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| radio isotope dating question. |
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| jollybear |
 Posted: Mon Dec 31, 2007 1:05 pm Post subject: radio isotope dating question. |
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| Hi, im new to this website, im not a science expert, but i have a question. I have recently been doing a study on creation vs evolution. And i recently read something about if a rock is dated by radiometric dating method one can get a date. Well if the rock has water flood over it, the uranium element can wash out, making the rock apear older then what it really is. However, my question is this. Does the water wash away the uranium from the surface of the rock, or does the water go THROUGH the rock some how? And if it does go through the rock, hence bringing out some uranium element, can water go through marble? Someone recently gave me that point, so i said i would look into it, and i cant find anything from websites, so i thought i would come on here and ask someone. If their is enough pressure below the sea, can the water go through marble and wash away any uranium?(im asuming uranium also is in marble, as i said im no science expert). Could someone be so kind as to help me out on this question. Im not looking for opinions, assumptions, or views or beliefes, only facts for this question.(allthough if you do offer your opinions, assumptions or beliefes, im open to hear them, but please state explicitly if its a asumption, since im not a science expert and i dont want to be misled by anything. Thank you. |
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| solidsquid |
| Posted: Mon Dec 31, 2007 1:57 pm Post subject: |
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There are many radiometric dating techniques. And often, a combination of relative and absolute techniques are utilized to determine age of formations and items within them.
Do you happen to have a reference to what you read or where that claim comes from, because it sounds a bit fishy to me. Water simply running over rock won't change the radioactive decay rate. |
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| jollybear |
| Posted: Mon Dec 31, 2007 3:07 pm Post subject: Hello |
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Hi, thanks for your reply. Yes, i read that that if the rock was in a flood, doesent matter if it was worldwide, or local flood, if it was in a flood, it could wash away some of the uranium from the rock, making it look older then what it really is. The source i read this from is from a credible website, because its a .org website, i hear they are the most credible. However here is the website source i got it from, you tell me what you think. Its a little ways down within the article, under the green heading "but is it a good date?". Website is " http://www.answersingenesis.org/creation/v24/i3/kids.asp "
Tell me what you think. |
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| KALSTER |
| Posted: Mon Dec 31, 2007 3:19 pm Post subject: |
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The answer on its validity is in the name: answersingenesis. So it is a creationist website, so it is NOT an objective viewpoint. Remember also, that radiometric dating looks at the proportions between two isotopes of an element to determine its age. So even if some of the material was washed away, the little that is left would still reflect the proportions between the isotopes. Only when very little is left, does it become more difficult to get an accurate date, in which case the data cannot and does not get taken as accurate.
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| jollybear |
| Posted: Mon Dec 31, 2007 10:44 pm Post subject: Hello |
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Right, its a creationist website. So, it is trying to disprove evolution and show that dating methods they use are not relieble. So, ive read other parts on the website and they have talked about if rocks are in a flood and the flood subsides, the water filters through the rocks and does whats called "leaching by fluids". So the parent and daughter isotopes can be removed by the water filtering through the rocks. Also it talks about their is much evedence showing that the rocks have a "open system". meaning parent and daughter isotopes can get into the rock from other sources, and can be removed, hence making the dates unreliable. Yes their would still be a decay rate of the isotopes, but more of the same type of isotope can be added by outside the rock, and removed from the rock by other means, like water.
But my next question is, can water PENETRATE marble? Can it wash uranium or other adoms out of marble? I gaus i should also ask, is uranium in marble in the first place? Or some other element within marble? And can it get washed out? Is marble an open system? Im trying to find information on this to. |
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| Scifor Refugee |
| Posted: Thu Jan 03, 2008 9:32 am Post subject: |
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I assume you are talking about dating rocks by comparing the ratio of uranium-238 to lead-206. Why would water "wash out" the uranium? Is there any evidence that this actually happens, or is it just something that someone on your creationist web page made up?
Last edited by Scifor Refugee on Fri Jan 04, 2008 8:47 am; edited 1 time in total |
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| Ophiolite |
| Posted: Thu Jan 03, 2008 11:29 am Post subject: |
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It is worth restating Kastler's point, because it is a vital one: the age is determined by measuring the ratios of original and daughter isotopes. While there might be some preferential difference of removal of parent daughter isotopes I cannot readily see this effecting U-Pb.
