This week on Facebook and Twitter we are showcasing a number of photos of profile walls from our excavations, in a section called “Stratigraphy Week!
” I thought this would be a good opportunity to discuss one of the more important elements of archaeological excavation: reading stratigraphy.
The method was developed by Willard Libby in the late 1940s and soon became a standard tool for archaeologists.
Libby received the Nobel Prize in Chemistry for his work in 1960.
Fagg, a man of boundless curiosity and energy, traveled across central Nigeria looking for similar artifacts.
As he recounted later, Fagg discovered local people had been finding terracottas in odd places for yearsburied under a hockey field, perched on a rocky hilltop, protruding from piles of gravel released by power-hoses in tin mining. He later dated the scarecrow headnow called the Jemaa Head after the village where it was foundto about 500 B. using a process called thermoluminescence which gauges the time since baked clay was fired.
There is no way for you to put the bottom layer of pasta on before you put the sauce on, and still maintain the same sequence or location of these different layers.
This works the same way for archaeology, and can be used to determine a sequence of events.He set up shop in a whitewashed cottage that still stands outside the village of Nok and soon gathered nearly 200 terracottas through purchase, persuasion, and his own excavations. Through a combination of luck, legwork, and new dating techniques, Fagg and his collaborators had apparently discovered a hitherto unknown civilization, which he named Nok.Soil analysis from the spots where the artifacts were found dated them to around 500 B. This seemed impossible since the type of complex societies that would have produced such works were not supposed to have existed in West Africa that early. One excavation site, near the village of Taruga, revealed something else Fagg had not expected: iron furnaces.The older a sample is, the less (the period of time after which half of a given sample will have decayed) is about 5,730 years, the oldest dates that can be reliably measured by this process date to around 50,000 years ago, although special preparation methods occasionally permit accurate analysis of older samples.The idea behind radiocarbon dating is straightforward, but years of work were required to develop the technique to the point where accurate dates could be obtained.Overview of Methods Superposition Stratigraphy Dendrochronology Radiocarbon C14 Radiometric Dating Methods Obsidian Hydration Dating Paleomagnetic/Archaeomagnetic Luminescence Dating Methods Amino Acid Racemization Fission-track Dating Ice Cores Varves Pollens Corals Cation Ratio Fluorine Dating Patination Oxidizable Carbon Ratio Electron Spin Resonance Cosmic-ray Exposure Dating This is an excellent overview of dating methodologies, and is a chapter in a textbook on Archaeology.