Abstract
Fluid inclusions in cassiterite and beryl were studied in greisen veins in a Proterozoic rapakivi granite stock in Eurajoki parish, southwestern Finland. In the greisen proper, formed by metasomatic alteration of granite, the cassiterite has primary fluid inclusions with filling temperatures and salinities generally increasing from the inner zones toward the margins of the crystals (filling temperatures from 260 degrees to 390 degrees C, salinities from 3 to 17 equiv. wt percent NaCl). In the central quartz-beryl veinlets, formed by open space filling, the beryl shows primary fluid inclusions with filling temperatures of 360 degrees to 480 degrees C and salinities of 11 to 17 equiv. wt percent NaCl. The secondary inclusions in beryl show filling temperatures of 360 degrees to 410 degrees C and salinities of 2 to 10 equiv. wt percent NaCl.
