Colour Centres in Alkali Silicate Glasses.

The controls of post-entrapment diffusion on the solubility of chalcopyrite daughter crystals in natural quartz-hosted fluid inclusions

“…Roedder, 1984). This is supported by spectrophotometric diffusion tests in the temperature range 400-900°C, which showed that over time hydrogen can migrate through quartz via bulk diffusion (Kats et al, 1962).…”

“…The incomplete dissolution of chalcopyrite in the two relocated moderate salinity inclusions is attributed to the fact that they were at greater depths (25 µm; Table 2) such that insufficient H 2 was able to diffuse back into them during rehydrogenation. Based on previous experimental estimates (Kats et al, 1962;Mavrogenes and Bodnar, 1994) inclusions at these depths would require run times of at least 330 hours to achieve 95% H 2 reequilibration.…”

“…6G). This suggests that the concentrations of H 2 were only sufficient for chalcopyrite dissolution near the sample surface (Kats et al, 1962).…”

“…All inclusions studied were located within 50 μm of the sample surface in order to be within the likely range of hydrogen diffusion during the rehydrogenation experiments (c.f. Kats et al, 1962;Mavrogenes and Bodnar, 1994).…”

“…Run times of 167 to 216 hours (Appendix Table A.1) were chosen to maximise the period in which H 2 could diffuse into the inclusions before the CrN had fully reacted with the water. These run times allowed for >90% re-equilibration of H 2 in fluid inclusions located within 20 µm of the sample surface at temperatures of ~600°C (Kats et al, 1962).…”