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Author | Topic: Flood Geology: A Thread For Portillo | |||||||||||||||||||||||||||||||||||||||||||
Boof Member (Idle past 267 days) Posts: 99 From: Australia Joined: |
So you and RAZD are both right. The fascinating thing is, if the right minerals are present you can get a geochronological age of both the formation of the rock (generally a crystallisation age of an igneous rock, say a volcanic layer) PLUS an age for the subsequent mountain building (ie a date for peak meatamorphism). Geology is fun!
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mindspawn Member (Idle past 2681 days) Posts: 1015 Joined:
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Hi Percy. I just want to apologise to you, I did read that original article incorrectly. Yes you are correct, the geologists are re-dating the Acatlan complex, not the Appalachians. When you corrected me on this, I should have investigated properly, instead I looked at the dates of the articles, so I apologise too for not checking your correction properly.
So agreed, its the Acatlan complex, not the Appalachians that the geologists are re-dating by 120 000 000 years.
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mindspawn Member (Idle past 2681 days) Posts: 1015 Joined: |
I did apologise to Percy regarding my mistake. however the point does still stand that geologists do get their dates badly wrong.
I'm curious why they did not already have radioactive dates for that Acatlan Complex? Why didn't geologists date the complex that way, and instead rely on revised plate tectonic info to re-date the complex. Any idea?
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mindspawn Member (Idle past 2681 days) Posts: 1015 Joined:
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So your guess is completely uninformed and based on your biased opinions rather than on any review of empirical objective data. It's a WAG (wild-ass guess). exactly! that's what the words "I don't know" mean. It means ....I don't know. And thats what a guess means..... a guess.
Curiously, science is based on evaluation of the best information we have available. Sometimes that information is incomplete due to gaps in the evidence available, and when any new information becomes available to fill those gaps -- as we see here in southern Mexico -- then there is either the possibility of confirming previous thought or of changing previous thought -- as we see here on the timing of the movement of tectonic plates in this area. It is fine to be skeptical, but you then need to investigate, to research the information, to see if your cursory impressions match fact.. So again, perhaps it is time for you to actually investigate this, and you can start by reading Age Correlations and An Old Earth, Version 2 No 1 So you are agreeing that information is incomplete sometimes, and then a mountain range can be dated according to incomplete information, and then re-dated when more complete information becomes available. That is my point as well, and its a pretty obvious point too.
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Dr Adequate Member (Idle past 305 days) Posts: 16113 Joined:
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Because its a logical progression of what would most likely have occurred. "Logical". Hmm.
The oceans before the PT boundary were cold, the oceans after the PT boundary were warm. That's a sweeping statement. Were the oceans always cold before the PT boundary? Were they cold during the Carboniferous? And yet the ichthyosaurs lay low during that period.
Evolution is one way to explain the sudden appearance of new types of marine life after the PT boundary, but the time frames seem too constricted to explain the new forms. Show your working?
A large inland sea in a warm region ... A large inland sea ... but apparently not so large that anyone's found it yet. Well, large seas are easy to overlook I guess. I know I'm always losing them.
... would explain how this marine life suddenly appeared in the sea and dominated subsequent to the transgression and regression at the PT boundary. But, the problem is, they do not in fact all pop up at or even near the PT boundary. What we actually see is a progression from the lizard-shaped ichthyopterygians without dorsal fins or tail-flukes to those with a more fish-like rounded body and having dorsal find and tail flukes --- true ichthyosaurs.
For some reason those ichthyopterygians least adapted to a marine lifestyle managed to spread and flourish before the true ichthyosaurs, which were still hiding in this elusive large sea until the Jurassic. Some of them waited 'til the Cretaceous. Meanwhile, as the later forms turned up, the earlier forms were driven out ... apparently they could all co-exist in a single sea, but the whole of the oceans didn't have enough niches for them. (Maybe you should postulate more large seas that no-one's managed to find yet, in which they were originally segregated.) If this is what you would call a "logical progression", I wonder what you would find bizarre and counter-intuitive.
