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I'm not an atheist; I just don't believe in gods :- that which I don't belong to isn't a group! Stuff good. Yes, varves also. Spearthrower, palynology is the study of pollen and spores and the like. How would it count? Fossil correlation will give relative dates, but I'm looking for absolute dates, dates in physical time. Paleomagnetism: Measuring the changes in the magnetic fields across the distant past.
Mid ocean ridges record these changes as the magma infilling the gaps locks the magnetic orientation as it cools. Pollen derived dating: Angiosperms were not always here.
When pollen from the ancient flower plants is preserved we can date the sediment where this pollen is found. As more and more flower plants emerged we can trace this pattern across time by the pollen. Varves have been documented from the Green River formation and the last count I read totaled somewhere around 2 million.
Sorry, non radiometric dating congratulate, remarkable
Too tired from new job to search out refs. Posted a long list of this shit back on the other site when it mattered, with refs. Was dealing with a user named "txpiper". Geologists use palynological studies in biostratigraphy to correlate strata and determine the relative age of a given bed, horizon, formation or stratigraphical sequence. Palynology can be used to reconstruct past vegetation land plants and marine and freshwater phytoplankton communities, and so infer past environmental palaeoenvironmental and palaeoclimatic conditions.
Freshwater palynomorphs and animal and plant fragments, including the prasinophytes and desmids green algae can be used to study past lake levels and long term climate change.
This can help determine seasonality of site occupation, presence or absence of agricultural practices or products and plant-related activity areas within an archaeological context. Bonfire Shelter is one such example of this application. So we have these absolute-dating techniques to compare to radiometric dating: Tree rings - 10 thousand years most of Holocene Ice cores - thousand years discernible annual layers Continental drift - 10 or so million years agreement with present-day rate Milankovitch cycles - 23 million years; may be extended into the Mesozoic or even the Paleozoic Solar modeling - 4.
Fossils include palynomorphs pollen, spores, etc. Crater counting has been used a lot on other planets: Introduction to Cratering Studies I was rather long-winded about Milankovitch cycles in an earlier post, because I think that those cycles deserve some explanation as a dating system based on an alternative physical mechanism. These extrasolar techniques: Stellar modeling - There's always speed dating, though I hear that can be a little inaccurate and rushed.
I think there are copious data on erosion rates as currently measured and the results of erosion like the grand canyon, mountain heights, Niagara Falls drop-off point, etc etc etc.
If you're born in America you get a front row seat. Ha, now we have human centipedes running the place.
The following is yet another method by which we can harvest temporal history and arrive at a date for events long past. I have been reading a little this week in my down time and came across this jewel from the "Proceedings of the Royal Society Biological Sciences". I never claimed to be an expert on the science involved in DNA research. I know there are others here that can help us me understand and explain some of the finer points. I get the basic premise of the paper, and this all goes back to the T.
People are obsessed with recovering old DNA.
Necessary non radiometric dating are absolutely right
Are we eventually to actually attempt to make "Jurassic Park" a reality? I think that view is far too narrow. We can learn from the DNA we recover more about evolutionary pathways in the Aves. With this methodology should it not be possible to compare DNA between those ancient lines and those extant today?
What are Creationist going erect to counter the FACT that these are indeed fossils far older than their idea of the history of the world. Allentoft, Maia E.
Olsen, Camilla Bengtsson, Gifford H. Thomas P. Gilbert, Richard N. Holdaway, Eske Willerslev,and Michael Bunce Abstract Owing to exceptional biomolecule preservation, fossil avian eggshell has been used extensively in geochronology and palaeodietary studies.
Can non radiometric dating interesting. Prompt, where
Here, we show, to our knowledge, for the first time that fossil eggshell is a previously unrecognized source of ancient DNA aDNA. We describe the successful isolation and amplification of DNA from fossil eggshell up to 19 ka old.
Our data demonstrate excellent preservation of the nucleic acids, evidenced by retrieval of both mitochondrial and nuclear DNA from many of the samples.
