High-grade localized metasomatic alteration of the granitic gneiss surrounding a clinopyroxene-rich pegmatoid dyke: Sondrum stenhuggeriet, Halmstad, SW Sweden
The Sondrum stone quarry (Halmstad, SW Sweden) exposes a transition from migmatized granitic gneissic country rock into a foliated clinopyroxene-free granitic gneiss, and then a central pegmatoid dyke dominated by clinopyroxene megacrysts. This transition zone represents a fracture-controlled, fluid-alteration zone that developed under conditions of 650-700 degrees C and 790MPa. Mineral chemical t