Richard,

You might want to look into a recent compilation of references/standards
isotopic values and general isotopic isotopic ranges of specific terrestrial
materials:

Coplen et al. (2002):
Compilation of minimum and maximum isotope ratios of selected elements in
naturally occuring terrestrial materials and reagents.
Water-Resources Investigations Report 01-4222 by US Dept. of the Interior/US
Geol. Surv.: 98 pp.

Of course, you can have a look into the somewhat older handbook by Jochen
Hoefs (1997)Stable isotope geochemistry. Springer: 201 pp (4th edition),
giving a good overview of isotopic ranges of different materials on Earth
too.

I hope this is helpful to you,
Pier.

************************************************************************Dr.
Pier A. de Groot
European Commission
Joint Research Centre
Institute for Reference Materials and Measurements (IRMM)
Retieseweg
2440 Geel
Belgium
Tel. +32 (0)14 571 628
Fax +32 (0)14 571 863
e-mail: [log in to unmask]

Visit my WEB-site about my “Handbook of Stable Isotope Analytical
 Techniques” at:
http://users.pandora.be/handbook/index.html
last update: 9 June, 2002.
************************************************************************



************************************************************************Dr.
Pier A. de Groot
European Commission
Joint Research Centre
Institute for Reference Materials and Measurements (IRMM)
Retieseweg
2440 Geel
Belgium
Tel. +32 (0)14 571 628
Fax +32 (0)14 571 863
e-mail: [log in to unmask]

Visit my WEB-site about my “Handbook of Stable Isotope Analytical
 Techniques” at:
http://users.pandora.be/handbook/index.html
last update: 9 June, 2002.
************************************************************************