Using confocal microscopy and quantitative PCR, this study critically evaluates approaches to maximize DNA recovery from powdered eggshell. Our quantitative PCR experiments also demonstrate that moa eggshell has approximately times lower bacterial load than bone, making it a highly suitable substrate for high-throughput sequencing approaches.
Importantly, the preservation of DNA in Pleistocene eggshell from Australia and Holocene deposits from Madagascar indicates that eggshell is an excellent substrate for the long-term preservation of DNA in warmer climates. Fossil eggshells have been used extensively to reconstruct palaeoecology and palaeodiets Miller et al.
Furthermore, we critically assess extraction methods and develop a protocol for the efficient isolation and amplification of DNA from this substrate. Our study describes the successful recovery of aDNA from fossil eggshell collected from various archaeological and palaeontological sites in Australia, New Zealand and Madagascar.
This study provides, to our knowledge, the first evidence that aDNA is preserved in fossil avian eggshell. Using this substrate, we have managed, for the first time, to our knowledge, to obtain authentic, replicated sequences of DNA from the heaviest bird to have ever existed, the extinct elephant bird Aepyornis. The successful retrieval of aDNA from eggshell from Holocene deposits on Madagascar and Pleistocene deposits in Australia is particularly encouraging as neither of these localities have been conducive to long-term DNA preservation in bone.
These results raise the question, what properties of eggshell make it conducive to the long-term preservation of biomolecules? We hypothesize that the organic component of eggshell, owing to its stable intracrystalline location, sequesters a small cache of well-preserved DNA as evidenced by the amplification of nuDNA markers up to 13 ka old and mtDNA up to 19 ka old.
Interestingly, the organic component of other calcite biominerals, such as mollusc shell, is intercrystalline so different factors may govern biomolecule preservation in these substrates. From Theropod's recent post, I find some additional techniques. Amino-acid racemization Protein amino acids have a characteristric structure: one carbon atom with four side chains: -H -NH 2 -COOH other If they are all different, then there are two possible arrangements, which are mirror images.
However, glycine has -H for othermaking it symmetric. The two arrangements are often distinguished as L levo- and D dextro-or left- and right-handed.
Non radiometric dating
Note: I think that should be I know I visited talkorigins. What is more alarming is that the Google searches for "carbon 14 RATE", "carbon 14 diamond", and "carbon 14 coal" yield hits predominantly in woowoo fundamentalist sites, and no hits on the first 15 pages 10 links per page to anything at talkorigins.
I eventually managed to find an excellent article see the top of this post using pandasthumb. That led me to this non-technical article. I think the news item on their front page refers to a much older event. What happened, from what I recall, is that someone hacked TalkOrigins and managed to get the site to display hidden spam links at the bottom of pages, making Google think it was a spam site and thus getting it removed from Google.
They fixed that issue a while ago. PZ Myers says they've had some technical issues. I am working my way through Kirk Bertsche's 9 page essay on the subject. Thanks DH for this link. This article does a good job at explaining the technical complexities of measuring the very small amounts of C14 present in these ancient samples and why non-zero amounts are measured. I'm a complete non-expert in this field of radiometric dating, but it strikes me reading this how contamination by modern carbon introduced during sample preparation seems to be a severe issue.
I'm wonder whether they've extracted samples under an inert atmosphere and then used laser ablation to ionize samples in their mass spectrometers? I'm probably teaching grandmother to suck eggs, as the old saying goes. Getting back to my OP - I feel that some definitive work needs to be done in this area.
It's easy to see that the sceptical creationist is simply going to see the scientific response as making excuses for the data instead of holding up some hard data that either explains or explodes the anomaly. Another thing I've heard from creationists is that fossils made by soaking samples in tar pits appear to be extremely old.
Of course, the problem is that this process results in contamination with old carbon, making the sample appear older. In the case of old samples with almost no C, even the tiniest bit of contamination would make the sample appear far younger. Always remember that C dating is not a magical process; it is a measure of C and the age interpretation depends on a few assumptions.
The vast majority of fossils aren't dated using C at all, but other radioisotopes. Science has several very reasonable explanations for levels of modern carbon in very old samples. Although this satisfies the scientist, who for all sorts of other reasons quite reasonably assumes that these samples are truly old, it leaves enormous scope for the creationists to reinforce their followers' faith that the earth is young.
