Ahornen-Member

Representation and status

Color CMYK
(0%,8%,51%,4%)
Color RGB
R: 245 G: 225 B: 120
Rank
lithostratigraphic Member (Subformation)
Validity
Unit is in Use
Status
valid formal name

Nomenclature

Deutsch
Ahornen-Member
Français
Membre du Ahornen
Italiano
Membro dell'Ahornen
English
Ahornen Member
Origin of the Name

Ahornenrus (heute Malorrus) (GL)

Historical Variants

Ahornenschichten (Frey 1965), Wildflysch = Ahornen-Schichten (Hantke et al. 2011), Ahornen Member (Menkveld-Gfeller et al. 2016)

Description

Description

Das Ahornen-Member ist charakterisiert durch das Auftreten von grünen, vulkanischen Gesteinsfragmenten im Sandstein. Die Basis des Members besteht häufig aus plattigem Mergelstein, welcher bereits zur Stad-Formation gehört.

Thickness
Meist 6-10 m (Frey 1965).

Components

Lithologic Content

Sandstein enthält grüne, vulkanische Gesteinsfragmente.

Hierarchy and sequence

Upper boundary

Taveyannaz-Formation (tektonischer Kontakt)

Lower boundary

Stad-Formation

Age

Age at top
  • Priabonian
Note about top

?

Age at base
  • Priabonian
Note about base

?

Geography

Geographical extent
Zentral- und Ostschweiz (Reusstal bis Linthtal).
Type locality
  • Ahornenrus = Malorrus (GL)
    Site particularities
    • typische Fazies
    Site accessibility
    • Grat
    Coordinates
    • (2716100 / 1192700)
    Note
    • Styger 1961 (Profil Bodenbach), Frey 1965

Palaenography and tectonic

  • Tertiary
Tectonic unit (resp. main category)
Kind of protolith
  • sedimentary
Metamorphism
non metamorphic

References

Definition
Menkveld-Gfeller Ursula, Kempf Oliver, Funk Hanspeter (2016) : Lithostratigraphic units of the Helvetic Palaeogene: review, new definition, new classification. Swiss J. Geosc. 109/2, 171-199

p.188: The Ahornen Member was first described by Frey (1965; ‘‘Ahornen-Schichten’’) at its type locality Ahornenrus (today Malorrus) (2716.100/1192.700). For further descriptions see Styger (1961; Bodenbach section). Lithology: The Ahornen Member that occurs at different locations of Central and Eastern Switzerland is characterized by the appearance of greenish volcanic rock fragments in the sandstone. This is in contrast to the remaining members of the Muot-da-Rubi Formation, in which such fragments are absent. The base here often consists of slaty marlstone, which already belongs to the Stad Formation. Overyling strata: Taveyannaz Formation, tectonic boundary; underlying strata: Stad Formation, Malor Member (exceptionally). Biostratiography: ?Priabonian. Current geographical extent: Central and Eastern Switzerland: Reuss valley to Linth valley. Tectonic units: Central and Eastern Switzerland: Lower Helvetic.
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