Geologic Column

Please see Message 9 for the opening post.Edited by Admin, : Shorten link.Edited by Admin, : Remove original content.Edited by Admin, : Change thread title.

I did a general search for this topic and couldn't find it. If there is a thread already, just let me know.Okay...where to begin. I just want to start this off kind of basic. First of all, how can this geologic column be of any use today when it was created using none of the dating methods that are wholly, if not unfortunately, accepted today? It's not like they looked at each layer they found and dated the things they found in it. They didn't have those methods then.Second, the geologic column, which seems sketchily created, is used to edit science. I believe that Hovind was previously credited with omitting information earlier in this thread but it appears that evolutionists would be guilty of the same thing. It seems fairly well covered that dates found using various dating techniques that do not comply with the geologic column are commonly thrown out. Does that sound like science to you? If you edit out all the information that does not flow with your theory, you have left the realm of science.Now, this is an idea that I have not read up on a whole lot but is interesting to me. Please tell me otherwise if I'm mistaken. The geologic column is based on circular reasoning. The organisms, or the fossils of organisms, are dated by which geologic layer that they are found in. It also turns out that the geologic layer is dated by what kind of organisms they find in it. Now wait a minute. If that is true than you are proving a theory with itself. It's like using a word in its own defintion. Tell me how this makes sense or point me in the right direction if I'm wrong.Edited by Admin, : Promoted by Admin from the last message of the [thread=-25,-3251] thread.Edited by Admin, : No reason given.

Thread moved here from the Proposed New Topics forum.

And for some reason with a 4th Nov date-stamp making it essentially invisible!!ABE: ah, that did the trick Edited by cavediver, : Solved the problem all by myself

Your final paragraph about circular reasoning is based on a common Creationist strawman version. What you are referring to are Zone Fossils. Zone Fossils are particular fossils that are found widely geographically distributed and only in narrow sections of the geological column (and thus time). And Zone Fossils are, indeed, used to date other fossils. Note that: other fossils. Zone fossils are not used to date themselves, they're identified and then used to date other fossils. There's nothing circular about that.

Well, that was weird.Yes, when the founders of geology discovered the "geologic column", they didn't have access to the methods we have today.When those methods were discovered, and applied, we proved that those early geologists were absolutely right, using methods of which they knew nothing.This is independent confirmation that they were right, using a different methodology of which they were unaware.You seem, for some reason that you don't explain, to think that this is a point against them.It is, in fact, independent confirmation that they were right. Of course, you give no specific examples, because this is a bunch of silly lies that creationists have made up. You're completely mistaken, as you would know if you'd ever bothered to study geology instead of reading halfwitted creationist lies about that subject.Your attitude is baffling to me. You admit that you know that you haven't "read up" on the subject. And you must be vaguely aware that scientists aren't complete morons.So you must know, really, that this is stupid bullshit. Point you in the right direction? Certainly, my dear sir. Do what you admit that you have not done, and read a textbook on basic geology.But you must know this. Creationist though you are, you must be dimly aware that if you want to learn about geology, some book entitled something like An Introduction To Geology is the place to start.Edited by Dr Adequate, : No reason given.

I think you are starting down a great path and that you will really enjoy the journey. It's true that Geology was the first science that absolutely nailed the coffin closed on both the concept of a young earth and that there was ever a world-wide flood. Further, geology did this long before we had any method to do absolute dating. The evidence from geology is simply so overwhelming that no one who examined the evidence could possibly continue believing in either of those fantasies.I would suggest that you start with some of the basics. In particular, read Geology- working up from basic principles. to start, so you understand a few of the basics, then move on to How to make sand. for a look at something as simple as sand, then read through Exploring the Grand Canyon, from the bottom up..Once you work through those I think you will have a better understanding of the geological column and why both a young earth and some imagined flood are simply silly.Once through those we can begin looking at dating itself.

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Aslan is not a Tame Lion

And I still can't figure out how anyone could get into a frame of mind where they can miss this point.But his very first argument, that he put in first place --- is that nineteenth century geology is backed up by twenty-first century physics.We ought to have a monthly competition for Dumbest Creationist Argument.In lieu of that, I guess there's always FSTDT.Edited by Dr Adequate, : No reason given.

