Radiocarbon dating of fossils

Absolute Dating
Contents:
  1. Navigation menu
  2. Dating Fossils – How Are Fossils Dated? - ezyliraxanag.tk
  3. What is Radiocarbon Dating?
  4. Carbon 14 Dating of Fossils

Because the half-life of carbon is 5, years, it is only reliable for dating objects up to about 60, years old. However, the principle of carbon dating applies to other isotopes as well. Potassium is another radioactive element naturally found in your body and has a half-life of 1. The use of various radioisotopes allows the dating of biological and geological samples with a high degree of accuracy. However, radioisotope dating may not work so well in the future.

Anything that dies after the s, when Nuclear bombs , nuclear reactors and open-air nuclear tests started changing things, will be harder to date precisely. Earthquakes on the Mississippi: The New Madrid Seismic Zone. This means that currently in a mole there are 1. After 40, years, there would be 0. Thus a sample that dates to 40, years by C14 dating still has about 7 billion C14 atoms per mole of carbon.

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This is still a large number of C14 atoms, and they had to come from somewhere! In general, organic matter in the fossil record dates by C14 dating to 20, to 40, years. Here are some specific results along this line; many more could be cited. Special care was taken to prevent contamination. There are many more such results: Fossils, coal, oil, natural gas, limestone, marble, and graphite from every Flood-related rock layer—and even some pre-Flood deposits—have all contained measurable quantities of radiocarbon.

All these results have been reported in the conventional scientific literature. Similarly, carefully sampled pieces of coal from ten U. Recent finds of Mary Schweitzer are also relevant for the dating of ancient bones. Even more, proteins in this tissue retain their structure.

Extraordinary efforts were made to eliminate all contamination from the measuring apparatus. If there had been contamination, then it would have introduced other substances into the soft tissue. Here is a discussion of this and related finds by Brian Thomas, a creation oriented author: These two new finds join dozens of others published over the last half-century, but evolutionary scientists still have a hard time accepting that these fossils retain original biochemicals. Robert Service wrote in Science: The [soft tissue fossil] claims were met with howls of skepticism from biochemists and paleontologists who saw no way that fragile organic molecules could survive for tens of millions of years, and wondered whether her samples were contaminated with modern proteins.

We can slow it down, but not by a lot. This shows that there are many such finds of protein in fossil specimens, and also that experts in the field have trouble seeing how proteins could survive in bone for millions of years. Here are more quotations from the Science article referenced above: Schroeter even went so far as to break down the mass spectrometer piece by piece, soak the whole thing in methanol to remove any possible contaminants, and reassemble the machine.

Just how those collagen sequences survived for tens of millions of years is not clear. There is another dating method based on the orientation of amino acids, whether they spiral to the right D or to the left L: All biological tissues contain amino acids. When an organism dies, control over the configuration of the amino acids ceases, and the ratio of D to L moves from a value near 0 towards an equilibrium value near 1, a process called racemization.

Thus, measuring the ratio of D to L in a sample enables one to estimate how long ago the specimen died. This dating method is considered to be accurate for ages up to several hundred thousand years. It is calibrated by C14 dating, and the ages given by the two methods are in close agreement after such calibration. A chart of the ratio of D to L for samples of various radiocarbon ages shows that even for samples dated to 30, or 40, years, the ratio of D to L is significantly less than one.

This is additional evidence that these bones are not millions of years old. At any rate, it would be interesting to determine the D to L ratio for the proteins found in dinosaur bones. Another interesting fact about amino acid dating is that the transformation of L to D forms seems to occur more and more slowly the older the sample is: Many fossils have been dated both by racemization and by C14 dating. The conventional time scale assumes that racemization occurs slower and slower as we go back in time. If we assume that racemization occurs at a constant rate, which is a reasonable assumption, then we get a time scale that is more compressed even than the C14 time scale.

This would imply that any date within 50, years by C14 dating is really at most 18, years, and even any date within a million years by conventional dating is really at most 18, years. This would imply that the dinosaur bones are also at most 18, years old! One response of evolutionary scientists to the relatively young C14 dates is to say that they are due to contamination of the bones by modern carbon, having a higher proportion of C But other times they accept C14 ages in the range of 20, to 40, years as valid.

