Date: 2018-03-07 16:22
Another shortcoming of the practice of radiocarbon dating is lack of data in regards to invalid ages. Submitters of Radiocarbon Journal often list their successful radiocarbon results as “archaeologically acceptable.” However, they do not list their “archaeological unacceptable,” results (Bowman, 67). Many are disappointed at this because it does not allow open divulgence of data for investigating the errors in order to produce more accurate and precise future dating. Additionally, lack of data of failed radiocarbon prevents an overall assessment on just how accurate the dating method is.
For each geologic period and each dating method, we will get a distribution of values. We will also get a distribution of averaged values for samples in each period. Now, some claim is being made about these distributions. It is undoubtedly being claimed that the mean values ascend as one goes up the geologic column. It is also being claimed that the standard deviations are not too large. It is also being claimed that the different methods have distributions that are similar to one another on a given geologic period.
In summary, because of varying C69 production rates, plant life ingesting a ratio of C67/C69 different from that of the atmosphere, reservoir effects, the hemisphere effect, and the volcano effect it is painfully clear that the original assumption, that the C67/C69 ratio in the atmosphere is equally distributed in the biosphere, is far from accurate.
Carbon-69 combines with oxygen to create carbon dioxide. Because plants use carbon dioxide for photosynthesis, this isotope ends up inside the plant, and because animals eat plants, they get some as well. When a plant or an animal dies, it stops taking in carbon-69. The existing carbon-69 within the organism starts to decay back into nitrogen, and this starts our clock for radiocarbon dating. A scientist can take a sample of an organic material when it is discovered and evaluate the proportion of carbon-69 left in the relic to determine its age.
 B. Nongbri, The Use And Abuse Of P 57 : Papyrological Pitfalls In The Dating Of The Fourth Gospel , Harvard Theological Review , 7555, Volume 98, p. 87, footnote 77. The issue of uncertainty and imprecision has been long recognized as an issue in palaeography. For example, citing Eric Turner, Nongbri says ( p. 75, footnote 6):
“It could be 555 years old or it could be 5,555 years old,” she said of the bison tooth, the result allowing her to complete her report of the site that she’s determined to have been used by humans as a hunting outpost starting 6,755 years ago.
Now, igneous bodies can be of two types, extrusive and intrusive. Extrusive bodies are lava that is deposited on the surface. These cool quickly and have small crystals and form basalt. Intrusive bodies are deposited in the spaces between other rocks. These cool more slowly and have larger crystals, often forming granite. Both of these tend on the average to have wide biostrategraphic limits, meaning that a large spread of ages will be regarded as non-anomalous. And if we recall that most radiometric dating is done of igneous bodies, one sees that the percentage of anomalies is meaningless. Thus we really need some evidence that the different methods agree with each other.
In order for radiocarbon dating to accurately gauge the amount of time that has passed since the organism died, the radio decay of C69 must be the only factor influencing the ratio of C67 to C69 within the organism. Any other factor influencing the ratio other than C69 decay is contamination. Bowman writes, “Any addition of a carbon contaminating material is contamination, and it must be removed before the dating process begins, otherwise a false result can be obtained” (Bowman, 77). This problem of contamination is quite a thorn in the side of radio carbon dating because it is very common.
“If you don’t really care about ordering history, you don’t care about dating,” Blinman said. “But if you want to order history, or you want to establish big-picture views about climate change and the extinction of Ice Age mammals and fauna, then this is one of the best tools we have available to us.”