Mark and Libby,
In the report by Coplen et al. (2002)[see reference below] Ca isotope
reference materials are also discussed. As reported by Coplen et al. (2002):
-The Berkeley Center for Isotope Geochemistry (Berkeley, California) reports
d44Ca values reelative to a high purity calcium carbonate laboratory
reference material (Skulan et al., 1997)
-Scripps Institution of Oceanography (San Diego, California) reports d44Ca
valuesrelative to sea water (Zhu and Macdougall, 1998)
-The University of Oxford expresses d44Ca values relative to NBS915a calcium
carbonate (Halicz et al, 1999)
-Russell et al. (1978) reported 40Ca/44Ca isotope ratio measurements
relative to reagent calcium fluoride
Somme more is given on absolute measurement of NBS915 and its replacement
NBS915a in the Coplen et al. (2002) report.
For the report, look at: http://pubs.water.usgs.gov/wri014222
Reference:
Coplen T. B., Hopple J. A., Böhlke J. K., Peiser H. S., Rieder S. E., Krouse
H. R., Rosman K. J. R., Ding T., Vocke R. D. J., Révész K. M., Lamberty A.,
Taylor P. D. P., and De Bièvre P. (2002) Compilation of minimum and maximum
isotope ratios of selected elements in naturally occurring terrestrial
materials and reagents. U.S. Department of the Interior - U.S. Geological
Survey, Reston, Virginia. Water-Resources Investigations Report 01-4222: 98
p.
My two pennies,
Pier.
**********************************************************************
Dr. Pier A. de Groot
Pastoor Moorkensstraat 16
2400 Mol - Achterbos
Belgium
Tel. +32 (0)14 326 205
e-mail: [log in to unmask]
Visit my WEB-site about my ³Handbook of Stable Isotope Analytical
Techniques² at:
http://users.pandora.be/handbook/index.html
last update: 6 October, 2003.
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