The geological column is useful because it was worked out using valid methods. Where radiometric dating is the only way of getting absolute dates, there are other methods of working out relative dates (at the simplest level distinguishing between "older", "younger" and "about the same" dates). What the early scientists who worked out the column did was to look at the positional relationships between rocks at convenient locations - and then identify correlations between these observations to build up a fuller picture.Age estimates can be produced as part of this, based on estimates of how long it took each layer to form. But these are a result after the fact - not something directly measured.It is not used to "edit science". It is a part of the evidence that must be taken into account. Scientists do not write off good evidence just because some other evidence conflicts with it.And finally there is no circularity in the use of index fossils. First, some fossils are identified as being restricted to a relatively narrow age range. And that dating is based on the rocks they are found in. When that is established it is possible to use those fossils to identify the age of OTHER rocks. So there is no circularity.

Dating isn't as simple as you might think, and with a poor understanding of the techniques and poor choice of samples you can easily get misleading results. If you date a fragment of pre-existing rock set within another layer (eg a xenocryst/xenolith,) it will not be representative of the rock as a whole. If you date human remains that have been buried, the age will not match that of the surrounding rock/sediment which is older than the interred remains. If you date lava that set last thursday with K/Ar dating, you will not get a correct date as the technique doesn't work on such a short timescale. There's nothing wrong with throwing out a date if there is good cause to believe sampling error or a badly chosen technique is to blame. It isn't just a case of picking and choosing which dates you like and which you do not.

This might be a silly question with a simple answer but where do they get the date for the rocks used to date the index fossils? Is it the same method that can get many erroneus answers in other situations? How do you know that the dates you get from this layer are not contaminated as well? If it happens so much in things that we already know the date of, why can't it happen for things we are guessing the date of?

By absolute dating methods, mostly radiometric.{Added in Edit} Typically we cannot date the sedimentary rocks in which fossils are found (although in some cases we can). So we date related igneous layers, usually but always by radiometric methods, and take advantage of Steno's Laws. It's probably easiest to understand from a few examples:We find fossils in layer A. Igneous layer B lies above layer A and is dated to 16,000,000 years. Igneous layer C lies below layer A and is dated to 18,000,000 years. There is no evidence that the three layers have been overturned or disturbed since formation. The fossils are between 16,000,000 and 18,000,000 years old.We find fossils in layer D. Igneous layer E lies below layer D and is dated to 48,000,000 years. Igneous "layer" F lies at about a 45 degree angle and cuts through both layer D and layer E, obvioulsy was formed after both of tehem, and is dated to 47,500,000 years. Other than "layer" F there is no evidence of overturning or disturbance to the layers. The fossils are between 47,500,000 and 48,000,000 years old.We find fossils in layer G. Igneous layer H lies below layer G and is dated to 32,000,000 years. We find the exact same fossils in layer I, somewhere far away from layers G and H. Igneous layer J lies above layer I and is dated to 31,000,000 years. These fossils are known to occur only in very thin strata and therefore only existed for a short period of time. The fossils are between 31,000,000 and 32,000,000 years old.Note that the dating is always done by absolute methods that have nothing to do with fossils, and the index fossils are only used to correlate between layers in different places, as in the last example. No. Nobody uses methods that are wrong any significant percentage of the time. The vast majority of the methods used are "age-diagnostic"; the method produces an age and an indication of how reliable that age is. If the samples are contaminated so as to prevent getting a good date, that's automatically detected.Wherever possible (and that's quite often) dates are obtained by multiple methods, both radiometric and non-radiometric, and almost always these different methods agree. (In the rare cases when they don't that's when things get really interesting, because that's where the real opportunities for new research are.) It's just not possible for there to be so much agreement unless the dates are correct. This agreement between methods is never addressed by creationists, no matter how often they are asked; they just try to deny that it exists. But it exists, and is a fact that must be explained by any viable theory. It is very rare for radiometric dating to give erroneous results for things for which we know the dates by other means. A few, a very few, erroneous dates obtained by creationists in "studies" that are usually if not always intentionally fraudulent is not "happens so much". When real scientists study the potential issues they do things like G.B. Dalrymple, “40Ar/36Ar Analyses of Historic Lava Flows,” Earth and Planetary Science Letters, 6 (1969): pp. 47-55. Many of the results are available at Ar-Ar Dating Assumes There Is No Excess Argon?, and I can send a PDF to anyone who is interested. Dalrymple studied 26 lava flows that occurred in historic times. He found that 19 of them had no excess argon, and would be dated correctly by K-Ar dating as soon as they get to be old enough. Of the remaining 8, 7 had so little excess argon that K-Ar dating would not be significantly affected once the rocks got old enough to be dated. One out of 26 lava flows had significant excess argon. So in the vast majority of cases K-Ar dates are correct ... and if only one out of the hundreds of thousands of dates we have is correct, the Earth is old.And he did all this using Ar-Ar, which is just one of the many widely used methods that detects contamination and open systems.Edited by JonF, : Add significantly to answer to first question

http://EvC Forum: The Geologic Column -->EvC Forum: The Geologic Columnandhttp://EvC Forum: Geologic Column -->EvC Forum: Geologic ColumnThe first had technical problems and lost a bunch of messages. It is closed.The second, which I think is pretty well done, is still open to new messages.Adminnemooseus

