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Archaeology dating accuracy

archaeology dating accuracy-65

In last Tuesday’s lecture, radiocarbon dating was covered briefly.It is an essential technology that is heavily involved in archaeology and should be explored in greater depth.

The basis for stratigraphy seems quite intuitive today, but its applications were no less than earth-shattering to archaeological theory.Radiocarbon dating uses the naturally occurring isotope Carbon-14 to approximate the age of organic materials. Often, archaeologists use graves and plant remains to date sites.Since its conception by Willard Libby in 1949, it has been invaluable to the discipline.In fact, many important archaeological artifacts have been dated using this method including some of the Dead Sea Scrolls and the Shroud of Turin.Though radiocarbon dating is startlingly accurate for the most part, it has a few sizable flaws.The half-life of an isotope like C14 is the time it takes for half of it to decay away: in C14, every 5,730 years, half of it is gone.

So, if you measure the amount of C14 in a dead organism, you can figure out how long ago it stopped exchanging carbon with its atmosphere.

All living things exchange the gas Carbon 14 (C14) with the atmosphere around them—animals and plants exchange Carbon 14 with the atmosphere, fish and corals exchange carbon with dissolved C14 in the water.

Throughout the life of an animal or plant, the amount of C14 is perfectly balanced with that of its surroundings. The C14 in a dead organism slowly decays at a known rate: its "half life".

In other words, artifacts found in the upper layers of a site will have been deposited more recently than those found in the lower layers.

Cross-dating of sites, comparing geologic strata at one site with another location and extrapolating the relative ages in that manner, is still an important dating strategy used today, primarily when sites are far too old for absolute dates to have much meaning.

Radiocarbon dating was invented in the 1950s by the American chemist Willard F.