|
Register | Sign In |
|
QuickSearch
Thread ▼ Details |
|
Thread Info
|
|
|
Author | Topic: Paleocurrents: the 'diverse' features of the GC were laid via rapid, correlated flow | |||||||||||||||||||||||
edge Member (Idle past 1737 days) Posts: 4696 From: Colorado, USA Joined: |
quote: Ah, there's a reason for that, you know.
quote: Not at all. At least that's not the way I was taught. Besides, you just said that you cannot find anything on higher velocities, so why do you presume Pettijohn to have thought the currents were unusual? The surprise they expressed was that the currents would so accurately reflect the paleoslope. They simply thought that there would be more noise.
quote: I'm sure we can find some Precambrian conglomerates for you. Maybe Joe could send us a reference when he has time.
quote: Not sure what you are saying here. Of course the representations should be regional.
quote: So are you saying that this does not happen even today? Sorry, TB, but we have plenty of fluviatile currents that can create oriented pebbles and ripple marks. There is nothing unusual here.
quote: Usually these are covered in college level geology courses that you have missed. I don't know of any current research in this area since it is pretty well known. Only creationists seem to be behind the curve on the subject and are trying to disprove uniformitarianism.
|
|||||||||||||||||||||||
edge Member (Idle past 1737 days) Posts: 4696 From: Colorado, USA Joined: |
quote: TB, could you show us this paleocurrent data for the Mancos shale or the Pierre Shale? I'd like to see the current velocity estimates for thes formations.
quote: Not at all. Your lack of geological training is showing up here. Non-marine formations can be quite extensive. But then we have been over this ground before. Did you just ignore us?
|
|||||||||||||||||||||||
Joe Meert Member (Idle past 5711 days) Posts: 913 From: Gainesville Joined: |
quote: JM: ROTFL! Where did you get this gem? I just finished a proposal on the Vindhyan sequence in India which has wonderful paleocurrent data. Cheers Joe Meert
|
|||||||||||||||||||||||
wehappyfew Inactive Member |
I'm back from Bermuda. Nice pictures of unconformities to follow, after developing and scanning...
So let's see what kind of trouble TB has gotten himself into while I was lounging on the beach and stuffing myself with gourmet food.
quote: This argument is directly contradicted by your own sources...
quote: The Moine series of Scotland is preCambrian. Your entire thesis is nullified by your own reference. This illustrates the pitfalls of relying on Creationist secondary sources (those with agendas that conflict with scientific honesty and integrity). Always check the primary literature. You can't argue with the data.
|
|||||||||||||||||||||||
Minnemooseus Member Posts: 3945 From: Duluth, Minnesota, U.S. (West end of Lake Superior) Joined: Member Rating: 10.0 |
quote: Actually, TB and I have been directly consulting the Pettijohn book (added by edit 6/17/02: Of course, the book isn't "the primary literature", but it is a reliable source). And I did notice that the Moine was pC, although I don't know if TB did (I think that info may have been elsewhere in the book, or perhaps I found it on the web). The discussion has, more or less, been on marine paleocurrents. I, though, have been trying, to some degree, point out the non-marine-ness of a least some of the geological units TB is citing. I don't have specific information at hand, but I suspect the Moine is also non-marine. Still a rather amusing self contridiction on TB's part. I've concluded, and I think TB agrees, that it is impossible to have further meaningful discussion on these paleocurrents, without more specific information on their nature, including the nature of the containing rock units. TB's source of inspiration was cited earlier in the string. He is a geologist/biologist who teaches at an Adventist university. He has apparently compiled a massive amount of paleocurrent data. The purpose of such is apparently to show widespread consistant paleocurrents in continental marine rocks, as support for "the flood". To what degree his compilation of paleocurrent info is only that of marine deposited rocks, I don't know. It would seem to be further amusement, if many of these paleocurrents were actually found to be from measurements in non-marine rocks. Moose ------------------BS degree, geology, '83 Professor, geology, Whatsamatta U Old Earth evolution - Yes Godly creation - Maybe [This message has been edited by minnemooseus, 06-18-2002]
