Quantitative combined multiscale structural and minero-chemical analysis to unravel the tectono-metamorphic evolution of cordieritemigmatite gneiss from the Valpelline Unit (Dent-Blanche Nappe, Western Italian Alps, Valle d’Aosta)
Articolo
Data di Pubblicazione:
2023
Citazione:
Quantitative combined multiscale structural and minero-chemical analysis to unravel the tectono-metamorphic evolution of cordieritemigmatite gneiss from the Valpelline Unit (Dent-Blanche Nappe, Western Italian Alps, Valle d’Aosta) / F. Caso. - In: RENDICONTI ONLINE DELLA SOCIETÀ GEOLOGICA ITALIANA. - ISSN 2035-8008. - 60:(2023 Apr 18), pp. 2-10. [10.3301/ROL.2023.20]
Abstract:
Among the Valpelline Unit migmatites, the cordierite-bearing ones represent
the most fascinating type, but little is known about their P-T evolution. Since
the complete understanding of these rocks results from the interplay of
petrological and multiscale structural investigations, a multidisciplinary
approach that combines quantitative microstructural and minero-chemical data,
discriminating different generations of superimposed foliations and stages
is provided. Two main deformational stages have been defined at the mesoand
microscale: the first (D1) is a solid-state deformation developing a foliation
(S1) preserved as isoclinal folds; the second (D2) is related to the development
of the main foliation (S2), associated with cordierite and garnet growth, and
melt production. The regional S2 wraps cordierite, garnet and melt aggregates.
Temperatures for the cordierite-growing stage, obtained by combining biotite
calibrated maps and Ti-in-biotite thermometer, range between ~700 and 780 °C.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
high-temperature metamorphism; mineral grain
orientations; X-ray chemical mapping; cordierite; migmatite
Elenco autori:
F. Caso
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