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Guns, Germs, and Steel: The Fates of Human SocietiesOne is that radiocarbon dating until the 1980s required relatively large amounts of carbon (a few grams), much more than the amount in small seeds or bones. Hence scientists instead often had to resort to dating material recovered nearby at the same site and believed to be "associated with" the food remains—that is, to have been deposited simultaneously by the people who left the food. A typical choice of "associated" material is charcoal from fires. But archaeological sites are not always neatly sealed time capsules of 96 • GUNS, GERMS,and steel materials all deposited on the same day. Materials deposited at different times can get mixed together, as worms and rodents and other agents churn up the ground. Charcoal residues from a fire can thereby end up close to the remains of a plant or animal that died and was eaten thousands of years earlier or later. Increasingly today, archaeologists are circumventing this problem by a new technique termed accelerator mass spec-trometry, which permits radiocarbon dating of tiny samples and thus lets one directly date a single small seed, small bone, or other food residue ...» | Код для вставки книги в блог HTML
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