Figure 1
From: Brillouin spectroscopy of fluid inclusions proposed as a paleothermometer for subsurface rocks
Schematic path followed by fluid inclusions (FIs).
Note that the axis are not to scale. (a) Commonly assumed path. A monophasic FI is formed at a temperature Tf and pressure Pf (A). During cooling, the pressure of the liquid is reduced along an isochore (curve AB) and the liquid becomes metastable with respect to the vapour phase (curve BCD). This may lead to nucleation of a vapour bubble (transition from D to E), producing a biphasic FI (E). During heating, the FI follows the bulk liquid-vapour equilibrium (LVE) (curve EFB), the bubble shrinks and eventually disappears at Th = TX (B). This assumption is valid for FIs with low fluid density and large volume. (b) Path modified by surface tension effects. Surface tension and the associated Laplace pressure lead to LVE at pressures below the bulk LVE (path EF)33. Eventually the bubble collapses (transition from F to C) at a temperature Th, bringing back the FI on the isochore (curve ABCD). Surface tension thus causes Th to be strictly less than TX. This effect is relevant for FIs with high fluid density and small volume33. In contrast, warming the monophasic FI along the isochore and finding with Brillouin spectroscopy the crossing point B with the bulk LVE curve gives the correct TX.
