Asp-Member

Representation and status

Color CMYK

(0%,24%,62%,2%)

Color RGB

R: 250 G: 190 B: 95

Rank

lithostratigraphic Member (Subformation)

Validity

Unit is in Use

Status

valid formal name

Status discussion

Nomenclature

Deutsch

Asp-Member

Français

Membre d'Asp

Italiano

Membro d'Asp

English

Asp Member

Origin of the Name

Asp (AG), 1km S Densbürgen

Historical Variants

«Lettenkohle» auct., Asp Member (Pietsch et al. 2016)

Description

Description

Dunkle, oft grünliche, z.T. siltig-sandige Tone mit Bonebeds, gegen oben zunehmend dolomitische Mergel und Dolomite. Lokal mit Kohlelagen. Die Basis des Asp-Members ist definiert als die erste dezimeterdicke Lage von schlammigem oder tonigem Mergel auf den Dolomiten des Stamberg-Members.

Thickness

4 - 6 m (Fischer et al. 1971) ; bis 15 m im Baselbieter Tafeljura und Oberer Rheingraben (Hauber 1991) ; 4 - 8 m im Aargauer Tafeljura, Schaffhausen und Zürcher Weinland (Pietsch et al. 2016) ; 7 - 15 m im Bodenseegebiet (Pietsch et al. 2016).

Components

• vertebrates
• brachiopods
• plants : Plantae
• bivalves
• arthropods

Typischer Fossilgehalt: Palaeestheria, Lingula, Myophoria.

Hierarchy and sequence

Superordinate unit

• Schinznach-Formation

Subordinate units

• «Grenzdolomit» (Schinznach-Fm.)
• «Estherien-Schiefer»

Units at roof

• Bänkerjoch-Formation (Gipskeuper)

Units at floor

• Stamberg-Member

Upper boundary

Bänkerjoch-Formation.

Lower boundary

Erste dm-mächtige tonige Mergellage über den Dolomiten des Stamberg-Members.

Age

Age at top

• Ladinian

Age at base

• Ladinian

Geography

Geographical extent

Nordschweizer Jura.

Type area

Östlicher Faltenjura

Type locality

• Asp (AG)
  Site particularities
  • typische Fazies
  Coordinates
  • (2646375 / 1255125)
  Note
  • Furrer 1977, Pietsch et al. 2016 Fig.14

Type profile

• Asp (AG)
  Site particularities
  • typische Fazies
  Site accessibility
  • verschwundener Aufschluss
  Coordinates
  • (2646375 / 1255125)
  Note
  • Furrer 1977, Pietsch et al. 2016 Fig.14
• Bohrung Weiach (ZH)
  Site particularities
  • Obergrenze
  • typische Fazies
  • Untergrenze
  Site accessibility
  • Bohrkern
  Coordinates
  • (2676810 / 1268680)
  Note
  • <p>Nagra Technisches Bericht NTB 86-01, Matter et al. 1988, Nagra 1989 (Nagra core store facility)</p> <p>- Typulokalität und Typusprofil der Weiach-Fm. zwischen 1169,62 und 2020,40 m (Nitsch &amp; Zedler 2009)</p> <p>- Typusprofil der Schinznach-Fm. (Pietsch et al. 2016 Fig.7)</p> <p>- Typusprofil des Asp-Mb. (Pietsch et al. 2016 Fig.7)</p> <p>- Referenzprofil der Bänkerjoch-Formation zwischen 739.35 und 814.08 m (Jordan 2016)</p> <p>- Referenzprofil des Ergolz-Mb. zwischen 704.32 und 724.32 m ("Schilfsandstein s.l." ohne basale "Dolomitbank"; Jordan et al. 2016)</p>

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

Conditions of formation

Littoral, deltaic to brackish environment with alternating marine and terrestrial intercalations.

Metamorphism

non metamorphic

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 base of the Asp Member is defined by the first decimetre-thick mud or argillaceous marl layer on top of the dolomites of the Stamberg Member. Traditionally the base was set with a millimetre- to centimetre-thick condensation layer called ‘‘Grenzbonebed’’ (e.g. Merki 1961). In this case the boundary is located within the dolomite and is therefore not always recognisable, particularly in drillings. Within the mud or argillaceous marl intervals, one (e.g. Asp, Fig. 14) or more (e.g. Eptingen, Fig. 12) thin dolomite beds can occur. They may be equivalent to the dolomite beds of the ‘‘Alberti-Schichten’’, especially the Alberti-Bank, which has been distinguished in southwestern Germany (Essigmann 1979; Nitsch 2015), where the thickness increases (up to 33 m in the Kraichgau Trough; Etzold and Schweizer 2005). Formerly this argillaceous succession was called ‘‘Estherienschiefer’’ (Fig. 2) after Euestheria minuta (Zieten 1833), which locally occurs in some layers (e.g. Disler 1914; Merki 1961; Gsell 1968). In addition to conchostraca and other invertebrates, plant remains (Brändlin 1911; Braun 1920) and vertebrate fossil components were found. Among the latter are remains of fish and teeth (e.g. Schmidt et al. 1924; Furrer 1977), bones (e.g. Brändlin 1911; Disler 1914; Merki 1961) amongst others of Nothosauridae (Frank 1928; Peyer 1932). Locally sandy layers are interbedded (e.g. Brändlin 1911; Merki 1961; Diebold et al. 2006). The dolomites within the mudrock or marl can have a sandy appearance (Braun 1920; Diebold et al. 2006). Dolomites follow above the argillaceous succession. Locally anhydrite nodules occur within the Asp Member (e.g. Matter et al. 1988a, b; Jordan et al. 2011). In outcrops the anhydrite-rich strata are often weathered to rauhwacke. Sandy or argillaceous layers often occur as well (Merki 1961; Essigmann 1979). The top of the Asp Member is defined by the last occurrence of continuous dolomite or rauhwacke strata overlain by marls or sulphates that already belong to the Bänkerjoch Formation. Therefore, the alternating strata consisting of massive anhydrite and dolomite that locally occur in the lowest part of the Bänkerjoch Formation do not belong to the Asp Member. The Asp Member shows a significant peak in gammalogs (Figs. 7, 15), which can be used to localise the top of the Schinznach Formation. In the Nagra boreholes Schafisheim, Riniken, Weiach and Benken a smaller peak marks the top of the Asp Member. In Siblingen this peak lies few metres deeper.

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