Prosa-Granit

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Representation and status

Index
gamma-Pr
Color CMYK
(0%,41%,59%,10%)
Color RGB
R: 230 G: 135 B: 95
Rank
lithostratigraphic Formation
Validity
Unit is in Use
Status
informal term

Nomenclature

Deutsch
Prosa-Granit
Français
Granite du Monte Prosa
Italiano
Granito del Monte Prosa
English
Prosa Granite
Origin of the Name

Monte Prosa (TI), östlich des Gotthardpasses

Historical Variants

Granit vom Fusse des Monte Prosa = Prosagranit (Grubenmann 1890), Monte Prosa-Granit = Prosa-Granit (Rutsch et al. 1966), Prosa granite (Mercolli et al. 1994), Prosa Granite (Berger et al. 2017)

Description

Description

engadinitgranitischem Chemismus

Hierarchy and sequence

Superordinate unit

Age

Age at top
  • Early Permian
Age at base
  • Early Permian

Palaenography and tectonic

Tectonic unit (resp. main category)
Kind of protolith
  • plutonic
Metamorphism
monocyclic

References

Definition
Grubenmann U. (1890) : Zur Kenntnis der Gotthard-Granite. Mitteilungen der Thurgauischen Naturforschenden Gesellschaft 9, 204-216

R. Müller und E. Niggli in: Rutsch et al. 1966: PROSA-GRANIT (= Granit vom Fusse des Monte Prosa = Monte Prosa-Granit) (Jungpaläozoikum oder Tertiär ; Gotthardmassiv)

U. Grubenmann (1890) in: Zur Kenntnis der Gotthardgranite. Verh. thurgauische natf. Ges., 9: 213.

Kleiner Granitstock des zentralen Gotthardmassivs, von Grubenmann vom Fusse des Monte Prosa (687.600/157.400, LK 265, 1,6 km ostnordöstlich der St. Gotthard-Passhöhe) beschrieben. Der z.T. verzahnte Kontakt mit dem Fibbia-Granitgneis ist scharf, der Prosa-Granit ist jünger als letzterer. Heller, granatführender Biotitgranit von engadinitgranitischem Chemismus. Von U. Grubenmann zum Tremola-Granit i.w.S. gerechnet. Sehr ähnlich dem Rotondo-Granit. Nach R. A. Sonder (1921) spätpaläozoische Intrusion; es gilt aber hinsichtlich des Alters für den Prosa-Granit heute das gleiche wie für den Rotondo-granit (>>>).

Literatur: U. Grubenmann (1890), R. A. Sonder (1921: 331, 341).
Definition
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.73: At map scale, the Rotondo Granite, representing the largest granitic body of this group with an exposed surface of ~25 km2, has a pronounced, rounded shape, with sharp discordant contacts to the surrounding gneisses of the polycyclic metamorphic basement. Its microstructure is massive and essentially undeformed; locally garnet occurs. Due to this, it was suggested that the intrusion could be of Alpine age (HAFNER 1958). The other small granite bodies intrude along the boundaries of the two larger and slightly older Fibbia Granite and Gamsboden Granite. The close spatial link between the granites of the Pesciora Group and those of the Val Lavaz Group underline an almost continuous intrusive activity as suggested by the age relationship.
SERGEEV et al.(1995) obtained an U/Pb age on zircon of 294± 1,1 Ma for the Rotondo Granite and the Tremola Granite (Fig. 4). SERGEEV & STEIGER (1995) suggested an age interval of 5,5 Ma for the intrusion of the Rotondo, Winterhorn, Cacciola, Prosa and Tremola Granites with an average age of 294,5+3,5/–2 Ma. OBERLI et al.(1981) obtained an age of 292±11 Ma for the Cacciola Granite, and BOSSART et al.(1986) an age of 293+4/–5 Ma for the Sädelhorn Diorite, both in agreement with the ages of the granitic members of the group. This time interval corresponds well with Early Permian (Sakmarian, 295– 290 Ma).
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