Gold deposits of the Zimbabwe craton

The hypothesis that gold deposits in the earth are fractal dusts is tested using data on gold mine distribution in the Zimbabwe craton. Mine distribution reflects deposit distribution only indirectly because of undiscovered deposits and economic factors. Nevertheless, box counting shows an approximately linear relationship between the logarithm of the number of squares necessary to cover all mines in the craton and the logarithm of the square size between 10 and 60 km, indicating a fractal distribution. More detailed data from two areas within the craton have a similar relationship between square sizes of 2.5-20km. Departure from the ideal fractal relationship is termed 'roll-off', and is very satisfactorily by random sampling of a fractal dust. The results are consistent with the hypothesis that gold deposits are fractal dusts with fractal dimensions of c. 1.0 and the distribution of mines can be regarded as a random sample of the distribution of deposits. Making this assumption, regions that have been incompletely but randomly explored can be identified and distinguished from regions containing large subareas that have been completely unexplored, and appropriate exploration strategies can be devised in either case.