Fluid and Solid Inclusions in Host Minerals of Permian Pegmatites from Koralpe (Austria): Deciphering the Permian Fluid Evolution during Pegmatite Formation

Fluid inclusions (FIs) and associated solids in host minerals garnet, tourmaline, spodumene, quartz from six pegmatite fields of Permian origin at Koralpe (Eastern Alps) have been investigated. Although pegmatites suffered intense Eoalpine high-pressure metamorphic overprint during the Cretaceous period, studied samples originate rock sections with well-preserved magmatic textures. Magmatic low-saline aqueous FIs garnet domains entrapped as part an unmixed fluid together primary N2-bearing that a rock-derived CO2-N2 dominated high-grade fluid. This is quartz. During mineral crystallization, mixing between solvus formed CO2-N2-H2O–rich various compositional degrees are preserved pseudo-secondary quartz, spodumene. Intense modification processes by in-situ mineral–fluid reactions high amount crystal-rich spodumene but also garnet. The distribution different types enables chronology growth (garnet-tourmaline/quartz-spodumene) their chemistry considered having exsolved parent melt rocks. Minimum conditions for crystallization ca. 4.5–5.5 kbar 650–750 °C constrained tourmaline that, unlike to not affected post-entrapment modifications. Late high-saline FIs, only recrystallized matrix, related post-pegmatite stage metamorphism.