Numerical Modelling of Ore‐forming Dynamics of Fractal Dispersive Fluid Systems

AbstractBased on an analysis of the fractal structures and mass transport mechanism of typical shear‐fluid‐ore formation system, the fractal dispersion theory of the fluid system was used in the dynamic study of the ore formation system. The model of point‐source diffusive illuviation of the shear‐fluid‐ore formation system was constructed, and the numerical simulation of dynamics of the ore formation system was finished. The result shows that: (1) The metallogenic system have nested fractal structure. Different fractal dimension values in different systems show unbalance and inhomogeneity of ore‐forming processes in the geohistory. It is an important parameter to symbolize the process of remobilization and accumulation of ore‐forming materials. Also it can indicate the dynamics of the metallogenic system quantitatively to some extent. (2) In essence, the fractal dispersive ore‐forming dynamics is a combination of multi‐processes dominated by fluid dynamics and supplemented by molecule dispersion in fluids and fluid‐rock interaction. It changes components and physico‐chemical properties of primary rocks and fluids, favouring deposition and mineralization of ore‐forming materials. (3) Gold ore‐forming processes in different types of shear zones are quite different. (1) In a metallogenic system with inhomogeneous volumetric change and inhomogeneous shear, mineralization occurs in structural barriers in the centre of a shear zone and in geochemical barriers in the shear zone near its boundaries. But there is little possibility of mineralization out of the shear zone. (2) As to a metallogenic system with inhomogeneous volumetric change and simple shear, mineralization may occur only in structural barriers near the centre of the shear zone. (3) In a metallogenic system with homogeneous volumetric change and inhomogeneous shear, mineralization may occur in geochemical barriers both within and out of the shear zone.