Most age determinations now are not based on whole rock analysis, but on individual mineral analysis. No significant 'washing out' will occur from individual minerals.
Marble has zero porosity and so water would not readily penetrate it. Fractured marble at shallow depth might permit some water movement, but for the reasons noted above this would not be relevant to age determinations.
The creationists, in fairly typical fashion, are grasping at straws.
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| leohopkins |
| Posted: Fri Jan 04, 2008 4:46 am Post subject: Re: Hello |
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| jollybear wrote: |
Right, its a creationist website. So, it is trying to disprove evolution and show that dating methods they use are not relieble. So, ive read other parts on the website and they have talked about if rocks are in a flood and the flood subsides, the water filters through the rocks and does whats called "leaching by fluids". So the parent and daughter isotopes can be removed by the water filtering through the rocks. Also it talks about their is much evedence showing that the rocks have a "open system". meaning parent and daughter isotopes can get into the rock from other sources, and can be removed, hence making the dates unreliable. Yes their would still be a decay rate of the isotopes, but more of the same type of isotope can be added by outside the rock, and removed from the rock by other means, like water.
But my next question is, can water PENETRATE marble? Can it wash uranium or other adoms out of marble? I gaus i should also ask, is uranium in marble in the first place? Or some other element within marble? And can it get washed out? Is marble an open system? Im trying to find information on this to. |
LMAO!! - What gets to me, what REALLY tickles me is that in todays modern society religion is on its deathbed. I love websites like that because they try and use every single truth there is and twist it around to suit their own needs. Their argument is weak and their sight is blind. 
And erm the fact that you have been looking at religious websites coupled with the fact that you seem to want to get your hands on a highly radioactive metal concerns me a little! 
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| jollybear |
| Posted: Mon Jan 07, 2008 7:36 pm Post subject: |
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Hi scifor. Well, no one on the creationist web page is making up anything. Its a respected creationist website. I am not blind to the fact that their can be corrupt ones out their, but then again, their is corrupt evolution groups out their just the same then. What their doing is, presenting data, interpreting it, and exposing some stuff from evolution too. Thats basickly what evolution does, they present data, interprete it, offer assumptions and try to expose creation evedence. Both sides do the same thing. Some are honest, some are not. However the ones that are honest, are not all correct, but their honest. This webpage i gave you is a respected webpage. But yes, they say their is evedence that the parent element in the rock can wash out by water or floods. Not all of it, but some of it. Plus its said their is evedence that doughter isotopes like argon can stay captured in the rock if the lava cools under water because its a gass form. So as long as the rock is under water, it will apear older then what it really is, because the water keeps the argon in. This is whats said. Again, im not a scientest, its not like i go out their, digging in the ground as a geologist, or search under water, or go to volcanic locations. I just dont do it, nor can i at this time. So i have to do research and put some trust in OTHERS discoveries in the field of science. Is that not what you all do as well? Im sure it is. Im sure not everyone on this site is a scientest, but im sure they are on here as well. So whoever is not a scientest on here, i dont doupt you dont know your stuff, but again, you have to trust in others research and discoveries. Its like if you go to the grocery store, you trust the food is good, so you buy it. You did not grow the food, but someone else did, and you just trust they did not poisen it.
Also ophiolite, you said "no significant washing out will accur from individual minerals." Are you talking about just the marble or the rock? Allot of water or flooding can leach parent isotopes out of the rock and keep doughter isotopes from escaping. But from what you said, it sorta is like you admit the elements can wash out. Because you said "no significant" which means, atleast some can wash out. Now supose their is a world wide flood, that lasts a whole year, that can wash out more then just a significant amount then. That would make rocks apear older then they really are then.