Also, as mentioned earlier, extraordinary methods were used to eliminate all possible contamination when measuring the C14 in these supposedly ancient bones.

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Dating Fossils – How Are Fossils Dated? - ezyliraxanag.tk

In addition, the preservation of soft tissue together with bone has implications for the possible contamination of the dinosaur bones. Based on current tests, it appears that many and perhaps all fossils with organic matter have young carbon 14 dates, and also that a significant number of dinosaur fossils have soft tissue. Thus many dinosaur bones with soft tissue should be typically found in similar environments as dinosaur bones with young C14 dates. However, it turns out that an environment that can preserve both bones and soft tissue has to be dry.

If such dinosaur bones with soft tissue had been wet for a significant length of time, bacteria would have consumed the remaining proteins and there would be no soft tissue left. This is how nutrients are made available to plants. But Mary Schweitzer has shown that the proteins are still there in the dinosaur bones. Thus these bones must have been dry since their burial. If this is so, then how could they be contaminated?

Contamination would have to come through water flowing through the bones. However, under such acidic conditions, bone is rapidly dissolved. Because the soft tissues and bones are still intact, they must have been kept very dry since their burial.

Half-life and carbon dating - Nuclear chemistry - Chemistry - Khan Academy

Perhaps a highly basic environment would inhibit bacterial growth and permit soft tissue to be preserved. But a basic environment breaks down organic matter and soft tissue: Common corrosives are either strong acids, strong bases, or concentrated solutions of certain weak acids or weak bases.

It may attack a great variety of materials, including metals and various organic compounds, but people are mostly concerned with its effects on living tissue: Concentrated or strong bases are caustic on organic matter and react violently with acidic substances.

What is Radiocarbon Dating?

The definition of caustic is: A strongly alkaline environment would destroy tissue because it is caustic. So if there is some wet environment permitting both bone and soft tissue to be preserved for millions of years, it must be highly unusual. It seems that it could not be highly acidic, highly basic, or neutral. So such an environment could not explain how fossil remains from all through the fossil record could contain significant amounts of C14, dating to about 40, years or less because most of them would not be in such an unusual environment, if it could even exist.

But if the environment were dry, then the bones could not be contaminated. Now, could air bring contamination to these bones? Air would bring moisture, which again would enable the growth of bacteria. Dry air would contain carbon dioxide, but this is a highly stable molecule and would not transfer carbon to the bone without an input of energy from somewhere.

In any event, such contamination would be on the surface and would be omitted by thorough cleaning methods.

Carbon 14 Dating of Fossils

Now, how much contamination would there have to be if the dinosaur bones were really of infinite C14 age as the scientists claim? Suppose X parts of carbon were original and Y parts were contamination.

This means that nearly one percent of the carbon would have to be contamination. Thus nearly 10 percent of the carbon would have to be contamination! Similarly, to get a measured age of 40, years if the contaminating material had a C14 age of 20, years would mean that nearly 10 percent of the total carbon would have to be contamination! Surely this would be noticed. This is a large amount and should be detectable by some means. This figure is for contamination from recent organic matter. If the contamination is by older carbon, then the amount would even have to be larger.

And in any case, in a dry environment, contamination would be impossible. This is not considered as contamination. This cutoff is purely arbitrary. Could contamination of the bones come from bacteria? And, of course, in a dry environment there would be essentially no bacteria. Dry environments preserve organic matter well.

Even if dinosaur bones were percent C14 originally in their carbon content, a ridiculous assumption, after a million years there would be very few C14 atoms left, and this much C14 in the beginning might give off too much radiation for the animal to survive. Also, this would require a lot of radiation entering the earth to generate so much C14, and this radiation alone would drive many species extinct. This is an absolute upper bound on the ages of these fossils regardless of atmospheric conditions, assuming no contamination.

Some people attempt to explain away these young dates by saying that neutrons were generated in the earth and created the C14 in the dinosaur bones. These neutrons could have been generated by the decay of uranium and thorium in the soil.


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However, referring to this possibility for C14 found in diamonds, Dr.