Experimental evidence that fluid inclusions do not leak
The possibility of leakage of fluids into or out of fluid inclusions subjected to large pressure gradients has always been considered a serious problem in the interpretation of inclusion data. As previous experimental evidence on leakage was contradictory, new experiments were performed. Inclusion vapor bubble diameters in twelve quartz crystals (≤ 3 mm; 8 localities), not sawn, ground or polished, were measured. The samples were run at Pa-.o,-4,000 bars, at T u 100°-410° C, for ≤ 17 days total, and remeasured after each run. Similar experiments at ≤ 155° C were made on sphalerite and calcite. Most inclusions in most samples (even those only 5am under the surface in quartz) showed no change in bubble diameter, hence no leakage. A few exceptions, mainly among inclusions homogenizing at T « Tru, had P internal » P internal, hence they ruptured and lost liquid during the 410° C run. From this work and a review of the literature, we conclude that most inclusions have not suffered major leakage. Some previous experiments indicating leakage may be explained by microfractures introduced during sample preparation. The present work does not, however, preclude the possibility of diffusion of small but chemically significant amounts of substances such as hydrogen in or out of inclusions.