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Author | Topic: Growing the Geologic Column | |||||||||||||||||||||||||||||||||||||||
edge Member (Idle past 1736 days) Posts: 4696 From: Colorado, USA Joined:
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So you all say but I think this is just a habit of thought and in actual practical fact has nothing to do with looking for oil or certain fossils.
And this is all according to whom?
OK, this is the sort of thing I've heard is necessary. I'd like to see it demonstrated and argued out some time. I'd suspect that the theory about thermal history would work but only because it's really about relative age and relative heat, not because the actual temperature could be or needs to be known. But that's my theory for whenever I get to see the arguments presented.
Again, wrong. THe only thing you know is that the dike is younger than the sediments. It represents a thermal event that may have affected either the source or the reservoir rocks depending on when the oil formed or migrated.
But just as a matter of fact I've been impressed with the sketchiness of the identification of the time periods on these petroleum cross sections, maybe something like "Ord" at the bottom of the stack and "Mio" at the very top with hardly anything noted in between.
So, you have seen actual company sections used for oil exploration? How did you manage that? And how do you judge the 'sketchiness' of the sections? Do you ever judge the sketchiness of your own scenario for geological events?
You've said nothing here that suggests you need to know more than the relative ages of the intrusive rocks, not actual age. Since actual ages are always assigned you are in the habit of taking them for real, but in practical reality you could do without them.
Well, at least you are consistently wrong. I didn't say that relative ages were available to tell which is younger. And what if both intrusive bodies were too old or too young? How would we know? Edited by Admin, : Add missing close quote dBCode.
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edge Member (Idle past 1736 days) Posts: 4696 From: Colorado, USA Joined:
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I would think it would be a lot harder to accumulate that much sand in one place on the Old Earth model than on the Flood model. In the Flood the water would do a lot of pulverizing as well as transporting and depositing. Where's all that sand going to come from over hundreds of millions of years? Can you identify a source on the South American continent and a method for its deposition and compression to such a huge depth and breadth?
So, you are not going to answer my question? Evasion noted.
Same tectonic event did different things in the two different locations: raised the plateau in South America, also in the Grand Canyon but there it also had a volcano (or two or three?) working with it and the rocks got tilted and metamorphosed in various ways.
So, deformation occurred at the GC in Precambrian time but not at Roraima?
What I said was that the HUGENESS isn't going to be repeated, of course there will always be sand and I suppose some sandstone created from it, just nothing on this huge scale.
Again, that was not my question. What process caused the huge accumulation of sandstones at Roraima?
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edge Member (Idle past 1736 days) Posts: 4696 From: Colorado, USA Joined: |
ABE: Here's what I mean: if for instance the cross section shows a stack of layers with a magma dike running from the Precambrian rocks at the very bottom to the Tertiary at the very top and spilling over the top, then we can conclude that the strata were all there first and then the volcanic event occurred.
Again, you assume that there was only one event. What about intrusives that do not penetrate into the Paleozoic and are actually cut off at the unconformity?
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Pressie Member Posts: 2103 From: Pretoria, SA Joined: |
Faith writes: Actually, the relative age of a rock is very imporatant in exploration and mining. ...interesting that even in this post of yours the age is really just windowdressing, what concerns you --Faith writes: That's very important in geology. ... as it should -- is the relationships between the rocks themselves...Faith writes: That's very important in geology, too. Everyone should consider what a rock can weather too, etc. That's why the weathering of rocks is such a huge part of geology. Minerology etc. Do you think that all those tens of thousands of geologists are all stupid? ... and their physical condition. ... Edited by Pressie, : No reason given.
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Pressie Member Posts: 2103 From: Pretoria, SA Joined: |
Faith writes: Seems like that's what you think about extrusions and intrusions.
Weird, Pressie, no idea where you get such a weird idea.
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Pressie Member Posts: 2103 From: Pretoria, SA Joined: |
Faith writes: Actually, no. Igneous rocks indicate igneous events. For example, we do have diabases 'running' from precambrian rocks to the Tertiary in the Karoo and the Karoo sediments were deposited in those valleys formed by those eroded diabases. The volcanic events occured first, then the sedimentation occurred later. Then more volcanic events to form the dolerites and basalts after the main sedimentation events. ABE: Here's what I mean: if for instance the cross section shows a stack of layers with a magma dike running from the Precambrian rocks at the very bottom to the Tertiary at the very top and spilling over the top, then we can conclude that the strata were all there first and then the volcanic event occurred. Edited by Pressie, : No reason given. Edited by Pressie, : No reason given. Edited by Pressie, : No reason given.
