Unterer Betliskalk

Retour à Helvétique central

Représentation et statut

Couleur CMYK
(0%,0%,0%,100%)
Rang
unité lithostratigraphique
Usage
Ce terme n'est pas en usage.
Status
terme incorrect (mais utilisé de manière informelle)

Nomenclature

Deutsch
Unterer Betliskalk
English
Lower Betlis Limestone
Variantes historiques
Lower Betliskalk = lower Betlis member (Föllmi et al. 2006), lower Betlis Limestone (Föllmi et al. 2007)

Description

Épaisseur
Max. 100 m (Föllmi et al. 2007).

Hiérarchie et succession

Unités sus-jacentes
Limite inférieure
Föllmi et al. 2007: The switch-over from the deposition of the upper Oehrli Limestone to that of the overlying Betlis Formation near the Berriasian-Valanginian boundary represents a major turning point in the evolution of the Helvetic carbonate platform. The Berriasian photozoan mode of carbonate production is replaced by a heterozoan mode, which is repeatedly interrupted by episodes of incipient drowning (Fig. 2; Föllmi et al. 1994, 2006) and which lasted until the early Late Barremian. The limit between these two carbonate units itself embodies a sequence boundary which on the platform is marked by karstified and iron-stained emersion horizons and perforated hardgrounds (Burger 1985, 1986; Mohr 1992a).

Âge

Âge au sommet
  • Valanginien précoce

Note sur le sommet
pertransiens-Zone
Âge à la base
  • Valanginien précoce

Note sur la base
pertransiens-Zone
Méthode de datation
Ammoniten in der hangende Büls-Bank (Kuhn 1996, Föllmi et al. 2007).

Paléogéographie et tectonique

Termes génériques
Type de protolithe
  • sédimentaire

Références

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.353: On top of the thin unit of sandy marl [= Vitznau Formation] or directly on top of the upper Oehrli Member, a succession of platform carbonates is preserved (lower Betlis Limestone; Fig. 2; Strasser 1979, 1982; Burger & Strasser 1981; Kuhn 1996), which consists of maximally 100 m of a sandy grain- and packstone rich in echinoderms, bryozoans, bivalves, brachiopods, benthic foraminifera, and calcareous algae (Strasser 1979, 1982).
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