Toarcian (182.7 +/-0.7 Ma)

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Darstellung und Status

Index
toa
Farbe CMYK
40 / 5 / 0 / 0
Farbe RGB
R: 153 G: 206 B: 227
Rang
chronostratigraphische Stufe
Gebrauch
Element ist in Gebrauch
Status
gültiger formeller Begriff
Diskussion des Status

Nomenklatur

Deutsch
Toarcien (CH) (DE/AT: Toarcium / Toarc)
Français
Toarcien
Italiano
Toarciano
English
Toarcian (182.7 +/-0.7 Ma)
Herkunft des Namens

Named after the town of Thouars (Deux-Sèvres, France), S Saumur. The protected stratotype lies in an old quarry.

Historische Varianten

Lias supérieur (d'Orbigny 1842), Toarcien (d'Orbigny 1849), Thouarsien (Mayer-Eymar 1864, Mouterde 1956), 12e Etage = Toarcien (Greppin 1866)

Nomenklatorische Bemerkungen

Latin: Toarcium

Hierarchie und Abfolge

Obergrenze

Top lies just below the first appearance of the ammonite genus Leioceras.

Untergrenze

Base defined by the first appearance of Eodactylites mirabile (Tethyan Realm), or alternatively by the mass appearance of other dactylioceratids together with Paltarpites paltus.

Alter

Alter Top
  • Toarcien
Alter Basis
  • Toarcien

Geografie

Typusregion
Deux-Sèvres (Paris Basin, France)
Typusprofil
  • carrière de Vrines, Thouars
    Merkmale des Ortes
    • typische Fazies
    Zugänglichkeit des Ortes
    • geschützter Geotop
    Notizen
    • Proposed by d'Orbigny (1849) and further studied by Eudes-Deslongchamps and Welsch. Detailed biostratigraphy by Gabilly (1976), who pointed out the condensed nature (7 m altogether) of the section and the incompleteness of the record at the base.
Referenzprofile

Referenzen

Erstdefinition
d'Orbigny A. (1846) : Foraminifères fossiles du bassin tertiaire de Vienne (Autriche). Gide, Paris

Ce nom dérive de la ville de Thouars (Toarcium) (Deux-Sèvres), où l'on ne trouve que cet étage sur les roches aszoïques; où il a le plus beau développement en France et peut être regardé comme point type, point étalon. C'est la zone du Lima gigantea et de l'Ammonites bifrons.

Material und Varia

Bilder
Thouars_loctyp
  • Late Toarcian

    Rang
    chronostratigraphische Sub-Stufe
    Status
    gültiger formeller Begriff
    Age
    spätes Toarcien
  • Middle Toarcian

    Rang
    chronostratigraphische Sub-Stufe
    Status
    gültiger formeller Begriff
    Kurzbeschreibung
    The Middle Toarcian is defined biostratigraphically by the ammonite genera Hildoceras and Haugia.
    Age
    mittleres Toarcien
  • Early Toarcian

    Rang
    chronostratigraphische Sub-Stufe
    Status
    gültiger formeller Begriff
    Kurzbeschreibung

    The Early Toarcian is characterized almost worldwide by black shales (among which the well-known «Posidonienschiefer» of Southern Germany, and the French «schistes-carton») with an ammonite fauna composed mainly of dactylioceratids, harpoceratids and early hildoceratids.

    Age
    frühes Toarcien
    • Toarcian Oceanic Anoxic Event

      Rang
      OAE
      Status
      informeller Begriff
      Kurzbeschreibung

      Major oceanic anoxic event of the Early Toarcian (around 183 Ma ago), documented by black shale deposits found on all major continents (no oceanic drilling cores have recovered black shales of this age as there is little or no Toarcian ocean crust remaining in the world ocean). This event correlates with a marine extinction event.

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