Carbon dating limit
During the lifetime of an organism, the amount of c14 in the tissues remains at an equilibrium since the loss (through radioactive decay) is balanced by the gain (through uptake via photosynthesis or consumption of organically fixed carbon).
Plants take up c14 along with other carbon isotopes during photosynthesis in the proportions that occur in the atmosphere; animals acquire c14 by eating the plants (or other animals).It is confusing when the maximum date for Carbon 14 is listed as 60,000 years and 80,000 years in the same article (Chapter 4 Dating Methods by Roger Patterson and the reference article summary 4.2 by Riddle.) and as 50,000 years in another (The Answers Book) as well as 95,000 years in the Creation College lecture by Dr. This is why there is the disparity in the quoted limits to radiocarbon dating, as highlighted by this inquirer. This is due to the fact that the AMS instrument has to be calibrated, and yet the organic materials used for calibration (that are supposed to be so old they shouldn't have any detectable radiocarbon left in them) all contain so much radiocarbon that it means samples of unknown age can't yield dates above this radiocarbon barrier.Working with several collaboraters, Libby established the natural occurrence of radiocarbon by detecting its radioactivity in methane from the Baltimore sewer.In contrast, methane made from petroleum products had no measurable radioactivity.