Büls-Bank

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Représentation et statut

Couleur CMYK
siehe Betlis-Fm.
Couleur RGB
R: 160 G: 210 B: 120
Rang
Banc lithostratigraphique
Usage
Ce terme est en usage.
Status
terme local (informel)

Nomenclature

Deutsch
Büls-Bank
Français
Banc de Büls
Italiano
Strato del Büls
English
Büls Bed
Origine du nom

Hinterbüls (SG), Churfristen

Variantes historiques
Büls-Bank (Kuhn 1997), Büls Member (Föllmi et al. 2007)

Description

Épaisseur
Max. 5 m (Föllmi et al. 2007).

Composants

Fossiles
  • ammonites

Hiérarchie et succession

Unité hiérarchiquement supérieure
Unités sus-jacentes

Âge

Âge au sommet
  • Valanginien précoce
Note sur le sommet
Stephanophorus Zone / frühe campylotoxus-Zone (Wyssling 1986, Kuhn 1996)
Âge à la base
  • Valanginien précoce
Note sur la base
späte Pertransiens-Zone
Méthode de datation
Biostratigraphie (Ammoniten : Wyssling 1986, Kuhn 1996).

Paléogéographie et tectonique

  • Néocomien
  • Crétacé de l'Helvétique
Paléogéographie
plateforme nord téthysienne :
marge continentale européenne
Termes génériques
Type de protolithe
  • sédimentaire

Références

Définition
Kuhn Oliver (1996) : Der Einfluss von Verwitterung auf die Paläozeanographie zu Beginn des Kreide-Treibhausklimas (Valanginian und Hauterivian) in der West-Tethys. Diss. ETH Zürich

Die Phosphoritbildung der neudefinierten Büls-Schichten findet innerhalb der Pertransiens und Stephanophorus-Zone statt (Unter Valanginian), ...
Révision
Föllmi Karl B., Bodin Stephane, Godet Alexis, Linder Pascal, van de Schootbrugge B. (2007) : Unlocking paleo- environmental information from Early Cretaceous shelf sediments in the Helvetic Alps: stratigraphy is the key! Swiss J. Geosci. 100, 349-369

p.354: In distal parts of the platform, the lower Betlis Limestone is overlain by an up to 5 m thick and heterogeneous succession, which consists of sandy, glauconitic, hemipelagic carbonates and marl, which include a discrete level of phosphate nodules or a phosphatized hardground (Fig. 2; Fig. 3). This unit is identified both in different regions in Vorarlberg (Austria), as well as in eastern and central Switzerland (Hauswirth 1913; Heim 1910–1916; Haus 1937; Strasser 1979; Felber and Wyssling 1979) and has been defined as “Büls Beds” by Kuhn (1996). The Büls Member is underlain either by sediments of the Vitznau Formation or of the lower Betlis Limestone (Fig. 2) and overlain by sediments of the hemipelagic Sichel Limestone of the Diphyoides Formation. In the case this latter member is absent, the Büls Member bundle with the overlying Gemsmättli Bed and forms a single phosphate-rich bed (Kuhn 1996). This is the case for example at the type locality of the Gemsmättli Bed in the Pilatus region (Wyssling 1986). The Büls Member includes the oldest drowning unconformity within the Helvetic platform succession, and documents a first phase of highly reduced carbonate production on the platform (Föllmi et al. 1994, 2006). Its age is constrained by ammonite biostratigraphy in occurrences in Vorarlberg and eastern Switzerland and encompasses the late pertransiens and early campylotoxus zones (Wyssling 1986; Kuhn 1996).
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