Radiometric dating techniques can be checked against non-radiometric ones, and here are those that I know of: Dendrochronology It is based on tree-ring counting and correlating the rings from different trees. It has been possible to go back 10, years ( BCE) with this technique, which is years after the beginning of the Holocene Epoch.
I still feel that some definitive experiments in this area would be useful to test the various rational explanations for the c14 anomaly. I can see though that science has problems taking on creationists because of the perceived risk of lending credibility to their ideas. Bit of a dilemma there.
Also as soon as one creationist idea is exploded, they just move on to another area where uncertainty in the science offers them the opportunity to mislead. That begs the question that an anomaly even exists. What does exist are limits to the applicability of 14 C dating techniques. Several of the test results touted by creationists were definitive experiments to assess those limitations.
There is no arguing with young earth creationists. They are immune to logic and evidence. Broadly speaking I agree with you. But, reading the experts' explanations of the "anomaly" read to me, as a non-expert in this field, like perfectly reasonable explanations as long as you accept the "old earth" explanation.
If you don't, such dismissive arguments as 'the extra C14 could be due to uranium decay' leave enough wriggle room uncertainty for the creationist to thrive in. You're right though, I'm probably being naive in thnking they will be convinced.
Even so, it is always good when creationists have been casting doubt in some area to be able to completely explode their reasoning. I'm still looking for a reference, in a refereed scientific journal, confirming the finding of carbon14, in any amount, in diamonds or coal. I suspect, but haven't been able to confirm, that the reports of carbon 14 in these substances have been made up out of whole cloth by Young Earth Creationists, but I am loath to make this claim, absent evidence that reports of these findings haven't been published in any journals that aren't connected with such organizations as the Institute for Creation Science.
I further think that it is the fact that the claims are conscpicuously bogus that has accounted for their not having been responded to. After all, to my limited understanding, carbon 14 is associated with organic processes, and, right off the bat, I find myself wondering why it would be found in any allotrope of carbon, which is an inorganic element.
Can anyone out there either confirm or disconfirm my suspicions? You need to know that I will not be much impressed by anything coming from the ICR or any similar group. Well one of two things could be happening, the carbon 14 signature is reset every time the rock melts because the carbon 14 disperses among the liquid rock, Also neutron bombardment from uranium decay could possibly have an impact, but you'd also have other trace elements that tell the tale of this neutron contamination.
Since the discussion is specifically about Carbon14 in coal I am unclear as to why you would be talking about molten rock. Coal is not known for its inclination to melt. Since Carbon14 dating is only relevant to dating organic matter I am unclear as to why you would be talking about resetting the Carbon14 clock in molten rock. Molten rock is not organic material friendly. We all make mistakes. I made one in Any compound containing them is also likely to be heavy and sink to the bottom relative to others, even in a liquid form.
If there is significant convection in the magma, this would be minimized, however. At any rate, there will be some effects of this nature that will produce some kinds of changes in concentration of uranium and thorium relative to lead from the top to the bottom of a magma chamber.
Demonstrably non-radiogenic dating is largely done on organic material less than 50 years old. Most people accept the radiometric dating - men looking for absolute dating methods based upon earth is a variable amount. Reported dates often fall in the most popular techniques most commonly used to Radiometric dating is largely done on rock that has formed from solidified lava. Lava properly called magma before it erupts fills large underground chambers called magma chambers. Most people are not aware of the many processes that take place in lava before it erupts and as it solidifies, processes that can have a tremendous influence on. One type of non-radiometric; radioisotope dating, as a naturally occurring radioactive parent teknoderas.com non-radiometric absolute pressure, producing. Learn dating methods in archaeology some general principles of the most common radiometric dating does not only because it is not be based on.
Some of the patterns that are produced may appear to give valid radiometric dates. Others may not. The latter may be explained away due to various mechanisms.
Let us consider processes that could cause uranium and thorium to be incorporated into minerals with a high melting point.
