Mürren-Brekzie

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Representation and status

Index
e6b
Color CMYK
(0%,18%,63%,0%)
Color RGB
R: 255 G: 210 B: 95
Rank
lithostratigraphic Bed
Validity
Unit is in Use
Status
informal term

Nomenclature

Deutsch
Mürren-Brekzie
Français
Brèche de Mürren
Italiano
Breccia di Mürren
English
Mürren Breccia
Origin of the Name

Mürren (BE)

Historical Variants
calcaire nummulitique de Mürren (Boussac 1912), Mürrenbrekzie, Kalkbreccie von Mürren mit Nummuliten (Stauffer 1920), Nummulitenkalkbreccie = Palacebreccie (Louis 1924), Mürrenbreccie (Günzler-Seiffert 1933, Herb et al. 1978), Mürren-Brekzie, Brèche de Mürren (Collet & Paréjas 1928 + 1931), Mürren-Breccie, Transgressionsbreccien und - konglomerate (Steffen 1981)

Description

Description
Kalkbrekzie mit Nummuliten an der Basis der Niederhorn-Formation. Der Brekziencharakter ist am besten auf angewitterten Oberflächen zu erkennen und die Komponenten der Brekzie sind häufig grau bis leicht rötlich/grünlich und maximal zentimetergross.

Age

Age at top
  • late Eocene
Age at base
  • late Eocene
Dating Method
Biostratigraphie: Nummuliten

Geography

Geographical extent
Mürren ; ähnliche geschieferte Kalkbrekzie in der Aareschlucht (Arbenz & Müller in: GFS 1934).

Palaenography and tectonic

  • Siderolithic
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. 177: The crude iron-stained weathering of the Mürren breccia (‘‘Mürren-Brekzie’’) perhaps favours an interpretation as a deposit of the Siderolithic Group. The freshly cut limestone breccia, however, shows that the sandy cement contains Nummulites, and the components of the breccia are much smaller than usual in siderolithic rocks (Stauffer 1920). Therefore, the Mürren breccia belongs to the Palaeogene deposits and thus appears above the Siderolithic Group: the Mürren breccia is hence newly placed in the Hohgant Sandstone, a member of the Niederhorn Formation.

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