Membre de Buix

Torna a Tiergarten-Member

Rappresentazione e statuto

Colore CMYK
(0%,5%,3%,25%)
Colore RGB
R: 190 G: 180 B: 185
Rango
Membro litostratigrafico (Sotto-formazione)
Uso
Unità in uso.
Status
termine formale valido
Discussione del statuto

Nomenclatura

Deutsch
Buix-Member
Français
Membre de Buix
Italiano
Membro di Buix
English
Buix Member
Origine del nome
Carrière Les Creppes, NW de Buix = Bux (JU)
Varianti storiche
Kreide von St. Ursanne auct., Buix Member (Gygi 2000b, Gygi 2000c), Membre de Buix (Comment & Ayer)

Links

Synonymi
Kreidige Kalke von St-Ursanne

Descrizione

Descrizione
Weisse, weiche, kreidige, ungeschichtete Kalksteine mit kleinen Biohermen, im oberen Teil treten Silex-Knollen auf.
Geomorfologia
zone tendre
Potenza
0-35 m

Componenti

Fossili
  • coralli

Gerarchia e successione

Unità di rango superiore
Unità sovrastante
Unità sottostante

Età

Geomorfologia
  • Oxfordiano medio
Età alla base
  • Oxfordiano medio
Metodo di datazione
Biostratigraphie (ammonites de la Transversarium-Zone ; Gygi 1995)

Geografia

Estensione geografica
Partie nord du canton du Jura (Ajoie) et jura bâlois (région de Liesberg).
Località-tipo
  • Buix (JU)
    Caratteristiche del sito
    • typische Fazies
    Agibilità del sito
    • Steinbruch, Tongrube
    Coordinate
    • (2569670 / 1259815)
    Nota
    • Carrière Les Creppes (Gygi 2000b S.56 Profil RG347)
Sezione di riferimento
  • St-Ursanne (JU)
    Caratteristiche del sito
    • Untergrenze
    • typische Fazies
    Agibilità del sito
    • Steinbruch, Tongrube
    Coordinate
    • (2579200 / 1246370)
    Nota
    • 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)

Paleogeografia e tettonica

Termini generici
Tipo di origine
  • sedimentaria
Condizioni di formazione
"Rauracien", crayeux (faciès lagunaire)
Metamorfismo
non metamorfo

Referenze

Definizione
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
Revisione
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).
Pubblicazioni importanti
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
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