Grès des Vernettes

Rappresentazione e statuto

Colore CMYK

Cf. Membre de Mussel

Colore RGB

R: 245 G: 170 B: 170

Rango

Strato litostratigrafico

Uso

Unità in uso.

Status

termine informale

Nomenclatura

Deutsch

Vernettes-Sandstein

Français

Grès des Vernettes

English

Vernettes Sandstone

Origine del nome

Les Vernettes, quartier de Bonvy (France) situé au sud de Bellegarde-sur-Valserinne

Varianti storiche

Vernettes Beds (Pictet et al. 2016)

Descrizione

Potenza

Max. 2 m dans la région de Bellegarde-sur-Valserine, env. 1,2 m dans la région de Ste-Croix.

Gerarchia e successione

Unità sovrastante

• Argiles de La Presta

Età

Geomorfologia

• Primo Albiano

Osservazioni sul tetto

Zone à C. floridum + H. puzosiana + O. subhilli

Età alla base

• Primo Albiano

Osservazioni sulla base

Zone à L. irregularis + S. kitchini

Metodo di datazione

Biostratigraphie des ammonites (Pictet in prep.)

Geografia

Regione-tipo

Jura méridional

Referenze

Definizione

Pictet Antoine, Delamette Michel, Matrion Bertrand (2016) : The Perte-du-Rhône Formation, a new Cretaceous (Aptian-Cenomanian) lithostratigraphic unit in the Jura mountains (France and Switzerland). Swiss J. Geosc. 109/2, 221-240

From the base to the top of the Mussel Mb, five subunits have been identified (Fig. 8).

The third one, the Vernettes Beds (unit S9, Figs. 4, 8g–h), is a 0–10 m thick light green, white or orange, lightly marly sandstone. The microfacies is a glauconite and quartz-rich packstone (Fig. 8h). The Vernettes Beds includes a basal white phosphatic conglomerate, which delivered a rich benthic (echinids, bivalves, gastropods, brachiopods) and an abundant nectonic macrofauna (belemnites, and about 11 ammonites taxa, Fig. 8i, Pictet and Roux 1847–1854, Pictet and Campiche 1858–1871, Renz and Jung 1978). The ammonite fauna from these beds records the Aptian-Albian boundary and presents some unusual taxa. This fauna will be the subject of a future detailed palaeontological study.

Materiale e vario