Formation of quartz veins by local dissolution and transport of silica

A simple model is proposed for the (often) thick quartz veins observed in the Modum Complex in southern Norway. The formation of these veins cannot easily be explained by silica imported by hot ascending fluids. The proposed model has dissolution in the host rock adjacent to the veins as the source for silica. The suggested process for vein formation is represented by a reaction-diffusion equation and the process is studied in terms of a Damkِhler number. Estimates for the growth rate of quartz cement are derived. The estimates for the growth rate can be used to constrain poorly known parameters of the vein formation process, like for instance the degree of supersaturation in the host rock.