Retrograde eclogite

3D ModelNoAI

Lithology: The black porphyroblasts of former garnets are replaced by simplectite of amphibole and plagioclase. The omphacite matrix is partially replaced by symplectitic overgrowth of diopside and plagioclase. Light pink garnets fill the fractures and were probably formed or mobilised in the process of retrograde metamorphism.

Origin: Eclogite is formed by regional metamorphism under high to very high P and T. When exposed to lower P-T conditions during uplift towards the surface (exhumation), minerals that are no longer stable begin to react and transform into lower P and lower T equivalents through metamorphic reactions. Schematically, the decomposition of garnet can be described as follows: garnet + omphacite + water = amphibole + plagioclase. Similarly, the decomposition of omphacite can be written as follows: omphacite + quartz = diopside + plagioclase.

Locality: Pohorje, Slovenija

Dimensions: 11 x 7 cm

Inventory No.: 14484

3D model: Marko Vrabec. Description: Mirijam Vrabec