Radiocarbon date reports have been scanned in multi-page PDF files.
History / Biographical
Crepeele locale Radiocarbon Dates. C14 report by Beta Analytic Inc. for Crepeele site XUs 8, 30, 50.
From 2003 to 2008 field work took place at the Crepeele locale with 75 - 1m x1m units excavated.
To help establish the cultural sequence at the locale Radiocarbon dates were obtained from the three sites in the Crepeele locale.
Radiocarbon dating
The technique of radiocarbon dating was developed by Willard Libby and his colleagues at the University of Chicago in 1949.
Radiocarbon dating is used to estimate the age of organic remains from archaeological sites. Organic matter has a radioactive form of carbon (C14) that begins to decay upon death. C14 decays at a steady, known rate of a half life of 5,730 years. The technique is useful for material up to 50,000 years. Fluctuations of C14 in the atmosphere can affect results so dates are calibrated against dendrochronology. Radiocarbon dates are calibrated to calendar years.
Dates are reported in radiocarbon years or Before Present. Before Present refers to dates before 1950. The introduction of massive amounts of C14, due to atomic bomb and surface testing of atomic weapons, has widely increased the standard deviation on all dates after A.D. 1700 causing these dates to be unreliable.
Accelerated mass spectrometry can more accurately measure C14 with smaller samples and can date materials to 80,000 years.
Scope and Content
Sub sub series contains radiocarbon dates from: Crepeele, Sarah and Graham sites.
Field journal crew member Andrea Richards of excavation methods, items recovered, features, local environment and weather. Pages 27-33 relate to excavation unit 9 at the Graham 2004 site.
