Cristallina-Granodiorit
Back to Val-Lavaz-Gruppe (spätvariszische Intrusiva)Representation and status
- Index
- gammadelta-C
- Color CMYK
- (0%,48%,56%,6%)
- Color RGB
- R: 240 G: 125 B: 105
- Rank
- lithostratigraphic Formation
- Validity
- Unit is in Use
- Status
- informal term
Nomenclature
- Deutsch
- Cristallina-Granodiorit
- Français
- Granodiorite de Cristallina
- Italiano
- Granodiorite di Cristallina
- English
- Cristallina Granodiorite
- Origin of the Name
- Historical Variants
-
Cristallinagneiss = Gneiss de Val Cristallina (Alb. Heim 1883), Cristallinagranit (Heim 1891, Grubenmann 1892, Krige 1917, Winterhalter 1930), Kristallinagranit (Bossard 1929a), Cristallina-Granit (Alb. Heim), Herzynischer Granodiorit vom Typus Cristallina = Cristallinaquarzdiorit (Gansser & Dal Vesco 1964),Cristallina-Granodiorit = Cristallina-Gneis = Kristallina-Granit (Rutsch et al. 1966), Cristallinagranodiorit (Huber 1943, Arnold 1972), Cristallinagranodiorit = Granodiorit vom Typus Cristallina (Huber 1985), Kristallinagranodiorit [sic] (Koenig 1972), Crystallina-granodiorite [sic] (Purdy & Stalder 1973), Cristallina granodiorite (Mercolli et al. 1994)
Description
- Description
-
heller (graublau), mehr oder weniger gleichkörniger, massiger Granodiorit, z.T. verschiefert ; grauer, feinkörniger Biotitgneis
Bianconi & Strasky 2015, p.31: La Granodiorite di Cristallina si differenzia mineralogicamente dal Granito di Medel per l’assenza di fenocristalli di feldspato alcalino, un tenore minore di quarzo e feldspato alcalino e per un tenore più alto in plagioclasio e biotite. La struttura si distingue per una grana più fine e uno sviluppo del feldspato alcalino in origine xenomorfo. La tessitura si differenzia per una tendenza più marcata a uno sviluppo fusolare o laminato (NIGGLI et al. 2008)
Hierarchy and sequence
- Superordinate unit
- Subordinate units
- Stratigraphic discussion
-
A nord del Piz Garviel (foglio 126 Oberalppass) il Granito di Medel estende apofisi nella Granodiorite di Cristallina. HUBER (1943) considera il Granito di Medel come una facies marginale acida della Granodiorite di Cristallina.
Age
- Age at top
-
- Early Permian
- Age at base
-
- Late Carboniferous (= Pennsylvanian)
- Dating Method
-
328-305 Ma (Grünenfelder 1962), 305 +/-25 Ma (Grünenfelder 1963: zirconi).
Geography
- Geographical extent
- Östliches Gotthardmassiv.
Palaenography and tectonic
- Paleogeography
- European continental plate
- Tectonic unit (resp. main category)
- Kind of protolith
-
- plutonic
- Metamorphism
- monocyclic
References
- Definition
-
(2017) :
Geological Map of the Aar Massif, Tavetsch and Gotthard Nappes. Geological Special Map 1:100'000, Explanatory Notes 129
p.72: p.72: The Uffiern Diorite, the Cristallina Granodiorite and the Medel Granite constitute a single coherent plutonic complex towards the eastern end of the Gotthard Nappe. The Medel Granite is coarse-grained and locally porphyric, while the Cristallina Granodiorite is more fine-grained and equigranular. MERZ (1989) described the petrographic and structural characteristic of both units. VÖGELI et al.(2013) described the small occurrence of the Uffiern Diorite. The Medel Granite envelops the northern and the western part of the complex, whereas the Cristallina Granodiorite occupies the centre and the southern part. The roughly north–south oriented western intrusive contact of the Medel Granite perpendicularly crosscuts the steeply east–west oriented structures of the polycyclic metamorphic basement (Ausserbinn-Piz Cavel Zone) as well as the pre- to early Variscan metasedimentary and volcaniclastic sequences of the Val Rondadura Group. This is one of the important observations that allowed the reconstruction of the pre-Alpine evolution of the Gotthard Nappe (see MERCOLLI et al.1994 and references therein).