Also leo, relegion in todays society is absolutely not on its deathbed, allthough i would wish the false relegions would be, but their not, nor the true ones for that matter. Relegion is huge in todays world. Im not saying allot of people are true to their relegion, thats rare, but relegion is still big. macro Evolution is even a relegion. Definition of relegion is belief system, which macro evolution is. Its not a fact system. Also leo, from all the stuff i have read, not just from creation webpages, but from evolution pages as well, they also twist some stuff around to suit their ideas and assumptions. Keep that in mind. Also why would it consern you a little by me wanting to get my hands on a radioactive metal? |
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| sunshinewarrior |
| Posted: Tue Jan 08, 2008 2:38 am Post subject: |
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| jollybear wrote: |
Also ophiolite, you said "no significant washing out will accur from individual minerals." Are you talking about just the marble or the rock? Allot of water or flooding can leach parent isotopes out of the rock and keep doughter isotopes from escaping. But from what you said, it sorta is like you admit the elements can wash out. Because you said "no significant" which means, atleast some can wash out. Now supose their is a world wide flood, that lasts a whole year, that can wash out more then just a significant amount then. That would make rocks apear older then they really are then.
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Dear Jollybear
It seems to me that you'd like an unambiguous response: "there is no way this can happen and here's why", or else an admission that 'answersingenesis' has a point and that the theory of evolution through natural selection is crucially flawed. Here, however, are some things to think about:
1. The heavier metals are not usually more prone (one than the other) to leaching out and dissolving in water. That's what Ophiolite meant: there's no mechanism whereby this could be expected.
2. As Ophiolite pointed out, they're now testing using individual mineral samples, not whole rocks. If significant leaching had occured, then the sample would not be the same mineral - it's chemical structure would have changed.
3. We can easily choose (as scientists do) non-porous minerals to test.
4. If the porosity/leaching/diluvian theory is to have any credibility, mineral scientists (from within 'answersingenesis' if necessary) should simply test minerals within water at sufficient pressure and speed for a period of time, and demonstrate preferential leaching of initial isotopes. It's not rocket science but it could be good science.
For all these reasons, and more (but I don't know enough about radio-isotope dating to go into them) scientists are quite confident that their notions, predictions and dating are robust. Being scientists they do not go for the unambiguous absolute response, as unfortunately some in 'answersingenesis' tend to, but will qualify their statements in the knowledge that science is a genuinely progressive enterprise and there will always be more to learn.
Of course, this may not be satisfactory to you, but it might at least spur you on to learning more about radio-isotopes and dating using them, in an academic sense and with more rigour than just searching the internet, good though it can be as a starting point.
cheer
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| marnixR |
| Posted: Tue Jan 08, 2008 6:25 am Post subject: |
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jollybear, don't forget that we're not talking about a few samples here - we're talking about worldwide sampling of rocks, and often dated through a variety of radioactive decay methods (there's others than just U-Pb), ALL OF WHICH are in general agreement with one another that the earth is vastly older than the 6000 years of young earth creationists
even if the occasional sample is eroded or leached in some way, it's the comparison with a large body of comparable samples that will highlight these random few as anomalous samples
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| Mars |
| Posted: Tue Jan 08, 2008 12:44 pm Post subject: |
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Firstly, considering that I actually know something about petrology and mineralogy (been collecting them for 6 years...) please give me time to get a few things straight.
Regarding Ophiolite's statement of ''water would not readily penetrate it'' I'm certain he means that FLOODWATER would not penetrate it, i.e. water at a low temperature. Most if not all rocks can be permeated by hydrothermal fluids (very, very hot steam). Simple water cannot permeate rocks by flowing through them. I'm sure the more of you can explain simple physics and viscosity that when you get down to very microscopic levels (and if you are talking about washing out atoms we are at a quantum level. Then the surface tension of water is extremely high in comparison and indeed its viscosity so it will not flow through a rock unless under extremely high pressures (beit direct, i.e. a mountain sitting on top of it or indirect, high temperature/energy steam). It's cappillary action that stops fluids from moving around it rocks (the bane of many mineral collectors might I add!).
Also, to add to marnixR's point about the location of the rocks. These rocks can often come from drillcores from miles beneath the earth. How can you claim floodwaters permeated that depth of rock?
Also, the earth is clearly older than 6000 years because the first settlers in Ireland arrive around 9000 years ago in Mount Sandel, Northern Ireland.
