Membre de la Forclaz
Retour à nappe du NiesenReprésentation et statut
- Couleur CMYK
- (0%,11%,26%,31%)
- Couleur RGB
- R: 175 G: 155 B: 130
- Rang
- Membre lithostratigraphique (Sous-formation)
- Usage
- Ce terme est en usage.
- Status
- terme formel valide
- Discussion du statut
Nomenclature
- Deutsch
- Forclaz-Member
- Français
- Membre de la Forclaz
- Italiano
- Membro della Forclaz
- English
- Forclaz Member
- Origine du nom
-
Ruisseau de la Forclaz (VD), Ormont-Dessous
- Variantes historiques
-
Marnes et calcaires du torrent de la Forclaz (Badoux & Homewood 1978, Badoux & Gabus 1991), Forclaz member (Ringgenberg et al. 2001)
Description
- Épaisseur
- 30-50 m (Ringgenberg et al. 2001)
Composants
- foraminifères
- bivalves
Bositra buchi (Roemer 1836)
Hiérarchie et succession
- Unité hiérarchiquement supérieure
- Unités sus-jacentes
- Unités sous-jacentes
Âge
- Âge au sommet
-
- Bathonien
- Âge à la base
-
- Bathonien
- Méthode de datation
-
Foraminifères: Protopeneroplis striata (Weynschenk), Archeosepta platierensis (Wernli) (Badoux & Homewood 1978).
Géographie
- Région-type
- Vallée de la Grande Eau, entre Le Sépey et la Forclaz
Paléogéographie et tectonique
-
- Dogger
- Type de protolithe
-
- sédimentaire
Références
- Révision
-
2001) :
The Jurassic sequence of the Niesen nappe in the region of Le Sépey - La Forclaz (Swirtzerland): witness of the Piemont rifting in the Helvetic paleogeographic domain. Bull. Soc. vaud. Sci. nat. 87/4, 353-372
(
p.360: 2.1.5. Forclaz member (Bathonian) Good outcrops of this member are only found in La Forclaz stream (map 1:25'000 n°1285, Les Diablerets, geographic coordinates: 571'600/133'325 to 571 '775/133'650). It is 30 to 50 m thick and composed of turbiditic sandy limestones which alternate with marls. The proportion sand/marls is 1:1 and Tabe sequences are present. The detritic elements point to a more basinal environment than for the other members: limestones with little quartz, feldspars and white micas but a lot of spicules, recrystallized echinoderms, Lenticulina, Nodosoaria and little or no resedimented platform fragments. Marls interbeds are sometimes full of Posidonia bronni or bositra and ichnofossil imprints. Homewood and Badoux (1978) found Protopeneroplis striata (WEYNSCHENK) and Archeosepta platierensis (WERNLI) which indicate a Bathonian age. The transition to the Langy member is gradual, the bed thickness and the detritic fraction increase upward.