The pre-Alpine tectonic history of the Austroalpine continental basement in the Valpelline unit (Western Italian Alps)
Articolo
Data di Pubblicazione:
2013
Citazione:
The pre-Alpine tectonic history of the Austroalpine continental basement in the Valpelline unit (Western Italian Alps) / P. Manzotti, M. Zucali. - In: GEOLOGICAL MAGAZINE. - ISSN 0016-7568. - 150:1(2013), pp. 153-172. [10.1017/S0016756812000441]
Abstract:
The Valpelline unit is a large slice of continental crust constituting
the Austroalpine Dent Blanche nappe (NW Italy). The pre-Alpine evolution
of this unit holds important clues about the Palaeozoic crustal
structure at the northern margin of the Adria continent, about the
history of rifting in the Alpine region, and thus about the
thermomechanical conditions that preceded the Alpine convergent
evolution. Several stages of the deformation history and of partial
re-equilibration were identified, combining meso-and micro-structural
analyses with thermobarometry. Reconstructed pre-Alpine P-T-t-d paths
demonstrate that the Valpelline unit experienced an early stage at
pressures between 4.5 and 6.5 kbar followed by migmatite formation. A
subsequent stage reached amphibolite to granulite facies conditions.
This stage was associated with the development of the most penetrative
fabrics affecting all of the Valpelline lithotypes. The pre-Alpine
evolution ended with a weak deformation associated with a local
mineral-chemical re-equilibration under greenschist facies conditions at
approximate to 4 kbar and T < 450 degrees C. A Permo-Mesozoic
lithospheric extension is thought to be responsible for asthenosphere
upwelling, thereby causing high temperature metamorphism at medium
pressure and widespread partial melting, which led to upper crustal
magmatic activity.
Tipologia IRIS:
01 - Articolo su periodico
Elenco autori:
P. Manzotti, M. Zucali
Link alla scheda completa: