Bone is second only to charcoal as a material chosen for radiocarbon dating. It offers some advantages over charcoal. For example, to demonstrate a secure association between bones and artifacts is often easier than to demonstrate a definite link between charcoal and artifacts. Indeed many studies seek to determine the time of death of an animal, and there is no question concerning association if the sample consists of the animal’s bone(s).

However, bone presents some special challenges, and methods of pre-treatment for bone, antler, horn and tusk samples have undergone profound changes during the past 50 years. Initially most laboratories merely burned whole bones or bone fragments, retaining in the sample both organic and inorganic carbon native to the bone, as well as any carbonaceous contaminants that may have been present. Indeed, it was believed, apparently by analogy with elemental charcoal, that bone was suitable for radiocarbon dating "when heavily charred" (Rainey and Ralph, 1959: 366). Dates on bone produced by such methods are highly suspect. They are most likely to err on the young side, but it is not possible to predict their reliability.

The development of chemical methods to isolate carbon from the organic and inorganic constituents of bone was a major step forward. Berger, Horney, and Libby (1964) published a method of extracting the organic carbon from bone. Many laboratories adopted this method which produced a gelatin presumed to consist mainly of collagen. This method is called "insoluble collagen extraction" in this database. Longin (1971) showed that collagen could be extracted in a soluble form that permitted a greater degree of decontamination of the sample. Many laboratories adopted Longin’s method, called "soluble collagen extraction" in this database.

C.V. Haynes (1968) presented a method of extracting the inorganic carbon from bone. This method was considered suitable for use in areas where collagen is rarely or poorly preserved in bones. Subsequent research cast doubt on the reliability of this method. Hassan and others (1977; Hassan and Ortner, 1977) showed that the inorganic carbon contained in bone apatite is highly susceptible to contamination by either younger or older carbon in the burial environment. It now appears that insoluble collagen extractions usually err on the young side, if at all (Rutherford and Wittenberg, 1979), whereas bone apatite can produce ages either older or younger than the true age, often by a considerable margin.

Ongoing research has continued to refine methods of extracting collagen, especially from small samples destined for AMS dating. For example, D.E. Nelson and his collaborators have experimented with modifications of Longin’s method, including the use of ultra-filtration to isolate components into "two fractions of nominal molecular weights >30 kD and <30 kD (kilo-Daltons)" (Morlan, et al. 1990: 77; Brown, et al. 1988; Nelson, et al. 1986). T.W. Stafford (1990; Stafford, et al. 1987) has extracted amino acids from bones and measured their ages separately. Hedges and Van Klinken (1992) review other recent advances in the pre-treatment of bone.

References concerning dates on bone:

Berger, R., Horney, A.G., and Libby, W.F.
1964 Radiocarbon dating of bone and shell from their organic components. Science 144: 999-1001.

Brown, T.A., Nelson, D.E., Vogel, J.S., and Southon, J.R.
1988.Improved collagen extraction by modified Longin method. Radiocarbon 30(2): 171-177.

Hassan, A.A. and Ortner, D.J.
1977 Inclusions in bone material as a source of error in radiocarbon dating. Archaeometry 19(2): 131-135.

Hassan, A,A, Termine, J.D., and Haynes, C.V., Jr.
1977 Mineralogical studies on bone apatite and their implications for radiocarbon dating. Radiocarbon 19(3): 364-374.

Haynes, C.V., Jr.
1968 Radiocarbon: analysis of inorganic carbon of fossil bone and enamel. Science 161: 687-688.

Hedges, R.E.M. and Van Klinken, G.J.
1992.A review of current approaches in the pretreatment of bone for radiocarbon dating by AMS. Radiocarbon 34(3): 279-291.

Longin, R.
1971 New method of collagen extraction for radiocarbon dating. Nature 230: 241-242.

Morlan, R.E., Nelson, D.E., Brown, T.A., Vogel, J.S., and Southon, J.R.
1990 Accelerator mass spectrometry dates on bones from Old Crow Basin, northern Yukon Territory. Canadian Journal of Archaeology 14: 75-92.

Nelson, D.E., Vogel, J.S., Southon, J.R., and Brown, T.A.
1986 Accelerator radiocarbon dating at Simon Fraser University. Radiocarbon 28(2A): 215-222.

Rainey, F. and Ralph, E.
1959 Radiocarbon dating in the Arctic. American Antiquity 24(4): 365-374.

Rutherford, A.A. and Wittenberg, J.
1979 Evidence in support of soluble collagen extraction for radiocarbon bone dating. Saskatoon: Saskatchewan Research Council Report No. C79-22, 8 pp.

Stafford, T.W., Jr.
1990 Late Pleistocene megafauna extinctions and the Clovis culture: absolute ages based on accelerator 14C dating of skeletal remains. In Megafauna and Man: Discovery of America's Heartland, edited by L.D. Agenbroad, J.I. Mead, and L.W. Nelson. Hot Springs, S.D.: The Mammoth Site of Hot Springs, South Dakota, Inc., Scientific Papers, Volume 1: 118-122.

Stafford, T.W., Jr., Jull, A.J.T., Brendel, K., Duhamel, R.C., and Donahue, D.
1987 Study of bone radiocarbon dating accuracy at the University of Arizona NSF accelerator facility for radioisotope analysis. Radiocarbon 29(1): 24-44.