The Sklené garnet peridotite: petrology, geochemistry, and structure of a mantle-derived boudin in Moldanubian granulite.
Abstract
The Moldanubian Sklené garnet peridotite, which preserves mineralogical, geochemical, and structural evidence for a protracted mantle evolution, is a small boudin (1 m) enclosed by granulite of the Gföhl Assemblage. The peridotite has a porphyroclastic texture, in which large garnet and smaller olivine and pyroxene porphyroclasts reside in a fine-grained, recrystallized matrix of olivine, pyroxene, and pargasitic amphibole).
By comparison with other Moldanubian garnet peridotites in the Czech Republic, the Sklené peridotite likely represents a fragment of subcontinental lithospheric mantle. It experienced early partial fusion and depletion of incompatible elements at moderate pressure in the spinel stability field, followed by transport to high-pressure conditions.
Subsequently, the depleted peridotite was metasomatized by transient, primitive basaltic melts, with the addition of Rb, Th, U, Pb, and Sr.