Towards a 3D crustal geomodel of the Western Alps in the French Geological Reference Platform (RGF)

The French Geological Reference Platform (RGF) is a national programme for acquisition and management of geological data launched in the early 2010’s and coordinated by BRGM (https://rgf.brgm.fr). It involves the geosciences community to develop a new 3D knowledge of the underground to support innovative responses to a wide range of scientific first order questions as well as issues our society is facing. The RGF’s Alps and surrounding basins (Abp) worksite aims at a better understanding of the 3D structure of an emblematic mountain range and at addressing the impact of climate change and geological risk.

Within the RGF’s Abp, we proposed to build a 3D reference geomodel covering the area of the whole worksite ([41.5°N-48°N; 4°E-10°E]; ~350 000 km²) investigating the subsurface down to the Moho. This geomodel aims at federating the geoscientific community and intends to integrate existing data and information, e.g. geology, geophysics, relevant at that scale. It will be updated using the data acquired during the Abp worksite and serve to set up boundary information for local studies.

The geomodel is constructed in a collaborative approach where contributors discuss their data and knowledge and converge to a common interpretation of the investigated major geological boundaries that are the Moho (European lithosphere, Adriatic lithosphere, Ligurian backarc basin) and the boundaries of the subduction wedge.

We present here the state of progress of the geomodel based on the geological interpretive sections established at lithospheric scale by the RGF community (see Bellahsen at al., this session) and the integration of the available geophysical data and models (velocity models Vp and Vs, seismic reflection and refraction, gravimetry, etc.).

This work benefits from the French Geological Reference Platform - Alps and surrounding basins programme funding.