629 of 740 (734945)
08-03-2014 7:41 PM


Just as an FYI, Albian refers to an age period within the Cretaceous. Here is the wiki reference.
Albian - Wikipedia
Also, when the diagram refers to 'base of Tertiary' that means that the sediments above that line are of Tertiary age.

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edge
Member (Idle past 1706 days)
Posts: 4696
From: Colorado, USA
Joined: 01-09-2002


Message 631 of 740 (734947)
08-03-2014 8:07 PM
Reply to: Message 627 by herebedragons
08-03-2014 7:30 PM


No, it doesn't. If a fault slid 10 feet then stopped, and then sediment was deposited on top of it and then it slid again, the fault could then continue into the new layer.
This would be called a 'growth fault'. It implies contemporaneous sedimentation and faulting. When faulting stops, sedimentation continuous and eventually covers the top edge of the fault plane.
It could also deform the layers above, it would depend on forces and resistance involved (like what type of material the new deposit is).
The last stage of a growth fault would be minor draping of the sediments across a very small fault scarp.
This is sort of a special case for cross-cutting relationships which we usually consider to ironclad. Usually, if a fault cuts a rock, it is younger than the rock (or sediment deposit if not lithified). However, what happens when the fault terminates within a given layer? That means that the layer is both older (in part), and younger (in part) than the fault.
Whether intended or not, the diagram in question shows a large number of growth faults (crossing several strata in this case); which I would expect...

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edge
Member (Idle past 1706 days)
Posts: 4696
From: Colorado, USA
Joined: 01-09-2002


Message 634 of 740 (734951)
08-03-2014 8:23 PM
Reply to: Message 633 by Faith
08-03-2014 8:14 PM


But that would show up as a different upper surface on the new deposit (originally horizontal always) from the one it's depositing on which would have been distorted by the fault. I don't see that kind of thing anywhere on the diagram
At the scale of this diagram, you wouldn't.
Besides, your parallel surfaces notion is spurious for this type of sedimentation. Clearly, a stratum that pinches out in any direction does not have parallel contacts, and because of compaction, is very unlikely to maintain horizontality. There is a lot of that in this diagram.
It probably isn't part of the geological column...

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 Message 633 by Faith, posted 08-03-2014 8:14 PM Faith has replied

Replies to this message:
 Message 635 by Faith, posted 08-03-2014 9:13 PM edge has replied

  
edge
Member (Idle past 1706 days)
Posts: 4696
From: Colorado, USA
Joined: 01-09-2002


Message 636 of 740 (734959)
08-03-2014 9:31 PM
Reply to: Message 635 by Faith
08-03-2014 9:13 PM


I already took into account that it wouldn't maintain horizontality but it should at first since it would just lie over whatever was already there, distorted or not, just not after being distorted itself.
If faulting continued after the blue layer, then the brown and orange should be more offset. Which has been my point all along.
In a compaction situation, which is where most of the deformation is coming from the light blue layer would not have that hump on the left side of the diagram. All sediments are trending downward.
It looks to me like it is.
I was being facetious.

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Replies to this message:
 Message 637 by Faith, posted 08-03-2014 9:36 PM edge has replied

  
edge
Member (Idle past 1706 days)
Posts: 4696
From: Colorado, USA
Joined: 01-09-2002


Message 639 of 740 (734972)
08-03-2014 11:41 PM
Reply to: Message 637 by Faith
08-03-2014 9:36 PM


yes the brown and the orange should also be more offset, but the main point of the diagram was to show that new layers after a fault would not conform to the shape of the earlier ones, either when just deposited or after the fault was extended. And that diagram shows many differences in shape of layers so there's no problem with such a situation being recorded there.
Except that the faults occurred at various time during deposition and very little has occurred since the Tertary, thereby refuting your premise that all faulting took place after all deposition.

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 Message 640 by Faith, posted 08-03-2014 11:51 PM edge has replied

  
edge
Member (Idle past 1706 days)
Posts: 4696
From: Colorado, USA
Joined: 01-09-2002


Message 641 of 740 (734981)
08-04-2014 12:08 AM
Reply to: Message 640 by Faith
08-03-2014 11:51 PM


It's not a premise, I believe that's what the diagram evidences.
It is a notion that you picked up somehow and now use it to base your arguments for every section that you see.
Oh, and what you believe doesn't make any sense, for all of the reasons we have given you.
ABE: But I notice that you don't take issue with my statement that your premise is wrong, but rather make an argument regarding definitions. Is that your intent?
Edited by edge, : No reason given.
Edited by edge, : No reason given.

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edge
Member (Idle past 1706 days)
Posts: 4696
From: Colorado, USA
Joined: 01-09-2002


Message 657 of 740 (735012)
08-04-2014 1:15 PM
Reply to: Message 656 by Percy
08-04-2014 1:05 PM


Re: Flood debunkery revisited
Heh, heh...
Such are the effects of uncontrolled ad hocism.
Edited by edge, : No reason given.

