Southeast Archeological Center a
  • 3D Rendering of Shiloh Mound

    Southeast Archeological Center

    Cultural Resources National Park Service


Calibration of Radiocarbon Dates


Due to varying amounts of Carbon-14 uptake in the upper atmosphere during the end of the Pleistocene and throughout the Holocene, radiocarbon years do not match up with actual years before present. To figure out how the two are related, scientists study accumulations of biological or sedimentological materials that increase on a yearly basis, such as tree rings and lake sediments. Specific rings or sediment layers can then be Carbon-14 dated to see how far off the two are. As with all new technologies, there are discrepencies between various methods, but for the purposes of this web site, these differences are negligible. Radiocarbon years are referred to as rcbp (radiocarbon years before present) and "actual", or calibrated, years are referred to as B.P. (before present).