Zeglingen-Formation (Anhydritgruppe)

Representation and status

Index

tZ

Color CMYK

5 / 50 / 85 / 0

Color RGB

R: 245 G: 150 B: 60

Rank

lithostratigraphic Formation

Validity

Unit is in Use

Status

valid formal name

Scs Note

Name und Konzept genehmigt.

Scs Date

22.11.2014

Status discussion

Nomenclature

Deutsch

Zeglingen-Formation (Anhydritgruppe)

Français

Formation de Zeglingen

Italiano

Formazione di Zeglingen

English

Zeglingen Formation

Origin of the Name

Zeglingen (BL)

Historical Variants

«Mittlerer Muschelkalk» auct., «Anhydritgruppe» auct., Zeglingen-Formation (Jordan 2016)

Nomenclatorial Remarks

The Zeglingen Formation includes the Anisian evaporitic sequence and corresponds to the «Anhydritgruppe» («Mittlerer Muschelkalk») of the traditional Swiss scheme (e.g. Mu¨ller et al. 1984, see also Fig. 3. The only discrepancy concerns the «Unterer Dolomit» which is now part of the underlying Kaiseraugst Formation and was formerly considered as part of the «Anhydritgruppe» by some authors (c.f. Matter et al. 1988). One reason is that the German stratigraphic scheme incorporates the «Unterer Dolomit» into the Karlstadt Formation (former «Orbicularismergel»), which corresponds to the upper part of the Kaiseraugst Formation. On the other hand, a close examination shows that in most core reports, the boundary between «Wellengebirge» and «Anhydritgruppe» was set at the base of the first massive anhydrite sequence. The newly defined boundary also corresponds to the morphologic change from carbonate-dominated rocks (below), which resist erosion, to more soluble sulphates (above).

Description

Description

Heterogene, evaporitische Abfolge aus massiven und lagigen Anhydriten (nahe an der Oberfläche: Gips), Steinsalz, Wechselfolgen von Tonschiefer und Dolomit.

Geomorphology

Extrem dichte und weiche Gesteine, mit hoher Duktilität (Verformbarkeit, Dehnbarkeit) und geringer Porosität. Abscherhorizont und diapirisches Verhalten.

Thickness

40-150 m (Jordan 2016) ; 50-95 m (Jordan & Deplazes 2018)

Components

• halite
• anhydrite

Hierarchy and sequence

Subordinate units

• «Dolomitzone» (Zeglingen-Fm.)
• «Obere Sulfatschichten»
• «Salzlager»
• «Untere Sulfatschichten»

Units at roof

• Schinznach-Formation

Units at floor

• Kaiseraugst-Formation

Upper boundary

Gradueller, stratigraphischer Kontakt zur Schinznach-Fm.: Einsetzen von dickbankigen Kalken und Dolomiten über dünnbankigen, stromatolitischen Dolomiten.

Lower boundary

Transgressiver, stratigraphischer Kontakt zur Kaiseraugst-Fm.: Einsetzen der evaporitischen Fazies (oftmal mit massiver, basaler Anhydritbank) und der Corrensite bei der Ton-Mineralogie.

Age

Age at top

• Anisian

Note about top

Ilyrien

Age at base

• Anisian

Note about base

Ilyrien

Dating Method

Ilyrien (Hagdorn & Simon 2005, Geyer et al. 2011)

Geography

Geographical extent

Nordschweiz. Steinsalz-Ablagerungen treten nur NW der Linie Bern-Zürich-Schaffhausen auf.