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JonF Member (Idle past 198 days) Posts: 6174 Joined: |
The main evidence I have is what led me to this pondering: the fact that in many or most places I've seen on cross section the volcanic effects clearly occurred after the strata were all in place You have ignored the majority of the evidence. E.g. Message 214:
Count the tuffs which cannot be intrusive interspersed with sedimentary layers.
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Faith  Suspended Member (Idle past 1475 days) Posts: 35298 From: Nevada, USA Joined: |
I'm not sure what to do with your diagram. When I'm talking about volcanism after sedimentary deposits I'm looking for the deepest stack of sediments I can find because I'm trying to make a point about the hundreds of millions of years before tectonic or volcanic disturbance, and I've found hundreds of cross sections that include many that show this order pretty clearly. But your diagram, which required me to look things up, which is not fair on a thread like this, only goes back to the Pliocene and Pleistocene, too recent to show anything I have in mind, although if anything it could be a proof of what I'm talking about except earlier sediments aren't there to find out one way or another. It's being sediments among volcanic layers is also a different kind of example. But I'll put it into the mix to think about.
Edited by Faith, : No reason given.
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Faith  Suspended Member (Idle past 1475 days) Posts: 35298 From: Nevada, USA Joined: |
Sounds like something completely different to me. If a magna dike penetrates up through strata it has to have occurred after they were in place.
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Faith  Suspended Member (Idle past 1475 days) Posts: 35298 From: Nevada, USA Joined: |
Well, you keep agreeing with me in that post and then ask if I think geologists are stupid after you've agreed with me, so what is your point? The physical condition of the rocks is the important thing, and he RELATIVE ages. You agree with this so what's the problem?
Edited by Faith, : No reason given.
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Faith  Suspended Member (Idle past 1475 days) Posts: 35298 From: Nevada, USA Joined: |
Again, you assume that there was only one event. What about intrusives that do not penetrate into the Paleozoic and are actually cut off at the unconformity? I'm really not ASSUMING any of this, I just think it makes sense and I want to try to prove it if I can. That would mean stepping on geologists' toes I'm afraid, sorry about that, but who knows, maybe I'll end up agreeing with you. I just figure the cut-off intrusives went that high and no higher at that point. Edited by Faith, : No reason given.
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Faith  Suspended Member (Idle past 1475 days) Posts: 35298 From: Nevada, USA Joined: |
So, deformation occurred at the GC in Precambrian time but not at Roraima? Looks like it to me. Isn't that what I already said?
Again, that was not my question. What process caused the huge accumulation of sandstones at Roraima Deposition by the Flood, which is how all the thick rock slabs everywhere were formed. Edited by Faith, : No reason given.
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herebedragons Member (Idle past 888 days) Posts: 1517 From: Michigan Joined: |
Not recent enough??? How many millions of years ago was the flood?
If you have the flood deposits ending before the Pliocene, then it becomes problematic to explain how the stratigraphy in that diagram developed in only 4,000 years.
When I'm talking about volcanism after sedimentary deposits I'm looking for the deepest stack of sediments I can find because I'm trying to make a point about the hundreds of millions of years before tectonic or volcanic disturbance, You do realize that tuffs are volcanic, which means in that diagram there is tectonic and volcanic disturbances within the stack. There is NOT continuous deposition. If you keep moving the goalpost it will be certain that there will not be an example that invalidates your idea. HBDWhoever calls me ignorant shares my own opinion. Sorrowfully and tacitly I recognize my ignorance, when I consider how much I lack of what my mind in its craving for knowledge is sighing for... I console myself with the consideration that this belongs to our common nature. - Francesco Petrarca "Nothing is easier than to persuade people who want to be persuaded and already believe." - another Petrarca gem. Ignorance is a most formidable opponent rivaled only by arrogance; but when the two join forces, one is all but invincible.
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Faith  Suspended Member (Idle past 1475 days) Posts: 35298 From: Nevada, USA Joined: |
Sorry, I just automatically translate terms like Pliocene and Pleistocene into "highest of the strata," don't even pay attention to the time factor. How is it moving goalposts to be looking for a whole deep stack of layers for my examples, which I've clearly defined as my goal many times? Nothing else will make my point. volcanism at the very top of the stack is what I'd expect after all, even if it isn't completely at the top, so that example doesn't mean much, or it may confirm my expectations. I'd have to get into it more to figure it all out.
Edited by Faith, : No reason given. Edited by Faith, : No reason given.
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Faith  Suspended Member (Idle past 1475 days) Posts: 35298 From: Nevada, USA Joined: |
I wasn't including the Precambrian rocks in my statement.
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