Nature 252, 379 - 381 (29 November 1974); doi:10.1038/252379a0

Reliability of amino acid racemisation dating and palaeotemperature analysis on bones (Reply)

BADA

Scripps Institution of Oceanography, and Institute of Marine Resources, University of California, San Diego, La Jolla, California 92037

DR BADA REPLIES—Bender's review of my work is both inaccurate and incomplete. He has not cited two of my publications dealing with aspartic acid racemisation dating^1,2. (Although one paper was only recently published, I sent Bender a preprint the first of this year when he informed me he was writing a review.) In those articles I show that after 'calibrating' the amino acid racemisation reactions using a radiocarbon dated bone, it is then possible to date other bones from the same site, which are either too old or too small for radiocarbon dating. The only assumption in this approach is that the average temperature experienced by the calibration sample is representative of the average temperature experienced by the other sample. Ages thus deduced are in good agreement with radiocarbon ages determined on the same samples².

References

1.	Bada, J. L., and Protsch, R., Proc. natn. Acad. Aci. U.S.A., 70, 1331 (1973).
2.	Bada, J. L., et al., ibid., 71, 914 (1974).
3.	Bada, J. L., Earth planet. Sci. Lett., 15, 223 (1972).
4.	Bada, J. L., Kvenvolden, K. A., and Peterson, E., Nature, 245, 308 (1973).
5.	Bada, J. L., and Schroeder, R. A., Naturwissshaften (in the press).
6.	Manning, J. M., and Moore, S., J. biol. Chem., 243, 5591 (1968).
7.	Schroeder, R. A., thesis, Univ. California (1974).
8.	Green, C. R., and Sellers, W. D., Arizona Climate, 493 (University of Arizona Press, Tucson, 1964).
9.	Schroeder, R. A., and Bada, J. L., Science, 182, 479 (1973).
10.	Bada, J. L., Schroeder, R. A., and Carter, G. F., Science, 184, 791 (1974).
11.	Kvenvolden, K. A., and Peterson, E., Geol. Soc. Am. Abstr., 5, 704 (1973).
12.	Turekian, K. K., and Bada, J. L., in Calibration of Hominoid Evolution (edit. by Bishop, W. W. and Miller, J. A.), 171–185 (Scottish Academic Press, Edinburgh, 1972).
13.	Olson, E. A., thesis, Columbia Univ. (1963).
14.	Shackleton, N. J., and Opdyke, N. D., Quaternary Res., 3, 39 (1973).