Fluorine analysis

Fluoride ions may be relatively abundant in groundwater at one location and practically absent in that at another site hence the rate of fluoridation of the bone (the rate of increase in the relative amount of fluorine in the bone) varies from site to site. For instance, bones buried for a short time at a site in which the groundwater is rich in fluoride may acquire much more fluorine than bones buried for a very long time at a place where there is little fluoride in the groundwater. Therefore, fluorine analysis does not provide a tool for estimating the absolute age of buried bone, but only for dating bones at the same site, comparative to each other. The relative amount of fluoride in buried bone at a particular site thus provides a clue as to the length of time the bone has been buried. 

In the first half of the twentieth century much bone was dated using this method, and dates derived with it greatly contributed, for example, to unfolding the nature of the Piltdown bones (see Chapter 18). Experience has shown that bones buried in sand or gravel are suitable for dating with fluorine, while those buried in volcanic soils rarely yield useful dates dates derived from fluorine analysis results should, therefore, be used with caution (Schurr 1989 Oakley and Hoskins 1950). 

Reiche, I., Yignaud, C., Favre-Quattropani, L., and Menu, M. (2002b). Fluorine analysis in biogenic and geological apatite by analytical transmission electron microscopy and nuclear reaction analysis. Journal of Trace and Microprobe Techniques 20 211-231. 

Of the many destructive analytical techniques, only the most widely used methods, especially those based on the personal experience of the author during the past 28 years will be discussed fully More background information on the various techniques for fluorine analysis can be found in the literature [/, 2, 3, 4, J],... 

Fluorine Analysis by Ion Beam Techniques for Dating Applications... 

The technical aspects of fluorine detection by nuclear reactions as well as its applications to fluorine analysis in geological and archaeological objects are reviewed. Special attention is given to the determination of exposure ages of meteorites on the Antarctic ice shield and burial durations of archaeological bones and teeth. This information can be acquired by evaluation of the shape and penetration depth of the diffusion profile of fluorine that was incorporated by the sample from the environment. For a quantitative assessment of the data, several factors like ambient conditions and diagenetic state of the material have to be taken into account. 

M. Dobeli, A. Gaschen, U. Krahenbuhl, Fluorine analysis by ion beam techniques for dating applications, in A. Tressaud, (Ed.), Advances in Fluorine Science Fluorine and the Environment, Elsevier, Amsterdam, 2006. 

Fluorine Analysis by Ion Beam Techniques for Dating Applications 215 M. Dobeli, A.A.-M. Gaschen and U. Krahenbuhl... 

Fluorite, a mineral of calcium, is a compound of the metal with fluorine. Analysis shows that a 2.76-g sample of fluorite contains 1.42 g of calcium. Calculate the (a) mass of fluorine in the sample (b) mass fractions of calcium and fluorine in fluorite (c) mass percents of calcium and fluorine in fluorite. 

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