Stretched (tensile) liquid water is a metastable liquid which persists at negative pressures in the stability field of vapour. The lifetime of metastability is limited. Tensions down to - 1400 bar have been specifically measured in aqueous inclusions inside quartz monocrystals. Vapour nucleation (Tn) marks the end of metastability. The destructive effects related to vapour nucleation in transiently tensile fluids are observed in nature: phreato-magmatic explosions, geysers. Modelling the kinetics of tensile water is critical in order to control the risks associated to metastable liquids. Quartz-hosted synthetic fluid inclusions (FI) with known densities and chemistries have been placed into the metastable tensile field by isochoric cooling and their Tn have been measured. We show that the tensile strength of water in individual FI depends on the FI volume and shape, the method used to synthetize the FI and the fluid chemistry. Experiments on metastability lifetimes have been performed by placing FI at temperatures 0.5° to 10°C above th eir Tn. Eigth FI were chosen that encompass the diversity of FI volumes, shapes, densities, fluid chemistries and tensile strengths. Our results show that tensile water lifetimes are all the shorter as the trapped water is more stretched. An empirical kinetic law is proposed that allows the lifetimes of tensile water in FI to be calculated as a function of the FI volume and Tn. Our data can also be reconciled with the Classical Nucleation Theory. Our data finally show that water in natural porous reservoirs can remain stretched for geologically-relevant timescales. Tensile water can therefore control fluid-rock interactions in the continental crust.
Experimental study of water and aqueous solutions metastables : implications for the natural environment.