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Amino acids in modern and fossil woodsThe amino acid composition and the extent of racemization in several modern and fossil woods are reported. The method of analysis is described, and data are presented on the total amino acid concentration, the amino acid ratios, and the enantiomeric ratios in each sample. It is found that the amino acid concentration per gram of dry wood decreases with age of the sample, that the extent of racemization increases with increasing age, and that the amounts of aspartic acid, threonine, and serine decrease relative to valine with increasing age. The relative racemization rates of amino acids in wood, bone, and aqueous solution are compared, and it is shown that racemization in wood is much slower than in bone or aqueous solution. Racemization results for woods from the Kalambo Falls area of Zambia are used to calculate a minimum age of 110,000 years for the transition between the Sangoan and Acheulian industries at that site. This result is shown to be consistent with numerous radiometric dates for older Acheulian sites in Africa and to compare well with geologically inferred dates for the beginning of the Eemian and the end of the Acheulian industry in southern Africa.
Document ID
Document Type
Reprint (Version printed in journal)
External Source(s)
Lee, C.
(California Univ. La Jolla, CA, United States)
Bada, J. L.
(California, University La Jolla, Calif., United States)
Peterson, E.
(NASA Ames Research Center Planetary Biology Div., Moffett Field, Calif., United States)
Date Acquired
August 8, 2013
Publication Date
January 22, 1976
Publication Information
Publication: Nature
Volume: 259
Subject Category
Space Biology
Accession Number
Distribution Limits

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