Membre des Schistes à Miches

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Representation and status

Color CMYK
(0%,42%,61%,25%)
Color RGB
R: 190 G: 110 B: 75
Rank
lithostratigraphic Member (Subformation)
Validity
Unit is in Use
Status
incorrect name (though informally used)
Status discussion

Nomenclature

Deutsch
Schistes-à-Miches-Member
Français
Membre des Schistes à Miches
Italiano
Membro dei Schistes à Miches
English
Schistes à Miches Member
Historical Variants

Aalénien du torrent de la Raverette avec Posidonomya Bronni = Aalénien de la Raverette = Aalénien avec Posidonomya Bronni et des belemnites = Aalénien de l'écaille d'Oudioux (Lugeon 1938), Schistes noirs à miches = Schistes argileux noirs à miches pyriteuses (Badoux & Gabus 1991 p.13), Schistes à miches member (Ringgenberg et al. 2001)

Components

Fossil Content
  • ammonites
  • belemnites

Hierarchy and sequence

Superordinate unit
Units at roof

Age

Age at top
  • Aalenian
Age at base
  • Aalenian
Dating Method

Ammonites: Leioceras sp. (Badoux & Homewood 1978).

Geography

Geographical extent
Ultrahelvétique interne (Vallée de la Grande Eau).
Type area
Vallée de la Grande Eau (VD), entre Le Sépey et la Forclaz
Type locality
Point of interest
  • Torrent de la Raverette (VD)
    Site particularities
    • typische Fazies
    Site accessibility
    • Bachprofil
    Coordinates
    • (2571870 / 1134695)
    Note
    • Lugeon 1938
  • Ensex (VD)
    Site particularities
    • typische Fazies
    Coordinates
    • (2574500 / 1130200)
    Note
    • Badoux & Gabus 1991 p.13 ("Eisensandstein")

Palaenography and tectonic

Tectonic unit (resp. main category)
Kind of protolith
  • sedimentary

References

Definition
Ringgenberg Yann, Tomassi Alexander, Stampfli Gérard M. (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

2.1.1. «Schistes à miches» member (Aalenian) It consists of black clays full of micas containing calcareous, cherty and pyritic concretions that gave sometimes ammonites and bélemnites. Homewood and Badoux (1978) have found a specimen oî Leioceras giving an Aalenian age to the formation. At the top of the series, one can find a 2 m chaotic level with a matrix similar to the rest of the «Schiste à Miches» and containing segmented beds of micaceous sandstones. It is interpreted as a mudflow or a slump. The transition to the Raverette member is unexposed, but prior to the slump, there is a calcareous and micaceous polygenic bed of sandstone with chondrites that resembles the Raverette member. Therefore, the transition seems to be progressive and there is no reason to put a tectonic contact between those two members.
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