Fluid inclusions in minerals: from geosciences to the physics of water and back

Abstract

Natural mineral samples often contain small volumes of trapped fluid material. They carry information about the history of the host mineral and its environment, and for this reason are used by geoscientists. Physicists and physico-chemists have successfully harnessed water inclusions in quartz to bring liquid water to a metastable state, at a pressure well below its equilibrium pressure with vapor. The pressure can reach negative values as large as -140 MPa, which exceeds by far the limits of other techniques, and approaches the theoretical threshold for spontaneous nucleation of a vapor bubble. This has enabled a deeper understanding of nucleation and of the anomalies of water. In turn, the optical techniques developed to study water’s properties have recently found a new application in the reconstruction of palaeotemperatures in surface processes. I review here some aspects of fluid inclusions, these fascinating objects at the crossroads between disciplines.