Grès des Vernettes

Representation and status

Color CMYK

Cf. Membre de Mussel

Color RGB

R: 245 G: 170 B: 170

Rank

lithostratigraphic Bed

Validity

Unit is in Use

Status

informal term

Nomenclature

Deutsch

Vernettes-Sandstein

Français

Grès des Vernettes

English

Vernettes Sandstone

Origin of the Name

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

Historical Variants

Vernettes Beds (Pictet et al. 2016)

Description

Thickness

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

Hierarchy and sequence

Units at roof

• Argiles de La Presta

Age

Age at top

• Early Albian

Note about top

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

Age at base

• Early Albian

Note about base

Zone à L. irregularis + S. kitchini

Dating Method

Biostratigraphie des ammonites (Pictet in prep.)

Geography

Type area

Jura méridional

References

Definition

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.

Material and varia