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To be considered as an index fossil, a fossil must be consistently found in rocks of a date range narrow enough to be useful. Thus there need to be samples form a number of locations. I hope that you can understand that it would be very unlikely that all these samples were badly dated in a way that gives consistent results.

Added by edit:I started this post this morning, before JonF added his explanation to his previously written post, hence my comment that I didn't notice a clear answer to AF's question. I checked for additional messages, but I didn't reread the thread when I returned and resumed writing so I missed it. JonF does give an explanation for geologic dating, so my comment isn't a slight against him.End of addition.- I didn't notice a clear answer to this in the previous posts, so I'll venture to offer a very simplified explanation of the history of geologic dating. It'll be very brief and very simple, so it'll leave out important details. If I get anything wrong, or if essential details are missing, experts are welcome to correct me. Also, I'm sure that there will be questions; since I'm not a geologist, and since my knowledge of geology comes from the first year college sequence and whatever subsequent reading I have done, I'm sure that there will be questions I won't be able to answer.It was noticed that fossil species always occur in the same order in the geologic column. (Well, there are some exceptions, but these exceptions are very rare, and when they do occur, there are some things that are very "wrong" with the units in which they occur. I'll still use the word "always" with this caveat in mind.) Dinosaurs always occur below mammmoths. Trilobites always occur below dinosaurs. You never see trilobites above dinosaurs or mixed with dinosaurs. And for individual species, trilobite species Brachyaspidion microps is always found lower down that the species Paciphacops birdsongensis. There is a definite, consistent order to the fossils in the geologic strata, an order that cannot be explained by any flood model.And that is how the geologic column was originally constructed. As one moves down into the geologic column, there is a definite order to when one first observes occurrences of the various fossil species and when one observes that the various fossil species no longer occur. Any given species will occur in the same rock unit with only certain other species. And so the labels for the geologic units, like "Paleozoic, Mesozoic, Cenozoic" and "Triassic, Jurassic, Cretaceous" were defined, and are still defined, based on which species occurs in those units.So, when a geologist in Britain observes a certain fossil species in the rock unit she is studying, she knows that that particular unit is "Devonian". What that really means is that there are only a certain numbers of particular fossil species that will appear in that unit (one of which is the particular species she is observing), and that these species, generally, don't appear in any other rock unit. So a geologist in Russia, say, reading her description already knows which known fossil species will be found in that unit, and which ones will not.So this is the basis of the geologic column. It is noticed that rock units occur in horizontal layers, that in each layer only certain fossils species occur, and, in fact, only certain combinations of species will occur in the same rock units, and that there is a definite order in which the fossil species appear as one "reads" the column from top down.I will repeat to make sure that this is clear: this is what the geologic column means. Rock units generally occur in horizontal layers, only certain combinations of species will occur in the same layers, and there is a certain pattern to what species occur as one reads from top to bottom.-What can be the interpretation of these facts? Why does this pattern exist? It is a simple observation that when sediment layers form, the layers below are older than the layers above. It also makes sense logically: how can sedimentary layers be formed beneath already existing rock? There are exceptions to this general rule, but for brevity in this initial post I'll just say that these are usually pretty easy to identify.So this was another indication that the flood does not explain geology. When sediments settle out of water, we almost always see the courser materials settle first, then the finer materials on top. If the environment was chaotic, then maybe they won't sort very well. But one never sees finer material settle out first, then the courser materials over that. Yet this is exacly what we see in the geologic column. We often see mudstone and siltstone and sandstone alternate in various orders as one goes down the geologic column: if all these strata were formed from the same event we would either not see much differentiation, or we would always see large rocky material on the very bottom, above that sandstone which would grade into siltstone above, which, in turn, would grade into musdtone above that. Instead, we see mudstone, sandstone, and siltstone in all sorts of various orders, sometimes with quite abrubt boundaries between them. A single flood event cannot explain this; it is evident that these layers were formed at different times in different environments.So we have these layers that were obviously formed at different times. And we can pretty much conclude that the lower layers were formed before the upper layers. And, by observing processes today, geologists were able to come up with some estimates as to how long it took each layer to form. That is how they originally came up with the estimates of the lower levels of the geologic column being tens of millions or even hundreds of millions of years old. Of course, they were aware that these were very rough estimates, but