Fluid inclusions in granulites: peak vs. retrograde formation

Abstract

Various lines of evidence may indicate that CO2-rich fluid inclusions in granulites contain samples of the peak metamorphic fluid. The evidence for peak metamorphic formation of granulite facies fluid inclusions is often ambiguous. In some samples collected from the Adirondack Mountains, equilibrium mineral assemblages require that the peak metamorphic fluids (if any existed) were CO2-poor. These same samples contain high density CO2-rich fluid inclusions. Investigation of these inclusions has shown that the retrograde pressure temperature path in the Adirondacks was initially more nearly isobaric than isothermal. -from Author