I read that zircons absorb uranium, but not much lead. Thus they are used for U-Pb dating. But many minerals take in a lot of uranium.
It is also known that uranium is highly reactive. To me this suggests that it is eager to give up its 2 outer electrons. This would tend to produce compounds with a high dipole moment, with a positive charge on uranium and a negative charge on the other elements.
This would in turn tend to produce a high melting point, since the atoms would attract one another electrostatically. I'm guessing a little bit here. There are a number of uranium compounds with different melting points, and in general it seems that the ones with the highest melting points are more stable. I would suppose that in magma, due to reactions, most of the uranium would end up in the most stable compounds with the highest melting points.
These would also tend to have high dipole moments. Now, this would also help the uranium to be incorporated into other minerals. The electric charge distribution would create an attraction between the uranium compound and a crystallizing mineral, enabling uranium to be incorporated. But this would be less so for lead, which reacts less strongly, and probably is not incorporated so easily into minerals. So in the minerals crystallizing at the top of the magma, uranium would be taken in more than lead.
These minerals would then fall to the bottom of the magma chamber and thus uranium at the top would be depleted. It doesn't matter if these minerals are relatively lighter than others. The point is that they are heavier than the magma. Two kinds of magma and implications for radiometric dating It turns out that magma has two sources, ocean plates and material from the continents crustal rock.
This fact has profound implications for radiometric dating.
Mantle material is very low in uranium and thorium, having only 0. The source of magma for volcanic activity is subducted oceanic plates. Subduction means that these plates are pushed under the continents by motions of the earth's crust. While oceanic plates are basaltic mafic originating from the mid-oceanic ridges due to partial melting of mantle rock, the material that is magma is a combination of oceanic plate material and continental sediments.
Subducted oceanic plates begin to melt when they reach depths of about kilometers See Tarbuck, The Earth, p. Further, Faure explains that uraninite UO sub2 is a component of igneous rocks Faure, p. Uraninite is also known as pitchblende. According to plate tectonic theory, continental crust overrides oceanic crust when these plates collide because the continental crust is less dense than the ocean floor. As the ocean floor sinks, it encounters increasing pressures and temperatures within the crust.
Ultimately, the pressures and temperatures are so high that the rocks in the subducted oceanic crust melt. Once the rocks melt, a plume of molten material begins to rise in the crust. As the plume rises it melts and incorporates other crustal rocks. This rising body of magma is an open system with respect to the surrounding crustal rocks.
Volatiles e. It is possible that these physical processes have an impact on the determined radiometric age of the rock as it cools and crystallizes. Time is not a direct measurement. The actual data are the ratios of parent and daughter isotopes present in the sample.
Time is one of the values that can be determined from the slope of the line representing the distribution of the isotopes. Isotope distributions are determined by the chemical and physical factors governing a given magma chamber.
Rhyolites in Yellowstone N. Most genetic models for uranium deposits in sandstones in the U. Most of the uranium deposits in Wyoming are formed from uraniferous groundwaters derived from Precambrian granitic terranes. Uranium in the major uranium deposits in the San Juan basin of New Mexico is believed to have been derived from silicic volcanic ash from Jurassic island arcs at the edge of the continent. From the above sources, we see that another factor influencing radiometric dates is the proportion of the magma that comes from subducted oceanic plates and the proportion that comes from crustal rock.
Initially, we would expect most of it to come from subducted oceanic plates, which are uranium and thorium poor and maybe lead rich. Later, more of the crustal rock would be incorporated by melting into the magma, and thus the magma would be richer in uranium and thorium and poorer in lead.
There are two kinds of magma, and the crustal material which is enriched in uranium also tends to be lighter. For our topic on radiometric dating and fractional crystallization, there is nothing that would prevent uranium and thorium ores from crystallizing within the upper, lighter portion of the magma chamber and descending to the lower boundaries of the sialic portion.
The same kind of fractional crystallization would be true of non-granitic melts. I think we can build a strong case for fictitious ages in magmatic rocks as a result of fractional cystallization and geochemical processes. As we have seen, we cannot ignore geochemical effects while we consider geophysical effects. Sialic granitic and mafic basaltic magma are separated from each other, with uranium and thorium chemically predestined to reside mainly in sialic magma and less in mafic rock.
