Thursday, July 8, 2010


Carbon 14 dating has recently enabled an international team of researchers to establish an absolute chronology of Dynastic Egypt (approximately 1100-2700 years BC) for the first time. The analysis of short-lived organic samples archeologically attributed to a specific reign or period of Egyptian history, has confirmed previous chronological estimates, but has also called other estimates into question. These results are published in Science of 18 June 2010.

For more than 150 years, explorers and researchers throughout the world have been striving to gain a clearer understanding of one of the most fascinating civilizations: Ancient Egypt. A relative chronology of the kings who succeeded one another to the Egyptian throne has gradually been established through the study of epigraphic, historical or archaeological documents. However, determining an absolute chronology was much more difficult because at the beginning of each new reign, the clock went back to zero. Astrophysical data had already made it possible to envisage some temporal reference points, but such data was not sufficient to date each of the Egyptian dynasties precisely.

In order to determine the absolute chronology of this historical period, research teams in worldwide laboratories, including the Laboratoire de Mesure du Carbone 14 (CEA, CNRS, IRD, IRSN, Ministère de la Culture et de la Communication) collected 211 specimens of Egyptian artifacts from numerous European and American museums. Seeds, baskets, textiles, plants and fruits archaeologically attributed to a specific Egyptian reign or period, were dated using Carbon 14 technology. "The Department of Egyptian Antiquities at the Louvre Museum in Paris supplied us with samples of basket-ware attributed to the reign of Thoutmosis III, one of the most important periods of Ancient Egypt", explains Anita Quiles, Ph.D. student at the Laboratoire de Mesure du Carbone 14. Indeed, some of the dating was performed by using this laboratory's ARTEMIS device, which is the only accelerator mass spectrometer in France.

These analyzes, combined with the known or supposed duration of each reign and their successions, have made it possible to establish the first complete and accurate chronology of ancient Egyptian dynasties.

The chronology thus obtained is in line with most previous findings. However, it requires some historical rectifications. For example, the Old Kingdom appears to be older than the chronological estimates proposed hitherto. The results also suggest that the reign of Djoser during the Old Kingdom started between 2691 and 2625 BC, and that the New Kingdom started between 1570 and 1544 BC. A remarkable source of information for Egyptologists, this chronology will also contribute to a more accurate temporal framework for surrounding civilizations, such as Nubia or the Near East.

Carbon 14 is a radioactive carbon isotope. The radioactive period of 14C, which corresponds to the time after which the number of atoms is halved, is 5730 years. 14C forms in the upper atmosphere, which is bombarded by cosmic radiation. In the environment, an equilibrium is created between the production of 14C and its disappearance through disintegration. The equilibrium value is one radioactive 14C atom per 1,000 billion non-radioactive 12C atoms. This ratio is found in living organisms as a result of photosynthesis in plants and the food chain in animals. When the organism dies, 14C is no longer incorporated in the organism and the quantity of 14C atoms declines as a result of radioactive decay, while that of 12C remains constant. Dating is based on comparing the 14C/12C ratio of a sample with that of a standard sample. It is then possible to deduce the age of the sample, going back about 50,000 years.

(Photo: © Anita Quiles/CEA)

Centre National de la Recherche Scientifique

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