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mindspawn Member (Idle past 2681 days) Posts: 1015 Joined: |
So there's no possibility that all those alleles arose in such geographically limited area in 4500 years. No fludde, nope, no how, no way. I don't see how you get that confident conclusion from the information presented. Its about exactly as you would expect from bringing in 7 pigs onto the ark. You would start off with close to 14 alleles, maybe 12 alleles in some positions. He may have been instructed to get diverse types, that would make sense for species survival. Some genes would mutate more than other genes, some showing as little as 5 alleles, some as much as 20. Looking at that list I see nothing to contradict the figures put forward, I would have expected some alleles even higher than 20 actually, in those regions particularly susceptible to mutations as discussed earlier so I'm pretty pleased with that table.
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PaulK Member Posts: 17825 Joined: Member Rating: 2.2
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Aren't pigs unclean ? Wouldn't that mean only two pigs and a maximum of FOUR alleles ?
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JonF Member (Idle past 189 days) Posts: 6174 Joined:
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Yup, pigs are unclean. That's why I chose them. Maximum four alleles, in "reality" fewer. Unless, of course, there were extra stowaway pigs scuttling around unnoticed and hiding in mouseholes with the mice.
He may have been instructed to get diverse types, that would make sense for species survival
Again, Making Stuff Up. God gave him specific instructions and didn't mention diversity. (14 individuals or four is way too low for species survival, but the abncient Hebrews didn't know that). How and why did he choose such genetically diverse animals? I bet it would be essentially impossible, even given modern technology. to find 14 (or, in this case, four) animals with 14 (four) different alleles for 90% of their genes. Do you think Noye chose his animals by sequencing their entire genome? Or how? No, even if there were 14 alleles of pigs on the alleged ark, your own calculations show that 19 and 20 alleles of any two genes would be very very improbable. But we have the "reality" of a maximum of four pig alleles on the alleged ark and essentially certainly fewer. We have your own calculation of zero or one (after some correction for non-coding DNA, which by definition cannot contain alleles) alleles per gene expected to arise in 4500 years. We have observations of Spanish pigs with 17 of 18 genes showing 6 or more alleles (twice your maximum expectation more than four) and averaging (the maximum number in each row) 8.3 alleles per gene, over four times your expected maximum number of additions even if there were four alleles on the alleged ark. We have observations of Brazilian peccaries with 18 of 18 genes showing seven (three times your maximum expectation more than four) or more alleles per gene and an average of 11 alleles per gene, seven times your maximum expectation more than four. We compare the two tables and note different numbers of alleles for some common genes between the two, which guarantees that both studies are missing some alleles in the world's population by restricting their samples to a geographically localized area, so the real number of alleles world wide is guaranteed to be larger. Sorry for your preconceptions, but you got the number of pigs per ark way wrong, and the reality of today's observations is that there absolutely was no bottleneck in swine 4500 years ago, or even much more time than that. {Edit} Replaced "7.9 alleles per gene, four times your expected maximum number of additions" with "8.3 alleles per gene, over four times your expected maximum number of additions" I will have some more to say about the model a little later {/Edit} Edited by JonF, : No reason given. Edited by JonF, : math error, see note
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roxrkool Member (Idle past 1010 days) Posts: 1497 From: Nevada Joined:
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Actual dates, if the samples are collected appropriately, are not often wrong, but it does depend on what you are dating. So if you think you are age dating an igneous stock, but mistakenly collect a much later (younger), but similar looking igneous dike, you could assign an incorrect date to the stock. Eventually we figure it out because geologic field relationships often help us recognize errors.
I have not read the paper, but scientists generally only date things when they feel it is important to do so. Besides, it costs money and many times we already have a good idea of the age of rocks based on stratigraphic / field relationships, age dating in nearby areas, etc.
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Percy Member Posts: 22480 From: New Hampshire Joined: Member Rating: 4.8
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mindspawn writes: So agreed, its the Acatlan complex, not the Appalachians that the geologists are re-dating by 120 000 000 years. I think if you go back to the linked articles that you'll find that the Acatlan Complex hasn't been redated either. It's been reinterpreted as a late-forming extension of the Appalachians. The 1991 article I cited gave the same age as the 2006 article you cited, about 300 million years. There's been no redating. An actual redating of anything by amounts that large would merit headlines. It would be an enormous surprise, and it wouldn't be buried in a technical article titled, Vestige of the Rheic Ocean in North America: The Acatln Complex of southern Mxico. --Percy
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FliesOnly Member (Idle past 4166 days) Posts: 797 From: Michigan Joined:
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mindspawn writes: Not to pile on, you have a lot to deal with already...but are you suggesting the Noah went around a collect genetically diverse organisms for the Ark? Or did he simply pick and choose from the hundreds of each species that showed up...obviously selecting those that were genetically "unique" from each other (i.e. different alleles)? How did he manage to do that, you suppose? What about alleles whose effects were hidden from Noah cuz, well...cuz they were "inside" the organism? What about recessive alleles? Pleiotropy? Co-dominance? Incomplete dominance? The list goes on.
