PALEOVAUL       Palaeontology in Vaulnaveys-le-Bas

Who ?

Four passionate guys linked by science and an interest in the paleontological heritage. We are convinced that, even as non-professional paleobotanists, there is a place for us and a mission to carry out in the traditional scientific world. Our collaborative involvement as volunteers holds to a strict moral code which rejects the past and present looting and destruction of fossil sites and the paleontological business.



How ?

On a regular basis, through all seasons, we go prospecting. We follow a process which originates from our own experience, know-how in the field and from feed-back from professional paleobotanists. All collected specimens are washed with water and some are gently prepared, then are either stored for a short period of time in personal collections in order to be more easily studied or are immediately given to the Museum of Natural History in Grenoble.

Which period is studied ?

The Carboniferous

Carboniferous is a period of the earth’s history that extends from -360 to -300 million years. It belongs to the Paleozoic era and is labelled Carboniferous in reference to the iconic coal deposits that, for a long time, has typified this period of the earth’s history. This period is made of rhythmic climate variations oscillating from dryer to wetter climates, with a global trend toward the driest climates. Carboniferous is characterized by a very high diversity of plants. It is also well known for the enormous size of its fauna, mainly arthropods. Carboniferous includes the Mississippian and Pennsylvanian, the names of which come from very fossiliferous deposits in North America. Each of these divisions is split into the Lower, Middle and Upper ages, from the oldest to the earliest age respectively. The Vaulnaveys-le-Bas deposit is in the Upper Pennsylvanian. The precise age is still under investigation. The estimated time-range is indicated on the figure by a yellow arrow.

The site

Vaulnaveys-le-Bas is a rural district of Isère, of 1243 inhabitants. The fossiliferous unit, known for centuries, probably 1880, spread on the slopes of Belledonne moutain range. It is prospected on a regular basis by our team since 2015.

With the agreement of the municipality, in collaboration with the Natural History Museum of Grenoble and the National History Museum of Paris, we particpate to the preservation of this outstanding fossiliferous deposit.



Rebuilding this former environment

Approximately three hundred million years ago, Vaulnaveys-le-Bas was located near the equator in the middle of a single supercontinent, The Pangea, which comprised almost all the emerged lands. Two oceans bordered this continent, the Tethys Ocean on the east and Panthalassa Ocean on the west. The movement of two tectonic plates, one from the South and the other from the North, caused the collision of two supercontinents which created the Pangea. An enormous mountain range extending thousands of kilometers in length and hundreds in width, rose up all along the border where the collision occurred. This mountain-chain is called the Hercynian Massif (otherwise known as the Variscan orogeny) and Vaulnaveys-le-Bas would eventually be located inside, forming an intramountain sedimentary basin.

There was global warming during the Carboniferous. Climate, in an oscillatory manner, alternated from glaciation to dryer phases. Floral assemblages are testimonials of these climate changes as seen in Vaulnaveys-le-Bas which is a very peculiar example.

The Hercynian chain is now entirely eroded and fossiliferous sediments deposited during the Carboniferous are completely hidden under thousands of meters of more recent secondary and tertiary era sediments. But due to their outcropping associated with the tectonic shift and the formation of the Alpine mountain range which carried them to the slopes of the mountain and sometimes up to its summits (Grande Lauzière at 2700 meters), they have become once again accessible for research. In the Belledonne Massif, “l’Accident Médian de Belledonne” caused these sediments to be separated from each other by a large crack. We are studying the fossilized contents found in Vaulnaveys-le-Bas which are some of these remaining fragments of carboniferous deposits.





Our scientific publications about Vaulnaveys-le Bas :

-  Rastel D, Vallois B, Jouve A. Equisetites spatulatus (Zeiller,1895) only described from the Late Carboniferous is not in fact part of the genus Equisetites. A combined morphologic and taphonomic studies of new discoveries show that such an identification was wrong. Ann. Pal 2019.
- Rastel D, Vallois B, Jouve A, Belleserre G. A Late Carboniferous fossiliferous deposit of French Alps in Vaulnaveys-le-Bas : first description and heritage interest. Bull Soc Linn Lyon 2019.


More extended all audiences documentation on paleontology of south Belledonne mountain range (in French) : Vallois B. 2017. Vaulnaveys en pays Vizillois, un site remarquable du carbonifère (fascicule disponible sur le site de l’association culturelle de Vaulnaveys-le-Bas); Vallois B, Bellesserre G. Fossiles 2015.

How to follow us

On Facebook : PALEOCARBIS (Carboniferous in Isère, field trips , events, conferences,…) More general on palaeobotany : le Forum des sciences de la vie et de la terre. Our testimonials on Nature-Isère.
DO NOT MISS the specimens stored in the Natural History Museum of Grenoble, France. Photos are available online.

       

Contact :


Akcnowledgments to :

Mr Jean-Marc Gauthier, Mayor of Vaulnaveys-le-Bas and his municipal team who support our group. Mrs Marie-Pierre Davallet-Pin for her logistic involvement in our projects.

Photographs and drawings :

Photos are from our team but for the village view from C.S.G. Communauté de Communes du Sud Grenoblois 2011. The Town hall square drawing is from Mrs France ROSSET.


Webmaster : Mr Pascal Goutte-Solard ( )














Our portrait gallery Click here






Do not miss on youtube,

Alexis Rastier

Creator and host of videos on palaeontology

To see Vaulnaveys-le-Bas, select : « Le Carbonifère Alpin »