The Radiocarbon Dating Methods
Dating method tools have become quite widely used and accepted in recent years and is important to our study since it professes to supply absolute dates for events within the past 30 or 40 thousand years. This, of course, covers the apparent periods of Biblical history, as well as more recent dates, and so bears directly upon the question of the Flood and other related events.
The method was first developed by W. F. Libby in 1946. Since that time, literally thousands of such measurements have been made, by workers in many different laboratories, and a great variety of archaeological and Recent geological datings have been obtained. The formation of radiocarbon (that is, Carbon 14, the radioactive isotope of ordinary carbon) from cosmic radiation was first discovered, however, by Serge Korff, an authority on cosmic rays. Describing the Carbon 14 dating method which has resulted, Korff says: Cosmic ray neutrons, produced as secondary particles in the atmosphere by the original radiation, are captured by nitrogen nuclei to form the radioactive isotope of carbon, the isotope of mass 14. This isotope has a long half-life, something over 5500 years. By the application of some very well thought-out techniques, Libby and his colleagues have actually not only identified the radiocarbon in nature, but have also made quantitative estimates thereof. Since this carbon in the atmosphere mostly becomes attached to oxygen to form carbon dioxide, and since the carbon dioxide is ingested by plants and animals and is incorporated in their biological structures, and further, since this process stops at the time of the death of the specimen, the percentage of radiocarbon among the normal carbon atoms in its system can be used to establish the date at which the specimen stops metabolizing.
Assumptions in the Method
There is no doubt that this constitutes a very ingenious and powerful dating tool, provided only that the inherent assumptions are valid. Kulp lists the assumptions as follows: There are two basic assumptions in the carbon 14 method. One is that the carbon 14 concentration in the carbon dioxide cycle is constant. The other is that the cosmic ray flux has been essentially constant—at least on a scale of centuries.
To which we might add the assumption of the constancy of the rate of decay of the carbon 14 atoms, the assumption that dead organic matter is not later altered with respect to its carbon content by any biologic or other activity the assumption that the carbon dioxide content of the ocean and atmosphere has been constant with time, the assumption that the huge reservoir of oceanic carbon has not changed in size during the period of applicability of the method, and the assumption that the rate of formation and the rate of decay of radiocarbon atoms have been in equilibrium throughout the period of applicability. Every one of these assumptions is highly questionable in the context of the events of Creation and the Deluge.
But it is maintained that the method has been verified beyond any question by numerous correlations with known dates. Here an observation by Libby himself is interesting and in point:
The first shock Dr. Arnold and I had was that our advisors informed us that history extended back only 5000 years. We had thought initially that we would be able to get samples all along the curve back to 30,000 years, put the points in, and then our work would be finished. You read books and find statements that such and such a society or archaeological site is 20,000 years old. We learned rather abruptly that these numbers, these ancient ages, are not known; in fact, it is at about the time of the first dynasty in Egypt that the last historical date of any real certainty has been established.
It is obvious, therefore, that any genuine correlation of the radiocarbon method with definite historical chronologies is limited only to some time after the Flood and Dispersion. The major assumptions in the method are evidently valid for this period, but this does not prove their validity for more ancient times, the periods in which we would infer that the assumptions are very likely wrong and therefore the datings also wrong.
Attempts to apply the carbon 14 method to earlier datings have, in fact, been called in serious question by geologists for entirely different reasons than our own. Charles B. Hunt, who is recent president of the American Geological Institute, has cautioned: In order that a technique or discipline may be useful in scientific work, its limits must be known and understood, but the limits of usefulness of the radiocarbon age determinations are not yet known or understood. No one seriously proposes that all the determined dates are without error, but we do not know how many of them are in error—25%? 50%? 75%? And we do not know which dates are in error, or by what amounts, or why.
Hunt emphasizes particularly the danger of contamination of the sample by external sources of carbon, especially in damp locations. The sharp reduction in previously estimated dates for the close of the glacial period (a date which had been estimated mainly on the basis of counts of varved clays presumably laid down by the retreating ice sheet) has been a source of much argument among Pleistocene geologists as to the relative merits of the varve method (which gave a date of over 20,000 years) and the radiocarbon method (which gave a date of about 11,000 years). The American specialist in varve chronologies, Dr. Ernst Antevs, has sharply criticized the radiocarbon method, as a result:
In appraising C 14 dates, it is essential always to discriminate between the C 14 age and the actual age of the sample. The laboratory analysis determines only the amount of radioactive carbon present … However, the laboratory analysis does not determine whether the radioactive carbon is all original or is in part secondary, intrusive, or whether the amount has been altered in still other irregular ways besides by natural decay.
A conference on radiocarbon dating held in October, 1956, resulted in the following conclusions about the reliability of the method: Local variation, especially in shells, can be highly significant. Possible variations in the size of the exchange reservoir under glacial climates are unimportant. The most significant problem is that of biological alteration of materials in the soil. This effect grows more serious with greater age. To produce an error of 50 percent in the age of a 10,000 year old specimen would require the replacement of more than 25 percent of the carbon atoms. For a 40,000-year-old sample, the figure is only 5 percent, while an error of 5000 years can be produced by about 1 percent of modern materials. Much more must be done on chemical purification of samples.
The problem of atmospheric contamination by fossil fuels has also come in for some consideration, since the burning of coal and oil during the past century and more has added measurably to the amount of carbon dioxide in the carbon cycle. A recent study on the quantitative aspect of this factor concludes:
… it follows that atmospheric carbon dioxide has probably been diluted to the extent of about 3½ percent with carbon dioxide from the combustion of fossil fuels. The radiocarbon evidence indicates, on the basis of a comparison of the radiocarbon assays of old, historically dated marine shells from the Atlantic coast with the assays of their modern counter-parts, that there has been a perceptible dilution of shallow oceanic carbonates with dead carbon from fossil fuels. The limited data available suggest that the extent of dilution is possibly one to two percent.
This means that the standard figures as to present content of carbon dioxide in the exchange reservoir of carbon, on which radiocarbon age calculations are based, are incorrect with respect to conditions under which older specimens were formed and have since been decaying. Although this might be corrected approximately by modifying the standard to one before the Industrial Revolution, the following caution is also in order: Since completion of the present list, a careful study has been made of a series of samples of known age. It was found that the activity of radiocarbon in the atmosphere was going up and down even before the Industrial Revolution.
This particular correction, however, is only of the order of a few hundred years for most computed dates, so apparently is negligible for the purposes of our studies. Much more important are the effects of the aforementioned assumptions in the method, when viewed in the light of the probable events occurring during and immediately after the Flood.
The Genesis Flood
The Biblical Record and its Scientific Implications
by John C. Whitcomb and Henry M. Morris