BETA ANALYTIC LABORATORY
> One of the basic assumptions in carbon-14 dating
> is that the sample being analyzed has undergone
> only radioactive decay and has remained unaltered
> by any other process over the years since it
> ceased interaction with the biosphere.
> This assumption, however, is rarely true. The
> archaeological artifacts and geological specimens
> sent to labs for radiocarbon dating are usually
> found embedded or buried with other materials that
> may have affected their radiocarbon content. Any
> carbon-containing material that affects the carbon
> 14 content of any given sample is therefore a
> The occurrence of contamination can be natural or
> artificial. Natural contamination pertains to the
> introduction of contaminants to the sample by its
> surrounding material. For example, bone samples
> can be contaminated by the presence of limestone
> or organic acids in the soil (like humic or fulvic
> acids) where the bones were found. Another example
> of a natural contaminant is plant root penetration
> on wood, charcoal, or soil.
> Artificial contamination refers to the
> introduction of contaminants by man during the
> collection, field conservation, or packaging of
> the samples. Labeling of bone samples with animal
> glue is an example of artificial contamination.
> Other contaminants that may be introduced during
> sample collection and packaging are biocides,
> conservation chemicals like polyvinyl acetate and
> polyethylene glycol, cigarette ash, and labels and
> wrappers that are made of paper.
Yeah, that didn't come out right as I was only thinking after pretreatment, sorry. Ironically, it still does not change the point as it applies even more so to samples contaminated in the field. So as it pertains to field collection this would mean that all 400+ samples between 2 studies taken 11yrs apart were contaminated the same way with the same basic amounts of modern carbon to make them all fall within the same contaminated date range that just so happens to be c 4,000-2,000BC which according to your chart below would require 50% modern contamination or more for every single sample to make 18,000BC into 3,000BC.
> It must be plausible because they have charts for
What is implausible Audrey is for this to happen amongst 400+ samples from 2 different studies taken 11yrs apart. For a sample to be 18,000BC or more to get it to c. 3,000BC its modern contamination would need to be 50%. You also quote the pretreatment part where they specifically examine each sample to remove such contaminants to avoid this very contamination. If all these samples were collected with fingers, stowed away in shirt pockets, and the whole sample used as it was found there would be an argument to be made, but obviously this is not how it is done. It is the job and the expertise of the lab to ferret out and test the most pristine section of the sample. You guys are harping on this as if it were only one sample and one test but it was over 400 over 2 different collections and they all say the same thing.
Edited 2 time(s). Last edit at 19-Jun-16 19:55 by Thanos5150.