TY  - JOUR
A1  - Loprieno, Andrea
A1  - Bousquet, Romain
A1  - Bucher, Stefan
A1  - Ceriani, Stefano
A1  - Dalla Torre, Florian H.
A1  - Fügenschuh, Bernhard
A1  - Schmid, Stefan M.
T1  - The valais units in Savoy (France) a key area for understanding the palaeogeography and the tectonic evolution of the Western Alps
JF  - International journal of earth sciences
N2  - The Valais units in Savoy (Zone des BrSches de Tarentaise) have been re-mapped in great detail and are subject of combined stratigraphic, structural and petrological investigations summarized in this contribution. The sediments and rare relics of basement, together with Cretaceous age mafic and ultramafic rocks of the Valais palaeogeographical domain, represent the heavily deformed relics of the former distal European margin (External Valais units) and an ocean-continent transition (Internal Valais unit or Versoyen unit) that formed during rifting. This rifting led to the opening of the Valais ocean, a northern branch of the Alpine Tethys. Post-rift sediments referred to as "Valais trilogy" stratigraphically overlie both External and Internal Valais successions above an angular unconformity formed in Barremian to Aptian times, providing robust evidence for the timing of the opening of the Valais ocean. The Valais units in Savoy are part of a second and more external mid-Eocene high-pressure belt in the Alps that sutured the Brian double dagger onnais microcontinent to Europe. Top-N D1-deformation led to the formation of a nappe stack that emplaced the largely eclogite-facies Internal Valais unit (Versoyen) onto blueschist-facies External Valais units. The latter originally consisted of, from internal to external, the Petit St. Bernard unit, the Roc de l'Enfer unit, the MoA >> tiers unit and the Quermoz unit. Ongoing top-N D2-thrusting and folding substantially modified this nappe stack. Post 35 Ma D3 folding led to relatively minor modifications of the nappe stack within the Valais units but was associated with substantial top-WNW thrusting of the Valais units over the Dauphinois units along the Roselend thrust during W-directed indentation of the Adria block contributing to the formation of the arc of the Western Alps.
KW  - Alpine geology
KW  - Valais ocean
KW  - Palaeogeography
KW  - Structural geology
KW  - Tectonics
KW  - Metamorphism
Y1  - 2011
U6  - https://doi.org/10.1007/s00531-010-0595-1
SN  - 1437-3254
VL  - 100
IS  - 5
SP  - 963
EP  - 992
PB  - Springer
CY  - New York
ER  -