Syndeformational Uplift of Variscan High-pressure Rocks (Col de Bérard, Aiguilles Rouges Massif, Western Alps)

Ophiolites of the Alpine belt derive from the closure of the Mesozoic Tethys Ocean that was interposed between the palaeo-Europe and palaeo-Adria continental plates. The Alpine orogeny has intensely reworked the oceanic rocks into metaophiolites with various metamorphic imprints. In the Western Alps, metaophiolites and continental-derived units are distributed within two paired bands: An inner band where Alpine subduction-related high-pressure (HP) metamorphism is preserved, and an outer band where blueschist to greenschist facies recrystallisation due to the decompression path prevails. The metaophiolites of the inner band are hugely important not just because they provide records of the prograde tectonic and metamorphic evolution of the Western Alps, but also because they retain the signature of the intra-oceanic tectono-sedimentary evolution. Lithostratigraphic and petrographic criteria applied to metasediments associated with HP metaophiolites reveal the occurrence of distinct tectono-stratigraphic successions including quartzites with marbles, chaotic rock units, and layered calc schists. These successions, although sliced, deformed, and superposed in complex ways during the orogenic stage, preserve remnants of their primary depositional setting constraining the pre-orogenic evolution of the Jurassic Tethys Ocean.

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Kinematics and dynamics of tectonic nappes: 2-D numerical modelling and implications for high and ultra-high pressure tectonism in the Western Alps

Tectonophysics ◽

10.1016/j.tecto.2014.05.018 ◽

2014 ◽

Vol 631 ◽

pp. 160-175 ◽

Cited By ~ 29

Author(s):

Stefan M. Schmalholz ◽

Thibault Duretz ◽

Filippo L. Schenker ◽

Yuri Y. Podladchikov

Keyword(s):

High Pressure ◽

Numerical Modelling ◽

Western Alps ◽

Kinematics And Dynamics ◽

Ultra High Pressure

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The Pormenaz monzonite (Aiguilles-Rouges massif, western Alps): an additional evidence for a 330 Ma-old magnesio-potassic magmatic suite in the Variscan Alps

Journal of the Virtual Explorer ◽

10.3809/jvirtex.2004.00097 ◽

2004 ◽

Vol 16 ◽

Author(s):

François Bussy

Keyword(s):

Western Alps ◽

Aiguilles Rouges Massif ◽

Magmatic Suite

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Chromian jadeite, phengite, pumpellyite, and lawsonite in a high–pressure metamorphosed gabbro from the French Alps

Mineralogical Magazine ◽

10.1180/minmag.1980.043.332.04 ◽

1980 ◽

Vol 43 (332) ◽

pp. 979-984 ◽

Cited By ~ 23

Author(s):

C. Mevel ◽

J. R. Kienast

Keyword(s):

High Pressure ◽

Low Temperature ◽

Western Alps ◽

Alpine Orogeny ◽

French Alps ◽

Cr Substitution

SummarySmall ophiolitic bodies are enclosed in the calcschists of the Piemont zone (western Alps). They have been metamorphosed in the blueschist facies during the alpine orogeny. One of them, the Roche Noire massif, includes gabbro breccias. The magmatic mineralogy of the gabbro was plagioclase + clinopyroxene + minor chromite. There was no chemical homogenization during metamorphism because of the lack of penetrative deformation and on the site of previous chromites, chromium-rich high-pressure and low-temperature minerals (jadeite, phengite, pumpellyite, and lawsonite) were formed. The Al ⇌ Cr substitution does not affect other P- and T-dependent substitutions.

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