Éclogite du Lac Cornu
Back to Aig. Rouges MassifRepresentation and status
- Color CMYK
- (49%,0%,37%,31%)
- Color RGB
- R: 90 G: 175 B: 110
- Rank
- lithostratigraphic Formation
- Validity
- Unit is in Use
- Status
- informal term
Nomenclature
- Deutsch
- Lac-Cornu-Eklogit
- Français
- Éclogite du Lac Cornu
- Italiano
- Eclogite del Lac Cornu
- English
- Lac Cornu Eclogite
- Origin of the Name
- Historical Variants
-
éclogites des Aiguilles Rouges (Joukowsky 1902), Lac Cornu retrograded eclogites (Liégeois & Duchesne 1981), --- (Paquette et al. 1989), masse-relique d'éclogites du lac Cornu (Pairis et al. 1992), mafic éclogites of Lac Cornu (Pfeifer & von Raumer 1996), éclogites du lac Cornu (Drouet & Leloup 2015)
Description
- Description
-
14 kbar, min. 700°C (Schulz & von Raumer 1993)
Age
- Age at top
-
- Late Ordovician
- Age at base
-
- Middle Ordovician
- Dating Method
-
453 +3/-2 Ma (Paquette et al. 1989), 458 +/-5 Ma (Bussy et al. 2011), 463 +/-3 Ma (Bussy et al. 2011 ; protolithe éclogite rubannée)
References
- Definition
-
(2001) :
Mont-Blanc, Aiguilles-Rouges massifs (External Massifs) - an example of polyorogenic evolution. Fieldtrip Guide 1, 53-84, Univ. Lausanne
p. 65: (Retro-)eclogitized pyroxenites, lherzolites and N-MORB-type basalts are outcropping in the Lake Cornu area (Aiguilles Rouges). Paquette et al. (1989) interpreted an upper intercept U-Pb zircon age of 453 +2/-3 Ma as a magmatic crystallization age. These rocks were derived from a depleted mantle source (initial ε Nd = +6). They have been originally thought to be emplaced in a thinned continental crust associated with the initial stages of oceanic rifting (Paquette et al., 1989) and more recently to be emplaced in a back-arc setting associated with an active continental margin (Dobmeier et al., 1999). The latter interpretation is supported by the contemporaneous intrusion of several granites of calc-alkaline (Itype) or peraluminous (S-type) character, as expected in an active continental (or island-arc) margin.
- Important Publications
-
(1981) : The Lac Cornu retrograded eclogites (Aiguilles Rouges massif, Western Alps France): evidence of crustal origin and metasomafic alteration. Lithos 14, 35-48