Carbon 14 dating used
Raw (i.e., uncalibrated) radiocarbon ages are usually reported in radiocarbon years "Before Present" (BP), with "present" defined as CE 1950.
Such raw ages can be calibrated to give calendar dates.
Radiocarbon dating (usually referred to simply as carbon-14 dating) is a radiometric dating method.
It uses the naturally occurring radioisotope carbon-14 (14C) to estimate the age of carbon-bearing materials up to about 58,000 to 62,000 years old.
Hence, it is a good way of determining the age of certain archaeological artifacts of biological origin (could be bone, fiber, wood, plant remnants etc.) up to about 50,000 years old.
The Amount of Carbon-14 in today’s atmosphere is not used to as the starting point for Carbon-14 analysis. Atomic testing has doubled the amount of carbon 14 in today’s atmosphere So wood known to be from 1890 is used as the starting point for Carbon14 analysis.After plants die or are consumed by other organisms, the incorporation of all carbon isotopes, including 14C, stops.Thereafter, the concentration (fraction) of 14C declines at a fixed exponential rate due to the radioactive decay of 14C. ) Comparing the remaining 14C fraction of a sample to that expected from atmospheric 14C allows us to estimate the age of the sample.Carbon has two stable, nonradioactive isotopes: carbon-12 (12C) and carbon-13 (13C).There are also trace amounts of the unstable radioisotope carbon-14 (14C) on Earth.