Therwil-Member
Back to Membre de CourrouxRepresentation and status
- Color CMYK
- (0%,0%,0%,100%)
- Color RGB
- R: 250 G: 220 B: 130
- Rank
- lithostratigraphic Member (Subformation)
- Validity
- Unit is in Use
- Status
- valid formal name
Nomenclature
- Deutsch
- Therwil-Member
- Français
- Membre de Therwil
- Italiano
- Membro di Therwil
- English
- Therwil Member
- Origin of the Name
- Historical Variants
-
Horizont / Bank mit Ostrea cyathula (Gutzwiller 1914, Herzog 1956, Bitterli-Brunner & Fischer 1988), Cyathulabank (Koch 1923, Bitterli 1945, Fischer 1965a, Naef et al. 1985, Picot 2002, Becker 2003, Grimm 2005, Picot et al. 2008), Therwil Member (Pirkenseer et al. 2018)
- Nomenclatorial Remarks
-
Un horizon à Crassostrea cyathula existe également dans le bassin de Delémont, mais dans des niveaux plus anciens (Membre des Près Roses de la Formation de Lörrach).
Description
- Thickness
- Généralement 2 m dans la région bâloise (Pirkenseer et al. 2018).
Hierarchy and sequence
- Superordinate unit
- Units at roof
- Units at floor
Geography
- Geographical extent
- Partie méridionale du fossé du Haut-Rhin dans la région bâloise (Therwil, Ettingen) et extrême nord du bassin de Laufon (Brislach).
- Type area
- Région bâloise (BL)
Palaenography and tectonic
- Paleogeography
- Rhine Graben
- Tectonic unit (resp. main category)
- Kind of protolith
-
- sedimentary
References
- Definition
-
(2018) :
A revised Palaeogene lithostratigraphic framework for the Northern Swiss Jura and the Southern Upper Rhine Graben and its relationship to the North Alpine Foreland Basin. Riv. Italiana Pal. Strat. 124/1, 163–246
p.214: The Therwil Mb is dominated by disarticulated valves of Crassostrea cyathula, which either form a densely packed, sometimes sandy coquina or are distributed in a matrix of mainly bluish grey, massive marls. In the area of Basel the member seems to be developed as a relatively continuous bed of maximal 2 (possibly to 5) m thickness that pinches out near Brislach (30 cm; Koch 1923) in the Laufen subbasin.
Gutzwiller (1893) indicates a continuous occurrence of the coquina bed between the villages Therwil and Ettingen (at least 4 km). Towards the north and the west the bed dissolves into oyster patch “reefs”, isolated valves in massive marls or is entirely absent (e.g. drilling Hirtzbach; Vonderschmitt 1942).