Micha,

an extrapolation of the high temperature data of Sheppard to
temperatures below 100C leads for oxygen isotopes of course to very
high fractionation factors. A combination of the extrapolated Katz &
Matthews  data from 1977 with the new Kim & ONeil 1997 data gives
reliable results. But remember also Land 1980.

Good luck
Michael
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Dr. Michael E. Boettcher
Biogeochemistry
Max Planck Institute for Marine Microbiology
Celsiusstr.1
D-28359 Bremen
e-mail: [log in to unmask]
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