Two notable features of the mineralization in SW England are the asymmetrical pattern of mineral lodes and the mineral zoning within this distribution. Despite the fact that many theories have been advanced to explain the mechanisms of mineralization qualitatively no numerical models have been produced. In this paper, the finite element technique is used to construct a very simple model which helps to explain general features of the pattern of mineralization.
The model describes the steady state convection of fluid in the environment of the Cornubian batholith. Convection is driven by the radiothermal contrast between the granite and the host rocks. Results show that the locations of upward flowing, hot fluids are determined by the three-dimensional shape of the batholith. Initially, upward flow was concentrated along the axis of the batholith and these regions correlate with high temperature mineralization. Erosion of the cover rock above the granites altered the fluid flow pattern such that the upward flow became concentrated outside the outcropping granites. These regions correlate with low temperature mineralization. A correlation also exists between kaolinization and areas of downward flowing fluid for present day levels of erosion.