About the job archaeologist radioactive dating
Most archaeologists rely on buried buildings, bodies, ancient hearths, or iron tools, having different physical "signatures" from the surrounding soil.Ground penetrating radar, for example, pumps radio waves into the earth then measures the patterns reflected back.
They were made from a plant that grew along the Nile valley. Still, few can claim the delicacy of Sir Leonard Woolley, who in the 1920s excavated the great Sumerian city of Ur.While digging in the royal cemetery he noticed a small hole just below where a small gold cap and some gold nails had been found. When the soil was cleared away, the shaft of a lyre — preserved as a plaster cast — emerged.Woolley was able to reconstruct the entire instrument, even though its original wood had long since vanished. Before artifacts can be interpreted, they have to be dug up!For hundreds of years after the fall of Rome, hunks of marble were hacked off the map for building material. In 1562, Cardinal Alessandro Farnese made a valiant attempt to collect the surviving sections.Since then every attempt to piece together the 1,163 fragments has failed.Radiocarbon Dating Up until the 1950s archaeological finds were dated mostly by guesswork — and the results could be off by many centuries.
But the discovery of radiocarbon revolutionized archaeology and other sciences as well.
Careful notes are kept of changes in sediment, and of each object (however fragmentary) found within each square.
The idea is to create a 3-D picture of the area — a picture through time.
Plants and animals contain carbon in the same mixture as the atmosphere. By measuring how much — or, rather, how little — C-14 remains, researchers can calculate how much time has elapsed since death occurred. An object may be contaminated by carbon from another source.
Or, it may not "belong" at the level where the carbon-containing material was found. They know where not to dig — where nothing interesting exists. Excavation is expensive, and there is nothing an archaeologist likes less than staring at an empty hole.
"Archaeology is the science of rubbish." -archaeologist Stuart Piggot The Forma Urbis Romae may just be the world's biggest jigsaw-puzzle.