|In the Lab
The end of the lower Jurassic, about 183 million years ago, is a period of profound global environmental changes accompanied by the extinction of numerous marine organisms. While the responses of marine invertebrates to the crisis is relatively well documented, ecological changes within vertebrate communities (fish, sharks, marine reptiles) remain poorly understood. Several deposits of the end of the Lower Jurassic, however, have yielded in abundance remains of vertebrates, providing valuable information on the vertebrate assemblages from this period: this is the case for Early toarcian Lagerstätten in Germany or England. However, these deposits have a limited vertical extension and do not allow to understand the response of these communities to climatic and environmental changes recorded at that time.
In this context, the marine deposit of Charnay (Rhône) are a scientific
landmark and are demonstrably of significant value for our heritage.
Indeed, the sedimentary record spans the entire lower Jurassic-middle
Jurassic transition, which is only rarely observable in France and
Europe. Beyond this stratigraphic interest, the deposits of Charnay are
also exceptional for their palaeontological content containing
vertebrate remains from various levels that are lacking elsewhere in
the world (Middle and Upper Toarcian and basal Aalenian). The
palaeontological potential of the Lafarge quarry has been recognized
since the beginning of its activity in the early 1980s, thanks to the
effort and enthusiasm of amateur palaeontologists. Abundant discoveries
led to the creation of an association of amateurs (Section GeoPaleo),
which aims to bring together members around a common theme: the
establishment of a reference collection.