Author:
MANZOTTI PAOLA,ZUCALI MICHELE
Abstract
AbstractThe 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 ≈ 4 kbar and T < 450°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.
Publisher
Cambridge University Press (CUP)
Reference76 articles.
1. Synmagmatic deformation in the underplated igneous complex of the Ivrea-Verbano zone
2. Contributo alla conoscenza del ricoprimento della Dent Blanche;Diehl;Memorie degli Istituti di Geologia e Mineralogia dell'Università di Padova,1952
3. Permo-Triassic pegmatites in the eo-Alpine eclogite-facies Koralpe complex, Austria: age and magma source constraints from mineral chemical, Rb-Sr and Sm-Nd isotope data;Thoni;Schweizerische Mineralogische und Petrographische Mitteilungen,2000
4. Granulites and related rocks in variscan median Europe: A dualistic interpretation
Cited by
31 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献