Aquamarine from the Masino-Bregaglia Massif, Central Alps, Italy

2009 ◽  
Vol 45 (3) ◽  
pp. 204-207 ◽  
Author(s):  
Rosangela Bocchio ◽  
Ilaria Adamo ◽  
Franca Caucia
Keyword(s):  
Central Alps ◽  
Massif Central

scholarly journals Microstructures, mineral chemistry and geochronology of white micas along a retrograde evolution: An example from the Aar massif (Central Alps, Switzerland)

2017 ◽  
Vol 721 ◽  
pp. 179-195 ◽  
Author(s):  
Alfons Berger ◽  
Philip Wehrens ◽  
Pierre Lanari ◽  
Horst Zwingmann ◽  
Marco Herwegh
Keyword(s):  
Mineral Chemistry ◽  
Central Alps ◽  
Massif Central ◽  
Aar Massif

Mesoscopic faults in the Bregaglia (Bergell) massif, Central Alps

1991 ◽  
Vol 198 (1) ◽  
pp. 53-72 ◽  
Author(s):  
P. Passerini ◽  
G. Sguazzoni ◽  
M. Marcucci
Keyword(s):  
Central Alps ◽  
Massif Central

scholarly journals Deformation along the roof of a fossil subduction interface in the transition zone below seismogenic coupling: The Austroalpine case and new insights from the Malenco Massif (Central Alps)

Geosphere ◽  
2020 ◽  
Vol 16 (2) ◽  
pp. 510-532
Author(s):  
Paraskevi Io Ioannidi ◽  
Samuel Angiboust ◽  
Onno Oncken ◽  
Philippe Agard ◽  
Johannes Glodny ◽  
...  
Keyword(s):  
Transition Zone ◽  
Shear Zones ◽  
White Mica ◽  
Seismogenic Zone ◽  
Central Alps ◽  
Massif Central ◽  
Brittle Ductile Transition ◽  
Wide Range ◽  
Deformation Processes ◽  
Transition Field

Abstract A network of fossil subduction plate interfaces preserved in the Central Alps (Val Malenco, N Italy) is herein used as a proxy to study deformation processes related to subduction and subsequent underplating of continental slices (in particular the Margna and Sella nappes) at depths reported to in the former brittle-ductile transition. Field observations, microfabrics, and mapping revealed a network of shear zones comprising mostly mylonites and schists but also rare foliated cataclasites. These shear zones are either located at the contacts of the two nappes or within the boundaries of the Sella unit. Microprobe results point to two different white mica generations, with higher-pressure (Si-rich) phengites rimming lower-pressure (Si-poor) phengites. Garnet is locally observed overgrowing resorbed pre-Alpine cores. Pressure-temperature estimates based on pseudosection modeling point to peak burial deformation conditions of ∼0.9 GPa and 350–400 °C, at ∼30 km depth. Rb/Sr geochronology on marbles deformed during the Alpine event yields an age of 48.9 ± 0.9 Ma, whereas due to incomplete recrystallization, a wide range of both Rb/Sr and 40Ar/39Ar apparent ages is obtained from deformed orthogneisses and micaschists embracing 87–44 Ma. Based on our pressure-temperature, structural and geochronological observations, the studied shear zones last equilibrated at depths downdip of the seismogenic zone in an active subduction zone setting. We integrate these new results in the frame of previous studies on other segments of the same Alpine paleosubduction interface, and we propose that this system of shear zones represents deformation conditions along the subduction interface(s) in the transition zone below the seismogenic zone during active subduction.

New U-Pb zircon data and constraints on the age and mode of migmatization in the Aar massif, Central Alps

2000 ◽  
Vol 12 (6) ◽  
pp. 1245-1260 ◽  
Author(s):  
Sakiko N. Olsen ◽  
Clark M. Johnson ◽  
Brian L. Beard ◽  
Lukas P. Baumgartner
Keyword(s):  
Central Alps ◽  
Massif Central ◽  
Aar Massif
Sign in / Sign up

Export Citation Format

Share Document