strati.ch - Lexique lithostratigraphique de la Suisse

Représentation et statut

Variantes historiques: Oberer Grünsand (Mayer-Eymar 1868), Oberer Grünsand = Assilinengrünsand = Wuhrstein (Jeannet et al. 1935), Upper Greensand (Lihou 1995)

Fossiles

Assilina exponens

Unité hiérarchiquement supérieure

Âge au sommet

Âge à la base

Note sur la base

Lutétien précoce (Lihou 1995)

Termes génériques

Type de protolithe

Définition: Jeannet Alphonse, Leupold W., Buck P. Damian (1935) : Stratigraphische Profile des Nummulitikums von Einsiedeln-Iberg. Berichte der Schwyzerischen Naturforschenden Gesellschaft 1. Heft (1932/1935), 35–51

Révision: Lihou Joanne C. (1995) : A new look at the Blattengrat unit of eastern Switzerland: Early Tertiary foreland basin sediments from the south Helvetic realm Eclogae geol. Helv. 88/1, 91-114

p.105: In all sections except Fanenstock (Fig. 4) and Gula-Schwamm (Fig. 5), the hematitic infiltration zone is overlain by a fine glauconitic sandstone, called the Upper Greensand. Only in the Merenegg and Gulawand profiles can a gradual transition from a glauconitic limestone to sterile greensand with flecks of phosphate be seen. The biogenic greensand often contains large, early Lutetian assilinids, like Assilina exponens and spira, which prefer water depths of > 50 m (Racey 1988), plus medium-sized discocyclinids like Discocyclina discus and small nummulitids. The basal Assilina Greensand of the Bürgen (Nummulitic) Formation in the NHF unit has a very similar fauna (Crampton 1992) and is probably a correlative of the Upper Greensand in the Blattengrat unit. In the Upper Windegg profile, the base of the greensand contains a horizon of phosphatised macrofossils, representing a condensed marine horizon, equivalent to the "Steinbach Fossilschicht" in the Einsiedler thrust zone. Where the Upper Greensand is absent, at Fanenstock (Fig. 4) and Gula Schwamm (Fig. 5), the hematitic infiltration zone passes directly up into the pelagic Flecken Marl.