Membre de Buix

Representation and status

Color CMYK

(0%,5%,3%,25%)

Color RGB

R: 190 G: 180 B: 185

Rank

lithostratigraphic Member (Subformation)

Validity

Unit is in Use

Status

valid formal name

Status discussion

Nomenclature

Deutsch

Buix-Member

Français

Membre de Buix

Italiano

Membro di Buix

English

Buix Member

Origin of the Name

Carrière Les Creppes, NW de Buix = Bux (JU)

Historical Variants

Kreide von St. Ursanne auct., Buix Member (Gygi 2000b, Gygi 2000c), Membre de Buix (Comment & Ayer)

Links

Synonyms

Kreidige Kalke von St-Ursanne

Description

Description

Weisse, weiche, kreidige, ungeschichtete Kalksteine mit kleinen Biohermen, im oberen Teil treten Silex-Knollen auf.

Geomorphology

zone tendre

Thickness

0-35 m

Components

• corals

Hierarchy and sequence

Superordinate unit

• Formation de St-Ursanne

Units at roof

• Membre du Vorbourg (sensu Ziegler 1962 emend.)
• Formation de Vellerat

Units at floor

• Grellingen-Member
• Formation de St-Ursanne
• Chestel-Member

Age

Age at top

• middle Oxfordian

Age at base

• middle Oxfordian

Dating Method

Biostratigraphie (ammonites de la Transversarium-Zone ; Gygi 1995)

Geography

Geographical extent

Partie nord du canton du Jura (Ajoie) et jura bâlois (région de Liesberg).

Type locality

• Buix (JU)
  Site particularities
  • typische Fazies
  Site accessibility
  • Steinbruch, Tongrube
  Coordinates
  • (2569670 / 1259815)
  Note
  • Carrière Les Creppes (Gygi 2000b S.56 Profil RG347)

Reference profiles

• St-Ursanne (JU)
  Site particularities
  • Untergrenze
  • typische Fazies
  Site accessibility
  • Steinbruch, Tongrube
  Coordinates
  • (2579200 / 1246370)
  Note
  • Referenzprofil im ehemaligen Steinbruch der Kalkfabrik in St-Ursanne (Pümpin 1965 Pl.1 Profil 2, Gygi 1982 Fig.4, Gygi 2000b p.56 Profil RG336, Gygi 2000c)

Palaenography and tectonic

Tectonic unit (resp. main category)

• Jura :
  Juragebirge

Kind of protolith

• sedimentary

Conditions of formation

"Rauracien", crayeux (faciès lagunaire)

Metamorphism

non metamorphic

References

Definition

Gygi R. A. (2000) : Integrated stratigraphy of the Oxfordian and Kimmeridgian (Late Jurassic) in northern Switzerland and adjacent southern Germany. Denkschriften der Schweizerischen Akademie der Naturwissenschaften 104, 152 S.

p.56

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.128: Buix Member (Gygi 2000b). Previously "Kreide von St. Ursanne" ; Member of the St-Ursanne Formation (Synonymy: Gygi 2000b p. 56) The Buix Member was renamed by Gygi (2000b. p. 56). lt is named after the village of Buix north of Porrentruy in Canton Jura (LK 1065 Bonfol) where it crops out in the quarry of Les Creppes (unpublished section RG 347) where it is easily accessible. However, the base ofthe member is not visible in that quarry. A complete outcrop of the member is in the quarry of the former lime works near the railway station of St-Ursanne, Canton Jura. This section has been studied in detail by Pümpin (1965. PI. 1. section 2). Gygi (2000b. p. 56) proposed beds 8-10 in Pümpin's section to be the reference section of the Buix Member. A schematic version of this section was later published by Gygi (1982. Fig. 4). This is section RG 336 at coordinates 579.200/246.370. LK 1085. St-Ursanne. The Buix Member is a massive, yellowish-white to pure white, more or less porous and friable limestone which was compared with chalk by Ziegler (1962). Coral bioherms occur in this unit near Leymen. France. Flüh, Canton Solothurn, and Delémont. St-Ursanne and Buix. Canton Jura. Locally, the limestone was slightly dolomitic. but the euhedral dolomite crystals have been dissolved and left empty pores as in the unpublished section RG 344. beds 3 and 8 near Courtemaîche, Canton Jura. In this case, the rock weathers in perpendicular rods as was observed by Liniger (1970. p. 7). Large chert nodules occur in the upper Buix Member in the sections RG 343 and 344 at Courtemaîche. The mean thickness of the member is about 35 m. The age was established biochronologically with ammonites by Gygi (1995. Fig. 2) that were found by V. Pümpin at St-Ursanne near the boundary between the Antecedens and the Luciaeformis Subzones in the Transversarium Zone. The Buix Member occurs in the Ajoie region in the northern part of Canton Jura and near Liesberg. Canton Baselland. It is the lagoonal facies of the upper St-Ursanne Formation (Fig. 1).

Important Publications

Ziegler M. A. (1962) : Beiträge zur Kenntnis des unteren Malm im zentralen Schweizer Jura. Mitt. geol. Inst. ETH und Univ. Zürich

Pümpin V.F. (1965) : Riffsedimentologische Untersuchungen im Rauracien von St. Ursanne und Umgebung (Zentraler Schweizer Jura). Eclogae geol. Helv. 58/2, 799-876