Sexmobi cmo - Cal bp radiocarbon dating
Radiocarbon dating: radioactive carbon decays to nitrogen with a half-life of 5730 years.In dead material, the decayed 14C is not replaced and its concentration in the object decreases slowly.Archaeologists use the remains of the past to help solve the puzzles of history.
Site numbers in the United States are based on the "Smithsonian Trinomial System" where each State has its own number (e.g., WA=45), the County within the state has a two letter abbreviation (e.g., Crook County = CR), and sites within the county are given numbers consecutively as they are found and recorded (i.e., 45xxnnn).
So, a site labelled as "45CR121" would be the 121st site recorded in Crook County, Washington.
To obtain a truly absolute chronology, corrections must be made, provided by measurements on samples of know age.
The most suitable types of sample for radiocarbon dating are charcoal and well-preserved wood, although leather, cloth, paper, peat, shell and bone can also be used.
Carbon-14 dates usually appear to be reasonably accurate whenever they can be checked against historical records.