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Author | Topic: Growing the Geologic Column | |||||||||||||||||||||||||||||||||||||||
edge Member (Idle past 1736 days) Posts: 4696 From: Colorado, USA Joined: |
The way to prove if today's deposition is in fact building on THE Geologic Column would be to show what lies BENEATH the new deposition. But I gather nobody cares to deal with that concept, you'd rather make up your own idea of geologic columns and claim to defeat it with a bunch of irrelevancies.
I guess you missed it, but I mentioned the modern sediments being deposited on layers going continuously back to Permian time under the Mississippi River Delta.
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edge Member (Idle past 1736 days) Posts: 4696 From: Colorado, USA Joined: |
How very odd! You excoriate me for failing to appreciate that people who are not posting on this forum know what is in the dirt beneath recent deposits, and somehow you assume it would answer my request that this be known without giving the slightest information about what exactly is supposedly known.
That's what you miss when you don't read others' posts. I provided a link or an image showing exactly what Cora described.
Is it the Geo Column or not?
According to you, it would be. Continuing right up to the present and, evdently, beyond.
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edge Member (Idle past 1736 days) Posts: 4696 From: Colorado, USA Joined: |
I know it's an abstraction and as long as you keep repeating that as if I hadn't said it myself many times I am not going to read the links you've posted. Fair is fair.
Actually, it was your strawman version of "The Geological Column" that you were smacking down. The one that had to be 'growing upward', and wide as a continent, and whatever else you thought it should be. You were not discussing the same geological 'colulmn' that we were.
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edge Member (Idle past 1736 days) Posts: 4696 From: Colorado, USA Joined: |
So sorry, if I'm dealing with a dozen people I can miss anything and your attitude that I should have seen it, let alone even have a clue what it's supposed to prove, is off base.
Hmmm, maybe if you were a little less shrill, outrageous, ... maybe less disagreeable?
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edge Member (Idle past 1736 days) Posts: 4696 From: Colorado, USA Joined: |
Sorry, I have to suppose that's an honest opinion but as written it's just a shot in the dark and I have no reason to take it seriously. I'm the one who originally brought up the concept of the Geologic Column and you've all been feverishly engaged since then in proving me wrong, usually by misrepresenting me, often by missing the point altogether. So I really have little reason to take anything you say at face value.
Actually, it was you defining what you wanted the geo column to be. We agree that it is an abstraction, just not the same one that you created in your own mind.
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edge Member (Idle past 1736 days) Posts: 4696 From: Colorado, USA Joined: |
Sorry, I reject that characterization of anything I've said here. Look to yourself, you are the worst offender among a gaggle of snarkies.
You mean that's all the thanks I get for explaining things to you?
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edge Member (Idle past 1736 days) Posts: 4696 From: Colorado, USA Joined: |
In which messages did you acknowledge that it was an abstraction?
This was my question also. The only way I could make sense of it was that she has actually been setting up the 'geological column' as a strawman to be refuted at some point because it is so inconsistent. But that's still a reach.
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edge Member (Idle past 1736 days) Posts: 4696 From: Colorado, USA Joined: |
I went on to try to explain that there's no such thing and I never got the sense that she understood that.
As someone here put it so well, 'the geological column is a diagram'. That is particularly true of THE geological column.
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edge Member (Idle past 1736 days) Posts: 4696 From: Colorado, USA Joined:
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No, but thanks for the effort. I think really it's that I'm impressed with the examples where strata built to a great height before tectonic or any other force disturbed it, those diagrams I mentioned back on the other thread: the cross section of Great Britain, the cross section of a part of Utah, the cross section of the GC-GS area, ...
But your premise is not even true for even those areas. The Devonian-aged Old Red Sandstone overlies an angular unconformity related to the Caledonian orogeny of early Paleozoic age, all occurring at the time you had continuous deposition at the Grand Canyon.
These deposits are closely associated with the erosion of the Caledonian Mountain chain which was thrown up by the collision of the former continents of Avalonia, Baltica and Laurentia to form the Old Red Sandstone Continent- an event known as the Caledonian Orogeny. (Old Red Sandstone - Wikipedia) And, closer to home, why do you ignore the cross-section of Utah that I showed you? I mean, the one that showed uplift of the Uncompahgre Plateau in the Pennsylvanian Period. And yet you claim that nothing tectonic happened during those times... Things are actually a little bit more complex than you think.
