Geissberg-Member

Darstellung und Status

Index
i6G
Farbe CMYK
siehe Villigen-Formation
Farbe RGB
R: 185 G: 195 B: 215
Rang
lithostratigraphisches Member (Subformation)
Gebrauch
Element ist in Gebrauch
Status
gültiger formeller Begriff
Diskussion des Status

Nomenklatur

Deutsch
Geissberg-Member
Français
Membre du Geissberg
Italiano
Membro del Geissberg
English
Geissberg Member
Herkunft des Namens

Geissberg (AG) bei Villigen

Historische Varianten

Geissbergschichten p.p. (Moesch 1857 S.57), Geissbergschichten emend. (Moesch 1867 S.145, Tobler 1905 Tab.4a/5b, Baltzer 1906, Disler 1941, Hantke 1967), couches du Geissberge (de Tribolet 1872, BRGM-Doubs), Couches du Geissberg (de Tribolet 1873, Dreyfuss et al. 1956, Donzeau et al. 1997, Brentini 2018), Couches à Pholadomya pelagica = couches du Geissberg (Rollier 1888a), Argovien supérieur = Couches du Geissberg (Rollier 1910), Couches de Geissberg (Enay 1966, Charollais et al. 2013), Geissberg Member (Gygi 2000c), Geissberg-Schichten

Links

Synonyme
«Calcaire à Cardium»

Beschreibung

Beschreibung

Gebankte, kompakte, mikritische Kalksteine in Bänken von 10 cm bis 30 cm mit Mergelzwischenlagen von 2 cm bis 5 cm. Das Geissberg-Member zeigt keine scharfe Grenze zu dem liegenden Effingen-Member.

Mächtigkeit
Ca. 15 - 20 m am Geissberg (Gygi 2000c)

Komponenten

Fossilien
  • Ammoniten
  • Bivalven

Lithacosphinctes (Mühlberg 1908), Myacées

Hierarchie und Abfolge

Übergeordnete Einheit
Hangendes
Liegendes
Obergrenze

Crenularis-Member

Untergrenze

Unscharfe Grenze mit Effingen-Member: graduelle Zunahme des Karbonatanteils und der Dicke der Bänke (transgressive surface between sequence boundaries Ox6 and Ox7 ; Wetzel & Strasser 2001).

Alter

Alter Top
  • spätes Oxfordien
Alter Basis
  • spätes Oxfordien
Datierungsmethode

Biostratigraphie: Ammoniten der Berrense-Zone (Gygi 2012) oder Bimammatum-Zone (Enay 1966). Bifurcatum-Zone im südlichen Jura (Enay et al. 1988).

Geografie

Geographische Verbreitung
Aargauer Jura
Typusregion
Nördlicher Kt. Aargau
Typlokalität
  • Geissberg (AG), bei Villigen
    Merkmale des Ortes
    • typische Fazies
    Zugänglichkeit des Ortes
    • Grat
    Koordinaten
    • (2655000 / 1264400)
    Notizen
    • Chamerenfelsen am Westende des Geissbergs (Moesch 1857 S.57, Gygi 2000c)
Typusprofil
  • Gabenchopf (AG)
    Merkmale des Ortes
    • typische Fazies
    Zugänglichkeit des Ortes
    • Steinbruch, Tongrube
    Koordinaten
    • (2656650 / 1265050)
    Notizen
    • Steinbruch Gabenchopf am Geissberg (Gygi 2000c als Referenzprofil definiert ; Wetzel & Strasser 2001)
Point of interest
  • Ob Chilen (AG) bei Villigen
    Merkmale des Ortes
    • Obergrenze
    • Untergrenze
    • typische Fazies
    Zugänglichkeit des Ortes
    • Bachprofil
    Koordinaten
    • (2658055 / 1264245)
    Notizen
    • Ob Chilen = Ob. der Kirche (Gygi 1969 Pl.19 Profil RG63, Gygi 2000c)

Paläogeografie und Tektonik

  • Malm
Paläogeografie
Aargauisches Becken
Tektonische Einheit (bzw. Überbegriff)
Herkunftstyp
  • sedimentär
Bildungsbedingungen

Beckenfazies («argovien» ; represent the marginal part of the carbonate platform). Most of the beds are carbonate-rich tempestites which contain some shallow-water material. Further up, several packages of limestone beds can be distinguished; 42 m of micrite contain shallow-water biodetritus, commonly enriched in nests which are of biogenic or physical origin. The content in bioclasts steadily increases upward, pointing to a progradation of the platform. (Wetzel & Strasser 2001).

Metamorphose
unmetamorph

Referenzen

Erstdefinition
Moesch Casimir (1857) : Das Flötzgebirge im Kanton Aargau. Neue Denkschr. schweiz. natf. Ges. 15

... complexe schisteux compris entre les couches d'Effingen et celles de Baden.
Neubearbeitung
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.130: Geissberg Member (Moesch 1867) ; Member of the Villigen Formation The Geissberg lithostratigraphical unit (Geissbergschichten) was named by Moesch (1857. p. 57) and then encompassed all the limestone members included in the Villigen Formation sensu Gygi & Persoz (1986. p. 407) between the Effingen Member below and the Baden Member above. Moesch (1867 p. 145) restricted the unit to the rank of what is today a member and conceived it as the thickly bedded micritic limestones between the marly Effingen Member below and the glauconitic Crenularis Member above. According to Moesch (1857 p. 57). the cliff above the southern slope at the western end of Mt. Geissberg west of Villigen. Canton Aargau. must be considered to be the type locality of what is at present the Geissberg Member. This cliff is now called Chamerenfelsen and is located at coordinates 655.000/264.400. LK 1069 Frick. The thickness of the Geissberg Member at Mt. Geissberg near Villigen in the large quarry on the north slope of Mt. Geissberg, west of Gabenchopf near Villigen, is between 15 and 20 m. This quarry (coordinates ca. 656.650/265.050. LK 1070 Baden) is now considered to be the reference section of the Geissberg Member. An entire section of the member is also in the natural outcrop of the gully south of the part of the village Villigen called Ob Chilen. This is section RG 63 that is schematically represented in Gygi (1969. Pl. 19). The great thickness of the Geissberg Member near Baden (Gygi 1969 Pl. 19) is exceptional. The macrofossils ofthe Geissberg Member are mostly bivalves, but large ammonites of the genus Lithacosphinctes occur too (Mühlberg. 1908. p. 43). The Geissberg Member is delimited in the west by the Olten Member. In the northeast it grades into the lower Hornbuck Member (Fig.1).
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