Unterer Teil der Schrattenkalk-Formation
Back to Central HelveticsRepresentation and status
- Index
- c4-5u
- Color CMYK
- (31%,0%,13%,24%)
- Color RGB
- R: 135 G: 195 B: 170
- Rank
- lithostratigraphic Member (Subformation)
- Validity
- Unit is in Use
- Status
- incorrect name (though informally used)
Nomenclature
- Deutsch
- Unterer Teil der Schrattenkalk-Formation
- Français
- Partie inférieure de la Formation du Schrattenkalk
- Italiano
- Parte inferiore della Formazione dello Schrattenkalk
- English
- Lower part of the Schrattenkalk Formation
- Historical Variants
-
Unterurgon bzw. Unterer Caprotinenkalk (Baltzer 1906), Oberes Barrémien = Unterer Schrattenkalk (Urgonfazies) (Furrer 1938), Unterer Schrattenkalk (Schindler 1959), Lower Schrattenkalk Member (Föllmi et al. 2007)
Description
- Description
-
Hellgrau anwitternder, dickbankiger, fossilarmer Kalk.
- Geomorphology
- Helle Felswand.
- Thickness
- Bis über 100 m (Föllmi et al. 2007)
Age
- Age at top
-
- Earliest Aptian
- Age at base
-
- Late Barremian
- Note about base
-
Mitte spätes Barremian
Palaenography and tectonic
-
- Middle Cretaceous
- Cretaceous of the Helvetics
- Paleogeography
-
North Tethyan Shelf
:
marge continentale européenne - Tectonic unit (resp. main category)
- Kind of protolith
-
- sedimentary
- Metamorphism
- non metamorphic
References
- Definition
-
(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.11: The lower Schrattenkalk reaches a maximal thickness of over 100 m and is composed of carbonate pack- and grainstone rich in ooids, peloids, benthic foraminifera (e.g., miliolids, orbitolinids), green algae, rudists (e.g., Requienia), bryozoans, brachiopods, bivalves, echinoderms and corals. This unit is characterized by a strong progradational trend (Fig. 2) and by a rather rapid transition (within a few kilometers; Fichter 1934; Bollinger 1988) into the outer shelf marls and marl-limestone alternations of the Tierwis Formation [Hurst Beds]. The entire succession is considered as a second-order systems tract, which may form one single sequence with the underlying Drusberg Member and the Chopf Bed (Funk et al. 1993). It is not excluded that third-order sequence-stratigraphic subdivisions may be present within the lower Schrattenkalk, as is the case in the Vercors area (Arnaud et al. 1998).
The age of the lower Schrattenkalk is indicated by the ammonite fauna of the Chopf Bed and by orbitolinids in the overlying Rawil Member (see below) and can be constrained as sartousiana to oglanlensis zones. A diachrony of its base along a proximal-distal axis is highly probable and due to the progradational character of this unit.