Leutschenberg-Member

Representation and status

Color CMYK

(0%,35%,71%,4%)

Color RGB

R: 245 G: 160 B: 70

Rank

lithostratigraphic Member (Subformation)

Validity

Unit is in Use

Status

valid formal name

Nomenclature

Deutsch

Leutschenberg-Member

Français

Membre du Leutschenberg

Italiano

Membro del Leutschenberg

English

Leutschenberg Member

Origin of the Name

Leutschenberg (AG), WSW Zeglingen

Historical Variants

Unterer Trochitenkalk, Leutschenberg Member (Pietsch et al. 2016)

Description

Description

Bioturbierter, oft dolomitisierter Kalk (Mudstone bis Wackestone) an der Basis der Schinznach-Formation. Im unteren Teil treten lokal Crinoid- («Trochitenkalk») und Schalentrümmer auf.

Thickness

4 - 10 m (Merki 1961, Pietsch et al. 2016).

Components

• crinoids

Hierarchy and sequence

Superordinate unit

• Schinznach-Formation

Subordinate units

• Fützen-Bank

Units at roof

• Kienberg-Member

Units at floor

• Zeglingen-Formation (Anhydritgruppe)

Upper boundary

Kienberg-Member.

Lower boundary

Stromatolitischer Dolomit der Zeglingen-Formation.

Age

Age at top

• Anisian

Age at base

• Anisian

Geography

Geographical extent

Nordschweizer Jura.

Type area

Aargauer Jura

Type locality

• Leutschenberg (AG), W-Flank
  Site particularities
  • Obergrenze
  • Untergrenze
  • typische Fazies
  Coordinates
  • (2636950 / 1251250)
  Note
  • Merki 1961 Fig.8, Pietsch et al. 2016 Fig.8

Type profile

• Leutschenberg (AG), W-Flank
  Site particularities
  • Obergrenze
  • Untergrenze
  • typische Fazies
  Coordinates
  • (2636950 / 1251250)
  Note
  • Merki 1961 Fig.8, Pietsch et al. 2016 Fig.8

Palaenography and tectonic

• Triassic of the Jura Mountains

Paleogeography

Northern Tethyan Carbonate Platform :
Plateforme de Bourgogne, ... = Northern Tethyan Carbonate Platform (NTCP)

Tectonic unit (resp. main category)

• Jura :
  Juragebirge

Kind of protolith

• sedimentary

Metamorphism

non metamorphic

Metamorphic facies

• secondary dolomitisation

References

Definition

Pietsch Johannes S., Wetzel Andreas, Jordan Peter (2016) : A new lithostratigraphic scheme for the Schinznach Formation (upper part of the Muschelkalk Group of northern Switzerland). Swiss J. Geosc. 109/2, 285-307

The Leutschenberg Member represents the lowermost part of the Schinznach Formation. It mainly consists of bioturbated mud- and wackestones. Bedding planes and burrows are often dolomitised. The basal strata are locally dolomitic (Disler 1914; Merki 1961) and overlie stromatolitic dolomites of the Zeglingen Formation (Fig. 8).

At some localities strata rich in crinoid and shell detritus occur near the base of the Leutschenberg Member (Figs. 8, 10). They are between 5 cm (Fig. 10; see Merki 1961; Gsell 1968) and about 2 m thick (Merki 1961). Merki (1961) called these strata ‘‘Basale Trochitenbank’’. They often represent the lowermost part of the Leutschenberg Member, but similar lithology may occur in middle part as well (Disler 1914; Merki 1961). Due to their multiple occurrence at different stratigraphic levels within the lower part of the Leutschenberg Member they cannot be defined as a single bed. The Basale Trochitenbank rather comprises different crinoid-detritus-rich strata. Where these strata occur at the base of the Leutschenberg Member, they often contain dolomite clasts originating from the underlying ‘‘Anhydritdolomit’’ representing the top of the Zeglingen Formation (Merki 1961).

The top of the Leutschenberg Member is defined by the first occurrence of successional float- to rudstones rich in crinoid and shell detritus above bioturbated mud- and wackestones (see below; Figs. 8, 10). Thus, the ‘‘Basale Trochitenbank’’ of Merki (1961) is defined to form part of the Leutschenberg Member.

Important Publications

Pietsch Johannes S., Wetzel Andreas, Jordan Peter (2016) : A new lithostratigraphic scheme for the Schinznach Formation (upper part of the Muschelkalk Group of northern Switzerland). Swiss J. Geosc. 109/2, 285-307