Concerning isotope effects during snow evaporation, you may find an article entitled 'Mediciones de O-18 y H-2 en penitentes de nieve' by H. Pena, Direccion General de Aguas, Santiago de Chile (O-18 and H-2 measurements in snow 'penitentes': the penitentes are special snow ablation features of Andes in Northern Chile). The article was included in the IAEA-TECDOC no. 502 entitled 'Isotope Hydrolgoy investigations in Latin America' published by IAEA in 1989. This TECDOC can be obtained free of charge (if copies are still available) from the International Atomic Energy Agency, POBox 100, A-1400 Vienna, Austria. Fax +43-1-20607. In addition, I assume that the work of Moser and Stichler on isotope effects during snow evaporation is known (see for instance the Handbook of Environmental Geochemistry, vol. 1 (1980), Fritz and Fontes Editors, Elsevier). Roberto Gonfiantini At 10.25 07/04/98 +0100, you wrote: >Dear listmembers, > >We are working on water chemistry of closed-basins in the Andean cordillera >of Northern Chile. Precipitations occur mainly as snow. Our concern is >about isotopic composition of infiltrating melt-water. The snow cover >evaporates during the day. Under an arid climate, does the condensation >during the night offset evaporation enrichment of 18O and 2H which occurs >during the day? Does anyone know studies already done in such environments >? >Many thanks for you help. > >Francois Risacher >Centre de Géochimie de la Surface-CNRS. >Strasbourg. France > Istituto di Geocronologia e Geochimica Isotopica del CNR Via Cardinale Maffi 36 I-56127 Pisa Italy Phone +39-50-560110 - Fax +39-50-830127 E-mail [log in to unmask]