Holzflue-Member

Representation and status

Color CMYK

siehe Balsthal-Formation

Color RGB

R: 170 G: 195 B: 215

Rank

lithostratigraphic Member (Subformation)

Validity

Unit is in Use

Status

valid formal name

Nomenclature

Deutsch

Holzflue-Member

Français

Membre de la Holzflue

Italiano

Membro della Holzflue

English

Holzflue Member

Origin of the Name

Felsgrat Holzflue, nördlich Balsthal (SO)

Historical Variants

«Höhlenkalk» auct. (Lang 1863), Holzflue-Schichten (Gygi 1969), Holzflue Member (Gygi 2000b, Gygi 2000c)

Description

Description

Das Holzflue-Member besteht aus einer Wechsellagerung von weissen, oolithischen Grainstones und Mikriten.

Thickness

70 m an der Typlokalität

Hierarchy and sequence

Superordinate unit

• Balsthal-Formation

Subordinate units

• Balmberg-Oolith

Units at roof

• Formation de Reuchenette

Units at floor

• Steinibach-Member

Age

Age at top

• Early Kimmeridgian

Note about top

Planula-Zone

Age at base

• late Oxfordian

Note about base

Bimammatum-Z.

Dating Method

Mineralostratigraphie: Ton (Gygi 2000c S.133)

Geography

Geographical extent

Kanton Solothurn

Type area

Solothurner Jura (SO)

Type locality

• Holzflue (SO)
  Site particularities
  • typische Fazies
  Site accessibility
  • Grat
  Coordinates
  • (2619840 / 1241390)

Type profile

• Steinbachtobel (SO)
  Site particularities
  • Obergrenze
  • Untergrenze
  • typische Fazies
  Site accessibility
  • Bachprofil
  Coordinates
  • (2619370 / 1241350)
  Note
  • Steinbachtobel (Gygi 1969 Pl.18 Profil RG9, Gygi 2000b Pl.44 Profil RG438)

Palaenography and tectonic

• Malm 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

References

Definition

Gygi R. A. (1969) : Geologische Beschreibung des Aargauer-Jura und der nördlichen Gebiete des Kantons Zürich.

"Zwischen der Hauptmumienbank unten und der Kimmeridge-Stufe oben liegt eine Schicht, die Juillerat (1907) «oolithe blanche séquanienne» genannt hat. Da das Gestein nicht überall weiss und oolithisch ist und weil das Séquanien als Stufenname nicht mehr gebraucht werden kann, wird vorgeschlagen, die Schichten 9/15-19 Holzflue-Schichten zu nennen und Profil 9 zum Typusprofil zu erklären." S.86

Definition

Gygi R. A. (2000) : Annotated index of lithostratigraphic units currently used in the Upper Jurassic of northern Switzerland. Eclogae geol. Helv. 93/1, 125-146

p.133: Holzflue Member (Gygi 1969) ; Member of the Balsthal Formation ; Synonymy: Gygi (2000b. p. 63) The name Holzflue Member (Holzflue-Schichten) was proposed by Gygi (1969. p. 86) and refers to Mt. Holzflue north of Balsthal. Canton Solothurn. LK 1107 Balsthal. The type section is RG 9 in Gygi (1969. PI. 18) or the revised section RG 438 on plate 44 in Gygi (2(XX)b). respectively, that was measured at the same locality in the Steinebach gorge. Holzflue Member is a necessary name for the distal part of the Balsthal Formation. In the proximal part, the Laufen Member (Gygi 1995. p. 13) below and the Verena Member above can be distinguished above the Steinebach and Hauptmumienbank Members. At Balsthal and further to the east towards Olten this is impossible as is indicated in figure 1.
The Holzflue Member is 70 m thick at the type locality. Most of it is oolite, but there is a micritic intercalation in the type section: the middle part of bed 44 of section RG 438. The oolite in the upper part of the Holzflue Member is somewhat friable and weathers back as a hollow at Mt. Holzflue and north of the road tunnel in Steinebach gorge. The rock becomes a pure white, porous and very friable oolitic grainstone in the upper part of the quarry of Mösliloch at the western slope of Vorberg west of the village of Egerkingen. Canton Solothurn. LK 1108 Murgenthal. This is the upper part of bed no. 57 in the unpublished section RG 448. In one of the former quarries at the locality called Loch at Wangen. Canton Solothurn (west of Olten. LK 1088 Hauenstein), the rock of the Holzflue Member is a porous, white micrite (Gygi 1969. Pl.19). This is the type locality of the Wangen Member as conceived by Moesch (1867. p. 165).
The age of the Holzflue Member could only be established with clay minerals. The member belongs to the later part of the Bimammatum Chron and to the Planula Chron. The upper Holzflue Member at Mt. Holzflue cannot be distinguished from the Verena Member at St. Verena chapel, the type locality of the Verena Member (see below). The eastern boundary of the Holzflue Member is marked by the Olten Member, a limestone with hermatypic corals. There is a transition between the upper Holzflue Member and the upper Letzi Member at Olten (Gygi 1969. Pl. 19). The colour of the Holzflue Member is lighter than that of the oolitic Steinebach Member below that has a brownish tinge. But near Balsthal the uppermost Steinebach Member is an almost white friable oolite that weathers back. This was already noted by Delhaes & Gerth (1912. p. 18).