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edge
Member (Idle past 1706 days)
Posts: 4696
From: Colorado, USA
Joined: 01-09-2002


(1)
Message 677 of 740 (735063)
08-05-2014 11:35 AM
Reply to: Message 675 by Faith
08-05-2014 9:28 AM


Re: Order of events as shown on cross sections
You need the Base tertiary to show some sign of original horizontality, especially since it isn't faulted, which it doesn't, and you also have to take the salt dome into account that pushes it up.
Faith, the lower Tertiary has been there for 50 million years.
But regardless of that, it is not faulted to the degree that the deeper sediments are disrupted.
How does this square with your theory that all deformation occurred at once and after all sediments were deposited?
Stop with the evasion regarding horizontality. I don't care if the Tertiary sediments were pasted to a wall.
Edited by edge, : No reason given.

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 Message 675 by Faith, posted 08-05-2014 9:28 AM Faith has replied

Replies to this message:
 Message 682 by Faith, posted 08-05-2014 12:02 PM edge has replied

  
edge
Member (Idle past 1706 days)
Posts: 4696
From: Colorado, USA
Joined: 01-09-2002


(1)
Message 680 of 740 (735066)
08-05-2014 11:41 AM
Reply to: Message 672 by Faith
08-05-2014 9:05 AM


Oh yes, I did forget an important point: the formations made up of interspersed layers of volcanic and sedimentary layers that many posted appear to be volcanic in origin, the whole formation, that is why I don't include them in my view of the basically sedimentary Geologic Column.
How convenient for you.
So, if we have Paleozoic sedimentary rocks overlain by Permian/Triassic volcanics, in turn overlain by Jurassic and Cretaceous sediments we can just pull out those volcanics as if they didn't exist. All just to fit Faith's idiosyncratic version of geology.
You know, this could be fun.

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Replies to this message:
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edge
Member (Idle past 1706 days)
Posts: 4696
From: Colorado, USA
Joined: 01-09-2002


Message 684 of 740 (735072)
08-05-2014 12:04 PM
Reply to: Message 681 by JonF
08-05-2014 11:51 AM


No, she means you can write off the Jurassic and Cretaceous sediments as volcanic. Gotta be the kookiest things she's ever come up with, and that's saying something.
So, I was right.
This could be fun. We have several new classes of volcanic rock. The igneous petrologists will be most ecstatic.
We're gonna need a whole lot of new textbooks, though...

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edge
Member (Idle past 1706 days)
Posts: 4696
From: Colorado, USA
Joined: 01-09-2002


Message 685 of 740 (735074)
08-05-2014 12:10 PM
Reply to: Message 682 by Faith
08-05-2014 12:02 PM


Re: Order of events as shown on cross sections
The Base Tertiary and all the others have been there only 4300 years, ...
First of all, there is not 'Base Tertiary'. There is a base of the Tertiary, but it is not a formation, it is a contact.
... and that being the case all the faulting has occurred since then, ...
And no, if the faulting does not cut the base of the Tertiary, then it can't occur since the Tertiary.
I can't even imagine your confusion.
... and if some didn't go all the way up through some of the layers, big deal.
Yes, big deal. Mainly to you. This is only the most obvious change with time. You still have the faults that occurred before the salt that you have not attempted to explain.
So, is everything after the base of the Tertiary after the fludde, or is everything since the base of the salt post-fludde?

This message is a reply to:
 Message 682 by Faith, posted 08-05-2014 12:02 PM Faith has replied

Replies to this message:
 Message 687 by Faith, posted 08-05-2014 12:13 PM edge has replied

  
edge
Member (Idle past 1706 days)
Posts: 4696
From: Colorado, USA
Joined: 01-09-2002


Message 688 of 740 (735077)
08-05-2014 12:16 PM
Reply to: Message 687 by Faith
08-05-2014 12:13 PM


Re: Order of events as shown on cross sections
I don't think the faults occurred "before" the salt or before any of the deposits. I think they all occurred after.
Then you defy the evidence.
Why are there faults that terminate in the salt or just above, if they are younger than all of the sediments above the salt?

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edge
Member (Idle past 1706 days)
Posts: 4696
From: Colorado, USA
Joined: 01-09-2002


(1)
Message 689 of 740 (735079)
08-05-2014 12:20 PM
Reply to: Message 686 by Faith
08-05-2014 12:11 PM


I have hardly even begun to think about this stuff ...
This is clearly the case and it's surprising how far you've gotten off-track in such a short periods of time.
... and I certainly have no interest in discussing it with people whose whole M.O. is debunkery and ridicule of anything I say.
I will admit to being all for debunking unsupported ideas that run afoul of the data.
As far as the ridicule goes, perhaps if you were less arrogant and disrespectful, you'd get a better reception.

This message is a reply to:
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edge
Member (Idle past 1706 days)
Posts: 4696
From: Colorado, USA
Joined: 01-09-2002


Message 695 of 740 (735091)
08-05-2014 1:26 PM
Reply to: Message 693 by Faith
08-05-2014 12:49 PM


Re: I didn'tRe: Sedimentary rocks are sedimentary
I didn't mean to say that they are volcanic, but that they are connected with volcanism.
So then, you admit that there was active volcanism going back into the Paleozoic and the Precambrian. Now we are getting someplace. Would you agree that volcanoes are often related to faults?

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