Dating fission track

Another technique that has been used for dating obsidians, albeit only those that were heated in the past, is the ssion track technique (see Textbox 26) (Fleisher et al. 1975). Fission track dating was used, for example, to date the time when an obsidian knifeblade found at a cave in Elmenteita, in Kenya, was heated (see Fig. 24). Since the shape of the blade was distorted, it was deduced that the blade had been heated to a temperature sufficiently high to partially melt it. 

FIGURE 24 Obsidian knife. A knife made of obsidian in Mesoiithic times and found in Eimenteita, Kenya, which was heated in the distant past. The time of heating (3700 + 900 years ago) was determined by the fission tracks dating method (see Fig. 25). 

Uranium is a heavy element that has a number of isotopes (see Textbox 16). Minerals and rocks as well as human made materials such as ceramics and glass often contain trace amounts of uranium as impurities. The most abundant isotope of this element, uranium-238, is radioactive and most of it decays into thorium-234 by the emission of alpha particles  

Having enlarged and counted the tracks, all that is required to determine the age of a suitable solid by the fission track method is the determination of two values  

The track density, that is, the number of tracks per unit surface area 

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Fleischer, R. L., P B. Price, and R. M. Walker (1965a), Application of Fission Tracks and Fission Track Dating to Anthropology, General Electric Report 65-RI-3876M, pp. 1-12. 

Nishimura, S. (1971), Fission track dating of archaeological materials from Japan,... 

Poupeau, G., L. Bellot-Gurlet, O. Dorighel, T. Calligaro, J. C. Dran, and J. Salomon (1996), Obsidian circulation in Prehispanic times in Colombia and Ecuador A coupled PIXE/fission track dating approach, C. R. Acad. Sci., Series Ha, Sciences de la Terre et des Planetes 323(5), 443-450. 

Wagner, G. A. and P. van den Haute (1992), Fission Track Dating, Kluwer, Boston. 

Westgate, J. A., A. Sandhu, and P. Shane (1997), Fission track dating, in Taylor, R. E. and M. J. Aitken (eds.), Chronometric Dating in Archaeology, Advances in Archaeological and Museum Science Series, Vol. 2, Plenum, New York. 

Arias, C., Bigazzi, G., Bonadonna, F.P., Cipolloni, M., Hadler, J.C., Lattes, C.M.G. and Radi, G. (1986). Fission track dating in archaeology a useful application. In Scientific Methodologies Applied to Works of Art, ed. Parrini, P.L., Montedison Progetto Cultura, Milan, pp. 151-159. 

Bigazzi, G., Ercan, T., Oddone, M., Ozdogan, M. and Yegingil, Z. (1993). Application of fission track dating to archaeometry provenance studies of prehistoric obsidian artifacts. Nuclear Tracks and Radiation Measurements 22 757-762. 

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