Geophysical study of the Roches de Solutré-Pouilly-Vergisson (Grand Site de France)

6 months (January-June 2025)

The Roches de Solutré-Pouilly-Vergisson (hereinafter called “Roches”, https://rochedesolutre.com/) constitute an emblematic site of both cultural and scientific heritage. Paleontological and archaeological related work can be tracked back to the 19th century (e.g. work by H. Testot-Ferry and A. Arcelin). They have enabled significant advances in these areas, leading to the definition of an eponymous lithic culture: the Solutrean (lithic culture from Western Europe known between – 23,000 and – 18,000 years ago).
Remaining on the sidelines of this work, the geological and geomorphological understanding of the site has long been subject only to scarce dedicated studies. Recently, however, a greater attraction towards the geological and karst heritage has led to filling these gaps. The Roches were, for example, the subject of a study focusing on the rate of erosion of the reliefs and the main scarp retreat in relation to the karst structure (Master 2 internship by R. Cozzolino). One of the contributions of this work is the identification of “ghost-rock” structures and a better understanding of the role of karst in the morphological history of these sites.
Evidences of ghost-rock processes was already known in the Mâconnais region but had not been clearly identified yet at the Roches level.
The link between karst dynamics and the ghost-rock structuration is currently subject to debate and its importance in the developement of karsts and cave networks is sometimes considered negligible or on the contrary of a major importance (Malcles et al. 2023 and associated references). In addition to considerations of karstogenesis, the presence or absence of these ghost-rock structures raises questions regarding the hydrology of karst areas (e.g. annual hydrological support of springs).
Due to their simple structure, the Roches present a unique geometry allowing efficient deployment of geophysical methods aiming at a better constrain of the subsurface. This characterization of the near surface in turn allows to provide elements of understanding of the geology and geomorphology of the Rocks in order to be able to place the historical and paleontological knowledge in a better known framework.