So that sort of definitively trumps your theory.
To summarise, water cannot simply flow over or through rock and leach out selected minerals unless there is a chemical action going on which there is not. What you are saying effectively is if you put water in a glass the water is washing glass atoms out of the glass...stupidity.
Barry
P.S. I don't see the logic in a .org website being more reputable than any other. It means nothing. I can make a website called www.barryflannery.org in 5 minutes, so I must be reputable. Maybe I should tell people to send me money and they will receive salvation...? That's an idea! 
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| Lucifer |
| Posted: Tue Jan 08, 2008 12:52 pm Post subject: |
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Whatever could "wash" uranium (not a likely event under no circunstance), would "wash" too the lighter decayed isothopes (whose chemical properties are similar to uranium's). Actually, it would wash more of the lighter elements than of the heavier, thus by removing more of the lighter decay elements it would make the rock appear younger than it actually would be... not the opposite.
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| jollybear |
| Posted: Tue Jan 08, 2008 8:35 pm Post subject: |
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Hi sunshine. Thanks for your responce. I will check more into mineral dating as you proposed. You proposed also that i should learn radioisotope dating more on a academic level rather then a internet level. From my understanding, i can find the same information on the internet as i can in a library, or from buying a book or from going to college. It just takes digging and searching.
Hi barry. I have a question, and its a very good question. How do you know the first settlers in ereland arrived their around 9 thousand years ago in mt sandel? Whats the evedence that that is the time period they arrived? Not to mention that creationists say its about 6 to 10 thousand years old, the earth. But even though thats whats said, i still would like a answer to my question. If you dont mind. Please. Will greately apreciate it.
Also you made the point that steam or hot or warm water would make the elements in the rock leach or run out or become mobile going in, ect ect. Well, here is my theory, when noah's flood came on the scene, tons of volcanoes would come about because of this, making the water warmer then usual, pretty much all over. This would caus allot of the elements in the rock to leach, by heating up. PLUS, ive read that if lava flows in water, it holds in the argon, well thats what would be happaning on a grand scale with noah's flood. So that would make the rocks apear older then they really are. Also lucifer you said that the water would wash out the daughter elements rather then the parent ones? making it apear younger then it really is. How so? How do you figure this?
Also barry im not saying this is like putting water in a glass and the water leaches out atoms in the glass. Im saying its sorta like a water filter, it keeps out the lead, and flows the water through it. But after awhile, the filter is going to get weak, and the lead is going to leach out of the filter with the water. Now rock is like the filter, but its a tough thick filter to get through, but cant some get in, under the sircumstances you mentioned, with hot water?
Also as for .org websites, i only heard that by hearsay that they are more credible then html ones. I did not really check up on it. I got too many other things to research then to check that out. Thats not to say a html one is not credible, because it can be as well.
Hi marnix. I read something a rebuttle to what you said. It said and i past the qwote and its a big one, some of it i dont yet fully understand, but thats because if i actually went to a laberatory, i would see hands on how it all works; i learn better that way and through pictures, but anyhow, here is the qwote. "Let us consider the question of how much different dating methods agree on the geologic column, and how many measurements are anomalous, since these points are often mentioned as evidences of the reliability of radiometric dating. It takes a long time to penetrate the confusion and find out what is the hard evidence in this area.
In the first place, I am not primarily concerned with dating meteorites, or precambrian rocks. What I am more interested in is the fossil-bearing geologic column of Cambrian and later age.
Now, several factors need to be considered when evaluating how often methods give expected ages on the geologic column. Some of these are taken from John Woodmoreappe’s article on the subject, but only when I have reason to believe the statements are also generally believed. First, many igneous formations span many periods, and so have little constraint on what period they could belong to. The same applies to intrusions. In addition, some kinds of rocks are not considered as suitable for radiometric dating, so these are typically not considered. Furthermore, it is at least possible that anomalies are under-reported in the literature. Finally, the overwhelming majority of measurements on the fossil bearing geologic column are all done using one method, the K-Ar method. (And let me recall that both potassium and argon are water soluble, and argon is mobile in rock.) Thus the agreement found between many dates does not necessarily reflect an agreement between different methods, but rather the agreement of the K-Ar method with itself. For example, if 80 percent of the measurements were done using K-Ar dating, and the other 20 percent gave random results, we still might be able to say that most of the measurements on a given strata agree with one another reasonably well. So to me it seems quite conceivable that there is no correlation at all between the results of different methods on the geologic column, and that they have a purely random relationship to each other.
