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Carbon dating technique

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In this way large domed tombs (known as tholos or beehive tombs) in Greece were thought to predate similar structures in the Scottish Island of Maeshowe.

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In the early years of radiocarbon dating a product’s decay was measured, but this required huge samples (e.g. Many labs now use an Accelerator Mass Spectrometer (AMS), a machine that can detect and measure the presence of different isotopes, to count the individual C atoms in a sample.If 1% of the carbon in a 50,000 year old sample is from a modern contaminant, the sample will be dated to around 40,000 years.Because of this, radiocarbon chemists are continually developing new methods to more effectively clean materials.The total mass of the isotope is indicated by the numerical superscript.While the lighter isotopes C has decayed that what remains can no longer be measured. In 5,730 years half of the C in the atmosphere, and therefore in plants and animals, has not always been constant.This method requires less than 1g of bone, but few countries can afford more than one or two AMSs, which cost more than A$500,000.

Australia has two machines dedicated to radiocarbon analysis, and they are out of reach for much of the developing world.

Professor Willard Libby produced the first radiocarbon dates in 1949 and was later awarded the Nobel Prize for his efforts.

Radiocarbon dating works by comparing the three different isotopes of carbon.

In the 19th and early 20th century incredibly patient and careful archaeologists would link pottery and stone tools in different geographical areas by similarities in shape and patterning.

Then, by using the idea that the styles of objects evolve, becoming increasing elaborate over time, they could place them in order relative to each other - a technique called seriation.

Isotopes of a particular element have the same number of protons in their nucleus, but different numbers of neutrons.