Carbon 14 dating procedure
From the wikipedia article I referenced, it looks like there are some (smaller) geographic variations too.
Adult teeth are formed at known intervals during childhood.The method is known as bomb pulse dating and owes its efficacy to the large amount of $^$C that entered the atmosphere as a result of the testing of nuclear weapons.The $^$C atmospheric abundance peaked in the early to mid-1960s at around twice the longer-term average and has since declined pseudo-exponentially with an e-folding time of around 15 years.There are numerous applications of this technique - from dating human cells and cancerous tumours to figuring out when illegal drugs were harvested.The same phenomenon really precludes using traditional radio-carbon dating over the last 50 years, however, prior to this it appear that the behaviour of atmospheric $^$C was more constant - to a few percent (see below, from Giem 1997, adapted from Stuyver & Becker 1993).Given this, I see no reason why radio-carbon dating cannot be used for material that is 500 years old, since that should result in a $^$C/$^$C ratio change of order 10 percent which is several times larger than the natural variation.
However, if I interpret the plot above correctly, because the natural $^$C abundance was decreasing between 15 (and perhaps before this too?
I understand that the method can provide dating up to ca.
50,000 years into the past, but I'm interested in the other end of the time range: is there a point in time when younger (recent) specimens can no longer be dated with accepted accuracy?
) at about the same rate as the radioactive decay rate, this leads to an ambiguity in the age determination and then there would be a 50 year uncertainty in any radio-carbon age from about that time, even with very precise measurements, but you could reasonably confirm that something was at least 350 years old.
But then you see that beyond about 1700, the trend and magnitude of the change in the natural $^$C almost mimics the radioactive decay curve, so it must be very difficult to age anything younger than this in an unambiguous way.
With carbon-14 dating, what is the most recent date which can be accurately determined, and why?