Atom used in radiocarbon dating validating text box in vb
3.5 decays/gram/minute of carbon would be produced by a sample 11,460 years old.
However, atmospheric testing of nuclear weapons in the late 1950's and early 1960's greatly increased the amount of radiocarbon in the atmosphere, so the decay rate of 14 decays per minute more than doubled.
Before the industrial revolution, from 1800 - 1400 AD, the natural production of radiocarbon was high, so dates are "too young." From 1400 AD to 300 BC they are "too old," and prior to 300 BC , they are too young.
Therefore, radiocarbon dates are calculated to a "pre-bomb" age of 1950 A. Material which died after 1950 has such high amounts of radiocarbon its age is reported as "percent modern (1950)" (example 180% modern).
This bomb radiocarbon has been gradually removed from the atmosphere by by natural processes, but the "bomb spike" can be shown through the dating by means such as comparing the bottle date and radiocarbon age of wines.
Since the carbon in these fuels was ancient, it contained no radiocarbon.
Therefore, prior to atmospheric bomb testing, the proportion of radiocarbon to C was relatively low, giving relatively old ages.
When a living thing dies, it stops taking in carbon-14, and the carbon-14 decays into nitrogen-14 at a steady rate. It decays with Beta Minus (B-) decay with a half-live of about 5700 years.