Soil carbon dating

Campbell, C. A., Paul, E. A., Rennie, D. A., and McCallum, K. J. (1967a). Factors affecting the accuracy of the carbon-dating method in soil humus studies. Soil Sci. 104, 81-85. 

The resistance of soil organic matter to biological decomposition under natural conditions has long been known but probably somewhat underestimated until the advent of C dating. Results obtained recently by this technique show quantitatively the age of soil carbon, and by selection of samples and their fractionation the technique can be used to throw light on the reasons for the stability. 

Campbell (1965) made an extensive study of the carbon-dating method as applied to the study of problems in soil organic matter investigations and found it to be very satisfactory. The mean residence times of humus ftom the Ap-horizon of 5 Saskatchewan soils ranged from 250 years for a gray-wooded podzolic soil to 1000 years for black chernozemic soils the humus from chernozems from Alberta was even older. The calcium humates and non-hydrolyzable humic acids of the chernozems had an age of 1,400 years, whereas the age of the humic acid hydrolysate was only 25 years. This hydrolysate, which was a small fraction of the total humus, accounted for 80% of the nitrogen released per annum the major portion of the soil humus was found to be inert. In general, the humus of podzolic soils was much more labile than that of chernozems. 

However, some caution should be applied to carbon dating soil fractions... 

CAMPBELL C.A., PAUL E.A., RENNIE D.A. and McCALLAM K.J. 1967. Applicability of the carbon-dating method of analysis to soil humus studies. Soil Science, 104, 217-224. 

PAUL E.A., CAMPBELL C.A., REENIE D.A. and McCALLUM K.J. 1964. Investigations of the dynamics of soil humus, utilizing carbon dating techniques. Transactions of the 8th International Congress of Soil Science, Bucharest, 201-208. 

Investigations of the dynai nics of soil ntlizing carbon dating tecliniques. Tr sactions 8th International Congress of Soil Science, 201-208. 

Ku T-L, Bull WE, Frieman ST, Knauss KG (1979) °Th/ " U dating of pedogenic carbonates in gravelly desert soils of Vidal Valley, Southeastern California. Geol Soc Am Bull 90 1063-1073 Ku TH, Krauss KG, Mathieu GG (1977) Uranium in open ocean concentration and isotopic composition. Deep Sea Res 24 1005-1017... 

Frink, D. S. (1995), Application of the oxidizable carbon ratio (OCR) dating procedure and its implications for pedogenic research, in Pedological Perspectives in Archaeological Research, Soil Science Society Special Publication, Vol. 44, Soil Science Society of America, Madison, WI. 

The method should be able to handle the various standards and background samples that are used, such as the modern standard (oxalic acid) and "dead-carbon" (bituminous coal). Organic gases are sometimes submitted for dating, as well as peat, wood, soil, and organic tissue. Carbonates of differing forms make up about half of the samples run. The method should be applicable to these forms of carbon with minimum conversion. The less the sample is handled, the less chance there is of contamination, a major problem in samples of milligram size. 

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