|
|||||||||||||||||||||||
Tranquility Base Inactive Member |
Edge
The 'surprise' recorded by paleocurrent researchers clearly was related to the extent of correlation in time and space. Noise may have been a part of it but not the whole story. My statement about the meaningfulness of paleocurrent data is that they are typically represetative of a region which earlier you seemed to be be doubting. Of course rivers and streams generate paelocurrents but not ordered over tens of thousands of square miles!! I personally felt that Pettijohn was lacking in a section linking real currents today and paleocurrents. I looked for it and unless my memory fails me it is not there. If I were writing a chapter on paleocurrents I would have a section on that and the only reason I would leave it out would be because the research hasn't been done! I hint that that is the case but I somehow doubt that this is still true in the 2000s. If it is I might write up a research grant on it and switch to geology next year. [This message has been edited by Tranquility Base, 06-17-2002]
|
|||||||||||||||||||||||
Tranquility Base Inactive Member |
Edge
Can you tell nme about the Mancos shale or the Pierre Shale? I'm aware that the non-marine beds can be extensive. If they are then they're not rivers! You don't need to be trained in geology to know that! Maybe deltaic but not rivers.
|
|||||||||||||||||||||||
Tranquility Base Inactive Member |
Joe
OK, when I say 'zero paleocurrents in the Precambiran' I should say low spatial order. I admit I have based that on Chadwick's claim and am willing to recant! Chadwick's (and my) point is that the paleocurrents in the Precambrian are locally dictated (presumably by local 3D topography) and not non-locally dictated like those of the Paleozoic. I'm willing to be reeducated on the extent of non-localness of the Precambrian but that is not the same as simply showing that the Precambian has non-zero paelocurent observables as I have pointed out.
|
|||||||||||||||||||||||
Tranquility Base Inactive Member |
Wehappy
Good point about the Moine. I am basing my statement on Chadwick's stuff (see above post to Joe). The Moine example was an example of constant paleocurrent through time. Although we find that interesting we are even more interested in paleocurrents spatially. As I pointed out above I have no problem with local non0-zero paelocurrents in the Precambrian. The issue is spatial correlation. The straights of Gibraltar might be expected to display high velocity non-zero paelocurrents but not necessarily the rest of the Mediterranian.
|
|||||||||||||||||||||||
Tranquility Base Inactive Member |
Moose
I agree with much of your post and see above. By the way, I was introduced to paleocurrents by Pettijohn this January and formed my own impression of their significance. I strongly suspect that most of the paleocurrent data is from marine rocks because most rocks are marine! But I could be wrong. Q: Why do you still think that non-mariness would be a problem for us? Spatially ordered non-marine high velocity beds are diagnostic of the/many floods aren't they?
|
|||||||||||||||||||||||
wehappyfew Inactive Member |
quote: That is a very weak dodge. Your Pettijohn source mentions the spatial relationship... "a uniformity of orientation throughout..." that is consistent with the mainstream sedimentary facies interpretation for the Moine (a Proterozoic marine shelf). As Joe pointed out, pC paleocurrent data is plentiful (considering the scarcity of outcrop). Here's an example showing strong regional and spatial consistency with temporal variation controlled by regional tectonism and basin evolution...
Determination of [i][b]Basinwide[/i][/b] Paleocurrent Patterns in a shale using AMS "The parallel paleocurrent pattern down this paleoslope towards the SSE (fig 4) is what one might expect in such a setting (Pettijohn et al., 1987)" "Overall transport to the NNE... is in good agreement with the previously described northward decrease in grain size, sand content, and sandstone/shale ratio." "Paleoflow patterns indicate a change of basinal configuration between the lower and upper members of the Newland Formation." "The coherence of paleocurrent data within a given interval indicate remarkable long term stability of paleocurrent and sediment dispersal systems." Without a shred of data to support YOUR conclusions, this paleocurrent idea of yours appears to be another in a growing list of unsupportable fantasies constructed by an active imagination fueled by religious preconceptions.