He may have been instructed to get diverse types, that would make sense for species survival.
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NoNukes Inactive Member
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mindspawn writes: He may have been instructed to get diverse types, that would make sense for species survival. How did he manage to do that, you suppose? I would suggest that once magic gets invoked, that the discussion has reached a dead end. But there is simply no way that selectiong only a couple of pigs would allow for much diversity. The pigs would have to have super genomes, or magical ones. Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846) The apathy of the people is enough to make every statue leap from its pedestal and hasten the resurrection of the dead. William Lloyd Garrison. If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass
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RAZD Member (Idle past 1426 days) Posts: 20714 From: the other end of the sidewalk Joined:
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Hi foreveryoung,
When mountains form, they can change one kind of a rock into another. They can take flat layered rocks and turn them into folded layers or they can fault them. The rocks that are in mountains are generally not in the same condition that they were before the mountain building event. Indeed, and the heat\pressures involved that fold layers also can change the physical properties of the rock. This is where creationist comments about layers run into trouble: folding rock layers without the heat and pressure doesn't work, nor does folding layers of sediment before it is transformed into rock. These then become time dependent processes that cannot occur via a simplistic flood explanation. Enjoyby our ability to understand Rebel American Zen Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
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RAZD Member (Idle past 1426 days) Posts: 20714 From: the other end of the sidewalk Joined:
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Hi mindspawn,
I'm curious why they did not already have radioactive dates for that Acatlan Complex? ... Possibly because it is expensive to do, and they thought they had a good idea of what had happened. Enjoyby our ability to understand Rebel American Zen Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
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Percy Member Posts: 22480 From: New Hampshire Joined: Member Rating: 4.8
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I'm curious why they did not already have radioactive dates for that Acatlan Complex? Why didn't geologists date the complex that way, and instead rely on revised plate tectonic info to re-date the complex. Any idea? Again, the Acatlan Complex was not redated. Paragraph 2 of the abstract for the paper I cited earlier (Isotopic studies of the Acatlan complex, southern Mexico: Implications for Paleozoic North American tectonics) begins like this:
Isotopic studies show that the Acatlan complex records three tectonothermal events. The Sm-Nd whole-rock/mineral isochrons from schists as well as eclogites yield metamorphic ages of 410-380 Ma. This age of metamorphism is supported by U-Pb zircon data from a granitoid which yields an age of 370 34 Ma. A later intrusion of a large stock in the Late Pennsylvanian (287 2 Ma) was probably closely followed by a less significant deformational event. Small granitic intrusions and migmatites were later emplaced at 205-170 Ma (Rb-Sr and Sm-Nd mineral/ whole rock). They mention three metamorphic events. Note that the date from the Late Pennsylvanian event is 287 million years ago, pretty much the same age we think it is today. Here's the abstract from a paper by the very scientists you think redated the Acatlan Complex (Acatln Complex, southern Mexico: Record spanning the assembly and breakup of Pangea):
New structural, geochronological, and geochemical data from the Acatln Complex of southern Mexico show that it preserves a complete history of Pangea, from assembly to breakup. Previously interpreted to be a vestige of the Iapetus suture, the Acatln Complex records a history that can be sequentially linked to the Rheic Ocean, the paleo-Pacific, and the Gulf of Mexico. This record is interpreted to reflect: (1) the development of a rift-passive margin on the southern flank of the Rheic Ocean in the Cambrian—Ordovician; (2) the formation of an extensional regime along the formerly active northern margin of Gondwana throughout the Ordovician; (3) closure of the Rheic Ocean documented by subduction-related eclogite facies metamorphism and exhumation during the Late Devonian—Mississippian; (4) Permian—Triassic convergent tectonics on the paleo-Pacific margin of Pangea; and (5) interaction with a Jurassic mantle plume coeval with the opening of the Gulf of Mexico. Notice it makes no claims about redating the Acatlan Complex, and certainly not by any error as astoundingly large as 120 million years. The article that gave you the impression that there had been a redating was just trying to place events in a time sequence. --Percy
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