Let us consider again the claim that radiometric dates for a given geologic period agree with each other. I would like to know what is the exact (or approximate) information content of this assertion, and whether it could be (or has been) tested statistically. It’s not as easy as it might sound.
Let’s suppose that we have geologic periods G1 ... Gn. Let’s only include rocks whose membership in the geologic period can be discerned independent of radiometric dating methods. Let’s also only include rocks which are considered datable by at least one method, since some rocks (I believe limestone) are considered not to hold argon, for example.
Now, we can take a random rock from Gi. We will have to restrict ourselves to places where Gi is exposed, to avoid having to dig deep within the earth. Let’s apply all known dating methods to Gi that are thought to apply to this kind of rock, and obtain ages from each one. Then we can average them to get an average age for this rock. We can also compute how much they differ from one another.
Now we have to be careful about lava flows -- which geologic period do they belong to? What about rocks that are thought not to have their clock reset, or to have undergone later heating episodes? Just to make the test unbiased, we will assign altitude limits to each geologic period at each point on the earth’s surface (at least in principle) and include all rocks within these altitude limits within Gi, subject to the condition that they are datable.
The measurements should be done in a double-blind manner to insure lack of unconscious bias.
For each geologic period and each dating method, we will get a distribution of values. We will also get a distribution of averaged values for samples in each period. Now, some claim is being made about these distributions. It is undoubtedly being claimed that the mean values ascend as one goes up the geologic column. It is also being claimed that the standard deviations are not too large. It is also being claimed that the different methods have distributions that are similar to one another on a given geologic period.
The only correlation I know about that has been studied is between K-Ar and Rb-Sr dating on precambrian rock. And even for this one, the results were not very good. This was a reference by Hurley and Rand, cited in Woodmorappe’s paper. As far as I know, no study has been done to determine how different methods correlate on the geologic column (excluding precambrian rock).
The reason for my request is that a correlation is not implied by the fact that there are only 10 percent anomalies, or whatever. I showed that the fact that the great majority of dates come from one method (K-Ar) and the fact that many igneous bodies have very wide biostratigraphic limits, where many dates are acceptable, makes the percentage of anomalies irrelevant to the question I am asking. And since this agreement is the strongest argument for the reliability of radiometric dating, such an assumption of agreement appears to be without support so far.
The question of whether different methods correlate on the geologic column is not an easy one to answer for additional reasons. Since the bulk of K-Ar dates are generally accepted as correct, one may say that certain minerals are reliable if they tend to give similar dates, and unreliable otherwise. We can also say that certain formations tend to give reliable dates and others do not, depending on whether the dates agree with K-Ar dates. Thus we can get an apparent correlation of different methods without much of a real correlation in nature. It’s also possible for other matter to be incorporated into lava as it rises, without being thoroughly melted, and this matter may inherit all of its old correlated radiometric dates. Coffin mentions that fission tracks can survive transport through lava, for example. It may also be that lava is produced by melting the bottom of continents and successively different layers are melted with time, or there could be a tendency for lighter isotopes to come to the top of magma chambers, making the lava there appear older. But anyway, I think it is important really to know what patterns appear in the data to try to understand if there is a correlation and what could be causing it. Not knowing if anomalies are always published makes this harder.
