Abstract
Detailed microstructural and microprobe analyses were carried out on some small garnet idioblasts from phyllonites and two garnet porphyroblasts, respectively from a representative amphibolite and phyllonite rock sample. A consistent sequence of growth stages has been ascertained in this way in the two porphyroblasts, suggesting, combined with the structural reasoning, that their multistage growth is entirely pre-Alpine in both cases. The results discussed in the present paper indicate that, as the amphibolite lithons are related to deformation partitioning on the mesoscale, the persistence of Variscan garnet porphyroblast in the phyllonites is due to deformation partitioning on the microscale.
Riassunto
Alcuni piccoli idioblasti di granato provenienti da filloniti e due porfiroblasti di granato selezionati rispettivamente da due campioni rappresentativi di anfibolite e di fillonite, sono stati sottoposti a dettagliate analisi microstruttura-li e alla microsonda elettronica. In questo modo è stata evidenziata una sequenza di stadi di crescita simile nei due porfiroblasti, il che suggerisce, unitamente a motivi strutturali, che 1a loro crescita multistadiale è interamente pre-Alpina in entrambi i casi. I risultati discussi nel présente lavoro indicano che, come i litoni di anfibolite sono collegati a ripartizione delia deformazione su scala mesoscopica, 1a persistenza di porfiro-blasti di granato Varisici nelle fiiloniti è dovuta a ripartizione della deformazione su scala microscopica.
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Mela seduta deU’ll marzo 1995.
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Butturini, F., Peruzzo, L., Sassi, R. et al. Growth history of two garnet porphy rob lasts of the Cima Dura- Durreck Complex and its implication on the polymetamorphic evolution of this complex (Austrides, Eastern Alps). Rend. Fis. Acc. Lincei 6, 223–238 (1995). https://doi.org/10.1007/BF03001670
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DOI: https://doi.org/10.1007/BF03001670