IAEA-C-5

IAEA-C5 Two Creeks Wood was obtained by R.M. Kalin, S.W. Leawitt, A. Long and the IAEA from sub fossil wood (Picea sp.) originating from buried bed forest in eastern Wisconsin, USA, near the western shore of Lake Michigan. Before preparing this sample, many ¹⁴C laboratories have dated Two Creeks wood for about 40 years. It is believed that all individual trees preserved at that location grew within a time range of less than 500 years, with individual ages of logs at that site between 110 and 250 years based on ring counts. For this sample, 100 kg (wet) of wood specimens were taken from a single locality, selected for best preservation. In order to minimize microbiological activity after sampling, it was immediately air-dried for 30 days in a low humidity environment. Large pieces (20-50 cm) were sent to IAEA for pulverization and homogenizing. At the IAEA, the pieces were milled on a laboratory ice mill to chips (ca 5 cm long) and thoroughly mixed. Final milling and homogenization took place in a high-pressure steam mill. The recommended value of the reference material is the result of the statistical evaluation of an interlaboratory comparison [1, 2]. For carbon stable isotope delta values, please refer to Rozanski et al., 1992 [2]. Further details can be found on the Reference Sheet. 

Recommended value for C-14 activity

References:

1. 1. ROZANSKI, K., Consultants' group meeting on 14C reference materials for radiocarbon laboratories. February 18-20, 1991, Vienna, Austria. Internal Report, IAEA, Vienna (1991).

   2. ROZANSKI, K., STICHLER, W., GONFIANTINI, R., SCOTT, E. M., BEUKENS, R. P., KROMER, B., VAN DER PLICHT, J., The IAEA ¹⁴C Intercomparison exercise 1990, Radiocarbon, 34 3 (1992) 506-519.