Montestrutto glacial terrace, Settimo Vittone, Metropolitan City of Turin, Piedmont, Italyi

Regional Level Types
Montestrutto glacial terrace	Group of Outcrops
Settimo Vittone	Commune
Metropolitan City of Turin	Metropolitan City
Piedmont	Region
Italy	Country

Outcrops of paraschists, layers of leucocratic orthogneiss and metamorphic veins located near a glacial terrace, ca. 500 m east of the village of Montestrutto.

On the glacial terrace, banded lithologies prevail, consisting of eclogite-facies assemblages with garnet, Na-pyroxene (omphacite/jadeite) ± quartz ± glaucophane ± white mica (phengite and/or paragonite) ± zoisite ± carbonate and accessory rutile, apatite, and zircon. The bands reflect a wide range of relative modal proportions and grain sizes. The overall lithology, which includes paraschist with small boudins of garnet omphacitite and glaucophane eclogite, dips gently westward. Isoclinal folding and transposition are responsible for the nearly parallel association of layers of leucocratic orthogneiss with darker paraschists. The leucocratic orthogneiss is similar in chemical composition to that of the Argentera quarry. Within the thickest leucocratic orthogneiss layer, roundish megablasts of jadeite (~ Jd₉₅, ca. 5 cm across) occur, particularly close to the clear-cut contact with the paraschist. These unusual rocks resemble "metaconglomerates" because of the roundish jadeite porphyroblasts standing out on the surface. A few dm-thick layers of a boudinaged jadeite + quartz + phengite rock (possibly eclogite-facies veins) with asymmetric quartz-filled pressure shadows indicate not only the sense of shear but also the amount of the finite strain. Refolded quartz veins with minor phengite, cm-long rutile prisms and local carbonate rhombohedra (several dm thick) are common, especially on the northern side of the terrace.

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