Dear Peter,
In addition to Pier's references I want to draw your attention on

Barrera and Savin (1987) Effect of sample preparation on the
d18O-value of fine-grained calcite. Chemical Geology v. 66, 301-305.

Cheers,
Albert
-----------------------------
Dr. H. Albert Gilg
Lehrstuhl fuer Angewandte Mineralogie und Geochemie
Technische Universitaet Muenchen
Lichtenbergstr. 4
D-85747 GARCHING - Germany
Tel.:++49/89/289-13196
Fax.:++49/89/289-13205
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