Pesciora-Gruppe (Postvariszische Intrusiva)

Rappresentazione e statuto

Colore CMYK

(0%,40%,57%,8%)

Colore RGB

R: 235 G: 140 B: 100

Rango

Gruppo litostratigrafico

Uso

Unità in uso.

Status

termine informale

Nomenclatura

Deutsch

Pesciora-Gruppe (Postvariszische Intrusiva)

Français

Groupe de Pesciora

Italiano

Gruppo di Pesciora

English

Pesciora Group

Origine del nome

Pizzo Pesciora (VS), Obergoms

Varianti storiche

Jüngere Granite (Spillmann et al. 2011), Pesciora Group (Berger et al. 2017)

Nota sul nome

cf. Passo di Pesciora

Gerarchia e successione

Unità di rango inferiore

• Winterhorn-Granit
• Cacciola-Granit
• Rotondo-Granit
• Prosa-Granit
• Val-Tremola-Granit
• Sädelhorn-Diorit

Età

Geomorfologia

• Sakmarian

Età alla base

• Sakmarian

Paleogeografia e tettonica

• Rocce plutoniche variscane dell'Elvetico

Paleogeografia

placca continentale europea

Termini generici

• Gotthard

Tipo di origine

• plutonica

Referenze

Definizione

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).