Two kinds of arguments are offered. In the first place, Creationists argue that methods of radiometric dating employ false assumptions. They continue by using . Students, particularly Young-Earth Creationists, may come in with of radiometric dating and refuting misconceptions and creationist arguments on that topic. A very common claim of young earth creationists in trying to reject the evidence for an old earth is to loudly proclaim that radiometric dating.
Answers to Creationist Attacks on Carbon Dating | NCSE
Argon is a gas at Earth-normal temperatures, and in any state it exists only as single atoms. By contrast, potassium and calcium are two of the most active elements in nature. They both form compounds readily and hold onto other atoms tenaciously. What does this mean? It means that before a mineral crystallizes, argon can escape from it easily. It also means that when an atom of argon forms from an atom of potassium inside the mineral, the argon is trapped in the mineral.
So any Ar40 we find deep inside a rock sample must be there as a result of K40 decay. That and some simple calculations produce a figure for how long the K40 has been decaying in our rock sample. What happens if our mineral sample has not remained a closed system?
Creationists Blind Dates
What if argon has escaped from the mineral? What if argon has found its way into the mineral from some other source? If some of the radiogenic argon has escaped, then more K40 must have decayed than we think -- enough to produce what we did find plus what escaped.
In other words, a mineral that has lost argon will be older than the result we get says it is. In the other direction, if excess argon has gotten into the mineral, it will be younger than the result we get says it is.
An isochron dating method isochron dating is described in the next section can also be applied to potassium-argon dating under certain very specific circumstances. When isochron dating can be used, the result is a much more accurate date.
Radiometric Dating and Creation Science
Yet a fourth method, rubidium-strontium dating, is even better than potassium-argon dating for old rocks. The nuclide rubidium Rb87 decays to strontium Sr87 with a half-life of 47 billion years. Strontium occurs naturally as a mixture of several nuclides. If three minerals form at the same time in different regions of a magma chamber, they will have identical ratios of the different strontium nuclides.
The total amount of strontium might be different in the different minerals, but the ratios will be the same. Now, suppose that one mineral has a lot of Rb87, another has very little, and the third has an in-between amount. That means that when the minerals crystallize there is a fixed ratio of Rb As time goes on, atoms of Rb87 decay to Sr, resulting in a change in the Rb Sr87 ratio, and also in a change in the ratio of Sr87 to other nuclides of strontium. The decrease in the Rb Sr87 ratio is exactly matched by the gain of Sr87 in the strontium-nuclide ratio.
It has to be -- the two sides of the equation must balance.Radiometric Dating is Flawed!! Really?? How Old IS the Earth?
If we plot the change in the two ratios for these three minerals, the resulting graph comes out as a straight line with an ascending slope. This line is called an isochron. When every one of four or five different minerals from the same igneous formation matches the isochron perfectly, it can safely be said that the isochron is correct beyond a reasonable doubt.
There are numerous other radiometric dating methods: A full cite for this book is given in the bibliography.
ICR creationists claim that this discredits C dating. How do you reply? It does discredit the C dating of freshwater mussels, but that's about all. Kieth and Anderson show considerable evidence that the mussels acquired much of their carbon from the limestone of the waters they lived in and from some very old humus as well.
Carbon from these sources is very low in C because these sources are so old and have not been mixed with fresh carbon from - page 24 - the air. Thus, a freshly killed mussel has far less C than a freshly killed something else, which is why the C dating method makes freshwater mussels seem older than they really are. When dating wood there is no such problem because wood gets its carbon straight from the air, complete with a full dose of C The creationists who quote Kieth and Anderson never tell you this, however.
A sample that is more than fifty thousand years old shouldn't have any measurable C Coal, oil, and natural gas are supposed to be millions of years old; yet creationists say that some of them contain measurable amounts of C, enough to give them C ages in the tens of thousands of years.
How do you explain this? Radiocarbon dating doesn't work well on objects much older than twenty thousand years, because such objects have so little C left that their beta radiation is swamped out by the background radiation of cosmic rays and potassium K decay. Younger objects can easily be dated, because they still emit plenty of beta radiation, enough to be measured after the background radiation has been subtracted out of the total beta radiation.
However, in either case, the background beta radiation has to be compensated for, and, in the older objects, the amount of C they have left is less than the margin of error in measuring background radiation. As Hurley points out: Without rather special developmental work, it is not generally practicable to measure ages in excess of about twenty thousand years, because the radioactivity of the carbon becomes so slight that it is difficult to get an accurate measurement above background radiation.
K decay also forms plenty of beta radiation. Stearns, Carroll, and Clark point out that ". This radiation cannot be totally eliminated from the laboratory, so one could probably get a "radiocarbon" date of fifty thousand years from a pure carbon-free piece of tin. However, you now know why this fact doesn't at all invalidate radiocarbon dates of objects younger than twenty thousand years and is certainly no evidence for the notion that coals and oils might be no older than fifty thousand years.
Creationists such as Cook claim that cosmic radiation is now forming C in the atmosphere about one and one-third times faster than it is decaying. If we extrapolate backwards in time with the proper equations, we find that the earlier the historical period, the less C the atmosphere had. If we extrapolate - page 25 - as far back as ten thousand years ago, we find the atmosphere would not have had any C in it at all. If they are right, this means all C ages greater than two or three thousand years need to be lowered drastically and that the earth can be no older than ten thousand years.
Yes, Cook is right that C is forming today faster than it's decaying. However, the amount of C has not been rising steadily as Cook maintains; instead, it has fluctuated up and down over the past ten thousand years.
How do we know this? From radiocarbon dates taken from bristlecone pines. There are two ways of dating wood from bristlecone pines: Since the tree ring counts have reliably dated some specimens of wood all the way back to BC, one can check out the C dates against the tree-ring-count dates.