It is often mentioned that different methods agree on the K-T boundary, dated at about 65 million years ago. This is when the dinosaurs are assumed to have become extinct. This agreement of different methods is taken as evidence for a correlation between methods on the geologic column. One study found some correlated dates from bentonite that are used to estimate the date of the K-T boundary. I looked up some information on bentonite. It is composed of little glass beads that come from volcanic ash. This is formed when lava is sticky and bubbles of gas in it explode. So these small particles of lava cool very fast. The rapid cooling might mean that any enclosed argon is retained, but if not, the fact that this cooling occurs near the volcano, with a lot of argon coming out, should guarantee that these beads would have excess argon. As the gas bubble explodes, its enclosed argon will be rushing outward along with these tiny bubbles as they cool. This will cause them to retain argon and appear too old. In addition, the rapid cooling and the process of formation means that these beads would have Rb, Sr, U, and Pb concentrations the same as the lava they came from, since there is no chance for crystals to form with such rapid cooling. So to assume that the K-Ar dates, Rb-Sr dates, and U-Pb dates all reflect the age of the lava, one would have to assume that this lava had no Sr, no Pb, and that all the argon escaped when the beads formed. Since the magma generally has old radiometric ages, I don’t see how we could have magma without Pb or Sr. In fact, I doubt that there is fresh uncrystallized lava anywhere on earth today that has zero U/Pb and Rb/Sr ages, as would be required if bentonite gave an accurate date for the K-T boundary. So to me it seems to be certain that these ages must be in error.
Furthermore, the question arises whether bentonite always gives correlated ages, and whether these ages always agree with the accepted ages for their geologic period. I believe that bentonite occurs in a number of formations of different geologic periods, so this could be checked. If bentonite does not always give correlate and correct ages, this calls into question its use for dating the K-T boundary." |
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| marnixR |
| Posted: Wed Jan 09, 2008 12:25 am Post subject: |
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Forum Cosmic Wizard
Joined: 10 Apr 2007
Posts: 2436
Location: Cardiff, Wales
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so many statements, and so many of them false or half-truths
| Jollybear wrote: |
| In the first place, I am not primarily concerned with dating meteorites, or precambrian rocks. What I am more interested in is the fossil-bearing geologic column of Cambrian and later age. |
now why should you want to separate the precambrian from the phanerozoic rocks ? the laws of radioactive decay did not all of a sudden change at about 500 million years ago
| Jollybear wrote: |
| First, many igneous formations span many periods, and so have little constraint on what period they could belong to. The same applies to intrusions. |
even during periods of extended volcanic activity such as the Siberian or the Deccan traps, the activity is never continuous + discrete ash or lava layers can be perceived + measured
| Jollybear wrote: |
| In addition, some kinds of rocks are not considered as suitable for radiometric dating, so these are typically not considered. |
this conveniently ignores the method that existed in geology prior to radiometric dating, which is based on the principle of superposition (the fact that, when undisturbed, younger layers lie ono top of older layers) - if i find 2 ash layers with sedimentary rock inbetween, then i can be pretty sure that that this layer will be intermediary in age between the 2 datable ash layers
| Jollybear wrote: |
| Furthermore, it is at least possible that anomalies are under-reported in the literature. |
you wouldn't say that if you saw the argument between Leakey and Donaldson where the original date of the ash layer contradicted the age obtained from faunal correlation - the disagreement was highly public, but ultimately resolved through resampling on better samples
| Jollybear wrote: |
| Finally, the overwhelming majority of measurements on the fossil bearing geologic column are all done using one method, the K-Ar method. |
the only reason the K-Ar method is predominant is its ease of use and its suitability for the age range involving the phanerozoic - it does not mean that other methods can't be used for independent confirmation
| Jollybear wrote: |
| And let me recall that both potassium and argon are water soluble, and argon is mobile in rock |
so we're coming back to your original statement that plain water running over rock leaches out selected elements from that rock - surely you're aware that many of the elements that you claim are water soluble are present in the rock as oxides or silicates, the solubility of which is several orders of magnitude less than the element itself
| Jollybear wrote: |
| The measurements should be done in a double-blind manner to insure lack of unconscious bias. |
Several geologists farm their samples out to specialist laboratories, so in a way there's your double blind test - no rock comes with a label attached "240 million years old", the best the geologist can say at the time is that based on faunal correlation and/or superposition in the geologic column he suspects his samples to be of Triassic age
btw, why is this thread in the Astronomy section ? shouldn't it come under Earth Sciences ?
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the amicable forum where small is beautiful and even the trolls are intelligent
biology without evolution is but stamp collecting |
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