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edge Member (Idle past 1736 days) Posts: 4696 From: Colorado, USA Joined: |
Well, that's what I would have asked. That's why I consider it such a big deal to point out where there appears not to have been any such activity for millions of years, even if only in one location such as the Grand Staircase area. But when I've pointed that out here, the geologists have answered that it's no big deal if nothing happens tectonically for hundreds of millions of years in one location or another, so you'll have to ask them how that can be.
Except that we have show that there was deformation in other areas. And the fact that there is no reason why a given location may lie dormant for long periods of time is a different subject. I suppose for an absolutist, your position is understandable, every place undergoes deformation or none do... Edited by edge, : No reason given.
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edge Member (Idle past 1736 days) Posts: 4696 From: Colorado, USA Joined: |
Back on the other thread somebody did post pictures of lava layers that really look like lava layers between sedimentary layers but are not layers that were deposited within the sequence but as they all turn out to be, intrusive layers, sills.
Well, since we were discussing the Grand Canyon, the obvious example to satisfy you would be the Cardenas Basalt. The Cardenas Basalt is stratigraphically described by Wikipediea as:
Unit of: Unkar Group Underlies: Nankoweap Formation Overlies: Dox Formation (Cardenas Basalt - Wikipedia) The basal contact of the Cardenas Basalt with the underlying Dox Formation is ... Thus, the contact between the Cardenas Lavas and the Dox Formation is conformable and interfingering. This indicates that sands were still being deposited when the first lavas erupted and that deposition occurred during the transition from the accumulation of Dox Formation to Cardenas Basalt.[3][4][9] The contact between the Cardenas Basalt and the overlying Nankoweap Formation is an erosion surface that is a disconformity or even a slight angular unconformity. Locally, the contact is a low relief erosional surface associated with a thin weathering zone developed in the lavas of the Cardenas Basalt. And here is a cross setion showing the relationships:
Edited to add: I just noticed how this diagram shows the erosional unconformity between the Temple Butte and the Muav. Also, notice the presence of dikes and sills along with the Cardenas lava. Edited by edge, : No reason given.
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edge Member (Idle past 1736 days) Posts: 4696 From: Colorado, USA Joined: |
In her defense, I think that what we observe happening today DOES look strangely different than what we see in the rock record. But to me it highlights the fact that it takes lots of time (as well as specific circumstances) to convert these unconsolidated sediments into recognizable rock units. We just don't see it happening year by year as it would have had to happen in a global flood.
In order for Walther's Law to be in effect, you must have changing sea levels and this only really happens on a scale of geological time.If the Atlantic Ocean transgressed across New Jersey and into the mid-west, you'd see layers precursive to those Faith is talking about.
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edge Member (Idle past 1736 days) Posts: 4696 From: Colorado, USA Joined: |
Are you actually arguing that all igneous layers are intrusive?
Apparently that is the case. Faith seems to require that all deformation and volcanism and plate tectonics(?), occurred after the fludde. So, if there is an igneous body in the sedimentary sequence, it must have been intruded. This, of course, is at odds with geological observations.
Tuffs are not intrusive. And it's quite possible to determine when a lava layer is not intrusive.
It is weird to some people that igneous rocks can actually span the gap between intrusive and sedimentary. In fact, probably most volcanic rocks are, to some degree, 'sedimentary'. They come under the general term 'pyroclastic' and 'reworked' (for lack of a better term). I will say that volcanic stratigraphy is ... er, challenging at times; especially if you are not working with 'flood basalts' (not to be confused with The Fludde). That may be the reason that they are often not shown in generalized 'geological columns'.
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edge Member (Idle past 1736 days) Posts: 4696 From: Colorado, USA Joined: |
But it would sure be nice if just once in a while somebody responded to something like that reconstruction effort I drew, with something like "Wow, yes, now I see it, that's really brilliant how you put all that together," instead of the predictable denigration like how I supposedly "took liberties" with it and how there are really four or five tectonic events there (which I don't see at all) and so on.
Well, just on cursory review, you ignored the fact that there is an angular unconformity between the Stockton Formation and the units beneath it. It also appears that you ignore several fault surfaces. As a first attempt by a novice, maybe it's not too bad.
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edge Member (Idle past 1736 days) Posts: 4696 From: Colorado, USA Joined:
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I've read this through a number of times, and I know you've posted on it many times before, but right now I can't figure out why it can't be a sill. Would you please explain that again. Thanks.
If a contact has been eroded, then it was one time at the surface. If a lava is deposited at the surface, both the lower and upper contacts would show evidence of erosion. abe: the "erosional surface?" We live on an erosional surface, also known as an unconformity.
Or, since volcanic ash has been coming up, could it be that?
Believe it or not, we have learned how to tell lava flows from volcanic ash.
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