Admittedly, this old wood comes from trees that have been dead for hundreds of years, but you don't have to have an 8,year-old bristlecone pine tree alive today to validly determine that sort of date.
It is easy to correlate the inner rings of a younger living tree with the outer rings of an older dead tree. The correlation is possible because, in the Southwest region of the United States, the widths of tree rings vary from year to year with the rainfall, and trees all over the Southwest have the same pattern of variations. When experts compare the tree-ring dates with the C dates, they find that radiocarbon ages before BC are really too young—not too old as Cook maintains. For example, pieces of wood that date at about BC by tree-ring counts date at only BC by regular C dating and BC by Cook's creationist revision of C dating as we see in the article, "Dating, Relative and Absolute," in the Encyclopaedia Britannica.
So, despite creationist claims, C before three thousand years ago was decaying faster than it was being formed and C dating errs on the side of making objects from before BC look too young, not too old. But don't trees sometimes produce more than one growth ring per year? Wouldn't that spoil the tree-ring count? If anything, the tree-ring sequence suffers far more from missing rings than from double rings. This means that the tree-ring dates would be slightly too young, not too old.
No process rate is unchangeable. Every process in nature operates at a rate which is influenced by a number of different factors. If any of these factors change, the process rate changes. Rates are at best only statistical averages, not deterministic constants. Morris a, These rejoinders make it apparent that Morris's formulations of the assumptions underlying radiometric dating are only akin to the assumptions examined above. When geologists calculate the ages of rocks, they do assume that the system under consideration has remained closed in one particular respect.
They suppose that none of the daughter element has been added or subtracted. However, this does not commit them to the idea that the system was completely closed, that it engaged in no exchange of matter or energy with the environment. Like his memorable argument about the evolving junkyard, Morris's first reply only demonstrates his lack of understanding of basic concepts of physics. The crucial question is whether we can ever be justified in believing that the system was never contaminated by extra amounts of the daughter element.
I have tried to explain how geologists can sometimes obtain good evidence for this conclusion. Similarly, the second point is misguided. Geologists do not have to suppose that the system originally contained none of the daughter element. What is important is that they be able to compute the amount of the daughter element originally present. Clearly, it is required only that D0 be known, not that it be zero. It is perfectly possible to have excellent evidence for statements about events and situations that no human has observed.
Geologists draw conclusions about the composition of original rocks by applying claims about the possibilities of incorporating elements into minerals, claims that can be tested in the laboratory. So, for example, the thesis that certain minerals would have contained no original argon rests on a perfectly testable and well-confirmed claim.
While those minerals were in the molten state, prior to the solidification of the rock, argon would have diffused from them. It is only after the molten rock has solidified that the argon formed through radioactive decay becomes trapped within it.
Obviously, what is being applied in this case is our knowledge of the physical and chemical interactions of minerals and elements. Morris's third assumption, and his attempt to undermine it, raises a new issue. In deriving equation 4from which rock ages can be computed, I employed equation 1the equation of radioactive decay.
I asserted that l, which measures the rate of decay, is a constant. Morris suggests that the assertion is unwarranted.
However, the claim that l is a constant does not descend out of thin air. It is the result of our knowledge of nuclear physics. Although the sciences sometimes teach us that the rate at which a process occurs can be affected by a number of factors, as when we learn that the rate at which water boils is affected by the pressure or that the rate at which mutations occur varies with X-ray irradiation, what we sometimes discover is that a process is impervious to outside influence.
Precious little affects the time of passage for a light ray between two points. Similarly, nuclear physics tells us that radioactive decay is well insulated against external interference. The reason is that the emission of particles from an atomic nucleus is under the control of forces that are enormously more effective at short distances than the forces at work in most physicochemical reactions.
Extensive attempts to modify these rates under a variety of physicochemical conditions have produced no effects. For example, his chief weapon in arguing for the possibility of variable decay rates is a vague proposal that the capture of free neutrons or the impact of neutrinos could affect decay constants Morris a, The latter idea is linked to a paragraph quoted from a "Scientific Speculation" column.
But neither of these processes would affect rates of decay; even granting the possibility of change by neutrino impact or the practical likelihood of neutron capture, the result of these processes would be a modification not of the decay rate, but of the decaying nucleus. The old nucleus, which had been decaying at its specific rate, would be changed to a new nucleus, which would then change at its specific rate.
Note that if processes like these were to occur, they would be detectable since two separate sets of daughter elements would be produced. Morris's speculations are based on confusion. Morris then goes on to ignore the methods that geologists employ to ascertain the original amount of daughter element present in the rocks they attempt to date.
Radiometric Dating and Creation Science
His discussion of uranium-lead dating contains no mention of the simple technique for computing the initial abundance of lead that I described above. Needless to say, nothing is said about more sophisticated methods. His treatment of potassium argon dating includes the statement: However, argon is an inert gas, which does not become chemically bound to potassium minerals.
Moreover, the crystalline structure of some minerals makes them impermeable to argon. Hence the suggestion that the minerals that geologists date are easily contaminated is simply false.
My brief discussion has only looked at a sample of the objections that Morris and his colleagues notably Slusher; see Slusher offer against radiometric dating.
The errors I have identified are typical. No attempt is made to criticize the techniques that geologists carefully employ to determine the value of D0 or to test whether the system has been contaminated.
Instead, those techniques are ignored. The picture thus presented is that radiometric dating methods compute the ages of rocks by applying equation 4assuming dogmatically that D0 is zero and that the system is uncontaminated. Add to this distortion some vague speculations about changing decay rates perhaps based on a revisionist nuclear physics under development at the Institute for Creation Research? I shall deal with the positive arguments for a young earth in much less detail.