what else could they do? They didn't yet know that some rocks have a date stamp included in them.So it was proposed that each layer in the geologic column formed long ago, and the species that occurs in that layer were species that lived at the same time on the earth. So the reason that trilobites are always found below dinosaurs is because they lived earlier in the history of the earth, and then disappeared before the dinosaurs appeared. Then dinosaurs disappeared before mammoths appeared, and so dinosaurs are always found in lower strata than mammoths. And so forth.So, if it is known that species A and species B can occur in the same rock layer, then if a geologist in Britain observes species A in the unit she is studying and a geologist in Russia observes species B in his rock unit, then, by the above hypothesis, the two rock units are roughly the same age. If a geologist in North America observes species C in the rock units she is studying, and it is known that species C always occurs in layers higher in the geologic column than either species A or B, then one draws the conclusion that her rock units are significantly younger than the other two.So, based on the observation that the only known processes that could have formed all the sedimentary rocks would have taken a long amount of time, and based on the observation that the fossil species always occur in a definite order in the geologic column, we now have the basis for geologic dating. At this point we don't have any way of putting absolute numbers on these dates. We know that there was a period of time when the rocks labeled "Triassic" were formed, and they include the fossils of species that lived at that time. There was a period of time when the rocks labeled "Jurassic" were formed, and they include fossils of species that lived at that time.Except for a very few that seem to have lived on the boundary, the species found in the Triassic rocks are different from the species found in the Jurassic rocks. They lived at different times. And we don't (at this point in the discussion) really know how long ago these species lived, all we know is that the Triassic species lived before the Jurassic species because the Triassic species are always found below the Jurassic species.-So we now have geologic dating, but we can only give relative dates, that is, we only know that some species and some events occurred before others, but we cannot pin any dates on them. It's sort of like knowing that the American Civil War occurred at roughly the same time as the Franco-Prussian War in Europe, and that both occurred before the World War I, but not knowing the exact dates at which they occurred.Then radiometric dating was discovered. Physics, an entirely different discipline from traditional geology, potentially allows us to put actual dates on the geologic rock layers. Now this may not work: it might be possible that our interpretation of the rock layers as individual times in a long history may be wrong; it may be that in practice the radiometric dating may not work reliably. In either case, we would not expect to get consistent dates for the various rock layers.But, as it turns out, radiometric dating does work reliably. When the rock units that contain species labeled as Jurassic are dated, the answers are always between 199 million years ago and 145 years ago. When the rock layers containing Triassic fossils, assumed under the above hypothesis to have occurred in a distinct period in time that occurred before the Jurassic, the dates are always between 251 million years ago and 199 million years ago. And similarly for other strata.So it is important to note that radiometric dating provides additional information: we now have absolute dates when we previously had only relative dates. Also, the absolute dates observed from radiometric dating provides an independent check on the relative dating assumptions, and, in fact, is consistent with them and so provides amazing confirmation of the previous relative dating.So, to sum up, geologic dating was already well developed long ago, long before radiometric dating, based on the simple observation that the fossil species always occur in the same order in the geologic column. This dating was only relative -- it only allowed us to tell which periods of time occurred before or after which other periods.Radiometric dating finally allowed us to put precise ages on the rock units. But what is most important, radiometric dating gives an important confirmation that the previous geological dating system was correct. Traditional geologic dating was based simply on noting which fossil species were in the rock units, and in what order the fossil species appear. This has nothing whatsoever to do with chemistry or atomic physics. Radiometric dating is based on simply counting the amounts of radioactive isotopes and/or their daughters; it has nothing to do with geology or fossil species. Yet the two methods agree: rock units in different parts of the world that contain the same fossil species have the same radiometric dates. Rock units always date younger than the rock units that occur below them. If whenever species A and species B are found in the same locality it is observed that species A always occurs in layers below that of species B, then any rock units containing A will always have an older radiometric date than those containing species B, even when they are found in different parts of the world, even when they are collected in localities where A and B are not both found.This is the kicker. Radiometric dating did not have to agree with the conclusions drawn from traditional geology. But they do, and consistently.Edited by Chiroptera, : No reason given.

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Computers have cut-and-paste functions. So does right-wing historical memory. -- Rick Perlstein