«Calcaires à Thalassinoides»

Représentation et statut

Couleur CMYK
N/A
Couleur RGB
R: 125 G: 125 B: 125
Rang
Couches (Sous-membre)
Usage
Ce terme n'est pas en usage.
Status
terme local (informel)

Nomenclature

Deutsch
«Thalassinoides-Kalk»
Français
«Calcaires à Thalassinoides»
Italiano
«Calcare a Thalassinoides»
English
«Thalassinoides Limestone»
Origine du nom

Namengebendes Spurenfossil: Thalassinoides

Variantes historiques

Thalassinoides Limestone (Jank 2004 p.17, Jank et al. 2006), Calcaires à Thalassinoides (Comment et al. 2015)

Description

Épaisseur
Environ 30 m (Jank et al. 2006c, Comment et al. 2015).

Composants

Fossiles
  • ichnofossiles

Hiérarchie et succession

Unité hiérarchiquement supérieure
Unités sus-jacentes

Âge

Âge au sommet
  • Kimméridgien précoce
Note sur le sommet

zone à Platynota / zone à Baylei pars.

Âge à la base
  • Kimméridgien précoce
Note sur la base

zone à Platynota / zone à Baylei pars.

Paléogéographie et tectonique

  • Malm du Jura
Termes génériques
Type de protolithe
  • sédimentaire
Conditions de formation

Base de séquence transgressive.

Métamorphisme
non métamorphique

Références

Révision
Jank M., Wetzel A., Meyer C. A. (2006) : A calibrated composite section for the Late Jurassic Reuchenette Formation in northwestern Switzerland (?Oxfordian, Kimmeridgian sensu gallico, Ajoie-Region) Eclogae geol. Helv. 99, 175-191

Thalassinoides Limestone (≈30 m) (Plate 1, a):

The Reuchenette Formation starts with monotonous, thick- to massive-layered (m-thick), well-bedded, bioturbated, grey, micritic limestones with some bioclasts and reddish brown or greyish, coarse-grained, pseudo-oolitic (mainly rounded intraclasts and peloids) pockets, patches and strings within a micritic matrix. Generally, macrofossils are rare. Thin to thick-bedded layers fracture conchoidally and commonly contain abundant Thalassinoides. These burrows are often filled with the coarse-grained pseudo-oolitic material mentioned above. Between 22 m and 30 m (composite section; Fig. 4) several conspicuous horizons with Thalassinoides are filled with coarse spary cement (beds VAT-150, VAT-20, COE-240, COE-170, COE-180, VAB-40, VAB-30, RAS-25; see Fig. 4). Bed surfaces are often iron stained, occasionally bored and biogenically encrusted by oysters. About 9 m below the upper boundary of this interval, a 6–7 meters thick, white, chalky limestone with oncoids and coral clasts occurs within the monotonous, grey, micritic interval (e.g. beds RAS-45 to RAS-48; Fig. 4). In La Rasse another 3–4 m thick white layer is visible, intercalated into the grey limestones (beds RAS-57 to RAS- 60), as well. In Coeuve the top few meters bear a stromatolite layer.
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