La blastesi a feldspato nella Zona Dora-Maira, in Valle Angrogna (Alpi Cozie)

Diamanti, Antonella ; Garino, Laura

Atti della Accademia nazionale dei Lincei. Rendiconti della Classe di scienze fisiche, matematiche e naturali, Série 8, Tome 83 (1989) no. 1, pp. 225-231

Résumé

The study area is situated in the Cottian Alps (Western Alps, Piedmont, Italy), in the Angrogna Valley and in the inner-central side of the Dora-Maira Zone (fig. 1). The process leading to the feldspar blastic rocks was followed with special attention, in the different lithologies (fig. 2), finding out its main phases: from the thin albitic rim which sometimes surrounds the white mica (tav. I, fig. 1), up to the complete invasion of the preexisting structure of the rock (tav. I, fig. 2; tav. II, fig. 1). In the true plagioclaseblastites the bulk of the relic minerals sometimes still preserving the original schistosity, is completely soaked into a plagioclase uniform groundmass (tav. II, fig. 2).