Munt-Dado-Granit

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Darstellung und Status

Index
gamma-MD
Farbe CMYK
(0%,51%,49%,16%)
Farbe RGB
R: 215 G: 105 B: 110
Rang
lithostratigraphische Formation
Gebrauch
Element ist in Gebrauch
Status
informeller Begriff

Nomenklatur

Deutsch
Munt-Dado-Granit
Français
Granite du Munt Dado
Italiano
Granito del Munt Dado
English
Munt Dado Granite
Herkunft des Namens

Munt Dado (GR), nördlich von Trun

Historische Varianten

Munt Dado Granite (Berger et al. 2017)

Alter

Alter Top
  • Middle Pennsylvanian
Alter Basis
  • Middle Pennsylvanian
Datierungsmethode

Ca. 308.8 Ma (Schaltegger, unpubl.)

Geografie

Geographische Verbreitung
Südöstlische Rand des Aar-Massivs im Gebiet des Val Russein.

Referenzen

Erstdefinition
Berger Alfons, Mercolli Ivan, Herwegh Marco, Gnos Edwin (2017) : Geological Map of the Aar Massif, Tavetsch and Gotthard Nappes. Geological Special Map 1:100'000, Explanatory Notes 129

p.40: Bodies of hornblende granite, porphyric granite and diorite of different dimensions have been mapped by WEHRLI (1896) and WEBER (1922) in the region of the Val Russein at the southeastern border of the Aar Massif. On the present map these different granitic bodies and the diorite were grouped into units called Munt Dado Granite and Russein Diorite, respectively. Both magmas intruded the Gärsthorn and Sogn Placi Gneiss Complexes of the Ausserberg-Avat Zone and the Late Carboniferous metasedimentary and volcaniclastic rocks of the Val Lumpegna Formation. Petrographic details on some of these bodies can be found in WEHRLI (1896). WEHRLI (1896) describes two types of diorite: (1) massive amphibole diorites and (2) foliated diorites. Towards the west, the diorites grade into greenschist (WEHRLI 1896, NIEDERER 1932, NIGGLI 1944). Despite this tectonic overprinting, it is possible to distinguish these intrusive rocks from the granitic gneisses and amphibolites of the polycyclic metamorphic basement of the Ausserberg-Avat Zone (Gärsthorn Gneiss Complex). A more complex zone of mafic rocks, forming layers of different thickness, occurs within the gneisses of the Ausserberg-Avat Zone north of Sedrun. This zone is characterised by a heterogeneous mingling of gabbroic, dioritic, granodioritic and syenitic rocks (HUBER 1948). These dioritic rocks are macroscopically slightly different from the Russein diorites of WEHRLI (1896); an affinity of these enclaves to the Curtin Monzodiorite (Rötifirn Group) cannot be excluded. However, on the present map sheet these enclaves were not depicted. In absence of robust dating of the Munt Dado Granite and the Russein Diorite, and based on the petrographic affinity with the Düssi Diorite, both 
units were assigned to the Fruttstock Group.
The question arises if the Bugnei Granodiorite, formerly related by NIGGLI (1944) to the dioritic occurrences of the Val Russein, also belongs to the Fruttstock Group. This body with probable age similar to the plutonic rocks of the Fruttstock Group was strongly affected by intense deformation along the southeastern border of the Aar Massif (Clavaniev Zone, see p. 59 f.) at the contact with the Tavetsch and KELLER (1999), the Bugnei Granodiorite was assigned to the Clavaniev Zone.

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