Rossa-Orthogneis
Torna a falda del'AdulaRappresentazione e statuto
- Colore CMYK
- (0%,35%,29%,4%)
- Colore RGB
- R: 245 G: 160 B: 175
- Rango
- Formazione litostratigrafica
- Uso
- Unità in uso.
- Status
- termine locale (informale)
Nomenclatura
- Deutsch
- Rossa-Orthogneis
- Français
- Orthogneiss de Rossa
- Italiano
- Ortogneiss di Rossa
- English
- Rossa Orthogneiss
- Origine del nome
-
Rossa (GR)
- Varianti storiche
-
Rossa Orthogneiss (Cavargna-Sani 2013 p.35)
Età
- Geomorfologia
-
- Late Ordovician
- Età alla base
-
- Late Ordovician
- Metodo di datazione
-
459.3 +3.4/-1.7 Ma, 455.7 +2.6/-2.7 Ma (Cavargna-Sani 2013)
Referenze
- Definizione
-
(2013) :
The Adula nappe: stratigraphy, structure and kinematics of an exhumed high-pressure nappe. Thèse de doctorat, Université de Lausanne, 153 p.
p.35: The Rossa Orthogneiss and the Garenstock Augengneiss are considered separately because they are not connected in outcrop. They both have the same Ordovician age (Chapter 3.5). The Rossa Orthogneiss texture is usually fine-grained and does not exhibit the characteristic augengneiss texture typical of the Garenstock gneiss. However, some K-feldspar phenocrysts can be locally observed. Mafic boudins are rarely present, and eclogites were not found. Descriptions of this formation can be found in Frischknecht (in Jenny et al. 1923) and Kündig (1926). Frischknecht proposes a distinction between orthogneisses based on biotite content. However, the biotite content is strongly related to metamorphic grade (Spear 1995) and therefore cannot be used in the formation definition.