|
|||||||||||||||||||||||
Tranquility Base Inactive Member |
Wehappy, anywhere there are non-zero paleocurrents there is going to be regional consistency so we can agree on basinal 3D topography issues. We all understand that - it couldn't be any other way. I'm talking about continent-wide consistency and that is where Chadwick claims the Paleozoic and Mesozoic differ from the Precambrian and Cenozoic. If there is no mainstream collection of data on this then that is a mainstream lack. Chadwick has done the global story and that is his conclusion. I can't find a mainstream gobal view. Can you?
|
|||||||||||||||||||||||
wehappyfew Inactive Member |
quote: Your source - Chadwick - does not agree with your conclusion state above... "the Mesozoic appears not to be under the influence of any prevailing continent wide vectorial forces." "During the Paleozoic, in sharp contrast to Mesozoic, Cenozoic and Precambrian tendencies, clear and persistent continent-wide trends are normative. Sediments moved generally from east and northeast to west and southwest across the North American Continent. " So the Mesozoic and Cenozoic are essentially identical to the preCambrian, according to Chadwick. Chadwicks punchline appears to be this:Paleozoic paleocurrents indicate the influence of directional forces on a grand scale over an extended period. Various authors have attributed the directionality to such things as "regional slopes," but it is difficult to see how this could apply to deposits of such diverse origins over so wide an area. So it appears that Chadwick's central problem is his inability to incorporate the simple fact that the formation of Pangea dominated the sedimentary history of the Paleozoic. This is a singular event in Phanerozoic time, so of course the sedimentary and paleocurrent data are unique. At no other time in the last 600 million years has a continental landmass existed adjacent to N. America. The collision formed mountains. The mountains eroded for hundreds of millions of years, shedding sediments. It should be no surprise at all that these sediments traveled downhill onto the N. American craton. At all other times, including most of the preCambrian, sediments and currents flowed from the center of the craton outward - leaving no continent-wide vector. This appears to be another case of a Creationist applying the strictest, most outdated forms of gradualism and uniformitarianism to the geologic record, and coming up with a puzzled look on his face - as expected. His finding that the Proterozoic paleocurrents are, overall, directionless on a continental basis is equally unsurprising. Even with a few pre-Pangea supercontinents thrown in, averaging data over a few billion years will zero out almost anything.
|
|||||||||||||||||||||||
Tranquility Base Inactive Member |
Wehappy
Chadwick also says: "In the Mesozoic the currents exhibit increasing variability and shift from predominantly westerly to predominantly easterly." so I presumed there was still some continental tendancies. But in totality Chadwick is saying that is is primarily a Paleozoic phenomenon so I'll stick to the Paleozoic as being continent wide. The point is that the currents were sufficient to leave ordered paleocurrent observables. I still am almost 100% sure that shallow modern day epeiric seas would not display correlated paleocurrent obsevables! No-one here from either camp has been able to come up with anything relevant to this point other than intuition. And of course if these observations also extend to non-marine beds that is even more interesting for us.
|
|||||||||||||||||||||||
edge Member (Idle past 1737 days) Posts: 4696 From: Colorado, USA Joined: |
[QUOTE]Originally posted by Tranquility Base:
The point is that the currents were sufficient to leave ordered paleocurrent observables. I still am almost 100% sure that shallow modern day epeiric seas would not display correlated paleocurrent obsevables! No-one here from either camp has been able to come up with anything relevant to this point other than intuition. And of course if these observations also extend to non-marine beds that is even more interesting for us.[/B][/QUOTE] Good, then give us some data. You have refused to do so and it is getting rather tedious.
|
|
|
Do Nothing Button
Copyright 2001-2023 by EvC Forum, All Rights Reserved
Version 4.2
Innovative software from Qwixotic © 2024