Vallone delle Forciolline, Pontechianale, Cuneo Province, Piedmont, Italyi

Regional Level Types
Vallone delle Forciolline	Valley
Pontechianale	Commune
Cuneo Province	Province
Piedmont	Region
Italy	- not defined -

Along all the right side of Vallone delle Forciolline between Cresta Ticino and the Berardo Bivouac, Monviso SW ridge, an inverted ophiolitic stratigraphic sequence is exposed.

The sequence consists of: a basal level (a few tens of metres) of completely serpentinised peridotites; a gabbro complex (maximum thickness about 500 m); and a basaltic cover with pillow structures (about 500 m).

The most interesting portion of the ophiolitic sequence is the gabbro complex which is cut by a swarm of basaltic dykes, local1y so abundant as to suggest a "sheeted dyke complex". Most of the gabbro is massive, but lower part is locally layered displaying an alternation of cumulus troctolites (serpentinised), clinopyroxenites, and mela- to leucogabbros or anorthosites. The entire ophiolitic sequence shows a complicated Alpine metamorphic overprint, in which two main episodes can be recognised: the first is characterised by the widespread occurrence of zoisite and almandine-rich garnet and by incipient development of omphacite and glaucophane; the second is characterised by the development of greenschist-facies mineral assemblages with albite, chlorite, actinolite, epidote.

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References