Albert, in addition to the other references and advice given by the
isogeochem group you may also want to look at two other very useful
references:

Kita et al. (1985) Oxygen isotope fractionation between amorphous silica
and water at 34-93oC, Nature, 314, 83-84
Kita and Taguchi (1986) Oxygen isotopic behaviour of precipitating silica
from geothermal water, Geochemical Journal, 20, 153-157.

Good Luck
Kevin


Department of Geochemistry
Geological Survey of Japan
1-1-3 Higashi, Tsukuba 305
Japan
Fax: +81-298-54-3566 or 54-3533

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>Hi everybody,
>Does anybody know if some oxygen isotope
>studies on abiogenic (specially precious) opal exist ?
>I am aware of many studies on diagenesis of biogenic opal
>(cherts,...), but very few on non-biogenic opal (most of them
>from oceanic environments-silica chimneys, etc-,
>but none from continental environments).
>Thanks in advance for some informations.
>Cheers
>Albert Gilg
>-----------------------------
>H. Albert Gilg
>Lehrstuhl fuer Angewandte
>Mineralogie und Geochemie
>Technische Universitaet Muenchen
>Lichtenbergstr. 4
>D-85747 GARCHING - Germany
>Tel.:++49/89/3209-3196
>Fax.:++49/89/3209-3205
>e-mail: [log in to unmask]