Gneiss oeillé de Randa

Representation and status

Index

GO-R

Color CMYK

(0%,56%,56%,12%)

Color RGB

R: 225 G: 100 B: 100

Rank

lithostratigraphic Formation

Validity

Unit is in Use

Status

informal term

Nomenclature

Deutsch

Randa-Augengneiss

Français

Gneiss oeillé de Randa

Italiano

Gneiss occhiadino di Randa

English

Randa Augengneiss

Origin of the Name

Randa (VS)

Historical Variants

Randagneise = Randa-Augengneise (Jäckli 1950), Orthogneis von Randa, gneiss oeillés de Randa (Bearth 1963, Steck 1984), Gneiss oeillés de Randa = granito-gneiss oeillé de Randa (Sartori & Della Valle 1986), ortogneiss di Randa (Dal Piaz et al. 1992a), Randa orthogneiss = Randa augengneiss (Bussy et al. 1996b), Randa orthogneiss (Genier et al. 2008)

Description

Description

Vorwiegend grobflaserige Augengneise (Augengneis von Randa); homogene, mittelkörnige Gneise; Aplite. Métagranite peralumineux calc-alcalin (Thélin 1987)

Hierarchy and sequence

Superordinate unit

• Formation du Col de Chassoure

Age

Age at top

• Guadalupian (= Middle Permian)

Age at base

• Cisuralian (= Early Permian)

Dating Method

269 ±2 Ma (U/PB zircon: Bussy et al. 1996).

Palaenography and tectonic

Paleogeography

Briançonnais Terrane :

microcontinent briançonnais

Tectonic unit (resp. main category)

• Siviez-Mischabel

Kind of protolith

• plutonic

Metamorphism

monocyclic

Metamorphic facies

• greenschist facies (epizone)

References

Definition

Thélin Philippe (1987) : Nature originelles des gneiss oeillés de Randa (Nappe de Siviez-Mischabel, Valais). Mémoires de la Société Vaudoise des Sciences Naturelles 18/1, 75 pages