Linear to non-linear relationship between vein spacing and layer thickness in centimetre- to decimetre-scale siliciclastic multilayers from the High-Ardenne slate belt (Belgium, Germany)
Abstract Typical spacing distributions have frequently been described for fractures in thin sedimentary layers ( 40 cm). Vein spacing tends to increase to a maximum value becoming more or less independent of layer thickness. The resemblance with fracture spacing suggests that in an unfractured rock vein saturation can occur. High fluid pressures are responsible for vein nucleation but the stress state around the initial veins controls the spacing pattern. Subsequently, in a vein-saturated rock, or the existing veins will thicken by the process of crack-sealing, or a new cross-cutting vein generation will develop in case the regional stress field changes relatively with respect to the existing veins.