10/12/2023 0 Comments C 14 datingAdditional evidence of this nature has been presented in the Creation Research Society Quarterly (Brown 1975b). Evidence is given there which strongly suggests that in the more remote ancient times the initial C-14 concentration was much lower than has been the case over the past three or four thousand years. Work that has been done to determine the initial C-14 concentration in the past and make possible a conversion of radiocarbon age into real-time age has been reviewed in Origins, Volume 2, Number 1 (Brown 1975a). The initial C-14 concentration must be assumed on a speculative basis, unless calibration by a reliable independent dating technique is available.Ĭonversion of Radiocarbon Age into Corresponding Real Time There are no theoretical considerations or experimental data that suggest there has been a significant variation in the decay rate (half-life) (Brown 1974). Under this restriction a radiocarbon age will be directly equivalent to a real-time age if the C-14 concentration in the specimen was initially at the contemporary reference level, and if C-14 radioactive decay has not varied from its present rate. Another way of stating the same restriction is to say that there has been no chemical contamination, that the specimen has been chemically isolated. In practice radiocarbon laboratories are reluctant to specify a radiocarbon age greater than 40,000 due to uncertainties with respect to contamination from younger C-14.Ī radiocarbon age can have meaning in terms of real time only over time periods during which there has been no introduction of C-14 into the specimen and no loss of C-14 other than by spontaneous radioactive decay. "Infinite age" is commonly assigned to a specimen that has a C-14 concentration below the detection threshold of the procedures by which it was analyzed. Techniques under development for directly counting C-14 atoms by means of nuclear accelerators hold promise of extending this range to the vicinity of 70,000 years (Bennett 1979). Accordingly, the maximum age range of radiocarbon dating by conventional disintegration rate techniques is said to be approximately 55,000 years. To reach a concentration this low by radioactive decay from the contemporary reference level would require in the order of 55,000 years at the rate C-14 now spontaneously converts to nitrogen-14 (N-14). The better-equipped radiocarbon dating laboratories using the conventional gas or scintillation counting technique are capable of detecting concentrations of C-14 as low as 1.4×10 -15 (one atom of C-14 per 700 thousand billion C-12 atoms). The idealized contemporary environment reference level is 1.18×10 -12 C-14 atom per C-12 atom (one C-14 for 848 billion C-12 atoms), which is equivalent to an average of 13.6 disintegrations of C-14 per minute per gram of carbon. Radiocarbon age is a convenient and useful way to express the concentration of C-14 in natural organic and sedimentary material. The radiocarbon "date" or age for a specimen is a statement of the length of time that would be required for a specimen from an idealized contemporary environment to lose by spontaneous radioactive transformation sufficient carbon-14 (C-14) to have the same C-14 concentration as found in the test specimen. An increase of more than two orders of magnitude in this biosphere could make C-14 dates appear 51,000 years too old. The author suggests that the most significant change in the relationship of C-14 dates to real time could come from a dilution of the C-14 by a significantly larger biosphere in the past. Higher upper atmosphere water vapor content in the past would produce little effect, since a model based on our present knowledge of molecular relation- ships would allow for only limited changes. The influence of changes in the magnetic field of the sun on cosmic rays produces a negligible effect. Changes in the geomagnetic field which diverts cosmic rays might make C-14 dates appear as much as 11,000 years too old. Variation in the intensity of cosmic rays which produce C-14 is not considered by the author to be a significant source of discrepancy, since evidence indicates that in the past there has not been a significant change in the cosmic ray intensity. Also, a variety of models for the past history of the earth that might affect the accuracy of radiocarbon ages is evaluated. The author points out the difference between real time and radiocarbon age determinations which have to be adjusted to agree with Bristlecone Pine chronology or biblical chronology. This article discusses the basic principles and assumptions of radiocarbon age dating. #C 14 dating pdf#Download PDF JanuTHE INTERPRETATION OF C-14 DATES by
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