The record of temperature, wind velocity and air humidity in the dD and d 18 O of water inclusions in synthetic and Messinian halites Thomas Rigaudier a , Christophe Le ´cuyer a,⇑ , Ve ´ronique Gardien a , Jean-Pierre Suc b , Franc ßois Martineau a a Laboratoire de Ge ´ologie de Lyon, Universite ´ Lyon 1, CNRS, UMR 5276, Campus de la Doua, 69622 Villeurbanne, France b Institut des Sciences de la Terre de Paris (UMR 7193 CNRS), Universite ´ Pierre et Marie Curie, 4 Place Jussieu, Case 117, 75252 Paris Cedex 05, France Received 3 September 2010; accepted in revised form 25 May 2011; available online 2 June 2011 Abstract Deuterium and oxygen isotope fractionations between liquid and vapor water were experimentally-determined during evaporation of a NaCl solution (35 g L 1 ) as a function of water temperature and wind velocity. In the case of a null wind velocity, slopes of dD–d 18 O trajectories of residual waters hyperbolically decrease with increasing water temperatures in the range 23–47 °C. For wind velocities ranging from 0.8 to 2.2 m s 1 , slopes of the dD–d 18 O trajectories linearly increase with increasing wind velocity at a given water temperature. These experimental results can be modeled by using Rayleigh distilla- tion equations taking into account wind-related kinetics effects. Deuterium and oxygen isotope compositions of water inclu- sions trapped by the precipitated halite crystals were determined by micro-equilibration techniques. These isotopic compositions accurately reflect those of the surrounding residual waters during halite growth. Isotopic com- positions of water inclusions in twenty natural halites from the Messinian Realmonte mine in Sicily suggest precipitation tem- peratures of 34 þ10 4  C that match the homogenization temperatures obtained by microthermometry (median = 34 ± 5 °C). The similarity between the measured and experimental slopes of the dD–d 18 O evaporation trajectories suggests that the effect of wind was negligible during the genesis of these halite deposits. Hydrogen and oxygen isotope compositions of water inclusions from Realmonte halite also define a linear trend whose extrapolation until intersection with the Mediterranean Meteoric Water Line allows the characterization of the water source with dD and d 18 O values of 70 ± 10& and 11.5 ± 1.5&, respec- tively. These results reveal that the huge amounts of salts deposited in Sicily result from the evaporation of seawater mixed with a dominant fraction (P50%) of meteoric waters most likely deriving from alpine fluvial discharge. Ó 2011 Elsevier Ltd. All rights reserved. 1. INTRODUCTION Superficial water cycle plays a major role in the transfer of heat at Earth’s surface through the genesis, transport and condensation of humid air masses. These physical pro- cesses generate large isotopic fractionations for both water hydrogen and oxygen that are mainly controlled by Ray- leigh distillation and air temperature during condensation and also by relative air humidity and wind velocity during evaporation (Craig and Gordon, 1965). Therefore stable isotope compositions of precipitations are related to air temperature of formation and trajectories of humid air masses (Dansgaard, 1964). In the case of evaporating water, the unsaturated overlying air layer causes out of 0016-7037/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.gca.2011.05.034 ⇑ Corresponding author. Address: Laboratoire UMR CNRS 5125 ‘Pale ´oEnvironnements et Pale ´obioSphe `re’, Universite ´ Lyon 1, Lyon, Campus de la Doua, F-69622 Villeurbanne, France. Tel.: +33 472448376; fax: +33 472431688. E-mail address: clecuyer@univ-lyon1.fr (C. Le ´cuyer). www.elsevier.com/locate/gca Available online at www.sciencedirect.com Geochimica et Cosmochimica Acta 75 (2011) 4637–4652