PETROLOGIC AND FLUID INCLUSION STUDY OF CALC-SILICATE ROCKS, PRINCE RUPERT, BRITISH COLUMBIA.

Abstract

A coordinated petrologic and fluid inclusion study on calc-silicate samples, selected from an area of known metamorphic T and P, shows that the H//2O/CO//2 compositions of the fluid inclusions generally agree with those predicted from the observed mineral assemblages. In the calc-silicates fluid inclusions in matrix quartz grains are aqueous brines with high salinities and a high proportion of CaCl//2. The variations in fluid compositions in inclusions between samples supports the hypothesis that the fluid compositions are internally controlled. Density determinations, however, suggest the inclusions now observed were not formed at peak metamorphic T and P.