Structural control on fluid circulation in a graben system: Constraints from the Saint Pierre Bois quarry (Vosges, France)

Defining the fracture network and active fluid pathways are fundamental to characterizing a fractured reservoir. With this goal, we chose Saint Pierre Bois quarry (Vosges Massif, France) as natural analogue for Permian-Stephanian cover (arkoses)/Hercynian basement (granite) transition that serve geothermal reservoirs, example at Rittershoffen, Landau Insheim, where plants exploit kind of reservoir within Upper Rhine Graben (URG). During our study, along walls quarry, measured orientation on multiple 1D scanlines, sampled fills associated wall rock, porosity. Our interpretation dataset mineral deposits alteration indicates large unmapped fault zone (displacement around 10m) infer cross quarry. This comprises core (>50 m thick), which is most highly altered-fractured in In (20–25m some E-W faults displace arkose/granite transition. The two major sets (E-W NNE-SSW strikes) present damage (>100m thickness) typically randomly distributed, but sometimes grouped clusters (defined by high spacing coefficient variation). fractures result local tectonic inheritance relation Villé basin formation end Hercynian orogen. Based rock alteration, these structures constitute good fluid, first all meteoric during creation opening, then hot brine, clogged system quartz precipitation burial basin.