Type area

Östlicher Faltenjura

Type locality

• Zeglingen (BL)
  Site particularities
  • Obergrenze
  • typische Fazies
  Site accessibility
  • geschützter Geotop
  • Steinbruch, Tongrube
  Coordinates
  • (2636335 / 1251195)
  Note
  • ehemalige Gipsgrube Wissbrunn (heute Weissbrunn) (Merki 1961 Porfil 24 (jedoch unvollständig, tektonisch gestört und kaum sichtbar) ; Jordan 2016)

Type profile

• Zeglingen (BL)
  Site particularities
  • Obergrenze
  • typische Fazies
  Site accessibility
  • geschützter Geotop
  • Steinbruch, Tongrube
  Coordinates
  • (2636335 / 1251195)
  Note
  • ehemalige Gipsgrube Wissbrunn (heute Weissbrunn) (Merki 1961 Profil 24 ; Jordan 2016)

Reference profiles

• Bohrung Meienboden (BL)
  Site particularities
  • Obergrenze
  • Untergrenze
  • typische Fazies
  Site accessibility
  • Bohrkern
  Coordinates
  • (2619825 / 1260650)
  Note
  • <p>Bohrung S 106, Schweizer (Rhein-) Salinen AG (Widmer 1991: zwischen 430.9 m und 597.6 m (fully cored) ; Jordan 2016)</p>
• Tiefbohrung Böttstein (AG)
  Site particularities
  • Obergrenze
  • Untergrenze
  • typische Fazies
  Site accessibility
  • Bohrkern
  Coordinates
  • (2659342 / 1268556)
  Note
  • <p>Referenzprofil der Zeglingen-Formation: Peters et al. 1986: zwischen 197.20 m und 261.00 m (fully cored, with the exception of a very short sequence) ; Nagra core store facility</p>

Point of interest

• Felsenau (AG)
  Site particularities
  • typische Fazies
  Site accessibility
  • Steinbruch, Tongrube
  Coordinates
  • (2657550 / 1273550)
  Note
  • Gipsgrube (Wildi 1983 S.38, Zollinger 2005)

Palaenography and tectonic

• Triassic of the Jura Mountains
• Middle Triassic

Paleogeography

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

Tectonic unit (resp. main category)

• GeoMol CH
• Jura :
  Juragebirge

Kind of protolith

• sedimentary

Conditions of formation

Brackisch

Sequence

Regressiver Evaporit-Zyklus mit Subzyklen, Sabkha.

The Swiss salina basin with rock salt deposits in its centre is part of a greater marine system extending from the northern Central European basin to the south along proto Rhenish structures and further to the Burgundy basin in the Lyon area in France (Hagorn and Nitsch 2009). Dronkert et al. (1990) recognised a transgressive–regressive megacycle with eight meso-sequences and many subsequences. The marine salt deposits document a high stand which is followed by a regression ending in a sabkha type costal environment.

Metamorphism

non metamorphic

References

Definition

Jordan Peter (2016) : Reorganisation of the Triassic stratigraphic nomenclature of northern Switzerland: overview and the new Dinkelberg, Kaiseraugst and Zeglingen formations. Swiss J. Geosci. 109/2, 241-255

Massive and layered anhydrite (near surface: gypsum), rock salt, insets and alternations of shale and dolomite often containing magnesite, coelestine etc.; residuals like clay and breccias are found along the superficial outcrop area, as well as at several sites of syn- to early postsedimentation subrosion (Dronkert et al. 1990) throughout the entire area (see Fig. 6)

Important Publications

Jordan Peter (2016) : Reorganisation of the Triassic stratigraphic nomenclature of northern Switzerland: overview and the new Dinkelberg, Kaiseraugst and Zeglingen formations. Swiss J. Geosci. 109/2, 241-255

Widmer Thomas (1991) : Zur Stratigraphie und Sedimentologie der Anhydritgruppe (Mittlere Trias) in der Region Liestal-Arisdorf (Baselland, Nordwestschweiz). Beiträge zur Geologie der Schweiz, Geotechnische Serie 79, 108 Seiten

Dronkert H., Bläsi H.R., Matter A. (1990) : Facies and origin of triassic evaporites from the Nagra boreholes. Nagra Technischer Bericht NTB 87-02

Zollinger Thomas (2005) : Gipsfabrik und Bergwerk Felsenau. Mitteilungen der aargauischen Naturforschenden Gesellschaft 36, 61-72

Material and varia

beige, grau, weiss, rosa

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