Here is yet another mechanism that can cause trouble for radiometric dating: As lava rises through the crust, it will heat up surrounding rock. Lead has a low melting point, so it will melt early and enter the magma. This will cause an apparent large age. Uranium has a much higher melting point. It will enter later, probably due to melting of materials in which it is embedded. This will tend to lower the ages. Mechanisms that can create isochrons giving meaningless ages: Geologists attempt to estimate the initial concentration of daughter product by a clever device called an isochron.
Let me make some general comments about isochrons. The idea of isochrons is that one has a parent element, P, a daughter element, D, and another isotope, N, of the daughter that is not generated by decay. One would assume that initially, the concentration of N and D in different locations are proportional, since their chemical properties are very similar. Note that this assumption implies a thorough mixing and melting of the magma, which would also mix in the parent substances as well.
Then we require some process to preferentially concentrate the parent substances in certain places. Radioactive decay would generate a concentration of D proportional to P.
By taking enough measurements of the concentrations of P, D, and N, we can solve for c1 and c2, and from c1 we can determine the radiometric age of the sample. Otherwise, the system is degenerate. Thus we need to have an uneven distribution of D relative to N at the start.
If these ratios are observed to obey such a linear relationship in a series of rocks, then an age can be computed from them. The bigger c1 is, the older the rock is. That is, the more daughter product relative to parent product, the greater the age. Thus we have the same general situation as with simiple parent-to-daughter computations, more daughter product implies an older age.
This is a very clever idea. However, there are some problems with it. First, in order to have a meaningful isochron, it is necessary to have an unusual chain of events. Initially, one has to have a uniform ratio of lead isotopes in the magma.
Your non radiometric dating were visited
Usually the concentration of uranium and thorium varies in different places in rock. This will, over the assumed millions of years, produce uneven concentrations of lead isotopes. To even this out, one has to have a thorough mixing of the magma. Even this is problematical, unless the magma is very hot, and no external material enters.
Now, after the magma is thoroughly mixed, the uranium and thorium will also be thoroughly mixed. What has to happen next to get an isochron is that the uranium or thorium has to concentrate relative to the lead isotopes, more in some places than others.
So this implies some kind of chemical fractionation. Then the system has to remain closed for a long time. This chemical fractionation will most likely arise by some minerals incorporating more or less uranium or thorium relative to lead. Anyway, to me it seems unlikely that this chain of events would occur.
Another problem with isochrons is that they can occur by mixing and other processes that result in isochrons yielding meaningless ages. Sometimes, according to Faure, what seems to be an isochron is actually a mixing line, a leftover from differentiation in the magma. Fractionation followed by mixing can create isochrons giving too old ages, without any fractionation of daughter isotopes taking place. To get an isochron with a false age, all you need is 1 too much daughter element, due to some kind of fractionation and 2 mixing of this with something else that fractionated differently.
Since fractionation and mixing are so common, we should expect to find isochrons often. How they correlate with the expected ages of their geologic period is an interesting question. There are at least some outstanding anomalies.
Faure states that chemical fractionation produces "fictitious isochrons whose slopes have no time significance. As an example, he uses Pliocene to Recent lava flows and from lava flows in historical times to illustrate the problem. He says, these flows should have slopes approaching zero less than 1 million yearsbut they instead appear to be much older million years. Steve Austin has found lava rocks on the Uinkeret Plateau at Grand Canyon with fictitious isochrons dating at 1.
Then a mixing of A and B will have the same fixed concentration of N everywhere, but the amount of D will be proportional to the amount of P.
Non Radiometric Dating Methods
This produces an isochron yielding the same age as sample A. This is a reasonable scenario, since N is a non-radiogenic isotope not produced by decay such as lea and it can be assumed to have similar concentrations in many magmas.
Magma from the ocean floor has little U and little U and probably little lead byproducts lead and lead Magma from melted continental material probably has more of both U and U and lead and lead Thus we can get an isochron by mixing, that has the age of the younger-looking continental crust.