Sädelhorn-Diorit

Rappresentazione e statuto

Index

delta-S

Colore CMYK

(0%,41%,59%,10%)

Colore RGB

R: 230 G: 135 B: 95

Rango

Formazione litostratigrafica

Uso

Unità in uso.

Status

termine informale

Nomenclatura

Deutsch

Sädelhorn-Diorit

Français

Diorite du Sädelhorn

Italiano

Diorite del Sädelhorn

English

Sädelhorn Diorite

Origine del nome

Sädelhorns (VS)

Varianti storiche

grobkörnige porphyrartige Granite am Sädelhorn (Schmidt & Preiswerk 1908), Sädelhorndiorit (Eichenberger 1924), Sedelhorn-Diorit (Oberholzer 1955), Sädelhorn-Diorit = Sedelhorn-Diorit (Rutsch et al. 1966), Sedelhorn diorite (Mercolli et al. 1994), Sädelhorn Diorite (Berger et al. 2017)

Gerarchia e successione

Unità di rango superiore

• Spät- bis postvariszische Intrusiva

Età

Geomorfologia

• Primo Permiano

Età alla base

• Primo Permiano

Metodo di datazione

293 +/-4 Ma (Bossart et al. 1986)

Geografia

Estensione geografica

Westliches Gotthardmassiv, zwischen dem Merezenbachtal und dem Blinnental, in der Ostwand des Sedelhorns und am Stockji.

Paleogeografia e tettonica

Termini generici

• Gotthard

Tipo di origine

• plutonica

Metamorfismo

monociclico

Referenze

Definizione

Eichenberger Robert (1926) : Die geologischen Verhältnisse des oberen Saastales Schweizerischer Wasserwirtschaftsverband - Verbandsschrift 14, 14 S.

R. Müller und E. Niggli in: Rutsch et al. 1966: SÄDELHORN-DIORIT (= SEDELHORN-DIORIT) (Jungpaläozoikum ; Gotthardmassiv)

R. Eichenberger (1924) in: Geologisch-petrographische Untersuchungen am Südwestrand des Gotthardmassivs. Eclogae geol. Helv. 18/3: 453 und 457.

Kleines Dioritvorkommen des westlichen Gotthardmassivs, zwischen dem Merezenbachtal und dem Blinnental, in der Ostwand des Sedelhorns und am Stockhorn. Benannt nach dem Sädelhorn (= Sedelhorn der LK 265, 666.200/144.00, ca. 5 km südöstlich Münster und Oberwallis). Massiger Biotitgranit mit hypidiomorpher, leicht sperriger Struktur, von melaquarzdioritischem Chemismus. Durchbricht Orthogneise.

Literatur: R. Eichenberger (1924), W. Oberholzer (1955: 325-327).

Revisione

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).