Dear Hilmar,

high deuterium (and oxygen-18) values should be expected, and in fact have 
been found, in water evaporating in a arid environment. JCh Fontes and 
myself have published values of two evaporating ponds in Sahara and found 
values up to +129 per mil (coupled with +31.3 per mil in oxygen-18):

J-Ch Fontes and R. Gonfiantini, 1967: Comportment isotopique au cours de 
l'évaporation de deux bassins Sahariens (in French: Isotopic behaviour of 
two evaporating ponds in Sahara), EPSL vol. 3, pag. 258-266 and 386 
(corrected equations).

The relative humidity was in the order of 30 %. However, I assume however 
that even higher values can be found, depending on the air relative 
humidity and the evaporation stage.

The enrichment is much less in Saharian lakes with steady level (fixed by 
the water table of the surrounding groundwater which feeds the lakes): we 
have measured enrichments up to +20 per mil in deuterium and +15 per mil in 
O-18. In these casee, however, also the effect due to salt concentration 
plays a role. The paper is:

D.J. Burdon and R. Gonfiantini, 1991: Lakes in the Awbari Sand sea of 
Fazzan, Libya. In: The Geology of Libya (MJ Salem and MN Belaid, Editors), 
vol. 5, pag. 2027-2041. Elsevier.

Roberto Gonfiantini


At 17.06 11/11/2005 +0100, Prof. Dr. Hilmar Förstel wrote:

>   Dear colleagues,
>we are looking for high D/H ratios above 0 permil, preverently much more 
>above this level.
>We expect such values mainly from plant water enrichment in leaves or 
>better in fruits as lemons.
>Or has someone measured high emricments in other natural waters as ponds 
>or shrinking lakes.
>Someone some record to report ?
>Hilmar Förstel Jülich Germany
>
>
>
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Prof. Roberto Gonfiantini
Istituto di Geoscienze e Georisorse
Institute of Geosciences and Georesources
Area della Ricerca del CNR
Via G. Moruzzi, 1
I-56124 Pisa
Italy
Phone +39-050-315-2358
e-mail [log in to unmask] 


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